Method and system for filling gaps

Abstract

Methods and systems for filling gaps are disclosed. An exemplary method includes providing a substrate to a reaction chamber. The substrate includes a gap. The method further includes forming a convertible layer on the substrate and exposing the substrate to a conversion reactant. Thus, at least a portion of the convertible layer is converted into a gap fill fluid. The gap filling fluid at least partially fills the gap. The methods and systems are useful, for example, in the field of integrated circuit fabrication.

Description

Technical Field

[0001] The present disclosure relates generally to the field of semiconductor processing methods and systems, and to the field of integrated circuit manufacturing. In particular, methods and systems suitable for filling gaps are disclosed. Background Art

[0002] The reduction in size of semiconductor devices (such as logic devices and memory devices) has led to significant increases in the speed and density of integrated circuits. However, conventional device scaling techniques face significant challenges at future technology nodes.

[0003] For example, one challenge is finding suitable methods to fill gaps, such as grooves, trenches, vias, etc., with materials without forming any gaps or voids.

[0004] Any discussion set forth in this section, including discussion of problems and solutions, has been included in the present disclosure merely to provide context for the present disclosure. Such discussion should not be construed as an admission that any or all information was known at the time the present invention was made, or constitutes prior art. Summary of the invention

[0005] This summary is provided to introduce some concepts in a simplified form. These concepts are further described in detail in the detailed description of the example embodiments disclosed below. This summary is not intended to identify the 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.

[0006] Various embodiments of the present disclosure relate to methods of filling gaps, structures and devices formed using such methods, and apparatus for performing such methods and / or for forming such structures and / or devices. These layers can be used in various applications. For example, they can be used in the field of integrated circuit manufacturing.

[0007] Thus, a method for filling a gap is described herein. The method includes providing a substrate to a reaction chamber. The substrate includes a gap. The method also includes forming a convertible layer on the substrate. The method also includes exposing the substrate to a liquid phase conversion reactant. Thus, at least a portion of the convertible layer is converted into a gap filling fluid. Thus, the gap filling fluid at least partially fills the gap.

[0008] A system is further described herein. The system includes a reaction chamber. The system also includes a precursor gas source. The precursor gas source includes a metal precursor. The system also includes a deposition reactant gas source. The deposition reactant gas source includes a deposition reactant. The system also includes a controller. The controller is configured to control the flow of gas into the reaction chamber to form a layer on a substrate by the means and methods described herein.

[0009] These and other embodiments will become apparent to those skilled in the art from the following detailed description of certain embodiments with reference to the accompanying figures.The present invention is not limited to any particular embodiment disclosed. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] A more complete understanding of embodiments of the present disclosure may be obtained by referring to the detailed description and claims when considered in conjunction with the following illustrative drawings.

[0011] Figure 1 An embodiment of a method as disclosed herein is shown.

[0012] Figure 2 An embodiment of a method as disclosed herein is shown.

[0013] Figure 3a )and Figure 3b ) illustrates the operation of an embodiment of the method as described herein.

[0014] Figure 4 Another embodiment of a system 400 as described herein is shown in a stylized manner.

[0015] Figure 5 A stylized representation of a substrate 500 including a gap 510 is shown.

[0016] It should be understood that the elements in the drawings are shown for simplicity and clarity and are not necessarily drawn to scale. For example, the size of some elements in the drawings may be exaggerated relative to other elements to help improve the understanding of the illustrated embodiments of the present disclosure. DETAILED DESCRIPTION

[0017] Although certain embodiments and examples are disclosed below, those skilled in the art will appreciate that the invention extends beyond the specifically disclosed embodiments and / or uses of the invention and their obvious modifications and equivalents. Therefore, it is intended that the scope of the disclosed invention should not be limited by the specifically disclosed embodiments described below.

[0018] In the present disclosure, "gas" may include materials that are gaseous at normal temperature and pressure (NTP), evaporated solids and / or evaporated liquids, and may be composed of a single gas or a gas mixture depending on the circumstances. Gases other than process gases, i.e., gases that are not introduced through gas distribution components, other gas distribution devices, etc., may be used, for example, to seal reaction spaces, and may include sealing gases, such as rare gases. In some cases, the term "precursor" may refer to a compound that participates in a chemical reaction that produces another compound, particularly a compound that constitutes a membrane matrix or a main skeleton of a membrane; the term "reactant" may be used interchangeably with the term precursor.

[0019] As used herein, the term "substrate" may refer to any one or more underlying materials that may be used to form or on which a device, circuit, or film may be formed. The substrate may include a bulk material, such as silicon (e.g., single crystal silicon), other Group IV materials, such as germanium, or other semiconductor materials, such as Group II-VI or Group III-V semiconductor materials, and may include one or more layers overlying or underlying the bulk material. In addition, the substrate may include various features, such as grooves, protrusions, etc. formed in or on at least a portion of the substrate layer. For example, the substrate may include at least one of a bulk semiconductor material and a layer of insulating or dielectric material overlying at least a portion of the bulk semiconductor material.

[0020] As used herein, the terms "film" and / or "layer" may refer to any continuous or discontinuous structure and material, such as a material deposited by the methods disclosed herein. For example, the film and / or layer may include a two-dimensional material, a three-dimensional material, nanoparticles, a partial or complete molecular layer or a partial or complete atomic layer or a cluster of atoms and / or molecules. The film or layer may be composed in part or in whole of a plurality of dispersed atoms on a substrate surface and / or embedded in a substrate and / or embedded in a device manufactured on the substrate. The film or layer may include a material or layer having pinholes and / or islands. The film or layer may be at least partially continuous. The film or layer may be patterned, such as subdivided, and may be included in a plurality of semiconductor devices.

[0021] As used herein, a "structure" may be or include a substrate as described herein. A structure may include one or more layers covering a substrate, such as one or more layers formed according to a method as described herein. A device portion may be or include a structure.

[0022] As used herein, the term "deposition process" may refer to the introduction of precursors (and / or reactants) into a reaction chamber to deposit a layer on a substrate. A "cyclic deposition process" is an example of a "deposition process."

[0023] As used herein, the term "gap-filling fluid", also referred to as a "flowable gap fill", may refer to a composition of matter that is liquid or can form a liquid under the conditions of formation, and which has the ability to form a solid material in the gap. In some embodiments, the "gap-filling fluid" may be only temporarily in a flowable state, such as when the "gap-filling fluid" is temporarily formed by forming liquid oligomers from gaseous monomers during a polymerization reaction, and the liquid oligomers continue to polymerize to form a solid polymeric material; or when the gap-filling fluid solidifies after cooling; or when the gap-filling fluid undergoes a chemical reaction to form a solid material. For ease of reference, in some embodiments, the solid material formed by the gap-filling fluid may be referred to simply as the "gap-filling fluid".

[0024] Methods as described herein may include depositing a layer by a cyclic deposition process. The term "cyclic deposition process" or "cyclic deposition process" may refer to sequentially introducing precursors (and / or reactants) into a reaction chamber to deposit a layer on a substrate, and includes processing techniques such as atomic layer deposition (ALD), cyclic chemical vapor deposition (cyclic CVD), and hybrid cyclic deposition processes including an ALD component and a CVD component.

[0025] The method as described herein may include depositing a layer by an atomic layer deposition process. The term "atomic layer deposition" may refer to a vapor deposition process in which a deposition cycle (typically a plurality of consecutive deposition cycles) is performed in a process chamber. As used herein, the term atomic layer deposition is also meant to include processes designated by related terms, such as chemical vapor atomic layer deposition, atomic layer epitaxy (ALE), molecular beam epitaxy (MBE), gas source MBE, organometallic MBE, and chemical beam epitaxy when performed with alternating pulses of a precursor / reactive gas and a purge gas (e.g., an inert carrier gas).

[0026] Typically, for an ALD process, during each cycle, a precursor is introduced into a reaction chamber and is chemically adsorbed onto a deposition surface (e.g., a substrate surface that may include previously deposited material from a previous ALD cycle or other material) and forms a monolayer or sub-monolayer of material that does not readily react with additional precursors (i.e., a self-limiting reaction). Thereafter, a reactant (e.g., another precursor or a reactive gas) may subsequently be introduced into the process chamber for converting the chemically adsorbed precursor into the desired material on the deposition surface. The reactant is capable of further reacting with the precursor. During one or more cycles, such as during each step of each cycle, a purge step may be utilized to remove any excess precursor from the process chamber and / or to remove any excess reactant and / or reaction byproducts from the reaction chamber.

[0027] As used herein, the term "purge" may refer to the process of providing an inert or substantially inert gas to a reaction chamber between two gas pulses that react with each other. For example, a purge may be provided between a precursor pulse and a reactant pulse, such as using a rare gas, so as to avoid or at least minimize gas phase interactions between the precursor and the reactant. It should be understood that the purge may be performed in time or space, or both. For example, in the case of a time purge, the purge step may be used, for example, in a time sequence of providing a first precursor to the reaction chamber, providing a purge gas to the reaction chamber, and providing a second precursor to the reaction chamber, wherein the substrate on which the layer is deposited does not move. For example, in the case of a space purge, the purge step may take the form of moving the substrate from a first position where the first precursor is continuously supplied to a second position where the second precursor is continuously supplied through a purge gas curtain.

[0028] As used herein, "precursor" includes a gas or material that can be changed into a gaseous state and can be represented by a chemical formula that includes elements that can be introduced into the deposition process described herein.

[0029] The term "reactant" may refer to a gas or material that can become a gaseous state and react with a precursor.

[0030] In addition, in the present disclosure, any two numbers of a variable may constitute a feasible range for the variable, and any range indicated may include or exclude endpoints. In addition, any variable value indicated may refer to an exact value or an approximate value, and include equivalents, and may refer to an average value, a median value, a representative value, a majority value, etc. In addition, in the present disclosure, the terms "including", "consisting of" and "having" independently refer to "generally or broadly including", "comprising", "essentially consisting of" or "consisting of" in some embodiments.

[0031] In this disclosure, any defined meaning does not necessarily exclude the ordinary and customary meaning in some embodiments.

[0032] A method for filling a gap is described herein. The method includes providing a substrate including a gap to a reaction chamber. A single crystal silicon wafer may be a suitable substrate. Other substrates may also be suitable, such as a single crystal germanium wafer, a gallium arsenide wafer, quartz, sapphire, glass, steel, aluminum, a silicon-on-insulator substrate, plastic, etc.

[0033] The method further includes forming a convertible layer on the substrate and then exposing the substrate to a liquid phase conversion reactant. Thus, at least a portion of the convertible layer is converted into a gap-filling fluid that at least partially fills the gap.

[0034] The presently disclosed method allows for the formation of a gap-filling fluid containing a metal and a halogen.

[0035] In some embodiments, the gap filling fluid containing metal and halogen includes oligomers that undergo chain growth as the gaseous precursor polymerizes. Therefore, in some embodiments, a flowable gap filling fluid containing oligomers can be temporarily formed on the substrate surface, which solidifies as the oligomers undergo chain growth. Therefore, even at a temperature below the overall melting point of the convertible layer formed by the method disclosed herein, a flowable gap filling fluid can be obtained. Of course, the method currently described can also be used at a conversion temperature exceeding the melting point of the convertible layer formed by the method currently described. In this case, in some embodiments, the gap filling fluid can be solidified by cooling the substrate.

[0036] In some embodiments, the gap-filling fluid is formed anywhere where the convertible layer is present on the substrate. When the substrate has a surface that is completely covered by the convertible layer, the gap-filling fluid can be formed on the entire substrate surface, including external gaps and internal gaps in the substrate. When the substrate has a surface that is only partially covered by the convertible layer, the gap-filling fluid can be preferentially formed only in those places where the convertible layer is present. When the gap-filling fluid is formed outside the gap and inside the gap, in some exemplary operating modes, the gap-filling fluid can be drawn into the gap by at least one of capillary forces, surface tension, and gravity. It should be understood that the distal portion of the gap feature refers to the portion of the gap feature that is relatively far away from the substrate surface, and the proximal portion of the gap feature refers to the portion of the gap feature that is closer to the substrate surface than the lower / deeper portion of the gap feature.

[0037] Materials formed according to the present method may be advantageously used in the field of integrated circuit manufacturing.

[0038] Exemplary gaps include recesses, contact holes, vias, trenches, etc. In some embodiments, the depth of the gap is at least 5 nm to at most 500 nm, or at least 10 nm to at most 250 nm, or at least 20 nm to at most 200 nm, or at least 50 nm to at most 150 nm, or at least 100 nm to at most 150 nm.

[0039] In some embodiments, the width of the gap is at least 10 nm to at most 10000 nm, or at least 20 nm to at most 5000 nm, or at least 40 nm to at most 2500 nm, or at least 80 nm to at most 1000 nm, or at least 100 nm to at most 500 nm, or at least 150 nm to at most 400 nm, or at least 200 nm to at most 300 nm.

[0040] In some embodiments, the length of the gap is at least 10 nm to at most 10000 nm, or at least 20 nm to at most 5000 nm, or at least 40 nm to at most 2500 nm, or at least 80 nm to at most 1000 nm, or at least 100 nm to at most 500 nm, or at least 150 nm to at most 400 nm, or at least 200 nm to at most 300 nm.

[0041] The convertible layer may be suitably deposited using a deposition technique that produces a conformal layer, such as atomic layer deposition (ALD) or another cyclic deposition process. Alternatively, the convertible layer may be deposited using a deposition technique that produces a non-conformal layer (i.e., a non-uniform layer), such as a layer having a higher thickness on the flat surface of the substrate than inside the gap or trench; or a layer having a higher thickness inside the gap or trench than on the flat surface of the substrate. Examples of techniques that can produce non-conformal layers are chemical vapor deposition and plasma enhanced chemical vapor deposition.

[0042] Depositing the convertible layer may include performing a cyclic deposition process. The cyclic deposition process may include cyclic CVD, ALD, or a hybrid cyclic CVD / ALD process. For example, in some embodiments, the growth rate of a particular ALD process may be lower than that of a CVD process. One method of increasing the growth rate may be to operate at a deposition temperature higher than the deposition temperature typically used in the ALD process, resulting in certain parts of the chemical vapor deposition process, i.e., at least one of the non-self-limiting surface and gas phase reactions, but still utilizing the sequential introduction of reactants. Such a process may be referred to as cyclic CVD. In some embodiments, a cyclic CVD process may include introducing two or more precursors or reactants into a reaction chamber, wherein there may be an overlap time between the two or more precursors or reactants in the reaction chamber, resulting in an ALD component of the deposition and a CVD component of the deposition. This is referred to as a hybrid process. According to a further example, a cyclic deposition process may include a continuous flow of a reactant or precursor and periodic pulses of a second reactant or precursor entering the reaction chamber.

[0043] In some embodiments, the convertible layer is conformally deposited on the substrate. In other words, the convertible layer may have a constant thickness on the substrate surface, including in gaps, grooves, etc., for example within a tolerance range of 50%, 20%, 10%, 5%, 2%, 1%, 0.5%, or 0.1%.

[0044] In some embodiments, the convertible layer is deposited by a deposition method that produces a higher growth rate at the distal surface of the gap than at the proximal surface of the gap. In some embodiments, the growth rate at the distal surface of the gap is at least 200% to at most 500% higher than the growth rate at the proximal end, or at least 100% to at most 200%, or at least 50% to at most 100%, or at least 20% to at most 50%, or at least 10% to at most 20%, or at least 5% to at most 10%, or at least 2% to at most 5%, or at least 1% to at most 2%.

[0045] Suitable convertible layers include layers comprising at least one of a metal, a metal oxide, a metal nitride, and a metal carbide. For example, the convertible layer may include an element selected from the group consisting of tungsten (W), germanium (Ge), antimony (Sb), tellurium (Te), niobium (Nb), tantalum (Ta), vanadium (V), titanium (Ti), zirconium (Zr), rhodium (Rh), iron (Fe), chromium (Cr), molybdenum (Mo), gold (Au), platinum (Pt), silver (Ag), nickel (Ni), copper (Cu), cobalt (Co), zinc (Zn), aluminum (Al), indium (In), tin (Sn), hafnium (Hf), ruthenium (Ru), and bismuth (Bi).

[0046] In some embodiments, the convertible layer is at least partially metallic. In some embodiments, the convertible layer comprises a metal alloy. Thus, in some embodiments, the convertible layer comprises elemental metal, such as an elemental metal having an impurity content of less than 10 atomic %, less than 5 atomic %, less than 2 atomic %, or less than 1 atomic %.

[0047] Additionally or alternatively, the convertible layer may be at least partially semiconducting.

[0048] Additionally or alternatively, the convertible layer may be at least partially dielectric.

[0049] In some embodiments, the convertible layer includes a metal oxide.

[0050] In some embodiments, the convertible layer includes a metal nitride.

[0051] In some embodiments, the convertible layer comprises metal atoms capable of forming volatile halides or oxyhalides. Examples of these volatile halides and oxyhalides are RhBr 3 ,FeBr 3 ,FeBr 2 ,CrF 5 ,Co 6 Cl 12 ,MoCl 4 ,MoI 3 ,MoBr 3 ,AlCl 3 ,AlI 3 ,InBr 3 ,SnCl 2 ,SnBr 2 ,BiF 5 ,GeF 2 ,GeF 4 ,SbF 3 ,SbF 5 ,Te 2 Br,AuF 3 ,AuBr,PtBr 4 ,AgF 3 ,NiBr 2 ,CuBr 2 ,CoI,ZnCl 2 ,ZnI 2 ,NbCl 4 ,NbI 5 ,TaCl 5 ,TaI 5 ,TaF 5 ,TaBr 5 ,VF 4 ,VF 5 ,VBr 3,TiF 4 ,ZrI 4 ,ZrCl 4 ,ZrBr 4 ,HfCl 4 ,HfI 4 ,WOBr,WOCl 4 ,NbOCl 3 ,V 2 O 2 F 4 ,VOCl 2 ,VOCl 3 ,VOF 3 ,ZrF 6 (H 2 O) 2 or CoCl 2 (H 2 O) 2 .

[0052] According to some examples of the present disclosure, forming the convertible layer includes a thermal deposition process. In these cases, the deposition process does not include generating a plasma to form active species for the deposition process.

[0053] In some embodiments, the liquid phase conversion reactant comprises a halogen. Suitable halogen-containing conversion reactants include elemental halogens and hydrogen halides. For example, the conversion reactant may comprise a halogen selected from the group consisting of 2 , Cl 2 Br 2 or I 2 In addition or alternatively, the conversion reactant may include a hydrogen halide selected from HF, HCl, HBr or HI. In some embodiments, the halogen-containing conversion reactant is an aqueous solution.

[0054] In some embodiments, the liquid phase conversion reactant comprises a compound having a structure according to formula (i):

[0055] HXO n (i)

[0056] wherein X is a halogen selected from F, Cl, Br and I, and wherein n is an integer having a value of 1, 2, 3 or 4.

[0057] In some embodiments, the liquid phase conversion reactant is selected from the group consisting of semimetal halides, sulfonic acids, sulfonates, antimony salts, halogenated halogens, nitrohalides, oxyhalides, heteroleptic boron halides, sulfur halides, selenium halides, substituted pentafluorosulfanyls, substituted sulfur trifluorides, organic sulfuryl halides, and halogenated succinimides. In some embodiments, the liquid phase conversion reactant is selected from the group consisting of 2,2-difluoro-1,3-dimethylimidazolidine (DFI), perfluorodecanoic acid (PFDA), fluorosulfonic acid (HSO 3F), antimony pentachloride (SbCl 5 ), diethylaminosulfur trifluoride (DAST), dicarbonyl peroxide difluoride (C 2 F 2 O 4 ) and bromine trifluoride (BrF 3 In some embodiments, the liquid phase conversion reactant is selected from α-fluoroalkylamines. In some embodiments, the α-fluoroamines include compounds containing at least one carbon atom bonded to both a nitrogen atom and a fluorine atom. In some embodiments, the α-fluoroamines have the formula R 2 NCF 2 R', wherein the R groups are independently any C1 to C6 hydrocarbon, and the R' group is any one of the following: C1-C6 hydrocarbon, partially fluorinated C1-C6 hydrocarbon, perfluoroalkyl, perfluoroaryl, or -NR 2 In some embodiments, the R or R' group is cyclic. In some embodiments, the cyclic R or R' group is bound to the "NCF" of α-fluoroamine. 2 " fragment. In some embodiments, the α-fluoroamine is 1,1,2,2-tetrafluoroethyl-N,N-dimethylamine. In some embodiments, the α-fluoroamine is 2,2-difluoro-1,3-dimethylimidazolidine. In some embodiments, the α-fluoroamine is N,N-diethyl-1,1,2,3,3,3-hexafluoro-1-propylamine. In some embodiments, the α-fluoroamine is 2-chloro-N,N-diethyl-1,1,2-trifluoroethylamine.

[0058] In some embodiments, the liquid phase conversion reactant is selected from sulfur chloride, phosphorus chloride, acyl chloride, n-chlorosuccinimide and hypochlorite. In some embodiments, the liquid phase conversion reactant is selected from oxalyl chloride, acetyl chloride, thionyl chloride, sulfonyl chloride, alkylsulfonyl chloride, disulfur dichloride and sulfur dichloride. In some embodiments, the liquid phase conversion reactant is selected from phosphorus trichloride, phosphorus pentachloride, phosphorus oxychloride, dialkylphosphonic chloride, dialkylphosphonic chloride, alkylphosphonic dichloride, arylphosphonic dichloride, n-chlorosuccinimide, alkyl hypochlorite and tert-butyl hypochlorite.

[0059] In some embodiments, the liquid phase conversion reactant is selected from 1,1-dibromoalkane, 1,2-dibromoalkane, 1,1-diiodoalkane, 1,2-diiodoalkane, bromobenzene, iodobenzene, chlorobromide, chloroiodide, bromoiodide, oxalyl bromide, oxalyl iodide, silicon tetrabromide, silicon tetraiodide, dibromosilane, diiodosilane, thulium bromide, thulium iodide, tin bromide, tin iodide, aluminum bromide, aluminum iodide, titanium bromide, titanium iodide, phosphorus tribromide, phosphorus pentabromide, phosphorus oxybromide, phosphorus oxyiodide, N-bromosuccinimide, N-iodosuccinimide, tert-butyl hypobromite, ammonium bromide, ammonium iodide, pyridinium bromide, and pyridinium iodide.

[0060] In some embodiments, the liquid phase conversion reactant is selected from ortho-diiodoalkanes of the formula RR'XCCR"R"'X, wherein X is iodine, and wherein R and R' and R" and R'" are independently any C1 to C10 alkyl, including branched or cyclic variations, or are aryl containing 6-10 carbon atoms.

[0061] In some embodiments, the liquid phase conversion reactant is selected from n-iodosuccinimide, 1,3-diiodo-5,5-dimethylhydantoin, N-iodosaccharin, diiodosilane, iodotrimethylsilane, tetramethylammonium iodide, tetrabutylammonium iodide, pyridinium iodide, pyrazinium iodide, pyrrolidinium iodide, acetyl iodide, 2,2-dimethylpropionyl iodide, benzoyl iodide, boron triiodide, diphosphorus tetraiodide, and phosphorus triiodide.

[0062] In some embodiments, when the substrate is exposed to the active species, the substrate is maintained at a temperature of at least -25°C to at most 400°C, or at least 0°C to at most 200°C, or at least 25°C to at most 150°C, or at least 50°C to at most 100°C.

[0063] In some embodiments, the convertible layer is deposited at a substrate temperature of less than 800° C., or at least 50° C. to at most 500° C., or at least 100° C. to at most 300° C. In some embodiments, the convertible layer is deposited at a temperature of at least -25° C. to at most 300° C., or at a temperature of at least 0° C. to at most 250° C., or at a temperature of at least 25° C. to at most 200° C., or at a temperature of at least 50° C. to at most 150° C., or at a temperature of at least 75° C. to at most 125° C.

[0064] In some embodiments, the substrate is maintained at a temperature of less than 800°C, or at least -25°C to at most 800°C, or at least 0°C to at most 700°C, or at least 25°C to at most 600°C, or at least 50°C to at most 400°C, or at least 75°C to at most 200°C, or at least 100°C to at most 150°C when the substrate is exposed to the conversion reactants.

[0065] In some embodiments, when the gap-filling fluid is converted to the transition material, the substrate is maintained at a temperature below 800° C., or at least −25° C. to at most 800° C., or at least 0° C. to at most 700° C., or at least 25° C. to at most 600° C., or at least 50° C. to at most 400° C., or at least 75° C. to at most 200° C., or at least 100° C. to at most 150° C. In some embodiments, the temperature at which the substrate is maintained when the substrate is exposed to the conversion reactant is equal to the temperature at which the substrate is maintained when the gap-filling fluid is converted to the transition material.

[0066] In some embodiments, the presently described methods are performed at a pressure of less than 760 Torr, or at least 0.2 Torr to at most 760 Torr, at least 1 Torr to at most 100 Torr, or at least 1 Torr to at most 10 Torr. In some embodiments, the convertible layer is deposited at a pressure of at most 10.0 Torr, or at most 5.0 Torr, or at most 3.0 Torr, or at most 2.0 Torr, or at most 1.0 Torr, or at most 0.1 Torr, or at most 10. -2 Torr pressure, or up to 10 -3 Torr pressure, or up to 10 -4 Torr pressure, or up to 10 -5 Torr, or a pressure of at least 0.1 Torr to at most 10 Torr, or a pressure of at least 0.2 Torr to at most 5 Torr, or a pressure of at least 0.5 Torr to at most 2.0 Torr.

[0067] In some embodiments, the substrate is exposed to the conversion reactant for a duration of at least 0.1 seconds to at most 1000 seconds, or at least 0.2 seconds to at most 500 seconds, or at least 0.5 seconds to at most 200 seconds, or at least 1.0 seconds to at most 100 seconds, or at least 2 seconds to at most 50 seconds, or at least 5 seconds to at most 20 seconds.

[0068] In some embodiments, the method further comprises a step of curing the gap filling fluid. In some embodiments, curing can be performed after all the gap filling fluids have been deposited. Alternatively, curing can be performed in a cycle. For example, the method described herein may include a curing step after each step of exposing the substrate to the conversion reactant. Alternatively, the method described herein may include a curing step after exposing the substrate to every other step of the conversion reactant. Alternatively, the method described herein may include a curing step after at least 1% to at most 2% of the step of exposing the substrate to the conversion reactant, or at least 2% to at most 5%, or at least 5% to at most 10%, or at least 10% to at most 20%, or at least 20% to at most 50%, or at least 50% to at most 100%.

[0069] The curing step suitably comprises subjecting the substrate to some form of energy, such as at least one of heat, radiation, and particles. An exemplary curing step comprises exposing the substrate to UV radiation. Additionally or alternatively, the curing step may comprise exposing the substrate to a direct plasma, such as a rare gas plasma, such as an argon plasma. Additionally or alternatively, the curing step may comprise exposing the substrate to one or more reactive species, such as ions and / or free radicals generated in a remote plasma, such as a remote rare gas plasma, such as a remote argon plasma. Additionally or alternatively, the curing step may comprise exposing the substrate to photons, such as at least one of UV photons, photons in the visible spectrum, IR photons, and photons in the microwave spectrum. Additionally or alternatively, the curing step may comprise heating the substrate.

[0070] In some embodiments, the convertible layer may include niobium (Nb), such as metallic niobium or niobium oxide or niobium nitride. In such embodiments, the conversion reactant may suitably include one of chlorine or iodine. Thus, a NbCl-containing 4 or NbI 5 at least one gap-filling fluid.

[0071] In some embodiments, the convertible layer may include tantalum (Ta), such as metallic tantalum or tantalum oxide or tantalum nitride. In such embodiments, the conversion reactant may suitably include one of fluorine, chlorine, bromine and iodine. Thus, a layer comprising TaCl may be formed. 5 、TaI 5 、TaF 5 or TaBr 5 at least one gap-filling fluid.

[0072] In some embodiments, the convertible layer may include vanadium (V), such as metallic vanadium or vanadium oxide or vanadium nitride. In such embodiments, the conversion reactant may suitably include one of fluorine and bromine. Thus, a VOCl 3 、VF 4 、VF 5 or VBr 3 at least one gap-filling fluid.

[0073] In some embodiments, the convertible layer may include titanium (Ti), such as metallic titanium or titanium oxide or titanium nitride. In such embodiments, the conversion reactant may suitably include fluorine. Thus, a TiF-containing 4 The gap is filled with fluid.

[0074] In some embodiments, the convertible layer may include zirconium (Zr), such as metallic zirconium or zirconium oxide or zirconium nitride. In such embodiments, the conversion reactant may suitably include one of chlorine, bromine, and iodine. Thus, a ZrI 4 、ZrCl 4 or ZrBr 4 at least one gap-filling fluid.

[0075] In some embodiments, the convertible layer may include hafnium (Hf), such as metallic hafnium or hafnium oxide or hafnium nitride. In such embodiments, the conversion reactant may suitably include one of chlorine and iodine. Thus, a layer containing HfCl may be formed. 4 or HfI 4 at least one gap-filling fluid.

[0076] In some embodiments, the convertible layer may include rhodium (Rh), such as metallic rhodium or rhodium oxide or rhodium nitride. In such embodiments, the conversion reactant may suitably include bromine. Thus, a layer comprising RhBr may be formed. 3 The gap is filled with fluid.

[0077] In some embodiments, the convertible layer may include iron (Fe), such as metallic iron or iron oxide or iron nitride. In such embodiments, the conversion reactant may suitably include bromine. Thus, a layer comprising FeBr may be formed. 3 or FeBr 2 at least one gap-filling fluid.

[0078] In some embodiments, the convertible layer may include chromium (Cr), such as metallic chromium or chromium oxide or chromium nitride. In such embodiments, the conversion reactant may suitably include fluorine. Thus, a CrF-containing 5 The gap is filled with fluid.

[0079] In some embodiments, the convertible layer may include molybdenum (Mo), such as molybdenum or molybdenum oxide or molybdenum nitride. In such embodiments, the conversion reactant may suitably include chlorine, bromine, or iodine. Thus, a layer including Mo may be formed. 6 Cl 12 、MoCl 4 、MoI 3 or MoBr 3 at least one gap-filling fluid.

[0080] In some embodiments, the convertible layer includes gold (Au), such as metallic gold or an inorganic gold compound. In such embodiments, the conversion reactant may suitably include fluorine or bromine. Thus, a layer including AuF 3 or AuBr.

[0081] In some embodiments, the convertible layer includes silver (Ag), such as metallic silver or an inorganic silver compound. In such embodiments, the conversion reactant may suitably include fluorine. Thus, a layer including AgF may be formed. 3 The gap is filled with fluid.

[0082] In some embodiments, the convertible layer includes platinum (Pt), such as metallic platinum or an inorganic platinum compound. In such embodiments, the conversion reactant may suitably include bromine. Thus, a PtBr-containing 4 The gap is filled with fluid.

[0083] In some embodiments, the convertible layer includes nickel (Ni), such as metallic nickel or an inorganic nickel compound. In such embodiments, the conversion reactant may suitably include bromine. Thus, a layer including NiBr may be formed. 2 The gap is filled with fluid.

[0084] In some embodiments, the convertible layer includes copper (Cu), such as metallic copper or an inorganic copper compound. In such embodiments, the conversion reactant may suitably include bromine. Thus, a CuBr-containing 2 The gap is filled with fluid.

[0085] In some embodiments, the convertible layer includes cobalt (Co), such as metallic cobalt or an inorganic cobalt compound. In such embodiments, the conversion reactant may suitably include iodine. Thus, a gap-filling fluid containing CoI may be formed.

[0086] In some embodiments, the convertible layer includes zinc (Zn), such as metallic Zn or an inorganic Zn compound. In such embodiments, the conversion reactant may suitably include at least one of chlorine and iodine. Thus, a ZnCl 2 or ZnI 2 at least one gap-filling fluid.

[0087] In some embodiments, the convertible layer may include aluminum (Al), such as metallic aluminum or an inorganic aluminum compound, such as aluminum oxide or aluminum nitride. In such embodiments, the conversion reactant may suitably include chlorine or iodine. Thus, a layer comprising AlCl may be formed. 3 or AlI 3 at least one gap-filling fluid.

[0088] In some embodiments, the convertible layer may include indium (In), such as metallic indium or an inorganic indium compound, such as indium oxide or indium nitride. In such embodiments, the conversion reactant may suitably include bromine. Thus, a layer comprising InBr may be formed. 3 The gap is filled with fluid.

[0089] In some embodiments, the convertible layer may include tin (Sn), such as metallic tin or an inorganic tin compound, such as tin oxide or tin nitride. In such embodiments, the conversion reactant may suitably include at least one of chlorine and bromine. Thus, a SnCl 2 or SnBr 2 at least one gap-filling fluid.

[0090] In some embodiments, the convertible layer may include bismuth (Bi), such as metallic bismuth or an inorganic bismuth compound, such as bismuth oxide or bismuth nitride. In such embodiments, the conversion reactant may suitably include fluorine. Thus, a layer including BiF may be formed. 5 The gap is filled with fluid.

[0091] In some cases, it may be desirable to change the material formed by the methods described herein into a different form. Therefore, in some embodiments, the methods described herein also include a transformation process. Suitable transformation processes include one or more of thermal annealing, exposing the substrate to a reactant, exposing the substrate to a direct plasma, or exposing the substrate to reactive species such as ions or free radicals generated in a remote plasma.

[0092] In other words, the gap filling fluid in liquid or solid state can be subjected to a transformation process to form a solid state transformation material. Suitable transformation processes include exposure to direct or remote plasma, and exposure to thermal transformation. Suitable plasmas include remote and direct hydrogen plasma, oxygen plasma or nitrogen plasma. Suitable thermal transformation agents include gases and vapors containing at least one of hydrogen, oxygen or nitrogen. Therefore, the gap can be appropriately filled with a selected transformation material. The transformation material can include, for example, at least one of a metal, a nitride or an oxide.

[0093] In some embodiments, the conversion process includes exposing the substrate to a direct plasma, such as a direct nitrogen plasma or a direct oxygen plasma. Suitable nitrogen plasmas employ plasma gases including a nitrogen-containing gas or vapor, such as N 2 and / or NH 3 Suitable oxygen plasmas employ plasma gases comprising oxygen-containing gas or vapor, such as O 2 and / or H 2 O.

[0094] In some embodiments, the conversion process includes a thermal process, such as a thermal process including exposing the substrate to an oxygen reactant.

[0095] In some embodiments, converting the gap filling fluid comprises exposing the substrate to a reduction step and an oxidation step. In some embodiments, the reduction step precedes the oxidation step. Alternatively, the oxidation step may precede the reduction step. In some embodiments, the reduction step comprises exposing the substrate to a hydrogen plasma. In some embodiments, the oxidation step comprises exposing the substrate to an oxygen plasma.

[0096] In some embodiments, converting the gap filling fluid comprises exposing the gap filling fluid or the conversion material to a reduction step and a nitridation step. It should be understood that the nitridation step refers to a step of converting the material into a nitride. In some embodiments, the reduction step precedes the nitridation step. Alternatively, the nitridation step may precede the reduction step. In some embodiments, the reduction step comprises exposing the substrate to a hydrogen plasma. In some embodiments, the nitridation step comprises exposing the substrate to a nitrogen plasma. Suitable nitrogen plasmas include those wherein the plasma gas comprises N 2 NH 3 or including N 2 and H 2 A plasma of at least one of the mixtures.

[0097] In some embodiments, the transformation process can be performed once after filling the gap, or can be performed multiple times, that is, the gap filling step and the transformation step can be alternated and cyclically performed to fill the gap with the transformation material. Therefore, in some embodiments, the method described herein can include performing multiple super cycles. The super cycle includes, in the following order: forming a transformable layer on a substrate; exposing the substrate to a transformation reactant; and performing a transformation process on the substrate. In some cases, performing a cyclic transformation process can result in a transformation layer having favorable properties, such as higher etch resistance and / or less stress.

[0098] Thus, in some embodiments, the methods described herein include multiple super cycles. For example, the methods described herein may include at least 2 to at most 5, or at least 5 to at most 10, or at least 10 to at most 20, or at least 20 to at most 50, or at least 50 to at most 100 super cycles. The super cycles include forming a convertible layer on a substrate; exposing the substrate to a conversion reactant; and optionally converting a gap filling fluid into a conversion material.

[0099] The total number of supercycles included in the methods described herein depends, inter alia, on the desired total layer thickness. In some embodiments, the method comprises from at least 1 supercycle to at most 100 supercycles, or from at least 2 supercycles to at most 80 supercycles, or from at least 3 supercycles to at most 70 supercycles, or from at least 4 supercycles to at most 60 supercycles, or from at least 5 supercycles to at most 50 supercycles, or from at least 10 supercycles to at most 40 supercycles, or from at least 20 supercycles to at most 30 supercycles. In some embodiments, the method comprises at most 100 super cycles, or at most 90 super cycles, or at most 80 super cycles, or at most 70 super cycles, or at most 60 super cycles, or at most 50 super cycles, or at most 40 super cycles, or at most 30 super cycles, or at most 20 super cycles, or at most 10 super cycles, or at most 5 super cycles, or at most 4 super cycles, or at most 3 super cycles, or at most 2 super cycles, or a single super cycle.

[0100] A system is also described herein, the system comprising a reaction chamber, a precursor gas source, a deposition reactant gas source, and a controller. The precursor gas source comprises a metal precursor, the deposition reactant gas source comprises a deposition reactant. The controller is configured to control the flow of gas into the reaction chamber to form a layer on a substrate by the method described herein.

[0101] Optionally, the system further comprises one or more of an active substance source and a conversion reactant source. If present, the active substance source is arranged to provide the active substance. The conversion reactant source (if present) is arranged to provide the conversion reactant.

[0102] In some embodiments, the system includes two different, i.e., separate, reaction chambers: a first reaction chamber and a second reaction chamber. The first reaction chamber is configured to form a convertible layer on a substrate. The second reaction chamber is configured to expose the substrate to an active substance for converting a gap filling fluid or a solidified material into a conversion material, or both. In some embodiments, the first reaction chamber and the second reaction chamber form part of a combined tool, and the substrate moves between the first reaction chamber and the second reaction chamber without air interruption. In some embodiments, the first reaction chamber is maintained at a first reaction chamber temperature and the second reaction chamber is maintained at a second reaction chamber temperature. In some embodiments, the first reaction chamber temperature is lower than the second reaction chamber temperature, for example, at least 10°C lower to at most 100°C. In some embodiments, the first reaction chamber temperature is higher than the second reaction chamber temperature, for example, at least 10°C higher to at most 100°C. In some embodiments, the first reaction chamber temperature is equal to the second reaction chamber temperature, for example, in the range of 10°C, 20°C, 30°C, or 40°C.

[0103] In some embodiments, the second reaction chamber is configured to expose the material to the halogen reactant by at least one of the following methods: dip coating, spin coating, sol-gel, or a chemical bath.

[0104] According to further embodiments of the present disclosure, the methods and / or structures described herein may be used to form a device or a portion thereof. The device may include a substrate, one or more insulating layers, one or more metal layers, and one or more semiconductor layers. The device may also include a gap filled according to the method disclosed herein.

[0105] Also described are field effect transistors comprising a gate contact comprising a layer formed according to the methods described herein.

[0106] Also described are metal contacts comprising layers deposited by the methods described herein.

[0107] Also provided herein is a metal-insulator-metal (MIM) capacitor comprising a metal electrode comprising a layer formed by the method described herein.

[0108] Figure 1 A schematic diagram of an embodiment of the method described herein is shown. The method can be used to fill gaps, for example, to form electrodes in semiconductor devices. However, unless otherwise stated, the methods currently described are not limited to these applications. The method includes a step 111 of positioning a substrate on a substrate support. The substrate support is located in a reaction chamber. Suitable substrate supports include bases, pedestals, etc. The method also includes forming a convertible layer 112 on the substrate. Optionally, the reaction chamber is then purged. The method then includes exposing the substrate to a liquid phase conversion reactant 113. In some embodiments, exposure 113 is performed by at least one of the following methods selected from the group consisting of dip coating, spin coating, sol-gel, and chemical baths. In some embodiments, the conversion reactant is heated before and / or during exposure 113. In some embodiments, the conversion reactant is heated to a temperature between 20 and 200° C. In some embodiments, the exposure step 113 is performed in a sonic bath.

[0109] Thus, a gap-filling fluid is formed in the gap. Optionally, the steps of forming a convertible layer on the substrate 112 and exposing the substrate to a liquid-phase conversion reactant 113 are repeated 115 one or more times. When a sufficient amount of the gap-filling fluid has been formed in the gap, the method ends 114.

[0110] Optionally, purging is performed after forming the convertible layer 112 on the substrate by post-deposition purging. Purging can be accomplished by exposing the substrate to a purge gas, which can be accomplished by, for example, providing the purge gas to the reaction chamber. Exemplary purge gases include rare gases. Exemplary rare gases include He, Ne, Ar, Xe, or Kr. Alternatively, purging can include conveying the substrate through a purge gas curtain. During purging, excess chemicals and reaction byproducts (if any) can be removed from the substrate surface or reaction chamber before the substrate proceeds to the next step, for example, by purging the reaction space or by moving the substrate.

[0111] Figure 2 A further embodiment of the method described herein is schematically shown. Figure 2 The method is similar to Figure 1 214. The method of claim 214, as it also includes positioning a substrate on a substrate support 211, forming a convertible layer 212 on the substrate, and exposing the substrate to a liquid phase conversion reactant 213. As previously described, the steps of forming the convertible layer 212 on the substrate and converting the convertible layer to form a gap filling fluid 213 may be repeated 215 one or more times.

[0112] Figure 2 Methods and Figure 1 The method of 210 is different in that it also includes the step of transforming the gap filling fluid 214 to form a transformation material. Optionally, the step of transforming the gap filling fluid 214 is followed by a purge. The step of transforming the gap filling fluid 214 may include, for example, exposing the substrate to a direct plasma, such as a direct oxygen plasma or a direct nitrogen plasma. Optionally, Figure 2 The method includes a plurality of super cycles 216, wherein the steps of forming the convertible layer 212 on the substrate to converting the gap filling fluid 214 are repeated one or more times. After a predetermined amount of conversion material has been formed on the substrate, Figure 2 The method ends at 217.

[0113] Figure 3a )and Figure 3b ) illustrates the operation of the method described herein. In particular, Figure 3a )and Figure 3b ) shows a substrate 310 including a plurality of gaps 340. Figure 3a ) shows a convertible layer 320 conformally deposited on a substrate 310. Figure 3b ) shows the same substrate 310 after exposure to a conversion reactant. The conversion reactant exposure can convert at least a portion of the convertible layer 320 into a gap filling fluid that flows into the gap. Optionally, the gap filling fluid can then be cured to form a solidified material 330. Optionally, the solidified material 330 or the gap filling fluid can be converted into a conversion material, as described elsewhere herein.

[0114] Figure 4 Another embodiment of the system 400 described herein is shown in a stylized manner. The system 400 includes two different reaction chambers: a first reaction chamber 410 and a second reaction chamber 420. The first reaction chamber 410 is arranged to form a convertible layer on a substrate. The second reaction chamber 420 is arranged to expose the substrate to at least one of a conversion reagent and convert a gap filling fluid into a conversion material. In some embodiments, the substrate moves between the first reaction chamber 410 and the second reaction chamber 420 without air interruption. In some embodiments, the second reaction chamber 420 is configured to expose the material to a halogen reactant by at least one of the following methods: dip coating, spin coating, sol-gel, or a chemical bath.

[0115] Figure 5 A schematic diagram of a substrate 500 including a gap 510 is shown. The gap 510 includes a sidewall 511 and a distal end 512. The substrate also includes a proximal surface 520. In some embodiments, the sidewall 511 and the distal end 512 include the same material. In some embodiments, at least one of the sidewall 511 or the distal end 512 includes a dielectric, such as a silicon-containing dielectric, such as silicon oxide, silicon nitride, silicon carbide, or a mixture thereof. In some embodiments, at least one of the sidewall 511 and the distal end 512 includes a metal, such as a transition metal, a post-transition metal, or a rare earth metal. In some embodiments, the metal includes Cu, Co, W, Ru, Mo, Al, or an alloy thereof.

[0116] In some embodiments, the sidewall 511 and the distal end 512 have the same or substantially the same composition. In some embodiments, the sidewall 511 and the distal end 512 have different compositions. In some embodiments, the sidewall and the distal end 512 comprise a dielectric. In some embodiments, the sidewall 511 and the distal end 512 comprise a metal. In some embodiments, the sidewall 511 comprises a metal and the distal end 512 comprises a dielectric. In some embodiments, the sidewall 511 comprises a dielectric and the distal end comprises a metal.

[0117] In some embodiments, the proximal surface 520 has the same composition as the sidewall 511. In some embodiments, the proximal surface 520 has a different composition than the sidewall 511. In some embodiments, the proximal surface 520 has a different composition than the distal end 512. In some embodiments, the proximal surface 520 has the same composition as the distal end 512.

[0118] In some embodiments, the proximal surface 520, the sidewall 511, and the distal end 512 comprise the same material. In some embodiments, the proximal surface 520, the sidewall 511, and the distal end 512 comprise a dielectric. In some embodiments, the proximal surface 520, the sidewall 511, and the distal end 512 comprise a metal. In some embodiments, the proximal surface 520, the sidewall 511, and the distal end 512 comprise a semiconductor.

[0119] The illustrations presented herein are not meant to be actual views of any particular material, structure, or device but are merely idealized representations used to describe embodiments of the present disclosure.

[0120] The specific embodiments shown and described are illustrations of the present invention and its best mode and are not intended to limit the scope of these aspects and embodiments in any way. In fact, for the sake of brevity, the traditional manufacturing, connection, preparation and other functional aspects of the system may not be described in detail. In addition, the connecting lines shown in the various figures are intended to represent exemplary functional relationships and / or physical connections between various elements. Many alternative or additional functional relationships or physical connections may exist in actual systems, and / or may not exist in some embodiments.

[0121] It should be understood that the configuration and / or method described herein are exemplary in nature, and these specific embodiments or examples should not be considered 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 can be performed in the order shown, in other orders, or omitted in some cases.

[0122] 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, and any and all equivalents thereof.

Claims

1. A method for filling a gap, the method comprising: - providing a substrate to the reaction chamber, the substrate comprising a gap; - forming a convertible layer on a substrate; as well as - exposing the substrate to a liquid phase conversion reactant, thereby converting at least a portion of the convertible layer into a gap-filling fluid; Therein, the gap-filling fluid at least partially fills the gap.

2. The method according to claim 1, wherein: The convertible layer includes at least one of a metal, a metal oxide, a metal nitride, and a metal carbide.

3. The method according to claim 1, wherein: The convertible layer comprises metal atoms capable of forming volatile halides or oxyhalides.

4. The method according to claim 1, wherein: The convertible layer is at least partially metallic or semiconducting.

5. The method according to claim 1, wherein: Forming the convertible layer is performed in the first reaction chamber, and exposing the substrate to a liquid phase conversion reactant is performed in the second reaction chamber.

6. The method according to claim 5, wherein: The first and second reaction chambers form part of a cluster tool.

7. The method according to claim 1, wherein: The convertible layer includes an element selected from the group consisting of W, Ge, Sb, Te, Nb, Ta, V, Ti, Zr, Rh, Fe, Cr, Mo, Au, Pt, Ag, Ni, Cu, Co, Zn, Al, In, Sn and Bi.

8. The method according to claim 1, wherein: The liquid phase conversion reactant includes a halogen.

9. The method according to claim 1, wherein: The liquid phase conversion reactants are in the form of aqueous solutions.

10. The method according to claim 1, wherein: The liquid phase conversion reactants include hydrogen halide.

11. The method according to claim 1, wherein: The liquid phase conversion reactants include an oxygen-containing halogen acid.

12. The method according to claim 1, wherein: The exposing step is performed by at least one of the following methods selected from the group consisting of dip coating, spin coating, sol-gel, and chemical bath.

13. The method according to claim 1, wherein: The liquid phase conversion reactants are heated prior to and / or during the exposing step.

14. The method according to claim 13, wherein: The conversion reactants are heated to a temperature between 20 and 200°C.

15. The method according to claim 1, wherein: The step of exposing the substrate to the liquid phase conversion reactants is performed in an ultrasonic bath.

16. A system comprising: Reaction chamber; a precursor gas source including a metal precursor; a deposition reactant gas source including a deposition reactant; as well as A controller, wherein the controller is configured to control a gas flow into a reaction chamber to form a layer on a substrate by the method according to claim 1.

17. A multi-chamber reactor system comprising: a first reaction chamber configured to deposit a material layer on a substrate; as well as A second reaction chamber is configured to expose the material layer to a halogen reactant to form a flowable layer.

18. The multi-chamber reactor system according to claim 17, wherein: The first reaction chamber and the second reaction chamber form part of a cluster tool, and wherein the substrate moves between the first reaction chamber and the second reaction chamber without air breaks.

19. The multi-chamber reactor system according to claim 17, wherein: The second reaction chamber is configured to expose the material layer to the halogen reactant by at least one of the following methods: dip coating, spin coating, sol-gel, or chemical bath.

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