Patent Application
20250062118
An application data sheet is filed concurrently with this specification as part of the present application. Each application that the present application claims benefit of or priority to as identified in the concurrently filed application data sheet is incorporated by reference herein in its entirety and for all purposes.
Many semiconductor device fabrication processes involve formation of films including silicon-containing films such as silicon oxide or silicon nitride. Plasma enhanced atomic layer deposition (ALD) may be used to deposit silicon-containing films. Depositing a high-quality film can be particularly challenging when depositing films in gaps. Challenges can include the formation of voids and/or seams in the films.
The background description provided herein is for the purposes of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
Disclosed herein are methods and systems of depositing films in structures. In one aspect of the embodiments herein, a method of depositing a film is provided, the method including: providing a substrate having a structure including a gap to be filled in a process chamber; and performing one or more cycles of: (a) exposing the substrate to a plasma including a first gas to inhibit deposition on a portion of the gap, wherein the pressure of the process chamber during (a) is at least about 3 Torr; and (b) after (a), depositing dielectric material in the gap. In some embodiments, the gap has an aspect ratio between about 3:1 and about 7:1. In some embodiments, the gap has an aspect ratio of at least about 150:1. In some embodiments, the gap has a depth of at least about 1 μm. In some embodiments, the pressure of the process chamber during (a) is at least about 15 Torr. In some embodiments, the duration of (a) is less than about 30 seconds. In some embodiments, the duration of (a) is less than about 15 seconds. In some embodiments, the first gas includes a non-halogen-containing species. In some embodiments, the first gas includes a nitrogen-containing species. In some embodiments, the nitrogen-containing species is N2. In some embodiments, the first gas includes a halogen-containing species. In some embodiments, the halogen-containing species is a fluorine-containing species. In some embodiments, the halogen-containing species is a chlorine-containing species. In some embodiments, the halogen-containing species is nitrogen trifluoride (NF3). In some embodiments, the first gas includes an amine-containing species. In some embodiments, the first gas includes a hydrogen-containing species. In some embodiments, depositing dielectric material during (b) includes an atomic layer deposition (ALD) process.
In another aspect of the embodiments herein, a method of depositing a film is provided, the method including: providing a substrate having a structure including a gap to be filled in a process chamber, wherein the gap has an aspect ratio between about 3:1 and about 7:1; and performing one or more cycles of: (a) exposing the substrate to a plasma including N2 to inhibit deposition on a portion of the gap, wherein the pressure of the process chamber during (a) is at least about 3 Torr, and wherein a duration of (a) is less than about 30 seconds; and (b) after (a), depositing dielectric material in the gap.
These and other features of the disclosed embodiments will be described in detail below with reference to the associated drawings.
In the following description, numerous specific details are set forth to provide a thorough understanding of the presented embodiments. The disclosed embodiments may be practiced without some or all these specific details. In other instances, well-known process operations have not been described in detail to not unnecessarily obscure the disclosed embodiments. While the disclosed embodiments will be described in conjunction with the specific embodiments, it will be understood that it is not intended to limit the disclosed embodiments.
Semiconductor fabrication processes often include dielectric gap fill using chemical vapor deposition (CVD) and/or atomic layer deposition (ALD) methods to fill features. Described herein are methods of filling features with dielectric material including but not limited to silicon-containing films such as silicon oxide, and related systems and apparatuses. The methods described herein can be used to fill vertically oriented features formed in a substrate. Such features may be referred to as gaps, recessed features, negative features, unfilled features, or simply features. Filling such features may be referred to as gapfill. Features formed in a substrate can be characterized by one or more of narrow and/or re-entrant openings, constrictions within the feature, and high aspect ratios. In some implementations, a feature may have an aspect ratio of at least about 2:1, at least about 4:1, at least about 6:1, at least about 20:1, at least about 100:1, or greater. The substrate may be a silicon wafer, e.g., a 200-mm wafer, a 300-mm wafer, or a 450-mm wafer, including wafers having one or more layers of material such as dielectric, conducting, or semi-conducting material deposited thereon.
One aspect of the disclosure relates to a method of using an inhibitor plasma during atomic layer deposition (ALD) of dielectric material in gaps that facilitates void-free bottom gapfill. The inhibitor plasma creates a passivated surface and increases a nucleation barrier of the deposited ALD film. When the inhibitor plasma interacts with material in the feature, the material at the bottom of the feature receives less plasma treatment than material located closer to a top portion of the feature or in field because of geometrical shadowing effects. As a result, deposition at the top of the feature is selectively inhibited and deposition in lower portions of the feature proceeds with less inhibition or without being inhibited. As a result, button-up fill is enhanced, which creates a more favorable sloped profile that migrates the seam effect and prevents void formation. Halogen-containing plasmas can be effective inhibition plasmas. For example, for some applications, a plasma generated from nitrogen trifluoride (NF3) may provide an inhibition effect in a substantially reduced time compared to a plasma generated from molecular nitrogen (N2).
Examples of structures include 3D NAND structures, DRAM structures, and shallow trench isolation (STI) structures. The structures include gaps with the sidewalls of the gaps formed by a material susceptible to etch. In one example, 3D NAND structure includes oxide-nitride-oxide-nitride (ONON) stacks covered with a poly Si layer. In another example, structures may include lateral/tunnel structures that extend horizontally from a common vertical trench. Other examples of sidewall materials include oxides, metals, and semiconducting materials. The methods described herein are not limited to a particular class of sidewall material and may be used to inhibit any susceptible material. The structure may be provided to a deposition chamber for deposition of a protective liner. The deposition chamber may be the same chamber as the subsequent dielectric deposition or a different chamber.
Dielectric material is deposited in the gaps using an inhibition plasma at high pressure. (105). As discussed further below, this can involve cycles of inhibition plasma followed by ALD of the dielectric film. High pressure may increase the inhibition effective depth and decrease the duration of an inhibition plasma treatment, improving throughput.
At 201 the structure 200a may also be characterized by an inhibition effective depth (IED) line 204a (as shown by the dashed line). Inhibition plasma treatment may be characterized by an IED, which is the depth in a gap above which deposition is inhibited as a result of the inhibition plasma passivating the surface. The IED may be affected by multiple parameters, including the particular species used, a duration of the inhibition plasma treatment, plasma power, proportion of gas flow that is the species (rather than a carrier gas such as an inert gas, e.g., helium or argon), and pressure. In particular, the species used for inhibition may have a large effect on the IED. For example, plasmas generated from nitrogen trifluoride (NF3) may be up to 100 times more effective than molecular nitrogen (N2) for passivating a surface. For high aspect ratio and deep structures, e.g., at least about 100:1 and 3 μm or greater structures, NF3 is an ideal choice of species for inhibition to sufficiently inhibit the structure to avoid pinch off, while also not fully inhibiting the structure. However, for lower aspect ratio and/or shallower structures, halogen-containing inhibition gases may be unsuitable as they may fully inhibit the structure, even when performed at a high dilution, short duration, and low power (each of which decreases the inhibition effect of an inhibition plasma treatment). Non-halogen-containing species, such as N2, by contrast, does not passivate the surface as well as NF3 or other halogen-containing species, having a much smaller IED even with lengthy plasma inhibition treatments that slow down throughput, which is undesirable. For example, a 0.5 second plasma inhibition treatment with NF3 may fully inhibit a structure that is only partially inhibited by a 60 second plasma inhibition treatment using N2.
Returning to
Conversely,
As illustrated by
To address this concern, in some embodiments the inhibition plasma treatment may be performed at high pressure. High pressure refers to the pressure of the process chamber during the inhibition plasma treatment. High pressure may increase the effectiveness of the inhibition plasma, particularly for less effective inhibitors such as non-halogen-containing inhibition species, including non-halogen containing, nitrogen-containing species such as N2. In some embodiments, non-halogen-containing inhibition species may include amines, with examples including NH3, methylamine, dimethylamine, and trimethylamine. In some embodiments, non-halogen-containing species may include hydrazine. At high pressure, the duration of an inhibition plasma treatment may be significantly reduced without reducing the IED or even increasing the IED when compared to a low pressure inhibition plasma treatment. In some embodiments, a high pressure inhibition plasma treatment refers to a pressure of more than about 6 Torr, at least about 10 Torr, at least about 15 Torr, at least about 20 Torr, between about 10 Torr and about 30 Torr, or between about 15 Torr and 30 Torr.
High pressure inhibition plasma treatment may be particularly advantageous for inhibition plasma treatments using non-halogen-containing species, which typically have a significantly lower inhibition effect compared to halogen-containing species. As noted above, an inhibition plasma treatment using NF3 may be performed for as little as 0.5 seconds. Thus, increasing the pressure of an NF3 inhibition plasma may fully inhibit the structure for low aspect ratio structures regardless of other processing parameters that would decrease the inhibition effect (shorter duration, dilution with inert gas, low plasma power). By contrast, a non-halogen-containing species, such as N2, may be used for inhibition plasma treatments of between about 10 seconds and about 60 seconds. Performing an inhibition plasma treatment using N2 at high pressure may decrease the duration of the inhibition plasma treatment to achieve a particular IED from about 60 seconds (at a lower pressure, e.g., 6 Torr) to about 20 seconds or less at high pressure.
After the optional liner is deposited, n inhibition blocks are performed, with the operations of the first inhibition block (n=1) shown. The first operation is the inhibition plasma, which is a surface treatment. (308) As discussed above, the plasma may include halogen species including anion and radical species such as F−, Cl−, I−, Br−, fluorine radicals, etc. Other inhibition plasmas may be used. In some embodiments, the inhibition plasma is generated from non-halogen containing species, including nitrogen-containing, non-halogen-containing species. For example, plasmas generated from molecular nitrogen (N2), molecular hydrogen (H2), ammonia (NH3), amines, diols, diamines, aminoalcohols, thiols, alkyl halides, halides, HF, fluorine-containing species, chlorine-containing species, iodine-containing species, or combinations thereof may be used as inhibition plasmas. In some embodiments, the inhibition plasma treatment is performed at high pressure as described herein.
When the inhibition plasma interacts with material in the feature, the material at the bottom of the feature receives less plasma treatment than material located closer to a top portion of the feature or in field because of geometrical shadowing effects. As a result, deposition at the top of the feature is selectively inhibited and deposition in lower portions of the feature proceeds with less inhibition or without being inhibited. In
One or more additional inhibition blocks, including growth cycle and passivation, may be performed for a total of n inhibition blocks. (314). The number of inhibition blocks depends on how much material is used to fill the feature. Inhibition plasma, ALD, and passivation conditions may be changed from inhibition block to inhibition block to fill the feature. For example, an inhibition plasma duration may be 20 seconds until the bottom quarter of the feature is filled (inhibition block 1), then changed to 5 seconds for the middle 50% of the structure (inhibition block 2), etc. Each inhibition block may have a different IED, where process parameters for an inhibition plasma treatment for an inhibition block are changed to target a different IED. Each inhibition block may fill a portion of the feature below an IED of that inhibition block. In some embodiments, the chamber pressure may be decreased between inhibition blocks to reduce the IED for a subsequent inhibition block.
When the feature is nearly filled, inhibition may no longer be necessary, and the fill can be completed with n4 cycles of ALD fill. (316). In some embodiments, an optional cap or overburden layer of dielectric may then be deposited. (318). Plasma enhanced chemical vapor deposition (PECVD) may be used at this stage for a fast deposition.
ALD is a technique that sequentially deposits thin layers of material. ALD processes use surface-mediated deposition reactions to deposit films on a layer-by-layer basis in cycles. The concept of an ALD “cycle” is relevant to the discussion of various embodiments herein. Generally, a cycle is the minimum set of operations used to perform a surface deposition reaction one time. The result of one cycle is the production of at least a partial silicon-containing film layer on a substrate surface. Typically, an ALD cycle includes operations to deliver and adsorb at least one reactant to the substrate surface, and then react the adsorbed reactant with one or more reactants to form the partial layer of film. The cycle may include certain ancillary operations such as sweeping one of the reactants or byproducts and/or treating the partial film as deposited. Generally, a cycle contains one instance of a unique sequence of operations.
As an example, an ALD cycle may include the following operations: (i) delivery/adsorption of a precursor, (ii) purging of the precursor from the chamber, (iii) delivery of a second reactant and optional plasma ignition, and (iv) purging of byproducts from the chamber. The reaction between the second reactant and the adsorbed precursor to form a film on the surface of a substrate affects the film composition and properties, such as nonuniformity, stress, wet etch rate, dry etch rate, electrical properties (e.g., breakdown voltage and leakage current), etc.
In one example of an ALD process, a substrate surface that includes a population of surface-active sites is exposed to a gas phase distribution of a first precursor, such as a silicon-containing precursor, in a dose provided to a chamber housing the substrate. Molecules of this first precursor are adsorbed onto the substrate surface, including chemisorbed species and/or physisorbed molecules of the first precursor. When a compound is adsorbed onto the substrate surface as described herein, the adsorbed layer may include the compound as well as derivatives of the compound. For example, an adsorbed layer of a silicon-containing precursor may include the silicon-containing precursor as well as derivatives of the silicon-containing precursor. After a first precursor dose, the chamber is then evacuated to remove most or all of first precursor remaining in gas phase so that mostly or only the adsorbed species remain. In some implementations, the chamber may not be fully evacuated. For example, the reactor may be evacuated such that the partial pressure of the first precursor in gas phase is sufficiently low to mitigate a reaction. A second reactant, such as an oxygen-containing gas or nitrogen-containing gas, is introduced to the chamber so that some of these molecules react with the first precursor adsorbed on the surface. In some processes, the second reactant reacts immediately with the adsorbed first precursor. In other embodiments, the second reactant reacts only if a source of activation such as plasma is applied temporally. The chamber may then be evacuated again to remove unbound second reactant molecules. As described above, in some embodiments the chamber may not be completely evacuated. Additional ALD cycles may be used to build film thickness.
It should be noted that the processes described herein are not limited to a particular reaction mechanism. Thus, the process described with respect to
In some embodiments, a high pressure inhibition plasma treatment refers to a pressure of more than about 6 Torr, at least about 10 Torr, at least about 15 Torr, at least about 20 Torr, between about 10 Torr and about 30 Torr, or between about 15 Torr and 30 Torr.
The duration of an inhibition plasma treatment may be between about 0.3 seconds and about 60 seconds, between about 0.3 seconds and about 30 seconds, at least about 0.3 seconds, at least about 1 second, at least about 5 seconds, at least about 10 seconds, at least about 20 seconds, or at least about 30 seconds. Inhibition plasma treatment using a halogen-containing species may generally be for a shorter duration than a non-halogen-containing species, as the halogen-containing species may more effectively passivate the surface compared to non-halogen-containing species.
High pressure inhibition plasma treatment may be used for various aspect ratios and structure depths. In some embodiments, high pressure inhibition plasma treatment may be used for low aspect ratio structures. A low aspect ratio structure may have an aspect ratio between about 3:1 and about 7:1, less than about 10:1, between about 3:1 and about 10:1, between about 3:1 and about 15:1, or less than about 15:1. A low aspect ratio structure may have a depth of at least about 100 nm, at least about 1 μm, at least about 2 μm, or at least about 3 μm.
In some embodiments, IED may be characterized by a percentage, e.g., 30% IED refers to an inhibition effective depth of 30% of the total depth of a feature. Thus, if a feature has a depth of 1 μm, a 30% IED means deposition would be inhibited along the sidewall surface of the feature that is within 300 nm from the top of the feature, with the remaining depth not being inhibited. In some embodiments, the IED of a high pressure inhibition plasma treatment according to embodiments described herein may be about 20%, about 30%, about 40%, about 50%, about 60%, or about 70%.
In some embodiments, a low aspect ratio structure may be inhibited using a high pressure inhibition plasma treatment using a non-halogen-containing species. In some embodiments, halogen-containing species may fully inhibit a low aspect ratio structure, even in a non-high pressure environment or when diluting the halogen-containing species by co-flowing an inert gas.
In some embodiments, a high pressure inhibition plasma treatment may be used with halogen-containing species for high aspect ratio features. In some embodiments, a high aspect ratio feature may have an aspect ratio of at least about 10:1, at least about 30:1, at least about 100:1, at least about 150:1, or at least about 180:1. In some embodiments, a depth of a high aspect ratio feature is at least about 3 μm.
In some embodiments, the flow of non-halogen-containing species, such as N2, may be between about 10 slm and about 100 slm. In some embodiments, an inert gas may be co-flowed with the species used for inhibition. Inert gases may include helium, argon, xenon, or other gases that are non-reactive with the other species in the gas or surfaces of the substrate. The flow of inert gases, when used, may be between about 3.5 and about 15 slm. In some embodiments, oxygen- or hydrogen-containing species may be co-flowed with the species used for inhibition. If the species used for inhibition includes a nitrogen atom, the nitrogen atom may react with silicon-containing precursors or the silicon film to form silicon nitride. Adding oxygen- or hydrogen-containing species may inhibit conversion of silicon oxide or silicon to silicon nitride, respectively. In some embodiments, co-flows of oxygen- or hydrogen-containing species may be at least about 100 sccm, or between about 0 and about 5 slm.
In various embodiments, the plasma is an in-situ plasma, such that the plasma is formed directly above the substrate surface in the station. Example power per substrate areas for an in-situ plasma are between about 0.2122 W/cm2 and about 2.122 W/cm2 in some embodiments. For example, the power may range from about 1000 W to about 6000 W for a chamber processing four 300 mm wafers. In some embodiments, the power may be between about 2500 W and about 6000 W for four 300 mm wafers. Plasmas for ALD processes may be generated by applying a radio frequency (RF) field to a gas using two capacitively coupled plates. Ionization of the gas between plates by the RF field ignites the plasma, creating free electrons in the plasma discharge region. These electrons are accelerated by the RF field and may collide with gas phase reactant molecules. Collision of these electrons with reactant molecules may form radical species that participate in the deposition process. It will be appreciated that the RF field may be coupled via any suitable electrodes. Non-limiting examples of electrodes include process gas distribution showerheads and substrate support pedestals. It will be appreciated that plasmas for ALD processes may be formed by one or more suitable methods other than capacitive coupling of an RF field to a gas. In some embodiments, the plasma is a remote plasma, such that second reactant is ignited in a remote plasma generator upstream of the station, then delivered to the station where the substrate is housed.
Methods described herein may be used for depositing various dielectric films. While processes described herein may refer to depositing silicon-containing films, in various embodiments other dielectric films may be deposited, including carbon-containing films, aluminum-containing films, lanthanum-containing films, hafnium-containing films, strontium-containing films, zirconium-containing films, or any combinations thereof. In some embodiments the dielectric film may be a high-k dielectric film, where a high-k value refers to a high dielectric constant, e.g., a dielectric constant higher than silicon dioxide.
For depositing silicon-containing films, one or more silicon-containing precursors may be used. In some examples, silicon-containing precursors can include silanes (e.g., SiH4), polysilanes (H3Si—(SiH2)n—SiH3) where n≥1, organosilanes, halogenated silanes, aminosilanes, alkoxysilanes, and the like. Organosilanes such as methylsilane, ethylsilane, isopropylsilane, t-butylsilane, dimethylsilane, diethylsilane, di-t-butylsilane, allylsilane, sec-butylsilane, thexylsilane, isoamylsilane, t-butyldisilane, di-t-butyldisilane, and the like.
A halosilane includes at least one halogen group and may or may not include hydrogens and/or carbon groups. Examples of halosilanes are iodosilanes, bromosilanes, chlorosilanes, and fluorosilanes. Specific chlorosilanes are tetrachlorosilane, trichlorosilane, dichlorosilane, monochlorosilane, chloroallylsilane, chloromethylsilane, dichloromethylsilane, chlorodimethylsilane, chloroethylsilane, t-butylchlorosilane, di-t-butylchlorosilane, chloroisopropylsilane, chloro-sec-butylsilane, t-butyldimethylchlorosilane, thexyldimethylchlorosilane, and the like.
An aminosilane includes at least one nitrogen atom bonded to a silicon atom, but may also contain hydrogens, oxygens, halogens, and carbons. Examples of aminosilanes are mono-di-, tri- and tetra-aminosilane (H3Si(NH2), H2Si(NH2)2, HSi(NH2)3 and Si(NH2)4, respectively), as well as substituted mono-, di-, tri- and tetra-aminosilanes, for example, t-butylaminosilane, methylaminosilane, tert-butylsilanamine, bis(tert-butylamino)silane (SiH2(NHC(CH3)3)2 (BTBAS), tert-butyl silylcarbamate, SiH(CH3)—(N(CH3)2)2, SiHCl—(N(CH3)2)2, (Si(CH3)2NH)3 di-isopropylaminosilane (DIPAS), di-sec-butylaminosilane (DSBAS), SiH2[N(CH2CH3)2]2 (BDEAS) and the like. A further example of an aminosilane is trisilylamine (N(SiH3)). In some embodiments, an aminosilane that has two or more amine groups attached to the central Si atom may be used. These may result in less damage than aminosilanes having only a single amine group attached.
Further examples of silicon-containing precursors include trimethylsilane (3 MS); ethylsilane; butasilanes; pentasilanes; octasilanes; heptasilane; hexasilane; cyclobutasilane; cycloheptasilane; cyclohexasilane; cyclooctasilane; cyclopentasilane; 1,4-dioxa-2,3,5,6-tetrasilacyclohexane; diethoxymethylsilane (DEMS); diethoxysilane (DES); dimethoxymethylsilane; dimethoxysilane (DMOS); methyl-diethoxysilane (MDES); methyl-dimethoxysilane (MDMS); octamethoxydodecasiloxane (OMODDS); tert-butoxydisilane; tetramethylcyclotetrasiloxane (TMCTS); tetraoxymethylcyclotetrasiloxane (TOMCTS); triethoxysilane (TES); triethoxysiloxane (TRIES); and trimethoxysilane (TMS or TriMOS).
In some implementations silicon-containing precursors may include siloxanes or amino-group-containing siloxanes. In some embodiments, siloxanes used herein may have a formula of X(R1)aSi—O—Si(R2)bY, where a and b are integers from 0 to 2, and X and Y independently can be H or NR3R4, where each of R1, R2, R3 and R4 is hydrogen, unbranched alkyl, branched alkyl, saturated heterocyclic, unsaturated heterocyclic groups, or combinations thereof. In some embodiments, when at least one X or Y is NR3R4, R3 and R4, taken together with the atom to which each are attached, form a saturated heterocyclic compound. In some embodiments, the silicon-containing precursors are pentamethylated amino group containing siloxanes or dimethylated amino group containing siloxanes. Examples of amino group containing siloxanes include: 1-diethylamino 1,1,3,3,3,-pentamethyl disiloxane, 1-diisopropylamino-1,1,3,3,3,-pentamethyl disiloxane, 1 dipropylamino-1,1,3,3,3,-pentamethyl disiloxane, 1-di-n-butylamino-1,1,3,3,3,-pentamethyl disiloxane, 1-di-sec-butylamino-1,1,3,3,3,-pentamethyl disiloxane, 1-N-methylethylamino 1,1,3,3,3,-pentamethyl disiloxane, 1-N-methylpropylamino-1,1,3,3,3,-pentamethyl disiloxane, 1 N-methylbutylamino-1,1,3,3,3,-pentamethyl disiloxane, 1-t-butylamino-1,1,3,3,3,-pentamethyl disiloxane, 1-piperidino-1,1,3,3,3,-pentamethyl disiloxane, 1-dimethylamino-1,1-dimethyl disiloxane, 1-diethylamino-1,1-dimethyl disiloxane, 1-diisopropylamino-1,1-dimethyl disiloxane, 1-dipropylamino-1,1-dimethyl disiloxane, 1-di-n-butylamino-1,1-dimethyl disiloxane, 1-di-see butylamino-1,1-dimethyl disiloxane, 1-N-methylethylamino-1,1-dimethyl disiloxane, 1-N methylpropylamino-1,1-dimethyl disiloxane 1-N-methylbutylamino-1,1-dimethyl disiloxane, 1 piperidino-1,1-dimethyl disiloxane, 1-t-butylamino-1,1-dimethyl disiloxane, 1-dimethylamino-disiloxane, 1-diethylamino-disiloxane, 1-diisopropylamino-disiloxane, 1-dipropylamino-disiloxane, 1-di-n-butylamino-disiloxane, 1-di-sec-butylamino-disiloxane, 1-N methylethylamino-disiloxane, 1-N-methylpropylamino-disiloxane, 1-N-methylbutylamino disiloxane, 1-piperidino-disiloxane, 1-t-butylamino disiloxane, and 1-dimethylamino-1,1,5,5,5,-pentamethyl disiloxane.
Where a deposited film includes oxygen, an oxygen-containing reactant may be used. Examples of oxygen-containing reactants include, but are not limited to, oxygen (O2), ozone (O3), nitrous oxide (N2O), nitric oxide (NO), nitrogen dioxide (NO2), dinitrogen trioxide (N2O3), dinitrogen tetroxide (N2O4), dinitrogen pentoxide (N2O5), carbon monoxide (CO), carbon dioxide (CO2), sulfur oxide (SO), sulfur dioxide (SO2), oxygen-containing hydrocarbons (CxHyOz), water (H2O), formaldehyde (CH2O), carbonyl sulfide (COS), mixtures thereof, etc.
Where a deposited film includes nitrogen, a nitrogen-containing reactant may be used. A nitrogen-containing reactant contains at least one nitrogen, for example, nitrogen (N2), ammonia (NH3), hydrazine (N2H4), amines (e.g., amines bearing carbon) such as methylamine (CHSN), dimethylamine ((CH3)2NH), ethylamine (C2H5NH2), isopropylamine (C3H9N), t-butylamine (C4H11N), di-t-butylamine (CH19N), cyclopropylamine (C3H5NH2), sec-butylamine (C4H1N), cyclobutylamine (C4H7NH2), isoamylamine (C5H13N), 2-methylbutan-2-amine (C5H13N), trimethylamine (C3H9N), diisopropylamine (C6H15N), diethylisopropylamine (C7H17N), di-t-butylhydrazine (C8H20N2), as well as aromatic containing amines such as anilines, pyridines, and benzylamines. Amines may be primary, secondary, tertiary or quaternary (for example, tetraalkylammonium compounds). A nitrogen-containing reactant can contain heteroatoms other than nitrogen, for example, hydroxylamine, t-butyloxycarbonyl amine and N-t-butyl hydroxylamine are nitrogen-containing reactants. Other examples include NxOy compounds such as nitrous oxide (N2O), nitric oxide (NO), nitrogen dioxide (NO2), dinitrogen trioxide (N2O3), dinitrogen tetroxide (N2O4) and/or dinitrogen pentoxide (N2O5).
Where a deposited film includes carbon, a carbon-containing reactant may be used. Examples of carbon-containing reactants include, but are not limited to, hydrocarbons (CxHy) oxygen-containing hydrocarbons (CxHyOz), carbonyl sulfide (COS), carbon disulfide (CS2), fluorocarbons (CxFy), hydrofluorocarbons (CxHyFz), etc.
Where a deposited film includes hafnium, a hafnium-containing reactant may be used. Examples of hafnium-containing reactants include, but are not limited to, Hafnium isopropoxide isopropanol adduct (C12H28HfO4), Tetrakis(diethylamido)hafnium(IV) ([(CH2CH3)2N]4Hf), Tetrakis(ethylmethylamido)hafnium(IV) ([(CH3)(C2H5)N]4Hf), Tetrakis(dimethylamido)hafnium(IV) ([(CH3)2N]4Hf), Hafnium(IV) n-butoxide (C16H36HfO4), Hafnium(IV) tert-butoxide (Hf[OC(CH3)3]4), Dimethylbis(cyclopentadienyl)hafnium(IV) ((C5H5)2Hf(CH3)2), and Bis(trimethylsilyl)amidohafnium(IV) chloride ([[(CH3)3Si]2N]2HfCl2).
Where a deposited film includes strontium, a strontium-containing reactant may be used. Examples of strontium-containing reactants include, but are not limited to, Strontium isopropoxide (Sr(OCH(CH3)2)2), Strontium acetate ((CH3CO2)2Sr), Strontium tetramethylheptanedionate (C22H38O4Sr), and Strontium acetylacetonate hydrate ([CH3COCH═C(O—)CH3]2Sr·xH2O).
Where a deposited film includes lanthanum, a lanthanum-containing reactant may be used. Examples of lanthanum-containing reactants include, but are not limited to, Lanthanum(III) acetate hydrate (La(CH3CO2)3·xH2O), Tris(cyclopentadienyl)lanthanum(III) (La(C5H5)3), Lanthanum(III) acetylacetonate hydrate (La(C5H7O2)3·xH2O), and Tris(tetramethylcyclopentadienyl)lanthanum(III) (C27H39La).
Where a deposited film includes zirconium, a zirconium-containing reactant may be used. Example zirconium-containing reactants include, but are not limited to, bis(cyclopentadienyl)zirconium(IV) dihydride (C10H12Zr); bis(methyl-η5-cyclopentadienyl)methoxymethylzirconium (Zr(CH3C5H4)2CH3OCH3); dimethylbis(pentamethylcyclopentadienyl)zirconium(IV) (C22H36Zr); tetrakis(diethylamido)zirconium(IV) ([(C2H5)2N]4Zr); tetrakis(dimethylamido)zirconium(IV) ([(CH3N]4Zr); tetrakis(ethylmethylamido)zirconium(IV) (Zr(NCH3C2H5)4);
Where a deposited film includes aluminum, a aluminum-containing reactant may be used. Example aluminum-containing reactants include, but are not limited to, aluminum tris(2,2,6,6-tetramethyl-3,5-heptanedionate) (Al(OCC(CH3)3CHCOC(CH3)3)3); triisobutylaluminum ([(CH3)2CHCH2]3Al); trimethylaluminum ((CH3)3Al); tris(dimethylamido)aluminum(III) (Al(N(CH3)2)3), etc.
Process station 500 fluidly communicates with reactant delivery system 501 for delivering process gases to a distribution showerhead 506. Reactant delivery system 501 includes a mixing vessel 504 for blending and/or conditioning process gases for delivery to showerhead 506. One or more mixing vessel inlet valves 520 may control introduction of process gases to mixing vessel 504. Similarly, a showerhead inlet valve 505 may control introduction of process gasses to the showerhead 506. In some embodiments, an inhibitor or other gas may be directly delivered to the chamber body 502. One or more mixing vessel inlet valves 520 may control introduction of process gases to mixing vessel 504. These valves may be controlled depending on whether a process gas, inhibition gas, or carrier gas may be turned on during various operations. In some embodiments, an inhibition gas may be generated by using an inhibition liquid and vaporizing using a heated vaporizer.
As an example, the embodiment of
In some embodiments, liquid reactant may be vaporized at a liquid injector. For example, a liquid injector may inject pulses of a liquid reactant into a carrier gas stream upstream of the mixing vessel. In one scenario, a liquid injector may vaporize reactant by flashing the liquid from a higher pressure to a lower pressure. In another scenario, a liquid injector may atomize the liquid into dispersed microdroplets that are subsequently vaporized in a heated delivery pipe. It will be appreciated that smaller droplets may vaporize faster than larger droplets, reducing a delay between liquid injection and complete vaporization. Faster vaporization may reduce a length of piping downstream from vaporization point 503. In one scenario, a liquid injector may be mounted directly to mixing vessel 504. In another scenario, a liquid injector may be mounted directly to showerhead 506.
In some embodiments, a liquid flow controller (LFC) upstream of vaporization point 503 may be provided for controlling a mass flow of liquid for vaporization and delivery to process station 500. For example, the liquid flow controller may include a thermal mass flow meter (MFM) located downstream of the LFC. A plunger valve of the LFC may then be adjusted responsive to feedback control signals provided by a proportional-integral-derivative (PID) controller in electrical communication with the MFM. However, it may take one second or more to stabilize liquid flow using feedback control. This may extend a time for dosing a liquid reactant. Thus, in some embodiments, the LFC may be dynamically switched between a feedback control mode and a direct control mode. In some embodiments, the LFC may be dynamically switched from a feedback control mode to a direct control mode by disabling a sense tube of the LFC and the PID controller.
Showerhead 506 distributes process gases toward substrate 512. In the embodiment shown in
In some embodiments, a microvolume 507 is located beneath showerhead 506. Performing an ALD and/or CVD process in a microvolume rather than in the entire volume of a process station may reduce reactant exposure and sweep times, may reduce times for altering process conditions (e.g., pressure, temperature, etc.), may limit an exposure of process station robotics to process gases, etc. Example microvolume sizes include, but are not limited to, volumes between 0.1 liter and 2 liters. This microvolume also impacts productivity and throughput. While deposition rate per cycle drops, the cycle time also simultaneously reduces. In certain cases, the effect of the latter is dramatic enough to improve overall throughput of the module for a given target thickness of film.
In some embodiments, pedestal 508 may be raised or lowered to expose substrate 512 to microvolume 507 and/or to vary a volume of microvolume 507. For example, in a substrate transfer phase, pedestal 508 may be lowered to allow substrate 512 to be loaded onto pedestal 508. During a deposition process phase, pedestal 508 may be raised to position substrate 512 within microvolume 507. In some embodiments, microvolume 507 may completely enclose substrate 512 as well as a portion of pedestal 508 to create a region of high flow impedance during a deposition process.
Optionally, pedestal 508 may be lowered and/or raised during portions the deposition process to modulate process pressure, reactant concentration, etc., within microvolume 507. In one scenario where process chamber body 502 remains at a base pressure during the deposition process, lowering pedestal 508 may allow microvolume 507 to be evacuated. Example ratios of microvolume to process chamber volume include, but are not limited to, volume ratios between 1:500 and 1:10. It will be appreciated that, in some embodiments, pedestal height may be adjusted programmatically by a suitable computer controller.
In another scenario, adjusting a height of pedestal 508 may allow a plasma density to be varied during plasma activation and/or treatment cycles included in the deposition process. At the conclusion of the deposition process phase, pedestal 508 may be lowered during another substrate transfer phase to allow removal of substrate 512 from pedestal 508.
While the example microvolume variations described herein refer to a height-adjustable pedestal, it will be appreciated that, in some embodiments, a position of showerhead 506 may be adjusted relative to pedestal 508 to vary a volume of microvolume 507. Further, it will be appreciated that a vertical position of pedestal 508 and/or showerhead 506 may be varied by any suitable mechanism within the scope of the present disclosure. In some embodiments, pedestal 508 may include a rotational axis for rotating an orientation of substrate 512. It will be appreciated that, in some embodiments, one or more of these example adjustments may be performed programmatically by one or more suitable computer controllers.
Returning to the embodiment shown in
In some embodiments, the plasma may be monitored in-situ by one or more plasma monitors. In one scenario, plasma power may be monitored by one or more voltage, current sensors (e.g., VI probes). In another scenario, plasma density and/or process gas concentration may be measured by one or more optical emission spectroscopy sensors (OES). In some embodiments, one or more plasma parameters may be programmatically adjusted based on measurements from such in-situ plasma monitors. For example, an OES sensor may be used in a feedback loop for providing programmatic control of plasma power. It will be appreciated that, in some embodiments, other monitors may be used to monitor the plasma and other process characteristics. Such monitors may include, but are not limited to, infrared (IR) monitors, acoustic monitors, and pressure transducers.
In some embodiments, the plasma may be controlled via input/output control (IOC) sequencing instructions. In one example, the instructions for setting plasma conditions for a plasma process phase may be included in a corresponding plasma activation recipe phase of a deposition process recipe. In some cases, process recipe phases may be sequentially arranged, so that all instructions for a deposition process phase are executed concurrently with that process phase. In some embodiments, instructions for setting one or more plasma parameters may be included in a recipe phase preceding a plasma process phase. For example, a first recipe phase may include instructions for setting a flow rate of an inert and/or a reactant gas, instructions for setting a plasma generator to a power set point, and time delay instructions for the first recipe phase. A second, subsequent recipe phase may include instructions for enabling the plasma generator and time delay instructions for the second recipe phase. A third recipe phase may include instructions for disabling the plasma generator and time delay instructions for the third recipe phase. It will be appreciated that these recipe phases may be further subdivided and/or iterated in any suitable way within the scope of the present disclosure.
In some deposition processes, plasma strikes last on the order of a few seconds or more in duration. In certain implementations, much shorter plasma strikes may be used. These may be on the order of 10 ms to 1 second, typically, about 20 to 80 ms, with 50 ms being a specific example. Such very short RF plasma strikes require extremely quick stabilization of the plasma. To accomplish this, the plasma generator may be configured such that the impedance match is set preset to a particular voltage, while the frequency is allowed to float. Conventionally, high-frequency plasmas are generated at an RF frequency at about 13.56 MHz. In various embodiments disclosed herein, the frequency is allowed to float to a value that is different from this standard value. By permitting the frequency to float while fixing the impedance match to a predetermined voltage, the plasma can stabilize much more quickly, a result which may be important when using the very short plasma strikes associated with some types of deposition cycles.
In some embodiments, pedestal 508 may be temperature controlled via heater 510. Further, in some embodiments, pressure control for deposition process station 500 may be provided by butterfly valve 518. As shown in the embodiment of
Also mounted on the transfer module 603 may be one or more single or multi-station modules 607 capable of performing plasma or chemical (non-plasma) pre-cleans, or any other processes described in relation to the disclosed methods. The module 607 may in some cases be used for various treatments to, for example, prepare a substrate for a deposition process. The module 607 may also be designed/configured to perform various other processes such as etching or polishing. The system 600 also includes one or more wafer source modules 601, where wafers are stored before and after processing. An atmospheric robot (not shown) in the atmospheric transfer chamber 619 may first remove wafers from the source modules 601 to loadlocks 621. A wafer transfer device (generally a robot arm unit) in the transfer module 603 moves the wafers from loadlocks 621 to and among the modules mounted on the transfer module 603.
In various embodiments, a system controller 629 is employed to control process conditions during deposition. The controller 629 will typically include one or more memory devices and one or more processors. A processor may include a CPU or computer, analog and/or digital input/output connections, stepper motor controller boards, etc.
The controller 629 may control all of the activities of the deposition apparatus. The system controller 629 executes system control software, including sets of instructions for controlling the timing, mixture of gases, chamber pressure, chamber temperature, wafer temperature, radio frequency (RF) power levels, wafer chuck or pedestal position, and other parameters of a particular process. Other computer programs stored on memory devices associated with the controller 629 may be employed in some embodiments.
Typically there will be a user interface associated with the controller 629. The user interface may include a display screen, graphical software displays of the apparatus and/or process conditions, and user input devices such as pointing devices, keyboards, touch screens, microphones, etc.
System control logic may be configured in any suitable way. In general, the logic can be designed or configured in hardware and/or software. The instructions for controlling the drive circuitry may be hard coded or provided as software. The instructions may be provided by “programming.” Such programming is understood to include logic of any form, including hard coded logic in digital signal processors, application-specific integrated circuits, and other devices which have specific algorithms implemented as hardware. Programming is also understood to include software or firmware instructions that may be executed on a general purpose processor. System control software may be coded in any suitable computer readable programming language.
The computer program code for controlling the germanium-containing reducing agent pulses, hydrogen flow, and tungsten-containing precursor pulses, and other processes in a process sequence can be written in any conventional computer readable programming language: for example, assembly language, C, C++, Pascal, Fortran, or others. Compiled object code or script is executed by the processor to perform the tasks identified in the program. Also as indicated, the program code may be hard coded.
The controller parameters relate to process conditions, such as, for example, process gas composition and flow rates, temperature, pressure, cooling gas pressure, substrate temperature, and chamber wall temperature. These parameters are provided to the user in the form of a recipe, and may be entered utilizing the user interface. Signals for monitoring the process may be provided by analog and/or digital input connections of the system controller 629. The signals for controlling the process are output on the analog and digital output connections of the system 600.
The system software may be designed or configured in many different ways. For example, various chamber component subroutines or control objects may be written to control operation of the chamber components necessary to carry out the deposition processes (and other processes, in some cases) in accordance with the disclosed embodiments. Examples of programs or sections of programs for this purpose include substrate positioning code, process gas control code, pressure control code, and heater control code.
In some implementations, a controller, such as controller 550 or 629, is part of a system, which may be part of the above-described examples. Such systems can include semiconductor processing equipment, including a processing tool or tools, chamber or chambers, a platform or platforms for processing, and/or specific processing components (a wafer pedestal, a gas flow system, etc.). These systems may be integrated with electronics for controlling their operation before, during, and after processing of a semiconductor wafer or substrate. The electronics may be referred to as the “controller,” which may control various components or subparts of the system or systems. The controller 629, depending on the processing requirements and/or the type of system, may be programmed to control any of the processes disclosed herein, including the delivery of processing gases, temperature settings (e.g., heating and/or cooling), pressure settings, vacuum settings, power settings, radio frequency (RF) generator settings in some systems, RF matching circuit settings, frequency settings, flow rate settings, fluid delivery settings, positional and operation settings, wafer transfers into and out of a tool and other transfer tools and/or load locks connected to or interfaced with a specific system.
Broadly speaking, the controller may be defined as electronics having various integrated circuits, logic, memory, and/or software that receive instructions, issue instructions, control operation, enable cleaning operations, enable endpoint measurements, and the like. The integrated circuits may include chips in the form of firmware that store program instructions, digital signal processors (DSPs), chips defined as application specific integrated circuits (ASICs), and/or one or more microprocessors, or microcontrollers that execute program instructions (e.g., software). Program instructions may be instructions communicated to the controller in the form of various individual settings (or program files), defining operational parameters for carrying out a particular process on or for a semiconductor wafer or to a system. The operational parameters may, in some embodiments, be part of a recipe defined by process engineers to accomplish one or more processing steps during the fabrication of one or more layers, materials, metals, oxides, silicon, silicon dioxide, surfaces, circuits, and/or dies of a wafer.
The controller, in some implementations, may be a part of or coupled to a computer that is integrated with, coupled to the system, otherwise networked to the system, or a combination thereof. For example, the controller may be in the “cloud” or all or a part of a fab host computer system, which can allow for remote access of the wafer processing. The computer may enable remote access to the system to monitor current progress of fabrication operations, examine a history of past fabrication operations, examine trends or performance metrics from a plurality of fabrication operations, to change parameters of current processing, to set processing steps to follow a current processing, or to start a new process. In some examples, a remote computer (e.g. a server) can provide process recipes to a system over a network, which may include a local network or the Internet. The remote computer may include a user interface that enables entry or programming of parameters and/or settings, which are then communicated to the system from the remote computer. In some examples, the controller receives instructions in the form of data, which specify parameters for each of the processing steps to be performed during one or more operations. It should be understood that the parameters may be specific to the type of process to be performed and the type of tool that the controller is configured to interface with or control. Thus as described above, the controller may be distributed, such as by comprising one or more discrete controllers that are networked together and working towards a common purpose, such as the processes and controls described herein. An example of a distributed controller for such purposes would be one or more integrated circuits on a chamber in communication with one or more integrated circuits located remotely (such as at the platform level or as part of a remote computer) that combine to control a process on the chamber.
Without limitation, example systems may include a plasma etch chamber or module, a deposition chamber or module, a spin-rinse chamber or module, a metal plating chamber or module, a clean chamber or module, a bevel edge etch chamber or module, a physical vapor deposition (PVD) chamber or module, a chemical vapor deposition (CVD) chamber or module, an atomic layer deposition (ALD) chamber or module, an atomic layer etch (ALE) chamber or module, an ion implantation chamber or module, a track chamber or module, and any other semiconductor processing systems that may be associated or used in the fabrication and/or manufacturing of semiconductor wafers.
As noted above, depending on the process step or steps to be performed by the tool, the controller might communicate with one or more of other tool circuits or modules, other tool components, cluster tools, other tool interfaces, adjacent tools, neighboring tools, tools located throughout a factory, a main computer, another controller, or tools used in material transport that bring containers of wafers to and from tool locations and/or load ports in a semiconductor manufacturing factory.
It may be appreciated that a plurality of process stations may be included in a multi-station processing tool environment, such as shown in
RF subsystem 795 may generate and convey RF power to integrated circuit fabrication chamber 763 via radio frequency input ports 767. In particular embodiments, integrated circuit fabrication chamber 763 may comprise input ports in addition to radio frequency input ports 767 (additional input ports not shown in
As described above, one or more process stations may be included in a multi-station processing tool.
The depicted processing chamber 814 comprises four process stations, numbered from 1 to 4 in the embodiment shown in
In some embodiments, system controller 850 controls the activities of process tool 800. System controller 850 executes system control software 858 stored in mass storage device 854, loaded into memory device 856, and executed on processor 852. Alternatively, the control logic may be hard coded in the system controller 850. Applications Specific Integrated Circuits, Programmable Logic Devices (e.g., field-programmable gate arrays, or FPGAs) and the like may be used for these purposes. In the following discussion, wherever “software” or “code” is used, functionally comparable hard coded logic may be used in its place. System control software 858 may include instructions for controlling the timing, mixture of gases, amount of gas flow, chamber and/or station pressure, chamber and/or station temperature, substrate temperature, target power levels, RF power levels, substrate pedestal, chuck and/or susceptor position, and other parameters of a particular process performed by process tool 800. System control software 858 may be configured in any suitable way. For example, various process tool component subroutines or control objects may be written to control operation of the process tool components used to carry out various process tool processes. System control software 858 may be coded in any suitable computer readable programming language.
Although the foregoing embodiments have been described in some detail for purposes of clarity of understanding, it will be apparent that certain changes and modifications may be practiced within the scope of the appended claims. Embodiments disclosed herein may be practiced without some or all of these specific details. In other instances, well-known process operations have not been described in detail to not unnecessarily obscure the disclosed embodiments. Further, while the disclosed embodiments will be described in conjunction with specific embodiments, it will be understood that the specific embodiments are not intended to limit the disclosed embodiments. It should be noted that there are many alternative ways of implementing the processes, systems, and apparatus of the present embodiments. Accordingly, the present embodiments are to be considered as illustrative and not restrictive, and the embodiments are not to be limited to the details given herein.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US2022/081591 | 12/14/2022 | WO |
| Number | Date | Country | |
|---|---|---|---|
| 63265690 | Dec 2021 | US |
