Atomic Layer Etching Using Inhibitors

Abstract

Examples related to the use of inhibitors in atomic layer etching processes are provided. As an example, a method for performing atomic layer etching of a substrate is provided. The method includes performing a plurality of etching cycles. At least one process cycle of the plurality of etching cycles includes exposing the substrate to a modifying chemical in a modification step, exposing the substrate to an inhibiting chemical, and exposing the substrate to a volatilizing chemical in a removal step.

Description

[Background technology]

[0001] The manufacturing process of semiconductor devices may involve many steps of deposition, patterning, and removal of materials to form integrated circuits on a substrate. Various methods can be used to selectively remove material from a substrate. As an example, atomic layer etching (ALE) uses one or more process cycles to remove substrate material. In the process cycles, a modification step is used to modify the material on the film surface. A removal step then volatilizes and removes the modified film material. Highly uniform etching can be achieved with one or more ALE cycles. Summary of the Invention

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

[0003] Examples related to using inhibitor chemicals in atomic layer etching (ALE) processes are disclosed. In one example, a method for performing ALE of a substrate is provided. The method includes performing a plurality of process cycles. At least one process cycle of the plurality of etching cycles includes exposing the substrate to a modification chemical in a modification step, exposing the substrate to an inhibitor chemical, and exposing the substrate to a volatilization chemical in a removal step.

[0004] In some such embodiments, the substrate includes a feature, and exposing the substrate to a modifying chemistry includes exposing the feature to the modifying chemistry in a non-saturating regime.

[0005] In some such embodiments, exposing the substrate to the inhibitor chemical additionally or alternatively includes exposing the substrate to reactive inhibitor species generated by one or more of a remote plasma or an in situ plasma.

[0006] In some such embodiments, the method additionally or alternatively further comprises heating the substrate while introducing the inhibitor chemical.

[0007] In some such examples, exposing the substrate to an inhibiting chemical additionally or alternatively includes exposing the substrate to one or more of H2, HCl, Cl2, HBr, Br2, HI, an oxidizing chemical, or a ligand.

[0008] In some such embodiments, the oxidizing chemical additionally or alternatively comprises one or more of oxygen, ozone, hydrogen peroxide, water vapor, nitric oxide, or nitrous oxide.

[0009] In some such embodiments, exposing the substrate to a modification chemical in the modification step additionally or alternatively includes exposing the substrate to reactive species generated by a remote plasma that includes the modification chemical.

[0010] In some such examples, exposing the substrate to a volatile chemical in the volatilization step additionally or alternatively includes exposing the substrate to one of dimethylaluminum chloride, trimethylaluminum, boron trichloride, trimethylphosphine, silicon tetrachloride, titanium tetrachloride, acetylacetone, hexafluoroacetylacetone, or tin(II) acetylacetonate.

[0011] In some such embodiments, exposing the substrate to a modification chemical in the modification step additionally or alternatively includes exposing the substrate to the modification chemical in a non-saturating regime.

[0012] In some such embodiments, at least one process cycle includes a first process cycle and the plurality of process cycles additionally or alternatively includes a second process cycle that omits exposing the substrate to an inhibitor chemical.

[0013] In another embodiment, a processing tool for performing atomic layer etching (ALE) on a substrate is provided. The processing tool includes a process chamber. The processing tool further includes a substrate support disposed in the process chamber. The processing tool further includes a substrate heater disposed in the process chamber. The processing tool further includes one or more gas inlets into the processing chamber. The processing tool further includes flow control hardware configured to control gas flow through the one or more gas inlets. The processing tool further includes a controller operably coupled to the flow control hardware and the substrate heater. The controller is configured to control etching of a substrate supported by the substrate support. The controller is further configured to operate the substrate heater to heat the substrate. The controller is further configured to operate the flow control hardware to introduce a modification chemical into the process chamber in a modification step. The controller is further configured to operate the flow control hardware to introduce an inhibitor chemical into the process chamber. The controller is further configured to operate the flow control hardware to introduce a volatilization chemical into the process chamber in a removal step.

[0014] In some such embodiments, the processing tool further includes an inhibiting gas source.

[0015] In some such embodiments, the inhibiting gas source additionally or alternatively includes one or more of hydrogen gas, hydrogen chloride, chlorine gas, hydrogen bromide, bromine gas, hydrogen iodide, oxygen, ozone, hydrogen peroxide, water vapor, nitric oxide, nitrous oxide, or a ligand.

[0016] In some such embodiments, the processing tool additionally or alternatively includes a remote plasma generator, and the controller is configured to operate the remote plasma generator to generate the reactive inhibitor species.

[0017] In some such embodiments, the controller is additionally or alternatively configured to expose the substrate to the modifying chemistry in a non-saturating regime.

[0018] In some such embodiments, the controller is additionally or alternatively configured to cause a plurality of process cycles to be performed, where at least one process cycle of the plurality of process cycles is configured to omit introduction of an inhibitor chemical into the process chamber.

[0019] In another embodiment, a computer readable storage device is provided that includes instructions executable by a computing device having a processor for controlling a processing tool to operate flow control hardware of the processing tool to introduce a modifying chemical into a process chamber of the processing tool in a modification step. Further, the instructions are executable to control the processing tool to operate the flow control hardware to introduce an inhibitor chemical into the process chamber. Further, the instructions are executable to control the processing tool to operate the flow control hardware to introduce a volatile chemical into the process chamber in a removal step.

[0020] In some such examples, the executable instructions to operate the flow control hardware to introduce an inhibiting gas into the process chamber additionally or alternatively include executable instructions to operate the flow control hardware to introduce one or more of hydrogen gas, hydrogen chloride, chlorine gas, hydrogen bromide, bromine gas, hydrogen iodide, oxygen, ozone, hydrogen peroxide, water vapor, nitric oxide, nitrous oxide, or a ligand into the process chamber.

[0021] In some such embodiments, the executable instructions for operating the flow control hardware to introduce the modifying chemical in the modification step additionally or alternatively include executable instructions for operating the flow control hardware to introduce the modifying chemical into the processing chamber in a non-saturated regime.

[0022] In some such embodiments, the instructions are additionally or alternatively executable to operate flow control hardware to introduce an inhibitor chemical into the remote plasma generator. [Brief description of the drawings]

[0023] [Figure 1] FIG. 1 illustrates a block diagram of an exemplary processing tool.

[0024] [Diagram 2] FIG. 2 shows a flow diagram illustrating an exemplary method for performing an atomic layer etching (ALE) process.

[0025] [Diagram 3] FIG. 3 shows a flow diagram depicting an exemplary method of carrying out a process cycle that includes the introduction of an inhibitor chemical.

[0026] [Figure 4] FIG. 4 shows a flow diagram depicting an exemplary method of carrying out a process cycle that omits the introduction of an inhibitor chemical.

[0027] [Figure 5A] FIG. 5A illustrates a schematic of an exemplary substrate structure, showing some of its features before and after performing an ALE process. [Figure 5B] FIG. 5B illustrates a schematic of an exemplary substrate structure showing some of its features before and after performing an ALE process. [Figure 5C] FIG. 5C illustrates a schematic of an example substrate structure showing some of its features before and after performing an ALE process.

[0028] [Figure 6A] FIG. 6A illustrates a schematic of the results of etching a feature using an exemplary ALE process. [Figure 6B] FIG. 6B illustrates a schematic of the results of etching a feature using an exemplary ALE process. [Figure 6C] FIG. 6C illustrates a schematic of the results of etching a feature using an exemplary ALE process.

[0029] [Figure 7] FIG. 7 shows a flow diagram depicting an exemplary method for etching a surface in a feature.

[0030] [Figure 8] FIG. 8 illustrates a schematic of an exemplary computing device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0031] The term "aspect ratio" refers to the ratio of the depth or height of a substrate feature to the width of the substrate feature.

[0032] The term "atomic layer etching" (ALE) refers to a process in which etchable material on a substrate is removed in one or more cycles by sequentially modifying the material surface and removing the modified material species. An ALE process may involve alternating self-limiting chemical reactions that affect the surface atomic layer(s) of the substrate. One example of an ALE process involves fluorinating hafnium (Hf) using hydrogen fluoride (HF) to form hafnium fluoride, which is then converted to hafnium fluoride using dimethylaluminum chloride (DMAC) to form, for example, HfF4 or HfF. x O y Hafnia (HfO2) is etched by volatilizing it in the form of

[0033] The term "etchable material" refers to a substrate surface that can be modified and volatilized for removal via an ALE process. Examples of materials that can be etched include hafnium oxide (hafnia), silicon doped hafnia, hafnium zirconium oxide, tungsten oxide, hafnium silicate, aluminum oxide, zirconium oxide, indium oxide, silicon, silicon dioxide, gallium oxide, zinc oxide, indium gallium zinc oxide (InGaZnO), indium gallium arsenide (InGaAs), indium aluminum arsenide (InAlAs), aluminum (Al), cobalt (Co), copper (Cu), gallium (Ga), germanium (Ge), hafnium (Hf), indium (In), iron (Fe), nickel (Ni), tungsten (W), vanadium (V), zinc (Zn), zirconium (Zr), and silicon germanium (SeGe) with various Ge concentrations (e.g., 0-100% Ge).

[0034] The term "feature" refers to an indentation or protrusion on a substrate surface. Examples of features include grooves (e.g., slots), holes (e.g., vias of any suitable shape), and pillars.

[0035] The term "inhibitory chemical" refers to a chemical species that inhibits chemical etching in the ALE process. Inhibitory chemicals may inhibit etching by various mechanisms, such as slowing the reaction rate, blocking reactive sites, and / or reversing a reaction step. In various embodiments, inhibitory chemicals may include oxidizers, hydrogen-containing chemicals, and / or halogen-containing chemicals. Examples of inhibitory chemicals include hydrogen (H2), hydrogen chloride (HCl), chlorine (Cl2), hydrogen bromide (HBr), bromine (Br2), hydrogen iodide (HI), water (H2O), hydrogen peroxide (H2O2), oxygen (O2), ozone (O3), nitric oxide (NO), nitrous oxide (N2O), and ligands, including bidentate ligands. Examples of ligands include acetylacetone (ACAC) and diamines, such as ethylenediaminetetraacetic acid (EDTA), tetramethylethylenediamine (TMEDA), and 1,3-diaminopropane.

[0036] The term "intermediate structure" refers to a structure formed in a prior processing step that is modified in a subsequent processing step.

[0037] The term "modification chemical" refers to a chemical species used as part of a process cycle to chemically alter the substrate material surface. Surface modification may include fluorination, halogenation, hydrogenation, hydroxylation, oxidation, or other suitable chemical modification. In ALE, surface modification precedes removal by volatilization of the modified material species. Examples of modification chemicals include hydrogen fluoride (HF), fluorine (F2), xenon difluoride (XeF2), and nitrogen trifluoride (NF3).

[0038] The term "non-saturated regime" refers to processing conditions where chemical species do not completely saturate the surface of the substrate.

[0039] The term "process chamber" refers to an enclosure in which chemical and / or physical processes are performed on a substrate. The pressure, temperature, and atmospheric composition within the process chamber may be controllable to perform the chemical and / or physical processes.

[0040] The term "processing tool" refers to a machine that includes a process chamber and other hardware configured to perform a process on a substrate.

[0041] The term "purging" and variations thereof refer to the process of removing unwanted species from a process chamber.

[0042] The term "reactive inhibitor species" refers to radicals and other active species formed by the introduction of inhibitor chemicals into the plasma.

[0043] The term "saturation regime" refers to processing conditions under which a chemical species may saturate the surface on a substrate.

[0044] The term "substrate" refers to any object from which a layer or material can be etched.

[0045] The term "substrate support" refers to any structure for supporting a substrate in a process chamber. Examples of substrate supports include a pedestal and a chuck.

[0046] The term "uniform" and variations thereof refer to uniformity within a desired tolerance.

[0047] The term "volatile chemical" refers to a chemical that can react with the modified substrate surface to volatilize substrate material species and be removed by vacuum chamber purge and / or process chamber purge. Examples of volatile chemicals include dimethylaluminum chloride (DMAC), trimethylaluminum (TMA), boron trichloride, trimethylphosphine, silicon tetrachloride, titanium tetrachloride, acetylacetone, hexafluoroacetylacetone, and tin(II) acetylacetonate. The term "metal volatile chemical" refers to a chemical that can react with an oxidized metal to remove the metal. Examples of metal volatile chemicals include titanium tetrachloride (TiCl4), dimethylacetamide (DMAc), dimethylaluminum chloride (AlMe2Cl), acetylacetone, and acetylacetonate.

[0048] The term "3D DRAM" is an acronym for three-dimensional dynamic random-access memory.

[0049] The term "3D NAND" is an acronym for three-dimensional NOT AND memory and describes a memory architecture based on NOT AND logic gates.

[0050] The term "3D NOR" is an acronym for three-dimensional NOT OR memory and describes a memory architecture based on NOT OR logic gates.

[0051] As described above, the ALE process involves performing one or more process cycles to remove one or more layers from a substrate surface. ALE may be used to remove material from intermediate structures as part of a semiconductor manufacturing process. During the process cycle, a modification step is performed in which a modification chemical is introduced into a process chamber containing the substrate. The modification chemical reacts with one or more atomic layers of the substrate surface to form a modified surface. For example, a fluorinated surface may be formed by exposing the substrate to HF. A removal step is then performed in which a volatilizing chemical is introduced into the process chamber. The volatilizing chemical volatilizes at least a portion of the modified substrate material, thereby removing the material from the substrate surface. The volatilized material may then be removed from the process chamber. By repeating the process cycle in which the modification chemical saturates the substrate surface, a selected amount of substrate material may be removed in a highly uniform manner.

[0052] However, uniform etching of some features on a substrate can be challenging. For example, some features include relatively narrow widths and / or high aspect ratios. Diffusion of gas to the bottom of high aspect ratio features can result in a relatively slow process. As discussed above, etching with ALE is typically achieved by operating within the saturation regime of the modifying chemistry. However, performing ALE within the saturation regime on high aspect ratio features can be time consuming given that it may take a relatively long time for the modifying chemistry (as well as other process chemistries) to saturate the deeper surfaces within the feature.

[0053] Therefore, embodiments related to the use of inhibitor chemistries in ALE processes are disclosed. As described below, in some embodiments, inhibitor chemistries can be used to achieve highly uniform etching of high aspect ratio features within the non-saturation regime of the modifying chemistry.

[0054] One example of a process where uniform etching may be difficult is oxide etching in a channel hole in a 3D NAND memory fabrication process. In such a process, the sidewalls of the channel hole include alternating layers of different materials. A film of etchable material applied during a previous step may be etched via an ALE process to form a gate oxide structure. If the gate oxide thickness is not constant as a function of the depth of the channel hole, device performance may be compromised. For example, a gate oxide that is too thick may result in high switching voltages, while a gate oxide that is too thin may result in electrical shorts. Therefore, a uniform etch as a function of depth is desired to form a gate oxide with a constant thickness. However, since the channel hole may have a relatively high aspect ratio, it may take a significant amount of time to achieve such a uniform etch by operating the modification chemistry in the saturation regime. Additionally, the feature may include inwardly recessed structures and / or overhanging shelves such that the target etch plane is out of line of sight with respect to the feature opening.

[0055] Operating in the non-saturated regime and shortening the process time can cause non-uniform etching. For example, in the non-saturated regime, the surface modification chemicals may have a concentration profile in the channel hole that is depth dependent. For NAND gate oxide etching, the concentration of the modification chemical may be higher closer to the channel hole opening and lower farther from the channel hole opening. This may result in a higher etch rate in the channel hole closer to the opening and a lower etch rate deeper in the channel hole. This can result in non-uniform gate oxide thickness. Such non-uniform concentrations can also cause non-uniform film thickness in processes other than gate oxide etching.

[0056] Thus, as described in more detail below, an inhibitor chemical may be used to inhibit one or more of the modification and volatilization reactions in the ALE process. The inhibitor chemical may be deposited in a non-saturated regime, resulting in a depth-dependent concentration profile. A higher concentration of the inhibitor chemical closer to the opening of the feature may reduce the higher etch rate that occurs with a higher concentration of the modification chemical. As a result, a more uniform etch rate may be achieved even when the modification chemical is introduced in a non-saturated regime. In other embodiments, a saturated regime may be used, or a mixture of non-saturated and saturated regimes may be used in different process cycles during the ALE process.

[0057] In some embodiments, the inhibitor chemical may be introduced directly into the process chamber. In other embodiments, a remote plasma may be used to generate reactive inhibitor species from the inhibitor chemical. In such embodiments, the reactive inhibitor species may undergo surface reactions and recombine, reducing the concentration of the active species as they diffuse toward the bottom of the feature. As a result, a higher concentration of the inhibitor chemical may adsorb on surfaces within the feature closer to the feature opening than on surfaces deeper within the feature. Again, this allows for a reduction in the rate of etching caused by a higher concentration of the modifying chemical closer to the feature opening. As a result, a more uniform etch may be achieved. An exemplary ALE process is disclosed in detail below.

[0058] 1 shows a schematic diagram of an exemplary processing tool 100 for performing ALE using an inhibitor chemistry. The processing tool 100 includes a process chamber 102 and a substrate support 104 within the process chamber. The substrate support 104 is configured to support a substrate 106 disposed within the process chamber 102. The substrate support 104 may include a pedestal, a chuck, or other suitable structure. The process chamber 102 may further include a substrate heater 108.

[0059] The processing tool 100 further includes a showerhead 110, a gas inlet 112, and flow control hardware 114. In other embodiments, the processing tool may include nozzles or other devices for introducing gases into the process chamber 102 as opposed to or in addition to the showerhead. The flow control hardware is connected to a modifying chemical source 116, a volatilizing chemical source 118, an inhibiting chemical source 120, and a purge gas source 122. In some embodiments, the flow control hardware 114 is further connected to an oxidizing chemical source 124 and a metal volatilizing chemical source 126. The modifying chemical source 116 may include any suitable modifying chemical that modifies a material surface when exposed to an etchable material. Suitable modifying surfaces include fluorinated metal oxide surfaces, fluorinated boron oxide surfaces, or other surfaces that can be volatilized by the volatilizing chemical. Examples of modifying chemicals include HF, F2, XeF2, and NF3.

[0060] The volatile chemical gas source 118 includes any suitable chemical capable of reacting with the modified substrate surface to volatilize substrate material species. For example, in an embodiment in which HfO2 is etched with HF, examples of volatile chemicals include dimethylaluminum chloride (DMAC), trimethylaluminum (TMA), boron trichloride, trimethylphosphine, silicon tetrachloride, titanium tetrachloride, acetylacetone, hexafluoroacetylacetone, and tin(II) acetylacetonate.

[0061] The inhibitor chemical source 120 includes any suitable chemical species that inhibits etching in the ALE process. The inhibitor chemical inhibits etching by affecting a conversion step that precedes volatilization. The inhibitor chemical may inhibit etching by any suitable mechanism, such as slowing the reaction rate, blocking reactive sites, and / or reversing a reactive step. In some examples, the inhibitor chemical may include an oxidizer, a hydrogen-containing chemical, and / or a halogen-containing chemical. Chemical inhibitors, including oxidizers, can react with fluorinated surfaces to convert the fluorinated surfaces back to metal oxides. Hydrogen-containing chemicals can be used to hydrogenate the substrate surface and block fluorination sites. Halogen-containing chemicals (e.g., HCl, Cl2, HBr, Br2) can be used to halogenate the surface (e.g., chlorinate or brominate the surface) and block fluorination sites. In further examples, ligands can be used to block fluorination sites via chemisorption or physisorption. Blocking reactive sites slows the fluorination reaction rather than preventing the reaction entirely. In some embodiments, the inhibitor chemical may remain on the substrate for one or more additional process cycles. Examples of inhibitor chemicals include H2, HCl, Cl2, HBr, Br2, HI, H2O, H2O2, O2, O3, NO, N2O, and ligands. Examples of ligands include acetylacetone (ACAC) and diamines such as ethylenediaminetetraacetic acid (EDTA), tetramethylethylenediamine (TMEDA), and 1,3-diaminopropane.

[0062] In some embodiments, a substrate heater 108 is used to provide thermal energy to activate one or more reactions in the ALE process. In other embodiments, in addition to or as an alternative to heating the substrate, a remote plasma is generated via a remote plasma generator 130 to generate reactive inhibitor species. The remote plasma may form reactive inhibitor species from an inhibitor chemical. In such embodiments, the inhibitor chemical source 120 may be connected to the remote plasma generator 130, as well as one or more other gas sources. The remote plasma generator 130 is optional and may be omitted in some embodiments.

[0063] The purge gas source 122 may include any suitable inert gas, such as argon or nitrogen. In some embodiments, one or more additional purge gas sources may be included, each providing a different purge gas.

[0064] If included, the oxidizing chemical source 124 may include any suitable oxidizing gas. Examples include O2, O3, N2O, H2O, and H2O2.

[0065] Similarly, the metal volatilization chemical source 126 may include any suitable chemical for volatilizing the oxidized metal layer, examples include titanium tetrachloride (TiCl4), dimethylacetamide (DMAc), dimethylaluminum chloride (AlMe2Cl), acetylacetone, and acetylacetonate.

[0066] The flow control hardware 114 may be controlled to flow chemicals from the chemical sources 116, 118, 120, 122, 124, 126 through the gas inlet 112 into the process chamber 102. In some embodiments, the flow control hardware is also configured to control the flow of one or more chemicals into the remote plasma generator 130. The flow control hardware 114 may represent, in schematic form, any suitable components associated with the flow of gases into the process chamber 102 (and, in some embodiments, the remote plasma generator 130). For example, the flow control hardware 114 may include one or more mass flow controllers and / or valves controllable to place selected chemical sources in fluid communication with the gas inlet 112. As described above, the flow control hardware 114 may further be connected to the oxidizing chemical source 124 and the metal volatilizing chemical source 126. For example, in a first configuration, the flow control hardware 114 may place the modifying chemical source 116 in fluid communication with the gas inlet 112 such that the modifying chemical flows into the process chamber 102. In a second configuration, the flow control hardware 114 may place a volatilizing chemical source 118 in fluid communication with the gas inlet 112 to allow a volatilizing chemical to flow into the process chamber 102. In a third configuration, the flow control hardware 114 may place an inhibitor chemical source 120 in fluid communication with the gas inlet 112 to allow an oxidizable inhibitor chemical to flow into the process chamber 102. In a fourth configuration, the flow control hardware 114 may place a purge gas source 122 in fluid communication with the gas inlet 112 to allow a purge gas to flow into the process chamber 102. In some embodiments, in a fifth configuration, the flow control hardware 114 may place an oxidizing chemical source 124 in fluid communication with the gas inlet 112 to allow an oxidizing chemical to flow into the process chamber 102. In some embodiments, in the sixth configuration, the flow control hardware 114 may place the metal volatilization chemical source 126 in fluid communication with the gas inlet 112 to allow the metal volatilization chemical to flow into the process chamber 102.In yet another configuration, the flow control hardware 114 may place two or more such chemical sources in fluid communication with the gas inlet 112 .

[0067] The processing tool 100 further includes an exhaust system 140. The exhaust system 140 is configured to receive gases exiting the process chamber 102, including volatilized substrate species. In some embodiments, the exhaust system 140 is configured to actively remove gases from the process chamber 102 and / or apply a partial vacuum. The exhaust system 140 may include any suitable hardware, including one or more low vacuum pumps and / or one or more high vacuum pumps.

[0068] When using the optional remote plasma generator 130, the processing tool 100 may further include a radio frequency power source 142 electrically connected to the remote plasma generator 130. In other examples, the radio frequency power source 142 may perform in situ plasma processing by providing radio frequency power to the substrate support 104, the showerhead 110, or other suitable electrode structure. The processing tool 100 may further include a matching network 144 for impedance matching of the radio frequency power source 142. The radio frequency power source 142 may be configured for any suitable frequency and power. Examples of suitable frequencies include 400 kHz, 13.56 MHz, 27 MHz, 60 Mz, and 90 MHz. Examples of suitable powers include between 50 W (watts) and 50 kW of power. In some examples, the radio frequency power source 142 is configured to operate at a number of different frequencies and / or powers.

[0069] The controller 150 is operably coupled to the substrate heater 108, the flow control hardware 114, the remote plasma generator 130, the exhaust system 140, and the radio frequency power supply 142. The controller 150 may also be operably coupled to any other suitable components of the processing tool 100. The controller 150 is configured to control various functions of the processing tool 100 to perform the ALE process. For example, the controller 150 is configured to operate the substrate heater 108 to heat the substrate. The controller 130 is also configured to operate the flow control hardware 114 to flow a selected chemical or mixture of chemicals at a selected rate into the process chamber 102. The controller 150 is configured to operate the exhaust system 140 to remove gases from the process chamber 102. The controller 150 is further configured to operate the flow control hardware 114 and the exhaust system 140 to maintain a selected pressure in the process chamber 102. Additionally, the controller 150 is configured to operate the remote plasma generator 130 and / or the radio frequency power source 142 to form a remote plasma including the inhibitory chemical, as well as to control any other functions of the processing tool 100. The controller 150 may include any suitable computing system, examples of which are described below with reference to FIG.

[0070] 2 shows a flow diagram of an exemplary method 200 for etching a substrate. Method 200 may be performed using, for example, processing tool 100. Method 200 includes placing a substrate in a process chamber, at 202. In some embodiments, method 200 may include heating the substrate via a substrate heater, as shown at 203. The substrate may include a feature. Any suitable substrate may be used. Examples include semiconductor wafers. The substrate and / or the surface of the feature may include any suitable etchable material. Examples of materials that can be etched include hafnia, silicon doped hafnia, hafnium zirconium oxide, tungsten oxide, hafnium silicate, aluminum oxide, zirconium oxide, indium oxide, silicon, silicon dioxide, gallium oxide, zinc oxide, indium gallium zinc oxide (InGaZnO), indium gallium arsenide (InGaAs), indium aluminum arsenide (InAlAs), aluminum (Al), cobalt (Co), copper (Cu), gallium (Ga), germanium (Ge), hafnium (Hf), indium (In), iron (Fe), nickel (Ni), tungsten (W), vanadium (V), zinc (Zn), zirconium (Zr), and silicon germanium (SeGe) with various Ge concentrations (e.g., 0-100% Ge).

[0071] The features formed in the substrate may include any suitable intermediate structures in an integrated circuit manufacturing process. For example, the features may be formed in a 3D NAND, 3D DRAM, or 3D NOR manufacturing process.

[0072] The method 200 further includes, at 204, determining whether to perform a process cycle including an inhibitor gas or to perform a process cycle omitting the inhibitor gas. The determination may be based on the recipe of the particular process being performed. The term "first process cycle" is used herein to represent an atomic layer process cycle including the introduction of an inhibitor chemical. FIG. 3 illustrates an exemplary first process cycle. The term "second process cycle" is used herein to represent an atomic layer process cycle omitting the introduction of an inhibitor chemical. FIG. 4 illustrates an exemplary second process cycle. As described in more detail below, the ratio of the first process cycle to the second process cycle can be varied to control the degree of etch uniformity. Additionally or alternatively, the duration of exposure of the inhibitor chemical to the substrate can be varied to control the degree of etch uniformity. In some embodiments, the degree of etch uniformity may be controlled based on operating conditions or characteristics of features in the process chamber. Examples of operating conditions include temperature and pressure. Examples of feature characteristics include the aspect ratio of the feature, the depth of the feature, the material composition within the feature, the reactivity of the material within the feature with an inhibiting chemical, and whether the feature has reentrant characteristics.

[0073] 3 shows a flow diagram depicting an exemplary first process cycle 300 for etching a substrate disposed in a process chamber. The first process cycle 300 includes introducing an inhibitor chemical. The course of the first process cycle 300 can follow a previous process cycle 301, which can be the first process cycle 300 or the second process cycle 400.

[0074] In some embodiments, the first process cycle 300 may include etching a metal layer. Examples of metal layers include Al, Co, Cu, Ga, Ge, Hf, In, Fe, Ni, W, V, Zn, and Zr. For metal layers, the first process cycle 300 may include oxidizing the metal surface at 302. For example, an oxidizing chemical may be introduced into the process chamber. Examples of oxidizing chemicals include O2, O3, N2O, H2O, and H2O2. Additionally, for metal layers, the first process cycle 300 may include introducing BCl3 into the process chamber at 304. The BCl3 reacts with the oxidized metal surface to volatilize the metal species, leaving boron oxide on the surface. In other embodiments, materials other than BCl3 may be used to volatilize the oxidized metal. Examples include titanium tetrachloride (TiCl4), dimethylacetamide (DMAc), dimethylaluminum chloride (AlMe2Cl), acetylacetone, and acetylacetonate. In other embodiments that do not involve etching a metal layer, the first process cycle 300 may omit 302 and 304.

[0075] The first process cycle 300 includes introducing an inhibitor chemical to the process chamber at 304. As discussed above, the inhibitor chemical may affect one or more reaction steps prior to volatilization of substrate material species. For example, the inhibitor chemical may be selected to inhibit fluorination of the surface, to react with surface F, or to replace and / or remove F from the surface. The inhibitor chemical may include other suitable inhibitors, including oxidizers, hydrogen-containing chemicals, halogen-containing chemicals, or mixtures thereof. Examples of inhibitor chemicals include H2, HCl, Cl2, HBr, Br2, HI, H2O, H2O2, O2, O3, NO, N2O, and ligands. Examples of ligands include ACAC, and diamines such as ethylenediaminetetraacetic acid, tetramethylethylenediamine, and 1,3-diaminopropane. In some examples, HCl is used to chlorinate the substrate surface and block fluorination sites prior to introduction of the modification chemical. In some embodiments utilizing fluorine-containing modification chemistries, H2O2 or other suitable compounds may be used to oxidize and remove F from the substrate surface after fluorination but prior to the introduction of volatile chemicals.

[0076] In some embodiments, the inhibitor chemical is introduced through a showerhead or nozzle while the substrate is heated. In such embodiments, the inhibitor chemical may be introduced in a non-saturating regime, thereby non-uniformly adsorbing onto the substrate surface. For example, the inhibitor chemical deposited on a substrate feature may have a higher concentration closer to the feature opening than further from the feature opening.

[0077] In another embodiment, reactive hindering species generated in the remote plasma are introduced into the process chamber at 308. The reactive hindering species may be formed by introducing an inhibitory chemical into the remote plasma generator. As the reactive hindering species moves deeper into the feature, it may undergo a greater degree of surface reaction. This may reduce the concentration of the reactive hindering species as a function of the depth of the feature. Thus, the inhibitory effect may be greater closer to the feature opening and lesser closer to the bottom of the feature. The reactive species formed by the remote plasma may be deposited in a saturated or unsaturated regime in various embodiments.

[0078] The use of a remote plasma to deliver reactive species to the substrate may allow for the use of lower substrate temperatures, which may help avoid thermal degradation of the substrate, modifying chemicals, volatilized chemicals, and / or other species. In yet other embodiments, any other suitable energy source may be used. Additionally, in some embodiments, an in-situ plasma, such as an inductively coupled plasma (ICP), may be used. Because in-situ plasmas may have a directional kinetic energy component, a low-power in-situ plasma may be more beneficial than a high-power in-situ plasma in avoiding directional etching effects.

[0079] The first process cycle 300 further includes performing a modification step at 310, which includes introducing a modification chemical into the process chamber. In some embodiments, the modification chemical includes HF. HF can react with various surface materials to fluorinate the substrate surface layer. Other examples of modification chemicals include F2, XeF2, and NF3. Examples of substrate surface materials include hafnia, silicon doped hafnia, hafnium zirconium oxide, tungsten oxide, hafnium silicate, aluminum oxide, zirconium oxide, indium oxide, silicon, silicon dioxide, gallium oxide, zinc oxide, indium-gallium-zinc-oxide (InGaZnO), indium-gallium-arsenide (InGaAs), indium-aluminum-arsenide (InAlAs), and silicon germanium (SeGe) with various Ge concentrations (e.g., 0-100% Ge). In embodiments where 302 and 304 are performed to etch the metal layer, the modifying chemical may react with boron oxide on the substrate surface. In some embodiments, at 311, the modifying chemical is introduced into the process chamber in a non-saturated regime. Additionally or alternatively, some embodiments use a remote plasma generator to introduce reactive modifying species generated by a remote plasma. In any such embodiment, the modifying chemical may have a concentration gradient on the feature sidewall that is higher closer to the feature opening and lower further from the feature opening. The inhibiting chemical may have a similar concentration gradient. Thus, the inhibiting chemical may prevent differences in etch rate caused by the depth-dependent concentration gradient of the modifying chemical. This results in a relatively constant etch rate with depth. In some embodiments, the inhibiting chemical may be introduced after the introduction of the modifying chemical. Additionally, in some embodiments, the inhibiting chemical may be introduced after the introduction of the volatile chemical. In yet other embodiments, the inhibiting chemical is introduced together with the modifying chemical. In further embodiments, the inhibiting chemical may be introduced at any other suitable position in the process cycle.

[0080] The first process cycle 300 further includes an optional purging of the process chamber at 312. Purging of the chamber may be performed using a purge gas.

[0081] Continuing, the first process cycle 300 further includes performing a removal step including introducing a volatile chemical into the process chamber at 314. The volatile chemical reacts with the modified substrate surface to volatilize the substrate species. The volatilized species are then removed from the process chamber by purging at 316. Examples of volatile chemicals include dimethylaluminum chloride (DMAC), trimethylaluminum (TMA), boron trichloride, trimethylphosphine, silicon tetrachloride, titanium tetrachloride, acetylacetone, hexafluoroacetylacetone, and tin(II) acetylacetonate. The volatile chemical may be selected based on its effectiveness in volatilizing the substrate material species. In some embodiments, the substrate is heated via a substrate heater during processing. In some embodiments, the substrate may be heated to a temperature in the range of 100° C. to 400° C. In other embodiments, substrate temperatures outside this range may be used.

[0082] The first process cycle may be performed any suitable number of times during processing of a substrate. The first process cycle may precede a subsequent cycle 320, which may be the first process cycle 300 or the second process cycle 400.

[0083] 4 shows a flow diagram depicting an exemplary second process cycle 400 that omits the introduction of an inhibitor chemical. The course of the second process cycle 400 can follow a previous process cycle 301. The previous process cycle 301 can be the first process cycle 300 or the second process cycle 400.

[0084] In some embodiments, the second process cycle 400 may include etching a metal layer. In the case of a metal layer, the second process cycle 400 may include oxidizing the metal surface at 402. For example, an oxidizing chemical may be introduced into the process chamber. Additionally, in the case of a suitable metal layer, the second process cycle 400 may include introducing BCl3 or other suitable metal volatilizing chemical into the process chamber at 404. The BCl3 reacts with the oxidized metal surface to volatilize the metal species, leaving boron oxide on the surface. In other embodiments that do not involve etching a metal layer, the second process cycle 400 may omit 402 and 404.

[0085] The second process cycle 400 further includes performing a modification step at 410, which includes introducing a modification chemical into the process chamber. In some embodiments, the modification chemical includes HF, which reacts with the substrate to fluorinate the substrate surface layer. Other examples of modification chemicals include F2, XeF2, and NF3 as well. In some embodiments, the modification chemical is introduced into the process chamber at 411 in a non-saturating regime. In such embodiments, the modification chemical does not saturate and modifies the high aspect ratio sidewalls of the feature. Although the introduction of the inhibitor chemical is omitted in the second process cycle 400, the modification reaction at 410 may still be inhibited by an inhibitor chemical adsorbed during the previous process cycle 401 in some embodiments. The modification step may be used to modify any suitable substrate surface. Examples include those listed above in connection with the first process cycle 300.

[0086] The second process cycle 400 further includes an optional purging of the process chamber at 412. Purging the chamber may be performed with a purge gas and / or by removing gases from the process chamber via an exhaust system.

[0087] Continuing, the second process cycle 400 further includes performing a removal step that includes introducing a volatile chemical into the process chamber at 414. After modifying the substrate surface at the modification step 410, the volatile chemical reacts with the modified substrate surface to volatilize substrate material species. The volatilized species are then removed from the process chamber by purging at 416.

[0088] The second process cycle 400 may be performed zero or more times during processing of a substrate. The second process cycle 400 may precede a subsequent cycle 420, which may be a first process cycle 300 or a second process cycle 400. The second process cycle 400 may be inserted into the first process cycle 300 in any suitable order and with any suitable frequency.

[0089] Returning to Figure 2, if a decision is made to run a process cycle that includes the introduction of an inhibitory chemical, the method 200 includes performing a first process cycle, at 208. As discussed above, the first process cycle 300 of Figure 3 is an example of a first process cycle that is performed, at 208. Similarly, if a decision is made to run a process cycle without the introduction of an inhibitory chemical, at 204, the method 200 includes performing a second process cycle, at 210. As discussed above, the second process cycle 400 of Figure 4 is an example of a second process cycle that is performed, at 210.

[0090] At 212, the method 200 may perform additional process cycles, for example, according to an overall recipe for processing the substrate. If additional process cycles are to be performed, the method 200 returns to 204. The additional process cycles may result in an increased amount of material being etched from the substrate. If a target amount of substrate material has been etched away, the method 200 may proceed from 212 to 214 and end.

[0091] The relative proportion of process cycles using inhibitor chemicals and process cycles without inhibitors may vary based on factors such as the desired amount of uniformity in etching and / or the characteristics of the features. For example, an ALE process may include performing n first process cycles 300 followed by m second process cycles 400. The values ​​of n and m may be any suitable integers. These steps may be repeated any suitable number of times. In such an embodiment, the proportion P of process cycles that include introduction of inhibitor chemicals may be determined by P=n / (n+m). In some embodiments, n and m may vary during processing of a substrate.

[0092] FIG. 5A illustrates a schematic of an intermediate structure 500. The intermediate structure may represent any suitable structure formed at an intermediate stage in an integrated circuit manufacturing process. The intermediate structure 500 includes a feature 502 in a substrate 504. The substrate 504 includes a layer of an etchable material 506. The etchable material 506 may include a metal, a metal oxide, silicon, silicon oxide, or other suitable substrate material. The feature 502 may have a relatively high aspect ratio. For example, the feature 502 may have an aspect ratio in the range of 20:1 to 100:1 in some embodiments. In other embodiments, the feature may have an aspect ratio outside of this example range. It will be understood that the feature 502 and other substrate features illustrated herein may not be drawn to scale.

[0093] Feature 502 includes a low aspect ratio sidewall surface 510 relatively close to the opening of feature 511. Feature 502 further includes a high aspect ratio sidewall surface 512 relatively close to the bottom of feature 513.

[0094] In some embodiments, the substrate 504 may include a 3D NAND structure. Such an exemplary structure is shown in cutaway schematic diagrams in pre-etch form at 520 in FIG. 5B and in post-ALE form at 522 in FIG. 5C. As shown at 520, the 3D NAND structure includes alternating silicon oxide layers 524 and silicon nitride layers 526. In other embodiments, the 3D integrated circuit structure may include alternating oxide / polysilicon layers, or other suitable structures.

[0095] As shown at 520, the feature 502 includes a sidewall that includes a layer of etchable material 506. In some embodiments, the etchable material 506 includes hafnia.

[0096] The post-etch view of FIG. 5C shows the 3D NAND structure after performing the ALE process. Portions of the hafnia have been removed, leaving other portions that will form the gate oxide 530 of the transistor. In other embodiments, the etchable material 506 may include any suitable material for use in a 3D NAND structure. As shown in FIG. 5C, the gate oxide 530 is disposed under an overhanging oxide layer in a non-line-of-sight position within the feature 502.

[0097] As mentioned above, uniformly etching material from within high aspect ratio features can be difficult. For example, when performing a modification step on a substrate containing high aspect ratio features, the modification chemistry may slowly saturate the bottom of the feature. Full saturation of the modification chemistry (or volatile chemistry) within the feature may take a relatively long time, which may slow down the overall substrate processing. On the other hand, performing ALE in a non-saturating regime without the use of an inhibitor chemistry may result in more non-uniform etching of the high aspect ratio features. As a result, the gate oxide thickness may be inconsistent, some gates require a high turn-on voltage, and others may present a risk of shorting.

[0098] Thus, the use of such inhibitor chemistries may more effectively facilitate a reasonably uniform etch of the feature 502. The term "reasonably uniform" refers to uniformity within an acceptable range. Figures 6A-6C provide a schematic comparison of the etching of the intermediate structure 500 using three different exemplary etch processes. The time axes in Figures 6A-6C are qualitative and may not represent a quantitative difference between process times.

[0099] 6A illustrates performing ALE in the saturation regime of the modifying chemistry and omits the introduction of an inhibiting chemistry. Process 600 results in a relatively uniform etch of etchable material 506 in feature 502. However, process 600 is relatively slow and takes a longer time to obtain intermediate structure 602.

[0100] Process 610 of FIG. 6B illustrates performing ALE in a non-saturated regime. Additionally, process 610 omits the introduction of an inhibitor chemical. Due to the slower etch rate at the high aspect ratio sidewall surface, etchable material 506 is not etched uniformly. As shown at 612, etchable material 506 remains relatively thick at the high aspect ratio sidewall surface 512. A relatively thick layer of etchable material 506 may make further device processing difficult and / or cause operational problems in the integrated circuit being fabricated. For example, even if etchable material 506 is etched to an appropriate thickness at 510, the thickness at 512 may be too thick. Similarly, even if etchable material 506 is etched to an appropriate thickness at 512, the thickness at 510 may be too thin, as discussed above.

[0101] Next, process 620 in Figure 6C illustrates performing ALE including the introduction of an inhibitor chemical. Process 620 may be performed in a non-saturated regime of the modifying chemical. Thus, process 620 may be completed in a relatively short amount of time as compared to process 600. As shown at 622, the etchable material 506 in feature 502 is etched relatively uniformly.

[0102] As discussed above, the ratio of process cycles that include the introduction of an inhibitor to process cycles that omit the inhibitor may be selected to etch with a desired degree of uniformity. Additionally or alternatively, the duration of exposure of the inhibitor chemical to the substrate may be selected to achieve a desired degree of etch uniformity. The ratio and / or duration of exposure may be selected based on any suitable factors, such as the aspect ratio of the feature, the depth of the feature, the etchable material within the feature, whether the feature has an inwardly recessed feature, and / or other factors.

[0103] 7 shows a flow diagram of an exemplary method 700 for performing an ALE process. At 702, the method includes performing at least one process cycle on a substrate. In some embodiments, multiple process cycles are performed. The first process cycle 300 and the second process cycle 400 are examples of process cycles. In some embodiments, at 704, the substrate includes a feature. In some embodiments, the feature includes a relatively high aspect ratio, such as in the range of 50:1 to 70:1, at 706. In other embodiments, the feature may include an aspect ratio outside of this range.

[0104] Continuing with the method 700, performing the process cycle 702 may include performing a metal etch at 708. In such an embodiment, performing a metal etch at 710 includes oxidizing the surface of the metal layer. In such an embodiment, performing a metal etch further includes exposing the oxidized metal surface to a metal volatilization chemical at 712. Examples include BCl3, TiCl4, dimethylacetamide, dimethylaluminum chloride, acetylacetone, and acetylacetonate. Such compounds may be used to volatilize the oxidized metal species and form boron oxide at the surface. Suitable metals include Hf, W, Al, Zr, In, and Ga.

[0105] In some embodiments, method 700 may omit performing a metal etch at 708, for example, when etching oxides or other materials. Examples of substrate materials that may be etched via the disclosed ALE include hafnia, silicon-doped hafnia, hafnium zirconium oxide, tungsten oxide, hafnium silicate, aluminum oxide, zirconium oxide, indium oxide, silicon, silicon dioxide, gallium oxide, zinc oxide, indium-gallium-zinc-oxide (InGaZnO), indium-gallium-arsenide (InGaAs), indium-aluminum-arsenide (InAlAs), and silicon germanium (SeGe) with various Ge concentrations (e.g., 0-100% Ge). In embodiments where 710 and 712 are performed to etch a metal layer, the surface may include boron oxide and / or other boron-containing compounds.

[0106] At 714, the method 700 further includes performing a modification step. The modification step includes exposing the substrate to a modification chemical. In some embodiments, the modification chemical includes fluorine. Examples of such modification chemicals include HF, NF3, XeF2, and F2. In such embodiments, the method 700 includes fluorinating the substrate at 716. In some embodiments, when performing metal etching, fluorinating the substrate at 716 includes fluorinating the boron oxide surface formed at 712. In some embodiments, at 718, the modification chemical is exposed to the substrate in a non-saturating regime.

[0107] Continuing, at 720, the method further includes exposing the substrate to an inhibitory chemical. In some embodiments, at 722, the method includes introducing reactive inhibitory species generated by the remote plasma into the process chamber. Alternatively or additionally, in some embodiments, at 724, the inhibitory chemical may be introduced directly into the process chamber in a non-saturated regime. In some embodiments, at 726, the substrate is exposed to the inhibitory chemical prior to exposing the substrate to the modifying chemical. In some embodiments, at 728, the substrate is exposed to the inhibitory chemical after exposing the substrate to the modifying chemical. In some embodiments, the substrate is exposed to the inhibitory chemical both before and after the modifying chemical. In some embodiments, the inhibitory chemical is introduced into the process chamber together with the modifying chemical. Additionally, in some embodiments, the inhibitory chemical is introduced into the process chamber after introduction of the volatilizing chemical. In some examples, the inhibitor chemical includes one or more of H2, HCl, Cl2, HBr, Br2, HI, H2O, H2O2, O2, O3, NO, N2O, and ligands, including bidentate ligands.

[0108] Method 700 may optionally include performing one or more purges after 714 and / or after 720.

[0109] At 732, the method 700 includes performing a removing step. The removing step includes exposing the substrate to a volatile chemical. In some embodiments, the volatile chemical includes one of dimethylaluminum chloride (DMAC), trimethylaluminum (TMA), boron trichloride, trimethylphosphine, silicon tetrachloride, titanium tetrachloride, acetylacetone, hexafluoroacetylacetonate, or tin(II) acetylacetonate. Then, at 734, the removing step further includes purging the process chamber to remove the substrate species that were volatilized at 732.

[0110] Method 700 may further include performing one or more subsequent process cycles at 736. In some embodiments, the subsequent cycle includes a second process cycle and omits exposing the substrate to an inhibitor at 738. In some embodiments, the subsequent cycle includes a first process cycle and includes exposing the substrate to an inhibitor chemical at 740.

[0111] Thus, embodiments disclosed herein may provide efficient, uniform etching of substrates including high aspect ratio features. Although disclosed in the context of features having relatively high aspect ratios, embodiments of the present disclosure may be used to etch any suitable substrate including any suitable features. For example, embodiments of the present disclosure may be used to etch non-line-of-sight substrate surfaces, such as sidewalls in features having inwardly recessed structures, under overhanging shelves in 3D NAND structures, pillar sidewalls, or around nanowires in gate-all-around (GAA) structures.

[0112] In some embodiments, the methods and processes described herein may be coupled to a computing system of one or more computing devices. In particular, such methods and processes may be implemented as a computer application program or service, an application programming interface (API), a library, and / or other computer program product.

[0113] 8 illustrates a schematic of a non-limiting embodiment of a computing system 800 capable of performing one or more of the methods and processes described above. The computing system 800 is illustrated in simplified form. The computing system 800 may take the form of one or more personal computers, workstations, computers integrated with wafer processing tools, and / or network-accessible server computers.

[0114] Computing system 800 includes a logic machine 802 and a memory machine 804. Computing system 800 may optionally include a display subsystem 806, an input subsystem 808, a communication subsystem 810, and / or other components not shown in Figure 8. Controller 150 is an example of a computing system 800.

[0115] The logical machine 802 includes one or more physical devices configured to execute instructions. For example, the logical machine may be configured to execute instructions that are part of one or more applications, services, programs, routines, libraries, objects, components, data structures, or other logical entities. Such instructions may be implemented to perform tasks, implement data types, transform the state of one or more components, achieve a technical effect, or otherwise arrive at a desired result.

[0116] A logical machine may include one or more processors configured to execute software instructions. Additionally or alternatively, a logical machine may include one or more hardware or firmware logical machines configured to execute hardware or firmware instructions. The processors of the logical machine may be single-core or multi-core, and the instructions executed thereon may be configured for sequential, parallel, and / or distributed processing. Individual components of the logical machine may optionally be distributed among two or more separate devices, which may be remotely located and / or configured for cooperative processing. Aspects of the logical machine may be virtualized and executed by remotely accessible, networked computing devices configured in a cloud computing configuration.

[0117] The storage machine 804 includes one or more physical devices configured to hold instructions 812 executable by a logical machine to perform the methods and processes described herein. When such methods and processes are implemented, the state of the storage machine 804 may be transformed, for example, to hold different data.

[0118] The storage machine 804 may include removable and / or embedded devices. The storage machine 804 may include optical memory (e.g., CD, DVD, HD-DVD, Blu-ray disk, etc.), semiconductor memory (e.g., RAM, EPROM, EEPROM, etc.), and / or magnetic memory (e.g., hard disk drive, floppy disk drive, tape drive, MRAM, etc.), etc. The storage machine 804 may include volatile, non-volatile, dynamic, static, read / write, read-only, random access, sequential access, location addressable, file addressable, and / or content addressable devices.

[0119] It is to be understood that the storage machine 804 includes one or more physical devices, however, aspects of the instructions described herein may alternatively be propagated by a communication medium (e.g., electromagnetic signals, optical signals, etc.) that is not retained for a finite duration by a physical device.

[0120] Aspects of the logic machine 802 and the storage machine 804 may be embodied in one or more hardware logic components. Such hardware logic components may include, for example, field programmable gate arrays (FPGAs), program and application specific integrated circuits (PASICs / ASICs), program and application specific standard products (PSSPs / ASSPs), systems on a chip (SOCs), and complex programmable logic devices (CPLDs).

[0121] If included, the display subsystem 806 may be used to present a visual representation of the data maintained by the storage machine 804. This visual representation may take the form of a graphical user interface (GUI). As the methods and processes described herein modify the data maintained by the storage machine and thus transform the state of the storage machine, the state of the display subsystem 806 may likewise be transformed to visually represent the changes in the underlying data. The display subsystem 806 may include one or more display devices utilizing virtually any type of technology. Such display devices may be combined with the logic machine 802 and / or the storage machine 804 in a shared housing, or such display devices may be peripheral display devices.

[0122] If included, the input subsystem 808 may include or interface with one or more user input devices, such as a keyboard, mouse, or touch screen. In some embodiments, the input subsystem may include or interface with selected natural user input (NUI) components. Such components may be integrated or peripheral, and translation and / or processing of input actions may be handled on-board or off-board. Exemplary NUI components may include microphones for speech and / or voice recognition, and infrared, color, stereo, and / or depth cameras for machine vision and / or gesture recognition.

[0123] If included, the communications subsystem 810 may be configured to communicatively couple the computing system 800 to one or more other computing devices. The communications subsystem 810 may include wired and / or wireless communications devices compatible with one or more different communications protocols. As a non-limiting example, the communications subsystem may be configured for communication over a wireless telephone network, or a wired or wireless local or wide area network. In some embodiments, the communications subsystem may enable the computing system 800 to send and / or receive messages to and / or from other devices over a network, such as the Internet.

[0124] It will be understood that the configurations and / or approaches described herein are exemplary in nature, and that these specific embodiments or examples are not to be considered in a limiting sense, as numerous variations are possible. A particular routine or method described herein may represent one or more of any number of processing strategies. As such, the various operations shown and / or described may be performed in the order shown and / or described, in other orders, in parallel, or omitted. Similarly, the order of the processes described above may be changed.

[0125] The subject matter of the present disclosure includes all novel and non-obvious combinations and subcombinations of the various process, system and configurations, and other features, functions, operations, and / or attributes disclosed herein, and all equivalents thereof.

Claims

1. 1. A method of performing atomic layer etching of a substrate, comprising the steps of: performing a plurality of process cycles, at least one of the plurality of process cycles comprising: exposing the substrate to a modification chemical in a modification step; exposing the substrate to an inhibitory chemical; exposing the substrate to a volatile chemical in a removing step; A method comprising:

2. 2. The method of claim 1 , The method, wherein the substrate includes a feature, and exposing the substrate to the modifying chemistry comprises exposing the feature to the modifying chemistry in a non-saturating regime.

3. 2. The method of claim 1 , The method, wherein exposing the substrate to the inhibitory chemical comprises exposing the substrate to reactive inhibitory species generated by one or more of a remote plasma or an in situ plasma.

4. 2. The method of claim 1 , The method further comprising heating the substrate while introducing the inhibitor chemical.

5. 2. The method of claim 1 , Exposing the substrate to an inhibitory chemical may convert the substrate into H 2 , HCl, Cl 2 , HBr, Br 2 , HI, an oxidizing chemical, or a ligand.

6. 6. The method of claim 5, The oxidizing chemical is H 2 O, H 2 O 2 , O 2 , O 3 , NO, and N 2 O.

7. 2. The method of claim 1 , The method, wherein exposing the substrate to a modifying chemical comprises exposing the substrate to reactive species generated by a remote plasma that includes the modifying chemical.

8. 2. The method of claim 1 , 13. The method of claim 12, wherein exposing the substrate to a volatile chemical comprises exposing the substrate to one or more of dimethylaluminum chloride, trimethylaluminum, boron trichloride, trimethylphosphine, silicon tetrachloride, titanium tetrachloride, acetylacetone, hexafluoroacetylacetone, or tin(II) acetylacetonate.

9. 2. The method of claim 1 , A method, wherein exposing the substrate to the modification chemical in the modifying step comprises exposing the substrate to the modification chemical in a non-saturating regime.

10. 2. The method of claim 1 , The method, wherein the at least one process cycle comprises a first process cycle, and the plurality of process cycles further comprises a second process cycle that omits exposing the substrate to the inhibitory chemical.

11. 1. A processing tool for performing atomic layer etching on a substrate, comprising: A process chamber; a substrate support disposed within the process chamber; a substrate heater disposed within the process chamber; one or more gas inlets into the process chamber; flow control hardware configured to control gas flow through the one or more gas inlets; a controller operably coupled to the flow control hardware and the substrate heater, the controller being configured to control etching of a substrate supported by the substrate support; The controller comprises: operating the substrate heater to heat the substrate; operating the flow control hardware to introduce a modification chemical into the process chamber in a modification step; operating the flow control hardware to introduce an inhibitor chemical into the process chamber; A processing tool configured to operate the flow control hardware to introduce a volatile chemical into the process chamber in a removal step.

12. A processing tool according to claim 11, The processing tool further comprises an inhibiting gas source.

13. 13. A processing tool according to claim 12, comprising: The process tool, wherein the inhibiting gas source comprises one or more of hydrogen gas, hydrogen chloride, chlorine gas, hydrogen bromide, bromine gas, hydrogen iodide, oxygen, ozone, hydrogen peroxide, water vapor, nitric oxide, nitrous oxide, or a ligand.

14. A processing tool according to claim 11, The process tool, further comprising a remote plasma generator, the controller configured to operate the remote plasma generator to generate a reactive inhibitor species.

15. A processing tool according to claim 11, The controller is configured to expose the substrate to the modifying chemistry in a non-saturating regime.

16. A processing tool according to claim 11, The processing tool, wherein the controller is configured to perform a plurality of process cycles, at least one process cycle of the plurality of process cycles omitting introduction of the inhibitor chemical into the process chamber.

17. 1. A computer readable storage device, comprising: a process step of modifying the flow of the processing tool into a process chamber of the processing tool; Operate the flow control hardware to introduce an inhibiting gas into the process chamber; A computer readable storage device comprising instructions for operating the flow control hardware to control the processing tool to introduce a volatile chemical into the process chamber in a removal step.

18. 20. The computer readable storage device of claim 17, A computer-readable storage device, wherein the instructions executable to operate the flow control hardware to introduce an inhibiting gas into the process chamber comprise instructions executable to operate the flow control hardware to introduce one or more of hydrogen gas, hydrogen chloride, chlorine gas, hydrogen bromide, bromine gas, hydrogen iodide, oxygen, ozone, hydrogen peroxide, water vapor, nitric oxide, nitrous oxide, or a ligand into the process chamber.

19. 20. The computer readable storage device of claim 17, A computer-readable storage device, wherein the instructions executable to operate the flow control hardware to introduce the modifying chemical in the modifying step comprise instructions executable to operate the flow control hardware to introduce the modifying chemical into the process chamber in a non-saturated regime.

20. 20. The computer readable storage device of claim 17, A computer readable storage device, the instructions being executable to operate the flow control hardware to introduce the inhibitor chemical into a remote plasma generator.

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