Advanced self-aligning multi-patterning using tin oxide

Abstract

A method and apparatus for implementing a spacer-on-spacer multi-patterning scheme using a removable first spacer material and a complementary second spacer material, in certain embodiments, involves using a tin oxide spacer material as one of the spacer materials in the spacer-on-spacer self-aligned multi-patterning.

Description

[Technical Field]

[0001] [References] A PCT application is filed concurrently with this Application as part of this Application. Each application identified in the concurrently filed PCT application, for which this Application claims interest or priority, is incorporated herein by reference in its entirety for all purposes. [Background technology]

[0002] The assembly of advanced integrated circuits in the mass production of semiconductors often involves patterning small features. Various patterning techniques may be used to form structures with smaller pitches. Such structures can be assembled using multi-patterning processes such as double patterning and quad patterning, but this increases the number of deposition and etching operations, resulting in higher production costs for such structures.

[0003] The background and content descriptions included herein are provided solely for the purpose of providing a general overview of the contents of this disclosure. The research by the inventors named herein, to the extent described in this background section, is not considered prior art, either explicitly or implicitly, to compete with this disclosure, as is the case with any description that would not be considered prior art at the time of filing. [Overview of the project]

[0004] One embodiment includes a method for processing a substrate, the method comprising performing spacer-on-spacer patterning on a semiconductor substrate using at least one spacer containing tin oxide.

[0005] In various embodiments, spacer-on-spacer patterning includes depositing a first conformal spacer material on a patterned core material, forming a first spacer containing the first conformal spacer material by selectively etching the patterned core material, depositing a second conformal spacer material on the first spacer, forming a second spacer containing the second conformal spacer material by selectively etching the first spacer, and etching a target layer using the second spacer as a mask, wherein the first conformal spacer material contains tin oxide or the second conformal spacer material contains tin oxide.

[0006] In some embodiments, spacer-on-spacer patterning is performed to form features with a pitch of less than approximately 40 nm.

[0007] In some embodiments, tin oxide is deposited using tin halides, organometallic tin-containing compounds, chlorinated organometallic tin-containing compounds, and combinations thereof.

[0008] In various embodiments, tin oxide is deposited using one or more tin-containing precursors such as: tetrakis(dimethylamino)tin; tetrakis(ethylmethylamino)tin; N 2 ,N 3 -di-tert-butyl-butane-2,3-diaminotin(II); and 1,3-bis(1,1-dimethylethyl)-4,5-dimethyl-(4R,5R)-1,3,2-diazastannoridine-2-iridine.

[0009] In some embodiments, the tin-containing precursor is tetrakis(dimethylamino)tin, and tin oxide is formed by exposing a semiconductor substrate to the tin-containing precursor and an oxygen-containing precursor containing oxygen.

[0010] In various embodiments, tin oxide is provided by at least one of the following processes: chemical vapor deposition, atomic layer deposition, or a combination thereof.

[0011] In various embodiments, tin oxide is provided using plasma-excited atomic layer deposition (PEALD).

[0012] In various embodiments, tin oxide is deposited using one or more tin-containing precursors such as: tetrakis(dimethylamino)tin; tetrakis(ethylmethylamino)tin; N 2 ,N 3 -Di-tert-butyl-butane-2,3-diamino-tin(II); 1,3-bis(1,1-dimethylethyl)-4,5-dimethyl-(4R,5R)-1,3,2-diazastannoridine-2-iride; stannous fluoride (SnF2); tin(IV) chloride (SnCl4); tin(IV) bromide (SnBr4), tin hydride (SnH4); tin(II)(1,3-bis(1,1-dimethylethyl)-4,5-dimethyl-(4R,5R)-1,3,2-diazastannoridine-2-ylidene); tetraethyltin (SnEt4); tetramethyltin (SnM e4), dibutyltin diacetate (Bu2Sn(OAc)2); (dimethylamino)trimethyltin(IV) (Me3Sn(NMe2)); tetrakis(diethylamide)tin(IV) (Sn(NEt2)4); trimethyltin chloride; dimethyltin dichloride; methyltin trichloride; bis[bis(trimethylsilyl)amino]tin(II); hexaphenyldisin(IV); tin(II) acetylacetonate; trimethyl(phenylethynyl)tin; dibutyldiphenyltin; tetraallylutin; tetravinyltin; and hydrogenated tricyclohexyltin.

[0013] In some embodiments, tin oxide is deposited using an oxygen-containing reagent such as one or more of oxygen gas, oxygen plasma, water, ozone, hydrogen peroxide, and nitrous oxide.

[0014] In various embodiments, the first conformal spacer material includes tin oxide, and the second conformal spacer material includes any one or more of titanium oxide, silicon oxide, silicon nitride, hafnium oxide, and lead oxide.

[0015] In various embodiments, the first conformal spacer material is any one or more of titanium oxide, silicon oxide, silicon nitride, and lead oxide, and the second conformal spacer material includes tin.

[0016] In various embodiments, the first conformal spacer material includes tin oxide, and the first spacer is selectively etched by being removed using hydrogen gas.

[0017] Another aspect includes a method for processing a substrate, the method including conformally depositing a removable material over a core material, forming a spacer including the removable material by selectively removing horizontal regions of the removable material and removing the core material, and depositing a complementary material over the spacer including the removable material, such that the removable material is selectively etchable relative to the complementary material.

[0018] In various embodiments, the removable material includes tin oxide, and the complementary material is any one or more of titanium oxide, silicon oxide, silicon nitride, hafnium oxide, and lead oxide.

[0019] In various embodiments, the removable material is any one or more of titanium oxide, silicon oxide, silicon nitride, and lead oxide, and the complementary material includes tin oxide.

[0020] In some embodiments, the method includes removing the spacer including the removable material using hydrogen gas.

[0021] In various embodiments, the removable material includes tin oxide deposited using one or more of the following tin-containing precursors: tetrakis(dimethylamino)tin; tetrakis(ethylmethylamino)tin; N 2 ,N 3 -di-tert-butyl-butane-2,3-diamino-tin(II); 1,3-bis(1,1-dimethylethyl)-4,5-dimethyl-(4R,5R)-1,3,2-diazastannoridine-2-iride; stannous fluoride (SnF2); tin(IV) chloride (SnCl4); tin(IV) bromide (SnBr4); tin hydride (SnH4); tin(II)(1,3-bis(1,1-dimethylethyl)-4,5-dimethyl-(4R,5R)-1,3,2-diazastannoridine-2-ylidene); tetraethyltin (SnEt4); tetramethyltin (SnM e4); dibutyltin diacetate (Bu2Sn(OAc)2); (dimethylamino)trimethyltin(IV) (Me3Sn(NMe2)); tetrakis(diethylamide)tin(IV) (Sn(NEt2)4); trimethyltin chloride; dimethyltin dichloride; methyltin trichloride; bis[bis(trimethylsilyl)amino]tin(II); hexaphenyldisin(IV); tin(II) acetylacetonate; trimethyl(phenylethynyl)tin; dibutyldiphenyltin; tetraallylutin; tetravinyltin; and hydrogenated tricyclohexyltin.

[0022] In various embodiments, the tin-containing precursor is tetrakis(dimethylamino)tin, and a removable material is deposited by introducing the tin-containing precursor and an oxygen-containing precursor containing oxygen.

[0023] In some embodiments, at least one of the removable material and the complementary material is tin oxide deposited by a chemical vapor deposition process, atomic layer deposition, or a combination thereof.

[0024] In various embodiments, one of the removable material and the complementary material is tin oxide deposited using plasma-excited atomic layer deposition (PEALD).

[0025] In various embodiments, the removable material includes tin oxide deposited using an oxygen-containing reagent such as oxygen gas, oxygen plasma, water, ozone, hydrogen peroxide, and nitrous oxide.

[0026] Another embodiment includes a method for processing a substrate, the method comprising: providing a substrate having a patterned core material; conformally depositing a first material selected from the group consisting of silicon oxide, silicon nitride, titanium oxide, and lead oxide onto the sidewalls of the patterned core material; forming a first spacer by selectively removing the patterned core material; conformally depositing a tin oxide spacer material onto the sidewalls of the first spacer; and forming a second spacer containing the tin oxide spacer material by selectively removing the first spacer.

[0027] In various embodiments, the tin oxide spacer material is deposited using one or more tin-containing precursors such as: tetrakis(dimethylamino)tin; tetrakis(ethylmethylamino)tin; N 2 ,N 3-di-tert-butyl-butane-2,3-diamino-tin(II); 1,3-bis(1,1-dimethylethyl)-4,5-dimethyl-(4R,5R)-1,3,2-diazastannoridine-2-iride; stannous fluoride (SnF2); tin(IV) chloride (SnCl4); tin(IV) bromide (SnBr4); tin hydride (SnH4); tin(II)(1,3-bis(1,1-dimethylethyl)-4,5-dimethyl-(4R,5R)-1,3,2-diazastannoridine-2-ylidene); tetraethyltin (SnEt4); tetramethyltin (SnM e4); dibutyltin diacetate (Bu2Sn(OAc)2), (dimethylamino)trimethyltin(IV) (Me3Sn(NMe2)); tetrakis(diethylamide)tin(IV) (Sn(NEt2)4); trimethyltin chloride; dimethyltin dichloride; methyltin trichloride; bis[bis(trimethylsilyl)amino]tin(II); hexaphenyldisin(IV), tin(II) acetylacetonate; trimethyl(phenylethynyl)tin; dibutyldiphenyltin; tetraallylutin; tetravinyltin; and hydrogenated tricyclohexyltin.

[0028] In various embodiments, the tin oxide spacer material is deposited using an oxygen-containing reagent such as one or more of the following: oxygen gas, oxygen plasma, water, ozone, hydrogen peroxide, and nitrous oxide.

[0029] In some embodiments, the patterned core material contains silicon or carbon.

[0030] In some embodiments, the first material is one or more of titanium oxide, silicon oxide, silicon nitride, and lead oxide.

[0031] In various embodiments, the first material is selectively removed using a wet etching chemical reaction.

[0032] In various embodiments, the tin-containing precursor is tetrakis(dimethylamino)tin, and the tin oxide spacer material is deposited by exposing a substrate to the tin-containing precursor and an oxygen-containing precursor containing oxygen.

[0033] In some embodiments, the tin oxide spacer material is deposited using at least one of a chemical vapor deposition process, atomic layer deposition, or any combination thereof.

[0034] In various embodiments, the tin oxide spacer material is deposited using plasma-excited atomic layer deposition (PEALD).

[0035] Another aspect includes a method for processing a substrate, the method comprising providing a substrate having a patterned core material, conformally depositing a tin oxide material on the sidewalls of the core material from above the patterned core material, forming a tin oxide spacer by selectively removing the patterned core material, depositing a second spacer material on the sidewalls of the tin oxide spacer from above the tin oxide spacer, and forming a second spacer by selectively removing the tin oxide spacer.

[0036] In various embodiments, the second spacer material is any one or more of titanium oxide, silicon oxide, silicon nitride, hafnium oxide, and lead oxide.

[0037] In some embodiments, the tin oxide spacer is selectively removed by being removed using hydrogen gas.

[0038] In some embodiments, the tin oxide material is deposited using one or more of the following tin-containing precursors: tetrakis(dimethylamino)tin; tetrakis(ethylmethylamino)tin; N 2 ,N 3-di-tert-butyl-butane-2,3-diamino-tin(II); 1,3-bis(1,1-dimethylethyl)-4,5-dimethyl-(4R,5R)-1,3,2-diazastannoridine-2-iride; stannous fluoride (SnF2); tin(IV) chloride (SnCl4); tin(IV) bromide (SnBr4); tin hydride (SnH4); tin(II)(1,3-bis(1,1-dimethylethyl)-4,5-dimethyl-(4R,5R)-1,3,2-diazastannoridine-2-ylidene); tetraethyltin (SnEt4); tetramethyltin (SnM e4); dibutyltin diacetate (Bu2Sn(OAc)2); (dimethylamino)trimethyltin(IV) (Me3Sn(NMe2)); tetrakis(diethylamide)tin(IV) (Sn(NEt2)4); trimethyltin chloride; dimethyltin dichloride; methyltin trichloride; bis[bis(trimethylsilyl)amino]tin(II); hexaphenyldisin(IV); tin(II) acetylacetonate; trimethyl(phenylethynyl)tin; dibutyldiphenyltin; tetraallylutin; tetravinyltin; and hydrogenated tricyclohexyltin.

[0039] In various embodiments, the tin oxide material is deposited using an oxygen-containing reagent such as one or more of the following: oxygen gas, oxygen plasma, water, ozone, hydrogen peroxide, and nitrous oxide.

[0040] In some embodiments, the tin-containing precursor is tetrakis(dimethylamino)tin, and the tin oxide material is deposited by exposing the substrate to the tin-containing precursor and an oxygen-containing precursor containing oxygen.

[0041] In various embodiments, the tin oxide material is provided using at least one of the following processes: chemical vapor deposition, atomic layer deposition, or a combination thereof.

[0042] In some embodiments, tin oxide is provided using plasma-excited atomic layer deposition (PEALD).

[0043] Another embodiment includes an apparatus for processing a semiconductor substrate containing a semiconductor material, the apparatus comprising one or more process chambers, each including at least one process chamber including a shower head and a heated base; a plasma generator capable of generating plasma in at least one process chamber; one or more gas sources; one or more gas inlets supplying gas from one or more gas sources to one or more process chambers via the shower head; and a controller having at least one processor and memory, wherein the controller connects the at least one processor and memory to communicate with each other, the at least one processor is at least operably connected to flow control hardware, and the memory stores computer executable instructions that control the at least one processor, and controls the flow control hardware by performing spacer-on-spacer patterning on the semiconductor substrate using at least one spacer containing tin oxide. In various embodiments, instructions for producing spacer-on-spacer patterning include instructions for depositing a first conformal spacer material on a patterned core material and selectively etching the patterned core material to form a first spacer containing the first conformal spacer material, depositing a second conformal spacer material on the first spacer and selectively etching the first spacer to form a second spacer containing the second conformal spacer material, and etching a target layer using the second spacer as a mask, wherein the first conformal spacer material contains tin oxide, or the second conformal spacer material contains tin oxide.

[0044] Another embodiment includes an apparatus for processing a semiconductor substrate containing a semiconductor material, the apparatus comprising one or more process chambers, each including at least one process chamber with a showerhead and a heated base; a plasma generator capable of generating plasma within at least one process chamber; one or more gas sources; one or more gas inlets supplying gas from one or more gas sources to one or more process chambers via the showerhead; and a controller having at least one processor and memory, wherein the controller connects the at least one processor and memory to communicate with each other, the at least one processor is at least operably connected to flow control hardware, and the memory stores computer executable instructions for controlling the at least one processor and controls the flow control hardware at least by: conformally depositing a removable material on a core material; selectively removing horizontal regions of the removable material and removing the core material to form a spacer containing the removable material; and depositing a complementary material on the spacer containing the removable material so that the removable material is selectively etchable with respect to the complementary material.

[0045] Another embodiment includes an apparatus for processing a semiconductor substrate containing a semiconductor material, the apparatus comprising one or more process chambers, each process chamber including a shower head and a heated base; a plasma generator capable of generating plasma in at least one process chamber; one or more gas sources; one or more gas inlets supplying gas from one or more gas sources to one or more process chambers via the shower head; and a controller having at least one processor and memory, wherein the controller connects the at least one processor and memory to each other in a communicative manner, and the at least one processor is at least operably connected to flow control hardware, and the memory However, the flow control hardware stores computer executable instructions that control at least one processor and controls it at least by: placing a substrate having a patterned core material in one or more process chambers; conformally depositing a first material, which is one or more of silicon oxide, silicon nitride, titanium oxide, and lead oxide, onto the sidewall of the patterned core material and selectively removing the patterned core material to form a first spacer; conformally depositing a tin oxide spacer material onto the sidewall of the first spacer and selectively removing the first spacer to form a second spacer containing the tin oxide spacer material.

[0046] Another embodiment includes an apparatus for processing a semiconductor substrate containing a semiconductor material, the apparatus comprising one or more process chambers, each process chamber comprising a shower head and a heated base, a plasma generator capable of generating plasma in at least one process chamber, one or more gas sources, one or more gas inlets supplying gas from one or more gas sources to one or more process chambers via the shower head, and a controller having at least one processor and memory, wherein the controller connects the at least one processor and memory to communicate with each other, the at least one processor is at least operably connected to flow control hardware, and the memory stores computer executable instructions for controlling the at least one processor and controls the flow control hardware at least by: providing a substrate having a patterned core material, conformally depositing tin oxide material on top of the patterned core material onto the sidewall of the core material and selectively removing the patterned core material to form a tin oxide spacer, conformally depositing a second spacer material on top of the tin oxide spacer onto the sidewall of the tin oxide spacer and selectively removing the tin oxide spacer to form a second spacer.

[0047] These and other embodiments are described further below with reference to the drawings. [Brief explanation of the drawing]

[0048] [Figure 1A] Figure 1A is a schematic diagram of a substrate in an example of a quad patterning scheme. [Figure 1B] Figure 1B is a schematic diagram of a substrate in an example of a quad patterning scheme. [Figure 1C] Figure 1C is a schematic diagram of a substrate in an example of a quad patterning scheme. [Figure 1D] Figure 1D is a schematic diagram of a substrate in an example of a quad patterning scheme. [Figure 1E]Figure 1E is a schematic diagram of a substrate in an example of a quad patterning scheme. [Figure 1F] Figure 1F is a schematic diagram of a substrate in an example of a quad patterning scheme. [Figure 1G] Figure 1G is a schematic diagram of a substrate in an example of a quad patterning scheme. [Figure 1H] Figure 1H is a schematic diagram of a substrate in an example of a quad patterning scheme. [Figure 1I] Figure 1I is a schematic diagram of a substrate in an example of a quad patterning scheme. [Figure 1J] Figure 1J is a schematic diagram of a substrate in an example of a quad patterning scheme.

[0049] [Figure 2] Figure 2 is a process flow diagram illustrating the operation of a method performed according to a specific disclosed embodiment.

[0050] [Figure 3A] Figure 3A is a schematic diagram of a substrate in an example of a patterning scheme performed according to a particular disclosed embodiment. [Figure 3B] Figure 3B is a schematic diagram of a substrate in an example of a patterning scheme performed according to a particular disclosed embodiment. [Figure 3C] Figure 3C is a schematic diagram of a substrate in an example of a patterning scheme performed according to a particular disclosed embodiment. [Figure 3D] Figure 3D is a schematic diagram of a substrate in an example of a patterning scheme performed according to a particular disclosed embodiment. [Figure 3E] Figure 3E is a schematic diagram of a substrate in an example of a patterning scheme performed according to a particular disclosed embodiment. [Figure 3F] Figure 3F is a schematic diagram of a substrate in an example of a patterning scheme performed according to a particular disclosed embodiment.

[0051] [Figure 4] Figure 4 is a schematic diagram of an exemplary process chamber for carrying out a particular disclosed embodiment.

[0052] [Figure 5] Figure 5 is a schematic diagram of an exemplary process tool for carrying out a particular disclosed embodiment. [Figure 6] Figure 6 is a schematic diagram of an exemplary process tool for carrying out a particular disclosed embodiment. [Modes for carrying out the invention]

[0053] The following descriptions include numerous specific details to ensure a full understanding of each embodiment presented. The disclosed embodiments may be implemented even if some or all of these specific details are missing. In other examples, known process operations are not described in detail to avoid unnecessarily obscuring the disclosed embodiments. While the disclosed embodiments are described in conjunction with specific embodiments, it should be understood that there is no intention to limit the disclosed embodiments.

[0054] Semiconductor assembly processes involve patterning schemes that include the deposition and etching of materials to form specific structures within semiconductor devices. Patterning processes that can be used to assemble structures include double patterning and quad patterning. These are examples of multi-patterning schemes. As the patterning process progresses from double patterning to quad patterning, the patterning cost increases due to the increased number of operations required to deposit and etch the semiconductor substrate to realize the desired structure.

[0055] Figures 1A to 1J show an example of a quad patterning scheme. In Figure 1A, a substrate 107 having a target layer 105 is provided with a patterned core 101 and a second core layer 103 located beneath the patterned core 101. The patterned core 101 can be patterned using lithography, and each feature of the patterned core 101 can be referred to as a "printed" feature. In order to pattern the target layer 105 with a pattern having a smaller pitch, a first spacer material 109 is conformally formed on the patterned core 101 as shown in Figure 1B, and a first pattern is formed by removing the horizontal region of the first spacer material 109 to expose the top surface of the patterned core 101. As a result, a first spacer 119 having spacer material is generated from the first spacer material 109 as shown in Figure 1C. Each spacer 119 is positioned on the side of the patterned core 101 such that, by removing the horizontal region of the first spacer material 109, two vertical features of the spacer 119 remain for each positive feature of the patterned core 101. The patterned core 101 is removed in Figure 1D, leaving the first spacers 119 on the second core layer 103. As a result, the pitch of the first spacers 119 is half the print pitch formed from the lithographic patterning of the core material.

[0056] Next, the first spacer 119 is used as a mask to transfer the half-pitch pattern to the second core layer 103, forming the second patterned core 113 shown in Figure 1E. Then, the first spacer 119 is removed, leaving the second patterned core 113 on top of the target layer 105 as shown in Figure 1F. The second spacer material 120 is conformally deposited on top of the second patterned core 113 to form the structure shown in Figure 1G. The horizontal region of the second spacer material 120 is removed, creating a second spacer 121 on the sidewall of the second patterned core 113 as shown in Figure 1H. There are two second spacers 121 for each positive type feature of the second patterned core 113, which further halves the pitch. In Figure 1I, the second patterned core 113 is removed, leaving the second spacers 121, resulting in four features for each printed feature in Figure 1A. Subsequently, the target layer 105 is etched using the second spacer 121, as shown in Figure 1J, resulting in a patterned target layer 106 on the substrate 107.

[0057] The first and second spacers described in Figures 1A to 1J include silicon-containing materials for self-alignment patterning. For example, silicon oxide (SiO2), a low-elasticity material, is often used as a spacer material. However, because it is a low-elasticity material, if the limit size of the spacer is small, such as 12 nm or less, it may collapse under its own weight. The elastic modulus of silicon oxide spacers is approximately 30 GPa (gigapascals) to approximately 50 GPa.

[0058] As described above, the process schemes in Figures 1A-1J involve the transfer of the first spacer pattern to the second core in Figure 1E. The process uses both the first and second core materials to deposit the second core and incorporate the transfer etching process into the patterning scheme. There are several cost-saving options to reduce production costs by omitting this step, but these involve some trade-offs.

[0059] One option to reduce production costs is to omit the operation of transferring the first spacer pattern to the second core. This is done by using the same material for the first spacer so that it becomes the second core material when used to form the first spacer, allowing for the use of two different materials for every two sets of spacers, so that the second spacer is conformally and sequentially deposited directly on top of the features of the first spacer, which then acts as a mandrel. This is referred to as the “spacer-on-spacer” method. The “first” spacer material described herein is the spacer material deposited on the patterned core material with a larger pitch, and the “second” spacer material described herein is the spacer material deposited on top of the first spacer material in spacer-on-spacer patterning. In various embodiments, the “first” spacer material is the spacer material deposited on top of a patterned core material that has been defined or patterned by lithography.

[0060] Spacer-on-spacer patterning eliminates the need for both transferring the first spacer pattern to the second core and stacking the second core layer before patterning. This reduces costs and improves efficiency and wafer throughput. Furthermore, eliminating these steps reduces the likelihood of introducing defects into the wafer during production.

[0061] Spacer-on-spacer patterning can be used to reduce costs and assemble structures with narrower pitches. However, depending on the material, spacer-on-spacer patterning may be unsuitable due to issues such as etching selectivity, deposition challenges, and etching chemical reactions. For example, depositing certain spacer materials onto a patterned core material may result in degradation of the patterned core during deposition, potentially affecting the critical dimensions.

[0062] In some spacer-on-spacer patterning schemes, the first spacer material may be silicon. However, when removing the silicon as a mandrel material after forming second spacers on both sides of the silicon core, the conversion of silicon to its hydride requires removal at very high temperatures, making it difficult to remove silicon by hydrogen, even if silane is volatile. At such temperatures, the remaining silicon-containing substrate may bend, deform, or even become liquid.

[0063] In some spacer-on-spacer patterning schemes, the first spacer material may be titanium oxide. However, achieving selective etching using chlorine-based dry chemical reactions is difficult, and wet etching techniques can cause small features to collapse when etching with liquid. The liquid on the feature surface has finite surface tension, and wet etchant molecules on narrow structures can cause the liquid molecules to adhere to each other, potentially removing too much material when the liquid is removed. Therefore, solvent-based processes using nonpolar solvents such as isopropyl alcohol may be used. However, such processes are not environmentally friendly.

[0064] In a spacer-on-spacer patterning scheme, it may be desirable to allow the first spacer to be scaled up or down by using a first spacer. It may also be difficult to cleanly remove the first spacer from the substrate after forming a second spacer using a specific silicon-containing material.

[0065] Provided herein is a method for performing spacer-on-spacer patterning using a removable material as the first spacer material and a complementary material as the second spacer material. As used herein, "removable" refers to the ability to be removed by a hydrogen-containing gas or the like. Non-limiting examples of "complementary" materials include: silicon oxide is complementary to tin oxide, silicon nitride is complementary to tin oxide, and titanium oxide is complementary to tin oxide.

[0066] Certain disclosed embodiments include a method for incorporating a spacer material containing a Group IV metal heavier than silicon, such that the spacer material is compatible with organic and inorganic mandrels (e.g., non-limiting examples of carbon-containing cores and silicon-containing cores, respectively) without causing significant variation in critical dimensions in a self-aligning multi-patterning scheme. By omitting several operations used in quad patterning without affecting critical dimensions, defects are reduced, and a wider range of materials are available for use in a more efficient process.

[0067] The disclosed embodiments incorporate tin oxide as one of the spacer materials in a spacer-on-spacer patterning scheme. As used herein, tin oxide (hereinafter also referred to as SnO) refers to a substance containing tin (Sn) and oxygen (O), and optionally hydrogen. As used herein, tin oxide may further contain small amounts of other elements, such as carbon and nitrogen, in which case the total amount of other elements is 10 atomic percent or less (where hydrogen is not included in the content calculation). For example, SnO deposited by atomic layer deposition (ALD) can contain about 0.5 atomic percent to about 5 atomic percent of carbon. As used herein, the term "SnO" does not indicate the stoichiometry of an oxide and may vary. In some specific embodiments, the stoichiometry of SnO is about one tin atom for every two oxygen atoms. In some embodiments, SnO refers to tin dioxide.

[0068] Because SnO has a higher modulus of elasticity than silicon oxide, it makes a more robust spacer. The modulus of elasticity of SnO can be at least about 100 GPa. In one example, the modulus of elasticity of SnO may be about 100 GPa to 400 GPa. In another example, the modulus of elasticity of SnO may be about 120 GPa to 300 GPa, as a result, SnO can be incorporated into spacers with limit dimensions up to 6 nm before experiencing the possibility of SnO decay. Certain disclosed embodiments are particularly suitable for forming features in target layers with pitches of less than about 80 nm or less than about 40 nm because the SnO spacers are robust even at smaller pitches.

[0069] The spacer materials described herein possess unique properties. For example, it is possible to remove SnO with a lighter element to form a volatile material that selectively etches only SnO. For example, SnO can be removed by using hydrogen, which is selective for all other exposed materials on the substrate, to form a volatile and easily removable tin hydride.

[0070] Furthermore, certain disclosed materials have the ability to be dry-etched in hydrogen while also withstanding the high-temperature conditions used when depositing metal oxides or nitrides. Because they can withstand such deposition, they are less susceptible to changes in the critical dimensions of internally etched features.

[0071] These properties allow SnO to be used as a first spacer material, deposited on top of organic or inorganic materials, and then used as a second spacer by eliminating various operations used in other quad patterning processes.

[0072] Furthermore, because tin oxide deposits quickly, it can be formed more rapidly on the patterned core or the first spacer, depending on whether it is incorporated as the first or second spacer material.

[0073] Certain disclosed embodiments include using SnO as a second spacer material in a spacer-on-spacer patterning scheme, so that other materials can be used as the first spacer material. For example, silicon nitride (SiN) can be used as the first spacer on an organic or inorganic core, and the silicon nitride can function as the core of the second SnO spacer. Because SnO has a low wet etching rate in thermal phosphoric acid (H3PO4), the silicon nitride can be effectively removed in thermal phosphoric acid while retaining the SnO on the substrate, thereby forming a second SnO spacer that can be used as a mask for patterning a target layer.

[0074] By realizing certain disclosed embodiments that take advantage of the unique properties of SnO, various combinations of spacers on the spacer material can be used.

[0075] Certain disclosed embodiments involve using a removable film on a first conformal spacer material and a complementary film on a second conformal spacer material. Exemplary combinations include: the first conformal spacer material is SnO and the second conformal spacer material is silicon oxide; the first conformal spacer material is SnO and the second conformal spacer material is silicon nitride; the first conformal spacer material is SnO and the second conformal spacer material is titanium oxide; the first conformal spacer material is SnO and the second conformal spacer material is hafnium oxide; and the first conformal spacer material is SnO and the second conformal spacer material is another oxide, nitride, or carbide.

[0076] Table 1 below shows non-restrictive examples. [Table 1]

[0077] Figure 2 is a process flow diagram illustrating various operations that may be performed according to a particular disclosed embodiment.

[0078] In operation 201, a substrate having at least a core material and a target layer is provided. In some embodiments, the patterned core material contains silicon. In some embodiments, the patterned core material contains carbon. The patterned core material may be a photoresist, or it may be made from an amorphous carbon material or an amorphous silicon material. In some embodiments, the core material may be transparent. The core material is deposited by a deposition technique such as plasma-excited chemical vapor deposition (PECVD), which may involve generating a plasma in a deposition chamber containing the substrate from a deposition gas containing a hydrocarbon precursor. The hydrocarbon precursor is of formula C a H b (where a is an integer from 2 to 10, and b is an integer from 2 to 24) can be defined as follows. Examples include methane (CH4), acetylene (C2H2), ethylene (C2H4), propylene (C3H6), and butane (C4H 10 ), cyclohexane (C6H 12 Examples include benzene (C6H6) and toluene (C7H8). A dual-frequency (RF) plasma source including high-frequency (HF) power and low-frequency (LF) power may be used. The core material is deposited on a target layer before patterning. The target layer may be the layer that is ultimately patterned. The target layer may be a semiconductor layer, a dielectric layer, or other layer, and may be made from, for example, silicon (Si), silicon oxide (SiO2), silicon nitride (SiN), or titanium nitride (TiN). The target layer may be deposited by ALD, plasma-excited ALD (PEALD), chemical vapor deposition (CVD), or other suitable deposition techniques.

[0079] An exemplary substrate that may be provided in operation 201 is shown in Figure 3A. Figure 3A shows a substrate 307 having a target layer 305 with a patterned core 301. Although Figure 3A shows only three layers, it will be understood that additional layers may be present on the substrate in some embodiments. These may include, but are not limited to, etching stop layers (such as an etching stop layer between the target layer 305 and the substrate 307, or an etching stop layer between the patterned core 301 and the target layer 305).

[0080] Returning to Figure 2, in operation 203, the first conformal spacer material is deposited on the patterned core material, the horizontal region of the first conformal spacer material is removed, and the first spacer containing the first conformal spacer material is formed. This operation may be carried out at a temperature between approximately 50°C and approximately 200°C. This operation may be carried out at a chamber pressure between approximately 1.0 Torr and approximately 4.0 Torr. If plasma is used, the plasma power may be between approximately 400 W and approximately 4000 W for four wafers in the chamber. These process conditions may be used to deposit tin oxide as the first conformal spacer or as the second conformal spacer, as will be further described below.

[0081] In various embodiments, the first conformal spacer material is SnO. The first conformal SnO spacer material may be deposited using a tin-containing precursor and an oxygen-containing reagent, or by any suitable technique.

[0082] A tin-containing precursor may be flowed through a chamber having four stations for processing four wafers at a flow rate between approximately 400 sccm and approximately 3000 sccm. A non-limiting example of the tin-containing precursor is tetrakis(dimethylamide)tin (Sn(NMe2)4). The oxygen-containing reagent may be oxygen in some embodiments. The oxygen-containing reagent may be flowed through a chamber having four stations for processing four wafers at a flow rate between approximately 400 sccm and approximately 5,000 sccm. In some embodiments, an inert gas is flowed. In some embodiments, the inert gas is a carrier gas. Non-limiting examples of the inert gas are argon and nitrogen. Argon may be flowed through a chamber having four stations for processing four wafers at a flow rate between approximately 20,000 sccm and approximately 60,000 sccm.

[0083] The first conformal SnO spacer material may be amorphous. The first conformal SnO spacer material may be deposited by PEALD or thermal ALD. ALD is a technique for depositing thin layers of material using a continuous self-limiting reaction. The ALD process deposits films in layers over multiple cycles using surface-mediated deposition reactions. For example, an ALD cycle may include the following operations: (i) supply / adsorption of a precursor; (ii) purging of the precursor from the chamber; (iii) supply of a second reactant and optionally ignition of the plasma; and (iv) purging of by-products from the chamber. The reaction between the second reactant and the adsorbed precursor forms a film on the substrate surface, which affects the film's composition, heterogeneity, stress, wet etching rate, dry etching rate, and electrical properties (withstand voltage, leakage current, etc.).

[0084] An ALD cycle is the minimum set of operations used to carry out a single deposition reaction. In some embodiments, one cycle results in the formation of at least a partial SnO film layer on the substrate surface. This cycle may include certain auxiliary operations, such as clearing one of the reactants or by-products and / or processing the deposited partial film. Generally, one cycle includes an example of a specific sequence of operations.

[0085] Unlike chemical vapor deposition (CVD), the ALD process utilizes surface-mediated deposition reactions to deposit films in layers. In one example of the ALD process, a substrate surface containing a population of surface-active sites is exposed to a gas-phase distribution of a dose of a first precursor, such as a tin-containing precursor, supplied to a chamber containing the substrate. Molecules of this first precursor, including chemiadsorbed species and / or physiadsorbed molecules of the first precursor, are adsorbed onto the substrate surface. As described herein, when a compound is adsorbed onto the substrate surface, it should be understood that the adsorption layer may include not only the compound but also derivatives of that compound. For example, the adsorption layer of a tin-containing precursor may include not only the tin-containing precursor but also derivatives of the tin-containing precursor. After the administration of the first precursor, the chamber is then evacuated to remove most or all of the first precursor remaining in the gas phase, leaving most or only the adsorbed species. In some implementations, the chamber does not need to be completely evacuated. For example, the reactor may be evacuated to a sufficiently low partial pressure of the first precursor in the gas phase to mitigate the reaction. A second reactant, such as an oxygen-containing gas, is introduced into the chamber so that some of its molecules react with the first precursor adsorbed on the surface. In some processes, the second precursor reacts immediately with the adsorbed first precursor. In other embodiments, the second reactant reacts only after the activation source has been applied first. The chamber may then be evacuated again to remove any unbound second reactant molecules. As described above, in some embodiments, the chamber does not need to be completely evacuated. The film thickness may be increased using additional ALD cycles.

[0086] In some implementations, the ALD method includes plasma activation. As described herein, the ALD methods and apparatus described herein may also be conformal film deposition (CFD) methods, broadly described in U.S. Patent Application No. 13 / 084,399 (now U.S. Patent No. 8,728,956), filed April 11, 2011, entitled "Plasma-Activated Conformal Film Deposition," and U.S. Patent Application No. 13 / 084,305, filed April 11, 2011, entitled "Silicon Nitride Film and Method," both of which are incorporated herein by reference.

[0087] In some embodiments, the first conformal SnO spacer material is deposited at a temperature below approximately 200°C. In some embodiments, the first conformal SnO spacer material is deposited at a temperature lower than the temperature used to deposit the core material. Because SnO deposits quickly, the first few layers of SnO form and act as a barrier, reducing damage to the underlying patterned carbon core.

[0088] The following describes various techniques for depositing a first conformal spacer material, which is SnO. Although this example describes SnO, it will be understood that in embodiments where the second conformal spacer material is SnO but the first conformal spacer material is another material (such as those described above with respect to Table 1), the second conformal SnO spacer material may be deposited using any of the techniques described herein.

[0089] The first conformal SnO spacer material may be deposited by any suitable method, such as chemical vapor deposition (CVD) (including plasma-excited chemical vapor deposition (PECVD)), ALD (including PEALD), sputtering, etc. In some embodiments, it is preferable to conformally deposit the first conformal SnO spacer material along the surface of the patterned core 301, as shown in Figure 3B. In some embodiments, the first conformal SnO spacer material is conformally deposited to a thickness between approximately 5 nm and 30 nm, for example, approximately 10 nm to approximately 20 nm. One suitable method for depositing the conformal first conformal SnO spacer material is ALD. Thermal or plasma-excited ALD can be used. In a typical thermal ALD method, the substrate is provided to an ALD process chamber, where it is sequentially exposed to a tin-containing precursor and an oxygen-containing reagent, causing the tin-containing precursor and oxygen-containing reagent to react on the substrate surface to form SnO. The ALD process chamber is typically purged with an inert gas after the substrate has been exposed to a tin-containing precursor, before the oxygen-containing reactant is passed through the process chamber, preventing the reaction from occurring in most of the chamber. Furthermore, the ALD process chamber is typically purged with an inert gas after the substrate has been treated with the oxygen-containing reactant. Continuous exposure is repeated for several cycles. Non-limiting examples of the number of cycles include at least about 1 cycle, or at least about 10 cycles, or at least about 100 cycles, or between about 10 and 100 cycles. Cycles can be continued until a first conformal SnO spacer material of the desired thickness is deposited. Examples of suitable tin-containing precursors include non-halogenated tin-containing precursors, including organotin precursors such as tin(IV) chloride (SnCl4), tin(IV) bromide (SnBr4), etc., and organotin precursors such as organometallic tin-containing compounds having alkyl-substituted tin amides, etc. Specific examples of alkyl-substituted tin amides suitable for ALD include tetrakis(dimethylamino)tin(Sn(NMe2)4, tetrakis(ethylmethylamino)tin, N 2 ,N 3-di-tert-butyl-butane-2,3-diamino-tin(II), Sn(II)(1,3-bis(1,1-dimethylethyl)-4,5-dimethyl-(4R,5R)-1,3,2-diazastannolysin-2-ylidene).

[0090] Examples of SnO deposition precursors include tin halides, tin hydrides, organotin compounds, chlorinated organotin-containing compounds, and combinations thereof. Specific precursors include stannous fluoride (SnF2), SnCl4, SnBr4, tin hydride (SnH4), tetrakis(ethylmethylamino)tin (Sn(NMeEt)4), Sn(II)(1,3-bis(1,1-dimethylethyl)-4,5-dimethyl-(4R,5R)-1,3,2-diazastannolysin-2-ylidene), and N 2 ,N 3 Examples include, but are not limited to, di-tert-butylbutane-2,3-diaminotin(II), tetraethyltin(SnEt4), tetramethyltin(SnMe4), dibutyltin diacetate(Bu2Sn(OAc)2), (dimethylamino)trimethyltin(IV)(Me3Sn(NMe2)), and tetrakis(diethylamide)tin(IV)(Sn(NEt2)4).

[0091] Additional examples include: trimethyltin chloride as shown in (I) below; dimethyltindichloride as shown in (II) below; methyltintrichloride as shown in (III) below; bis[bis(trimethylsilyl)amino]tin(II) as shown in (IV) below (where TMS is trimethylsilyl); hexaphenyldisin as shown in (V); tin(II) acetylacetonate as shown in (IV); trimethyl(phenylethynyl)tin as shown in (VII); dibutyldiphenyltin as shown in (VIII); tetraallylsin as shown in (IX); tetravinyltin as shown in (X); hydrogenated tricyclohexyltin as shown in (XI); and trimethylphenyltin as shown in (XII). [ka] [ka] [ka] [ka] [ka] [ka] [ka] [ka] [ka] [ka] [ka] [ka]

[0092] Oxygen-containing reagents include, non-limitingly, oxygen, ozone, water, hydrogen peroxide, and NO. Mixtures of oxygen-containing reagents can also be used. Deposition conditions vary depending on the selection of ALD reagents; generally, more reactive precursors react at lower temperatures than less reactive precursors. The process is typically carried out at temperatures between approximately 20°C and 500°C, and at low atmospheric pressure. The temperature and pressure are chosen to keep the reagents in gaseous form within the process chamber to avoid condensation. Each reagent is supplied to the process chamber either alone or in gaseous form mixed with a carrier gas such as argon, helium, or nitrogen. The flow rate of these mixtures depends on the size of the process chamber and, in some embodiments, is between approximately 10 sccm and 10,000 sccm.

[0093] Specific examples of thermal ALD process conditions suitable for depositing the first conformal SnO spacer material provided herein are described in the paper by Li et al., “Tin Oxide with Controlled Morphology and Crystallinity by Atomic Layer Deposition onto Graphene Nanosheets for Enhanced Lithium Storage” (Advanced Functional Materials, 2012, 22, 8, 1647-1654), which is incorporated herein by reference in its entirety. This process involves sequentially and alternately exposing a substrate to SnCl4 (tin-containing precursor) and deionized water (oxygen-containing reactant) at a temperature of 200–400°C in an ALD vacuum chamber. In a specific example of the ALD cycle, a mixture of SnCl4 vapor and N2 carrier gas is introduced into the ALD process chamber for 0.5 seconds, followed by exposure of the substrate for 3 seconds. Next, the ALD process chamber is purged with N2 for 10 seconds to remove most of the SnCl4 from the process chamber, a mixture of N2 carrier gas and H2O vapor is passed through the process chamber for 1 second, and the substrate is exposed for 3 seconds. Then, the ALD process chamber is purged with N2, and this cycle is repeated. The ALD process is carried out at low atmospheric pressure (e.g., 0.4 Torr) and a temperature of 200-400°C.

[0094] Another example of suitable thermal ALD process conditions for depositing a SnO film in the method provided herein is provided in the paper by Du et al., “In situ Examination of Tin Oxide Atomic Layer Deposition using Quartz Crystal Microbalance and Fourier Transform Infrared Techniques” (J.Vac.Sci.Technol.A23,581(2005)), which is incorporated herein by reference in its entirety. In this process, the substrate is sequentially exposed to SnCl4 and H2O2 at a temperature of approximately 150–430°C in an ALD process chamber.

[0095] While the use of tin halide precursors in ALD is appropriate in many embodiments, in some embodiments, the use of non-halogenated organotin precursors is more preferable to avoid corrosion problems that may occur with the use of halogenated precursors such as SnCl4. Examples of suitable non-halogenated organotin precursors include alkylaminotin (alkylated tinamide) precursors such as tretrakis(dimethylamino)tin. An example of a suitable thermal ALD deposition method using this precursor is provided in the paper "Atomic Layer Deposition of Tin Oxide Films using Tetrakis(dimethylamino)tin" by Elam et al. (J.Vac.Sci.Technol.A26,244(2008)), which is incorporated herein by reference in its entirety. In this method, the substrate is sequentially exposed to tetrakis(dimethylamino)tin and H2O2 in an ALD chamber at a temperature of approximately 50–300°C. Advantageously, the use of this precursor allows for the deposition of the first conformal SnO spacer material at low temperatures below 100°C. For example, SnO films can be deposited at 50°C without the use of plasma, increasing the reaction rate. Another example of thermal ALD of SnO using tetrakis(dimethylamino)tin and H2O2 is provided in the paper by Elam et al., entitled "Atomic Layer Deposition of Indium Tin Oxide Thin Films Using Nonhalogenated Precursors" (J.Phys.Chem.C2008, 112, 1938-1945), which is incorporated herein by reference.

[0096] Another example of a low-temperature thermal ALD process using a reactive organotin precursor is provided in the paper by Heo et al. entitled "Low temperature Atomic Layer Deposition of Tin Oxide" (Chem. Mater., 2010, 22(7), 4964-4973), which is incorporated herein by reference in its entirety. In this deposition process (suitable for the deposition of SnO films provided herein), the substrate is subjected to N2A deposition in an ALD vacuum process chamber. 2 ,N 3 The substrate is sequentially exposed to di-tert-butyl-butane-2,3-diaminotin(II) and 50% H2O2. These reactants are vaporized and each is mixed with an N2 carrier gas and supplied to the process chamber. After each exposure of the substrate to the reactants, the chamber is purged with N2. Deposition can be carried out at a temperature of approximately 50–150°C.

[0097] Generally, hydrogen peroxide is effective as an oxygen-containing reagent for the formation of the first conformal SnO spacer material in the ALD process, but the decomposition of H2O2 may result in insufficient control of SnO film growth. In some embodiments, a more stable oxygen-containing precursor, such as NO, is used. An example of suitable process conditions using NO as an oxygen-containing reagent is provided by Heo et al. in their paper entitled "Atomic Layer Deposition of Tin Oxide with Nitric Oxide as an Oxidant Gas" (J.Mater.Chem., 2012, 22, 4599), which is incorporated herein by reference. This deposition involves sequentially exposing the substrate to cyclic Sn(II) amide (1,3-bis(1,1-dimethylethyl)-4,5-dimethyl-(4R,5R)-1,3,2-diazastannoridine-2-iridine) and NO at a temperature of approximately 130–250°C.

[0098] In some embodiments, the first conformal SnO spacer material is deposited by PEALD. Similar types of tin-containing precursors and oxygen-containing reagents as those used in thermal ALD are available. In PEALD, the ALD apparatus is equipped with a system for generating plasma in a process chamber and processing the substrate with that plasma. In a typical PEALD process sequence, the substrate is brought into the PEALD process chamber and exposed to a tin-containing precursor adsorbed on the substrate surface. The process chamber is purged with an inert gas (e.g., argon or helium) to remove the precursor from the process chamber, and the substrate is exposed to an oxygen-containing reagent introduced into the process chamber. Simultaneously with or delayed by the introduction of the oxygen-containing reagent, plasma is formed in the process chamber. The plasma facilitates the reaction between the tin-containing precursor and the oxygen-containing reactant on the substrate surface, resulting in the formation of the first conformal SnO spacer material. Next, the process chamber is purged with an inert gas, and a cycle consisting of adding a tin precursor, purging, adding an oxygen-containing reagent, plasma treatment, and a second purge is repeated the required number of times to form a first conformal SnO spacer material of the desired thickness.

[0099] An example of process conditions suitable for PEALD formation of SnO films is provided in the paper "The Fabrication of Tin Oxide Films by Atomic Layer Deposition using Tetrakis(ethylmethylamino)tin Precursor" by Seop et al. (Transactions on Electrical and Electronic Materials, 2009, 10, 5, 173-176), which is incorporated herein by reference. The substrate is provided into the PEALD process chamber and exposed to tetrakis(ethylmethylamino)tin for 4 seconds in the absence of plasma. Next, the tin-containing precursor is purged from the process chamber by flowing argon through it for 20 seconds. Then, O2 is injected for 2 seconds, followed by the injection of 100W of radio frequency (RF) power for 2 seconds. After this, an argon purge is performed, and one PEALD cycle is completed. In this example, the process is carried out at a temperature range of 50–200°C and a pressure of 0.8 Torr.

[0100] ALD (both thermal and plasma-excited) is the primary method for depositing conformal SnO spacer materials, but other SnO deposition methods such as CVD, PECVD, and sputtering are also understood to be usable.

[0101] Figure 3B is an exemplary schematic diagram showing how the first conformal spacer material 309 conformally deposits onto the patterned core 301.

[0102] The horizontal region of the first conformal spacer material is removed by etching.

[0103] The formation of the SnO spacer is shown in Figures 3B and 3C. First, the first conformal spacer material 309 is etched from the horizontal plane on the patterned core 301, as described above, without being completely etched from the position where it adheres to the sidewall of the patterned core 301. This etching exposes the target layer 305 in all locations except near the sidewall of the patterned core 301. Furthermore, this etching exposes the top of the patterned core 301. The resulting structure is shown in Figure 3C. The chemical reaction of this etching depends on the type of material used for the target layer 305 and the patterned core 301.

[0104] An example of a method for etching a horizontal region of a first conformal spacer material is described in U.S. Patent No. 9,824,893, issued November 21, 2017, which is incorporated in its entirety by reference for all purposes.

[0105] SnO can be etched using a variety of wet etching and dry etching techniques. In wet etching, the substrate is brought into contact with a wet etchant, which can be sprayed onto the substrate, for example. Alternatively, the substrate can be immersed in a wet (aqueous) etchant. In dry etching, the substrate is placed in a dry etching chamber, where it is brought into contact with a gaseous etchant, whether or not plasma is used. As used herein, "wet etching" refers to etching using a liquid etchant, and "dry etching" refers to etching using a gaseous (including vaporized) etchant, regardless of whether water is used. An example of a wet etching suitable for SnO is acid etching, in which the substrate is brought into contact with an aqueous solution of an acid such as HCl.

[0106] In one implementation method of HCl etching, the substrate is brought into contact with an aqueous solution prepared from an aqueous solution of HCl and chromium metal.

[0107] In another example of a wet etching process, the SnO layer is treated with aqueous HX (where X is Cl, Br, or I) in the presence of zinc powder. In this method, the oxide is directly reduced by the hydrogen formed by the reaction of zinc and HX. In another embodiment of wet etching, SnO is etched with aqueous phosphoric acid, provided, for example, in a H3PO4:H2O ratio of 1:3. Furthermore, the SnO film can be etched with a mixture of aqueous HNO3 and HCl or aqueous HI at a temperature of about 60°C.

[0108] One example of a dry etching chemical reaction for SnO removal is treatment with HBr in a plasma. This treatment is provided in the paper "Etch Mechanism of In2O3 and SnO2 thin films in HBr-based inductively coupled plasmas" by Kwon et al. (J.Vac.Sci.Technol.A28,226 (2010)), which is incorporated herein by reference in its entirety. The substrate is treated with an inductively coupled plasma formed in a process gas containing HBr and argon.

[0109] In another embodiment, the HBr-containing process gas further includes an oxygen-containing compound such as O2. In some embodiments, etching is performed by exposing the substrate to a plasma formed in a process gas containing HBr, O2, and N2. This type of etching allows for the selective removal of SnO material from materials such as silicon and silicon oxide. Note that the surface of the silicon mandrel is typically covered with a layer of silicon dioxide to prevent etching by this etching chemical reaction. In some embodiments, the process conditions for this etching step include applying a relatively high radio frequency (RF) bias to the substrate holder to increase the energy of ions in the plasma and increase the etching rate of the SnO material. Other dry etching chemical reactions suitable for SnO removal include plasma treatment in a mixture of Cl2 and hydrocarbons, and plasma treatment in a process gas containing chlorohydrocarbons such as CH2Cl2 or CHCl3. In some embodiments, a substrate containing an exposed SnO layer is brought into contact with a plasma formed in a process gas containing CH4 and Cl2.

[0110] Another dry etching chemical reaction suitable for removing SnO films is a hydrogen-based plasma. In some embodiments, SnO is etched by exposing the substrate to a plasma formed in a process gas containing H2. In some embodiments, the plasma is formed in a process gas formed in a mixture of H2 and hydrocarbons (e.g., CH4).

[0111] In some embodiments, the removal of the SnO layer from the horizontal portion of the substrate involves using two steps involving two different chemical reactions. The first step (referred to as the main etching) removes most of the SnO layer from the horizontal plane without completely exposing the underlying mandrel material layer, the underlying target layer, or an optional etching stop layer (ESL) material. The etching chemical reaction of the main etching therefore does not need to be selective. In some embodiments, the main etching is performed by treating the substrate with a plasma formed in a process gas containing Cl2 and hydrocarbons (e.g., Cl2 and CH4). After the SnO film has been etched by the main etching, or immediately before, the etching chemical reaction is switched to an over-etching chemical reaction. The endpoint of the main etching is detectable using an optical probe, which signals when the mandrel material, the underlying target layer, or the optional ESL material is exposed. The over-etching chemical reaction is used to remove the remaining SnO film without substantially etching the mandrel material, the underlying target layer, or the optional ESL material. The ratio of the etching rate of SnO to the etching rate of the mandrel material in the over-etching chemical reaction is preferably greater than 1. Similarly, the ratio of the etching rate of SnO to the etching rate of an optional ESL material is also preferably greater than 1. In some embodiments (for example, when silicon mandrels and silicon oxide ESLs are used), over-etching involves exposing a substrate having a residual SnO film, an exposed mandrel, and exposed ESLs to a plasma formed in a process gas containing HBr, N2, and O2.

[0112] In this process, SnO etching removes SnO from the horizontal plane (as shown in Figure 3C), but the vertical portion of the SnO layer on the sidewall of the mandrel remains on the substrate. Next, the mandrel, such as the patterned core 301 in Figure 3C, is removed from the substrate, leaving the exposed first spacer 319. The removal of the mandrel is performed by exposing the substrate to an etching chemical reaction that selectively etches the mandrel material. Therefore, the ratio of the etching rate of SnO to the etching rate of the mandrel material in this process is greater than 1, more preferably greater than 1.5. Furthermore, the etching chemical reaction used in this process should selectively etch the mandrel material relative to the ESL material. Various etching methods can be used, and a specific chemical reaction is selected depending on the mandrel material and the ESL layer material. If the mandrel is made of amorphous silicon and the ESL material is silicon oxide, the mandrel can be removed using an oxidizing oxygen-containing plasma. For example, a silicon mandrel can be selectively etched by exposing a substrate to a plasma formed in a process gas consisting of HBr and O2. This chemical reaction selectively etches silicon materials in the presence of SnO and silicon oxide. In some embodiments, a thin protective layer of silicon oxide is removed from the surface of the silicon mandrel before etching begins. This can be done by briefly exposing the substrate to a plasma formed in a process gas containing carbon fluoride. After removing the silicon oxide protective film from the mandrel, silicon is selectively etched. In some embodiments, it is preferable to use a relatively small RF bias on the substrate or no external bias at all in this step. If no external bias is used, the self-bias of the substrate (10-20V) is sufficient. Under no-bias or low-bias conditions, the HBr / O2 plasma selectively etches silicon in the presence of SnO and silicon oxide.

[0113] Returning to Figure 2, in operation 205, the patterned core material is selectively removed, leaving the first spacer on the substrate. The patterned core material is removed from the substrate. In some embodiments, the selective removal of the patterned core material during this operation involves flowing an etching gas suitable for the etching material used on the patterned core material. In embodiments where the patterned core material is a carbon-containing material, an oxygen-containing etching chemical reaction may be used. In some embodiments, the patterned core material is etched without the use of plasma. In some embodiments, the patterned core material is etched using plasma. For example, the patterned core material may be etched using an oxidizing oxygen-containing plasma.

[0114] In operation 207, a second conformal spacer material is deposited on top of the first spacer. The process conditions for this operation depend on the material selected for the second conformal spacer. The second conformal spacer material may be deposited by ALD or PEALD. In some embodiments, other techniques such as CVD or PECVD may be used.

[0115] As a result, the first spacer functions as a mandrel under the second conformal spacer material. The second conformal spacer material may be an oxide film, a nitride film, or a carbide film. Non-limiting examples of oxide materials that can be used for the second conformal spacer material include titanium dioxide and hafnium oxide. Non-limiting examples of nitride materials that can be used for the second conformal spacer material include silicon nitride. In such embodiments, the first conformal spacer material having SnO functions as a mandrel for the second conformal spacer material.

[0116] Figure 3D shows an example of a substrate after selectively removing the patterned core 301 and depositing a second conformal spacer material 320 on top of the first spacer 319, whose features now function as a second mandrel.

[0117] If the first conformal spacer material is SnO, the second conformal spacer material may include silicon dioxide, silicon nitride, titanium dioxide, hafnium oxide, or other oxides, nitrides, or carbide films. In particular, the silicon dioxide material used can be a silicon dioxide film deposited at high temperatures, as this allows the first conformal SnO spacer material to withstand higher temperature deposition conditions.

[0118] The second conformal spacer material may be deposited using any suitable technique such as ALD or PEALD.

[0119] In the case of silicon-containing oxides, nitrides, or carbides, a second conformal film may be deposited using a silicon-containing precursor. The deposition precursor is selected based on the material to be deposited in a larger gap. For example, a silicon-containing precursor may be selected for the deposition of silicon oxide. Exemplary silicon-containing precursors include those having the following structures. [ka] Here, R1, R2, and R3 may be the same substituent or different substituents, and may include silanes, amines, halides, hydrogen, or organic groups such as alkylamines, alkoxys, alkyls, alkenyls, alkynyls, and aromatic groups.

[0120] An example of a silicon-containing precursor is polysilane (H3Si(SiH2) n SiH3) (wherein n≧1), for example, silanes, disilanes, trisilanes, tetrasilanes, and trisilylamines. [ka]

[0121] In some embodiments, the silicon-containing precursor is an alkoxysilane. Possible alkoxysilanes include, but are not limited to, the following: H x -Si-(OR) y (wherein the formula x=1 to 3, x+y=4, and R is a substituted or unsubstituted alkyl group), and H x (RO) y -Si-Si(OR) y H x (In the formula, x = 1 to 2, x + y = 3, and R is a substituted or unsubstituted alkyl group).

[0122] Examples of silicon-containing precursors include: methylsilane; trimethylsilane (3MS); ethylsilane; butasilane; pentasilane; octasilane; heptasilane; hexasilane; cyclobutasilane; cycloheptasilane; cyclohexasilane; cyclooctasilane; cyclopentasilane; 1,4-dioxa-2,3,5,6-tetrasilacyclohexane; diethoxymethylsilane (DEMS); diethoxysilane (DES); dimethoxymethylsilane Lan; 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).

[0123] In some embodiments, the silicon-containing precursor may be an aminosilane having a hydrogen atom, such as bisdiethylaminosilane, diisopropylaminosilane, tert-butylaminosilane (BTBAS), or tris(dimethylamino)silane (3DMAS). Examples of aminosilane precursors include, but are not limited to:H x -Si-(NR) y(In the equation, x = 1 to 3, x + y = 4, and R is an organic group or a hydride group).

[0124] In some embodiments, halogen-containing silanes may be used such that the silane contains at least one hydrogen atom. The chemical formula of such a silane is SiX a H y (wherein the formula, y≧1) may be the case. For example, dichlorosilane (H2SiCl2) can be used in some embodiments.

[0125] Precursor molecules for depositing silicon carbide may include silicon-containing molecules having silicon-hydrogen (Si-H) bonds and / or silicon-silicon (Si-Si) bonds, as well as silicon-carbon (Si-C) bonds. In some embodiments, precursor molecules for depositing a silicon carbide-carbon-containing encapsulation layer may be silicon-containing and carbon-containing precursors. Precursor molecules for depositing silicon oxycarbide include silicon-containing molecules having silicon-hydrogen (Si-H) bonds and / or silicon-silicon (Si-Si) bonds, silicon-oxygen (Si-O) bonds, and / or silicon-carbon (Si-C) bonds. Precursor molecules for depositing silicon carbonitride include silicon-containing molecules having silicon-hydrogen (Si-H) bonds and / or silicon-silicon (Si-Si) bonds, and silicon-nitrogen (Si-N) bonds and / or silicon-carbon (Si-C) bonds. Precursor molecules for depositing silicon oxynitricarbide include silicon-containing molecules having silicon-hydrogen (Si-H) bonds and / or silicon-silicon (Si-Si) bonds, and silicon-nitrogen (Si-N) bonds, silicon-oxygen (Si-O) bonds and / or silicon-carbon (Si-C) bonds. In some embodiments, the silicon-containing precursor may include reactants having Si-O bonds and reactants having Si-C bonds. It will be understood that within the scope of this disclosure, any number of suitable reactants may be employed. The silicon-containing precursor contains one or more Si-H bonds and / or one or more Si-Si bonds. During the deposition process, the Si-H bonds and / or Si-Si bonds are cleaved and function as reaction sites for bond formation between silicon-containing precursors in the deposited silicon carbide film as a carbon-containing encapsulation layer. The cleaved bonds can also function as sites for crosslinking during heat treatment performed during or after deposition. Through bonding and crosslinking at the reaction sites, the main structure or matrix can be collectively formed on the resulting silicon carbide film as a carbon-containing encapsulation layer. In this specification, the silicon carbide film is described as an exemplary carbon-containing encapsulation layer, but it should be understood that other carbon-containing encapsulation layers may be deposited.For example, the carbon-containing encapsulation layer may include silicon carbide, oxygen-doped silicon carbide, nitrogen-doped silicon carbide, boron and nitrogen-doped silicon carbide, and combinations thereof. Furthermore, in some embodiments, the carbon-containing encapsulation layer may include one or more layers of carbon-containing material having any one or more of the materials specified above, and it will be understood that in some cases this may be referred to as a carbon-containing encapsulation film.

[0126] As discussed, the precursors employed in the formation of silicon carbide films may include silicon-containing precursors, at least a portion of which have at least one Si-H and / or at least one Si-Si bond. In certain embodiments, the silicon-containing precursor has at most one hydrogen atom on each silicon atom. Thus, for example, a precursor with one silicon atom has at most one hydrogen atom bonded to the silicon atom, a precursor with two silicon atoms has one hydrogen atom bonded to one silicon atom and optionally another hydrogen atom bonded to a second silicon atom, a precursor with three silicon atoms has at least one hydrogen atom bonded to one silicon atom and optionally one or two further hydrogen atoms bonded to one or two of the remaining silicon atoms, and so on. Furthermore, the silicon-containing precursor may also include at least one Si-O bond, at least one Si-N bond, and / or at least one Si-C bond. Any number of suitable precursors can be used to form a silicon carbide film, but at least some of the precursors will include silicon-containing precursors having at least one Si-H bond or Si-Si bond, and optionally at least one Si-O bond, Si-N bond, and / or Si-C bond. In various implementations, the silicon-containing precursor(s) do not contain OC or NC bonds. For example, the precursor(s) do not contain alkoxy(-OR) (wherein R is an organic group such as a hydrocarbon group) or amine(-NR1R2) (wherein R1 and R2 are independent hydrogen or organic groups).

[0127] In certain embodiments, at least some of the carbon supplied to the silicon carbide film is supplied by one or more hydrocarbon moieties on a silicon-containing precursor. Such moieties may originate from alkyl groups, alkene groups, alkyne groups, aryl groups, etc. In certain embodiments, the hydrocarbon group has a single carbon atom to minimize steric hindrance to Si-H and / or Si-Si bond cleavage reactions during deposition. However, the precursor is not limited to a single-carbon group and may use a larger number of carbon atoms, such as 2, 3, 4, 5, or 6. In certain embodiments, the hydrocarbon group is linear. In certain embodiments, the hydrocarbon group is cyclic.

[0128] In some embodiments, silicon-containing precursors belong to a certain chemical classification. Other chemical classifications of silicon-containing precursors may be adopted, and it will be understood that silicon-containing precursors are not limited to the chemical classifications discussed below.

[0129] In some embodiments, the silicon-containing precursor may be a siloxane. In some embodiments, the siloxane may be cyclic. Cyclic siloxanes may include cyclotetrasiloxanes, such as 2,4,6,8-tetramethylcyclotetrasiloxane (TMCTS), octamethylcyclotetrasiloxane (OMCTS), and heptamethylcyclotetrasiloxane (HMCTS). Other cyclic siloxanes may include, but are not limited to, cyclotrisiloxanes and cyclopentasiloxanes. Embodiments using cyclic siloxanes are ring structures that can introduce porosity into oxygen-doped silicon carbide films, where the pore size corresponds to the radius of the ring. For example, a cyclotetrasiloxane ring may have a radius of about 6.7 Å.

[0130] In some embodiments, the siloxane may have a three-dimensional or cage-like structure. The cage-like siloxane has silicon atoms bridged to one another via oxygen atoms, forming a polyhedron or any three-dimensional structure. An example of a cage-like siloxane precursor molecule is silsesquioxane. The cage-like siloxane structure is described in further detail in U.S. Patent No. 6,576,345 co-authored to Cleemput et al., which is incorporated herein by reference for all purposes. Similar to cyclic siloxanes, cage-like siloxanes can also introduce porosity into oxygen-doped silicon carbide films. In some embodiments, the porous scale is mesoporous.

[0131] In some embodiments, the siloxane may be linear. Suitable examples of linear siloxanes include, but are not limited to, disiloxanes such as pentamethyldisiloxane (PMDSO) and tetramethyldisiloxane (TMDSO), and trisiloxanes such as hexamethyltrisiloxane and heptamethyltrisiloxane.

[0132] In some embodiments, the silicon-containing precursor may be an alkylsilane or other hydrocarbon-substituted silane. Alkylsilanes contain a central silicon atom, one or more alkyl groups bonded to it, and one or more hydrogen atoms bonded to them. In certain embodiments, one or more alkyl groups contain one to five carbon atoms. The hydrocarbon groups may be saturated or unsaturated (e.g., alkenes (e.g., vinyl), alkynes, and aromatic groups). Examples include, but are not limited to, trimethylsilane (3MS), triethylsilane, pentamethyldisilamethane ((CH3)2Si-CH2-Si(CH3)3), and dimethylsilane (2MS).

[0133] In some embodiments, the silicon-containing precursor can be an alkoxysilane. Alkoxysilanes comprise a central silicon atom, one or more alkoxy groups bonded to it, and one or more hydrogen atoms bonded thereto. Examples include, but are not limited to, trimethoxysilane (TMOS), dimethoxysilane (DMOS), methoxysilane (MOS), methyldimethoxysilane (MDMOS), diethioxymethylsilane (DEMS), dimethylethoxysilane (DMES), and dimethylmethoxysilane (DMMOS).

[0134] Furthermore, instead of monosilanes, disilanes, trisilanes, or other higher-grade silanes may be used. An example of such a disilane in the alkylsilane classification is hexamethyldisilane (HMDS). Another example of a disilane in the alkylsilane classification is pentamethyldisilane (PMDS). Other types of alkylsilanes include alkylcarbosilanes, which can have a branched polymer structure with alkyl groups bonded to silicon atoms as well as carbons bonded to silicon atoms. Examples include dimethyltrimethylsilylmethane (DTMSM) and bis-dimethylsilylethane (BDMSE). In some embodiments, one of the silicon atoms may have a carbon-containing group or a hydrocarbon-containing group attached to it, and another silicon atom may have a hydrogen atom attached to it.

[0135] In embodiments involving the deposition of silicon oxide as a second conformal spacer material, the silicon oxide may be deposited using a silicon-containing precursor and an oxygen-containing reagent. The oxygen-containing reagent is, for example, a reagent or mixture of reagents containing at least one oxygen, such as oxygen or ozone.

[0136] In embodiments including the deposition of silicon nitride as a second conformal spacer material, the silicon nitride material may be deposited using a silicon-containing precursor and a nitrogen-containing reagent. The nitrogen-containing reagent is a reagent or mixture of reagents containing at least one nitrogen atom, and examples include ammonia, hydrazine, and amines (amines having carbon atoms) such as methylamine, dimethylamine, ethylamine, isopropylamine, t-butylamine, di-t-butylamine, cyclopropylamine, sec-butylamine, cyclobutylamine, isoamylamine, 2-methylbutan-2-amine, trimethylamine, diisopropylamine, diethylisopropylamine, and di-t-butylhydrazine, as well as aromatic-containing amines such as aniline, pyridine, and benzylamine. The amines may be primary, secondary, tertiary, or quaternary (e.g., tetraalkylammonium compounds). The nitrogen-containing reagent may contain heteroatoms other than nitrogen, for example, hydroxylamine, t-butyloxycarbonylamine, and Nt-butylhydroxylamine are nitrogen-containing reagents. Examples of nitrogen-containing reagents include nitrogen gas, ammonia, and amines.

[0137] In embodiments involving the deposition of titanium oxide as a second conformal spacer material, a titanium-containing reagent may be used. Titanium oxide can be deposited on a substrate by exposing the substrate to an oxidizing agent and a titanium-containing precursor that reacts to form titanium oxide on the substrate. In various embodiments, the titanium-containing precursor is titanium tetraiodide. In some embodiments, the titanium-containing precursor is an organometallic titanium precursor such as TDMAT, TEMAT, or TDEAT. In some embodiments, titanium chloride is used as the precursor. The oxidizing agent includes oxygen (O2), water (H2O) such as water vapor, ozone (O3), nitrous oxide (N2O), hydrogen peroxide (H2O2), and other suitable oxidizing agents. The precursor and oxidizing agent may be introduced separately or together, diluted with an inert carrier gas such as argon or nitrogen. The titanium oxide layer may be deposited by ALD, plasma-excited ALD (PEALD), or conformal film deposition (CFD). The ALD process deposits films layer by layer using surface-mediated deposition reactions. In one exemplary ALD process, a substrate surface containing a cluster of surface-active sites is exposed to a gaseous distribution of a first film precursor (P1), such as a titanium-containing precursor. Some molecules of P1 may form a condensed phase on the substrate surface. The reactor is then evacuated to remove the gaseous P1, leaving only the adsorbed species. A second film precursor (P2), such as an oxidizing agent, is then introduced into the reactor, causing some molecules of P2 to adsorb onto the substrate surface. The reactor is then evacuated again to remove unbound P2. Subsequently, the thermal energy imparted to the substrate activates a surface reaction between the adsorbed molecules of P1 and P2, forming a film layer. Finally, the reactor is evacuated to remove reaction byproducts and any unreacted P1 and P2, ending the ALD cycle. Additional ALD cycles may be introduced to increase the film thickness. In one example of a PEALD process, a plasma is started while the second film precursor P2 is being introduced into the reactor to activate the reaction between P1 and P2.

[0138] The following conditions are examples of suitable conditions for titanium oxide deposition by the ALD process. Deposition can occur at temperatures of approximately 50°C to 400°C, pressures of approximately 0.5 Torr to 10 Torr, and RF power of approximately 100W to 2500W using four 300mm stations. The process gas flow rates may be as follows: approximately 0.2 sccm to 2.0 sccm for the titanium-containing precursor (TDMAT), approximately 5,000 sccm to 10,000 sccm for the oxygen precursor or oxidant (O2, N2O) (e.g., 5,000 sccm of N2O), and approximately 0 to 10,000 sccm for the carrier gas (Ar or N2) (e.g., 5,000 sccm of Ar).

[0139] In embodiments involving the deposition of hafnium oxide, hafnium oxide may be deposited using a hafnium-containing precursor. Non-limiting examples include tetrakis(ethylmethylamino)hafnium, tetrakis(ethylmethylamide)hafnium, and hafnium tetrachloride. Tetrakis(ethylmethylamino)hafnium, tetrakis(ethylmethylamide)hafnium, and hafnium tetrachloride can be reacted with water, oxygen, or ozone to deposit hafnium oxide, respectively.

[0140] In embodiments involving the deposition of lead oxide, hafnium oxide may be deposited using a lead-containing precursor. Non-limiting examples include diethyl-dithiocarbamate lead, tetraphenyl-lead, and 2,2,6,6-tetramethyl-3,5-heptadione lead. Diethyl-dithiocarbamate lead, tetraphenyl-lead, and 2,2,6,6-tetramethyl-3,5-heptadione lead can each be reacted with ozone, oxygen plasma, or water vapor to form lead oxide.

[0141] Returning to Figure 2, in operation 209, the second conformal spacer material is etched to remove the horizontal portion. Such etching is performed using a gas and / or plasma chemical reaction based on the material used for the second conformal spacer material. The etching is performed selectively on the first SnO spacer. The robustness of the first SnO spacer allows for the removal of the horizontal portion of the second conformal spacer material using various etching chemical reactions. For example, if the second conformal spacer material is silicon oxide, a carbon fluoride-containing gas and / or plasma chemical reaction may be used to selectively remove the horizontal portion of the second conformal spacer material. In some embodiments, a bias is used to directionally etch the horizontal region of the second conformal spacer material. As a result of removing the horizontal region, a second spacer having the second conformal spacer material is formed.

[0142] In operation 211, the first spacer is selectively removed relative to the second spacer to form a mask made of the second conformal spacer material. Selective removal is performed by extrusion. During this operation, SnO is selectively removed by removing it from the substrate surface. SnO can be selectively dry-etched or removed using a hydrogen chemical reaction without causing etching of the second spacer, which is resistant to etching even when exposed to hydrogen. Such an etching process exhibits high etching selectivity for SnO relative to the second spacer.

[0143] When SnO is used as the second spacer instead of the first spacer, the removal of the first spacer may be performed using any etching technique suitable for etching silicon oxide, silicon nitride, titanium oxide, and lead oxide.

[0144] Figure 3E shows an example in which the horizontal region of the second conformal spacer material 320 is removed, the first spacer 319 is selectively removed from the substrate, and the second spacer 321 remains.

[0145] Returning to Figure 2, in operation 213, the target layer is etched using a mask. The etching chemical reaction and process conditions depend on the chemical properties of the target layer.

[0146] Figure 3F shows the patterned target layer 306 after etching the target layer 305 using the second spacer 321 as a mask. In this operation, the mask may be burned off during etching. The second spacer material does not need to be removable, as it can be etched or removed during the patterning of the target layer until the target layer is patterned. The patterned target layer 306 can have a pitch of approximately 40 nm or less.

[0147] In some embodiments, SnO can be used to create spacers in a self-aligning quad patterning scheme. SnO can form highly elastic spacers that allow for thinner spacers for smaller nodes requiring thinner spacers. This allows tin oxide spacers to be dry-etched with hydrogen while having a low wet etching rate with most wet etching chemicals, including but not limited to Standard Clean #1 (SC1), which contains dilute hydrofluoric acid, phosphoric acid, tetramethylammonium hydroxide (TMAH), 5 parts deionized water, 1 part ammonia water (29 wt% NH3), and 1 part 30% hydrogen peroxide (H2O2).

[0148] In the above example, SnO was used as the first conformal spacer material, and other oxides, nitrides, and carbides were used as the second conformal spacer material, but alternative embodiments may be used.

[0149] In some embodiments, the first conformal spacer material is SnO and the second conformal spacer material is silicon dioxide. In some embodiments, the first conformal spacer material is SnO and the second conformal spacer material is silicon nitride. In some embodiments, the first conformal spacer material is SnO and the second conformal spacer material is titanium dioxide. In some embodiments, the first conformal spacer material is SnO and the second conformal spacer material is hafnium oxide. In some embodiments, the first conformal spacer material is SnO and the second conformal spacer material is another oxide, or nitride, or carbide. In these examples, the first spacer of SnO can be removed using a hydrogen etching chemical reaction without etching silicon dioxide, silicon nitride, titanium dioxide, or hafnium oxide.

[0150] Since SnO can withstand process conditions even when silicon nitride is deposited at high temperatures, tin oxide can be used as the first conformal spacer material, and silicon nitride as the second conformal spacer material.

[0151] For example, in one exemplary alternative embodiment, SnO is deposited as the second conformal spacer material, while the first conformal spacer material is silicon nitride, titanium dioxide, hafnium oxide, amorphous silicon, or a high-temperature oxide. These two spacer materials are selected such that at least one of the conformal spacer materials contains SnO, and the other conformal spacer material contains a material that has etching contrast with SnO, such as lead oxide, silicon nitride, titanium dioxide, hafnium oxide, amorphous silicon, or a high-temperature oxide. In some embodiments, hafnium oxide cannot be removed, so hafnium oxide may not be used as the first conformal spacer material.

[0152] When SnO is used as the second spacer, the deposition technique described above may be used for operation 203 in Figure 2.

[0153] Tin oxide as a second conformal spacer material is particularly useful in embodiments where the first conformal spacer material is removed using a wet chemical reaction, even if there are surface tension problems when using a liquid if other materials such as silicon-containing materials are used as the second conformal spacer material. For example, dilute hydrofluoric acid can be used to remove silicon oxide. Since SnO is a robust material, if silicon oxide is used as the first conformal spacer material and dilute hydrofluoric acid is used to selectively remove the silicon oxide from the second conformal SnO spacer material, the risk of bending, buckling, and other strain problems in the SnO will be reduced.

[0154] Furthermore, certain disclosed embodiments are particularly suitable for forming features with very low line-wise roughness on their surface. For example, a feature may have a line-wise roughness of less than about 1.2 nm.

[0155] In some embodiments, when the other of the first or second conformal spacer material also contains a group IV element, etching of SnO as either the first or second conformal spacer material may also include passivating the substrate using an oxygen plasma flash operation to achieve sharp etching. The oxygen plasma flash operation forms silicon oxide, which is a more robust material than chlorine, and then proceeds to over-etching of chlorine. When removing the first conformal spacer material from a second conformal spacer material of a certain silicon-containing type (such as polysilicon), removing the first conformal spacer material by directly using a hydrogen chemical reaction without performing a plasma flash operation carries the risk of degradation on the second conformal spacer material. For robust silicon oxide, silicon nitride, or silicon carbide, a flash operation is not necessary to prevent etching of the second conformal spacer material when removing the first conformal spacer material.

[0156] While this specification describes spacer-on-spacer patterning, it will be understood that certain disclosed embodiments may be suitable for other applications where it is desirable to use removable materials and complementary materials to the removable materials, and to perform other patterning or processing schemes involving deposition and etching.

[0157] Device Another embodiment of the implementation disclosed herein is an apparatus and system configured to achieve the method described herein. A suitable apparatus includes hardware for achieving the process operation and a system controller having instructions for controlling the process operation according to the disclosed implementation. In some embodiments, a deposition apparatus for depositing a SnO layer is provided. In some embodiments, this is an ALD apparatus (e.g., a PEALD apparatus). In other embodiments, this may be a CVD apparatus or a sputtering apparatus including a SnO target. The apparatus includes a process chamber, a support for fixing the substrate in place during deposition, and an inlet for introducing process gas into the process chamber, and may also include a system for forming plasma within the process chamber. Furthermore, the apparatus includes a controller having program instructions for depositing a SnO layer according to the method provided herein.

[0158] The dry etching operations provided herein can be performed in a variety of apparatuses comprising supply lines and control mechanisms configured for supplying gaseous reagents. Suitable process chambers include plasma etching chambers, RIE chambers, isotropic etching chambers, and resist stripping chambers. In some embodiments, the dry etching apparatus includes a process chamber housing a support for holding a substrate and a supply line for supplying one or more process gases to the process chamber. In some embodiments, the apparatus further includes a system for generating plasma in the process gases. The process chamber may further include a controller that includes program instructions for performing etching. These instructions include instructions for supplying process gases, instructions for setting temperature and pressure within the process chamber, and instructions regarding plasma parameters.

[0159] The wet etching operations provided herein can be performed in a variety of apparatus configured to supply a wet etchant onto a substrate. These may be configured for immersing the substrate in the liquid etchant, spraying or flowing the etchant onto the substrate, or for other contact methods. In some embodiments, the apparatus includes a support for holding the substrate in place during etchant supply (in which case the support may be configured to rotate the substrate), and one or more supply ports (e.g., nozzles) configured to spray or flow the liquid etchant onto the substrate. The apparatus may further include a controller having programmable instructions for the wet etching process.

[0160] In another embodiment, a system is provided which includes a deposition chamber configured for depositing a SnO layer and one or more etching chambers (such as a RIE chamber or a wet etching chamber) configured for etching one or more materials on a substrate. The system further includes a controller having program instructions for depositing a SnO layer and forming a SnO spacer according to the method disclosed herein.

[0161] The PEALD apparatus will be described below as an example of an apparatus suitable for depositing SnO layers according to the method provided herein.

[0162] In some embodiments, conformal deposition of the SnO layer is carried out in a PEALD reactor, which is part of the Vector Excel deposition module available from Lam Research Corp. in Fremont, California. A suitable process chamber includes a support (wafer pedestal) for holding the wafer substrate during deposition, a generator for forming plasma within the process chamber, and conduits for supplying process gas components (tin-containing precursor, oxygen-containing reactant, carrier gas, etc.) into the process chamber. The apparatus is further configured to purge and / or evacuate the process chamber and maintain the inside of the process chamber at a desired pressure and temperature during deposition.

[0163] Examples of PEALD process chambers are described in U.S. Patents 6,416,822, 6,428,859, and 8,747,964, which are incorporated herein by reference in their entirety.

[0164] Figure 4 schematically shows one embodiment of a process station 400 that may be used to deposit a provided SnO film. For simplicity, the process station 400 is shown as a standalone process station having a process chamber body 402 for maintaining a low-pressure environment. However, it will be understood that multiple process stations 400 may be included in a common process tool environment. Furthermore, it will be understood that in some embodiments, one or more hardware parameters of the process station 400, including those discussed in detail below, may be programmed by one or more computer controllers.

[0165] The process station 400 is in fluid communication with a reagent supply system 401 for supplying process gas to a showerhead 406. The reagent supply system 401 includes a mixing vessel 404 for blending and / or conditioning the process gas for supply to the showerhead 406. One or more mixing vessel inlet valves 420 may control the introduction of process gas into the mixing vessel 404. Similarly, a showerhead inlet valve 405 may control the introduction of process gas into the showerhead 406.

[0166] Some reactants may be stored in liquid form before vaporization and during subsequent supply to the process station. For example, the embodiment in Figure 4 includes a vaporization point 403 for vaporizing a liquid reactant supplied to a mixing vessel 404. In some embodiments, the vaporization point 403 may be a heated vaporizer. The reactant vapor produced from such a vaporizer may be condensed in a downstream feed pipe. Exposure of an immiscible gas to the condensed reactant may generate particulate matter. This particulate matter may clog pipes, interfere with valve operation, or contaminate substrates. Some approaches addressing this problem involve cleaning and / or evacuating the feed pipe to remove residual reactant. However, cleaning the feed pipe may increase the cycle time of the process station and reduce the throughput of the processing station. Therefore, in some embodiments, the feed pipe downstream of the vaporization point 403 may be heat-trace. In some examples, the mixing vessel 404 may also be heat-trace. In one non-limiting example, the downstream pipe of the vaporization point 403 has a temperature profile that rises from approximately 100°C to approximately 150°C in the mixing vessel 404.

[0167] In some embodiments, the reactant liquid may be vaporized in a liquid injector. For example, the liquid injector may inject pulses of the liquid reactant into the carrier gas flow upstream of the mixing vessel. In one scenario, the liquid injector may vaporize the reactant by forcefully flowing the liquid from a higher pressure to a lower pressure. In another scenario, the liquid injector may atomize the liquid into dispersed microdroplets, which are then vaporized in the heating supply pipe. It will be understood that smaller droplets vaporize faster than larger droplets, thus reducing the delay time from liquid injection to the completion of vaporization. Faster vaporization may result in a shorter length of pipe downstream from the vaporization point 403. In one scenario, the liquid injector may be directly mounted to the mixing vessel 404. In another scenario, the liquid injector may be directly mounted to the showerhead 406.

[0168] In some embodiments, a liquid flow controller upstream of the vaporization point 403 may be provided to control the mass flow of the vaporized liquid supplied to the process station 400. For example, the liquid flow controller (LFC) may include a thermal mass flowmeter (MFM) located downstream of the LFC. The plunger valve of the LFC may then be adjusted in response to a feedback control signal from a proportional-differential-integral (PID) controller electrically connected to the MFM. However, stabilizing the liquid flow by feedback control may take more than two minutes. This may result in longer dosing times for the liquid reagent. Therefore, in some embodiments, the LFC may be dynamically switched between feedback control mode and direct control mode. In some embodiments, the LFC may be dynamically switched from feedback control mode to direct control mode by disabling the sense tubes of the LFC and the PID controller.

[0169] The showerhead 406 distributes the process gas toward the substrate 412. In the embodiment shown in Figure 4, the substrate 412 is positioned below the showerhead 406 and is shown resting on a base 408. It will be understood that the showerhead 406 may have any suitable shape and may have any suitable number and arrangement of ports for distributing the process gas toward the substrate 412.

[0170] In some embodiments, the microvolume section 407 is located below the showerhead 406. Performing the ALD process within the microvolume section rather than the entire volume of the process station can reduce reactant exposure and cleaning times, shorten the time required to change process conditions (e.g., pressure, temperature, etc.), or limit the exposure of the process station's robotics to process gases. Examples of microvolume section sizes include, but are not limited to, volumes between 0.1 liters and 2 liters. This microvolume section also impacts productivity throughput. A reduced deposition rate per cycle simultaneously shortens the cycle time. In certain cases, the latter effect can be dramatic enough to improve the overall throughput of a module with a given target film thickness.

[0171] In some embodiments, the base 408 may be raised or lowered to expose the substrate 412 to the minute volume portion 407 and / or to change the volume of the minute volume portion 407. For example, during the substrate transport stage, the base 408 may be lowered so that the substrate 412 can be mounted on the base 408. During the deposition process stage, the base 408 may be raised to position the substrate 412 within the minute volume portion 407. In some embodiments, the minute volume portion 407 may completely enclose not only the substrate 412 but also a portion of the base 408, forming a high-flow-impedance region during the deposition process.

[0172] Optionally, the base 408 may be lowered and / or raised between parts of the deposition process to adjust the process pressure, reagent concentration, etc., within the microvolume section 407. In one scenario where the process chamber body 402 remains at a reference pressure during the deposition process, the base 408 may be lowered to allow the microvolume section 407 to be evacuated. Examples of the ratio of the microvolume section to the volume of the process chamber include, but are not limited to, a volume ratio between 1:900 and 1:10. It will be understood that in some embodiments, the height of the base may be programmatically adjusted by a suitable computer controller.

[0173] In another scenario, the plasma density can be varied during plasma activation and / or processing cycles included in the deposition process by adjusting the height of the base 408. At the end of the deposition process stage, the base 308 can be lowered during another substrate transport stage to remove the substrate 412 from the base 408.

[0174] While the modifications of the microvolume portion described herein describe a height-adjustable base, it will be understood that in some embodiments, the volume of the microvolume portion 407 may be changed by adjusting the position of the shower head 406 relative to the base 408. Furthermore, it will be understood that the vertical position of the base 408 and / or the shower head 406 may be changed by any suitable mechanism within the scope of this disclosure. In some embodiments, the base 408 may include a pivot axis for rotating the orientation of the substrate 412. In some embodiments, it will be understood that one or more of these adjustment examples may be programmed by one or more suitable computer controllers.

[0175] Returning to the embodiment shown in Figure 4, the showerhead 406 and base 408 electrically communicate with the RF power supply 414 and matching network 416 to power the plasma. In some embodiments, the plasma energy may be controlled by controlling one or more of the process station pressure, gas concentration, RF source power, RF source frequency, and plasma power pulse timing. For example, the RF power supply 414 and matching network 416 may operate at any suitable power to form a plasma having radical species of a desired composition. Examples of suitable power are included above. Similarly, the RF power supply 414 may supply RF power at any suitable frequency. In some embodiments, the RF power supply 414 may be configured to control high-frequency and low-frequency RF power supplies independently of each other. Examples of low-frequency RF frequencies include, but are not limited to, frequencies between 50 kHz and 900 kHz. Examples of high-frequency RF frequencies include, but are not limited to, frequencies between 1.8 MHz and 2.45 GHz. It will be understood that any suitable parameters may be tuned discretely or continuously to provide plasma energy for surface reactions. In one non-limiting example, plasma power may be pulsed intermittently to reduce ion bombardment to the substrate surface compared to a plasma that is continuously powered.

[0176] 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 emission spectrometers (OES). In some embodiments, one or more plasma parameters may be programmed to adjust based on measurements from such in-situ plasma monitors. For example, OES sensors may be used in a feedback loop for programmed control of plasma power. In some embodiments, it will be understood that other monitors may be used to monitor the plasma and other process characteristics. Such monitors include, but are not limited to, infrared (IR) monitors, acoustic monitors, and pressure transducers.

[0177] In some embodiments, the plasma may be controlled via input / output control (IOC) sequence instructions. In one example, instructions for setting plasma conditions for a plasma process stage may be included in the corresponding plasma activation recipe stage of the deposition process recipe. In some cases, process recipe stages may be arranged sequentially so that all instructions for a deposition process stage are executed simultaneously with that process stage. In some embodiments, instructions for setting one or more plasma parameters may be included in recipe stages preceding the plasma process stage. For example, a first recipe stage may include instructions for setting the flow rates of the process gas and / or each of its components, instructions for setting the plasma generator to a power setpoint, and a time delay instruction for the first recipe stage. A subsequent second recipe stage may include instructions for enabling the plasma generator and a time delay instruction for the second recipe stage. A third recipe stage may include instructions for deactivating the plasma generator and a time delay instruction for the third recipe stage. It will be understood that these recipe stages may be further subdivided and / or repeated in any suitable manner within the scope of this disclosure.

[0178] In some embodiments, the base 408 may be temperature-controlled via a heater 410. Furthermore, in some embodiments, pressure control of the process station 400 may be provided by a butterfly valve 418. As shown in the embodiment of Figure 4, the butterfly valve 418 throttles the vacuum provided by a downstream vacuum pump (not shown). However, in some embodiments, pressure control of the processing station 400 may be controlled by changing the flow rate of one or more gases introduced into the process station 400.

[0179] The process station 400 also includes a controller 450 that can be programmed to perform functions for operating a particular disclosed embodiment. The controller 450 may have one or more features further described below with respect to the system controller 550 in Figure 5 or the controller 629 in Figure 6. In some embodiments, the controller 629 or the system controller 550 includes the controller 450.

[0180] In some embodiments, the substrates provided herein are processed in a multi-station tool. Figure 5 shows a schematic diagram of one embodiment of a multi-station processing tool 500 having an inbound load lock 502 and an outbound load lock 504, either or both of which may be equipped with a remote plasma source. An atmospheric robot 506 is configured to move a wafer from a cassette mounted via a pod 508 into the inbound load lock 502 via an atmospheric port 510. The wafer is then placed by the robot 506 on a pedestal 512 within the inbound load lock 502, the atmospheric port 510 is closed, and the load lock is pumped down. If the inbound load lock 502 is equipped with a remote plasma source, the wafer may be exposed to remote plasma processing within the load lock before being introduced into the processing chamber 514. Furthermore, the wafer may also be heated within the inbound load lock 502, for example, to remove moisture and adsorbed gases. Next, the chamber transfer port 516 to the processing chamber 514 is opened, and another robot (not shown) places the wafer into the reactor and positions it for processing on the base of the first station shown inside the reactor.

[0181] The illustrated process chamber 514 comprises four process stations numbered 1 to 4 in the embodiment shown in Figure 5. Each station has a heated base (indicated as 518 for station 1) and a gas line inlet. It will be understood that each process station may have different or more purposes in some embodiments. Although the illustrated process chamber 514 comprises four stations, it will be understood that the process chamber according to this disclosure may have any suitable number of stations. For example, in some embodiments the process chamber may have five or more stations, and in other embodiments the process chamber may have three or fewer stations.

[0182] Figure 5 also shows an embodiment of a wafer handling system 590 for transporting wafers within the processing chamber 514. In some embodiments, the wafer handling system 590 may transport wafers between various process stations and / or between process stations and load locks. It will be understood that any suitable wafer handling system may be employed. Non-limiting examples include wafer carousels and wafer handling robots. Figure 5 also shows an embodiment of a system controller 550 employed to control the process conditions and hardware state of the multi-station processing tool 500. The system controller 550 may include one or more memory devices 556, one or more mass storage devices 554, and one or more processors 552. The processors 552 may include a CPU or computer, analog and / or digital input / output connections, a stepping motor controller board, etc.

[0183] In some embodiments, the system controller 550 controls all activities of the processing tool 500. The system controller 550 is stored in a mass storage device 554, loaded into a memory device 556, and runs system control software 558 on the processor 552. The system control software 558 may include instructions for controlling timing, gas mixing, chamber and / or station pressure, chamber and / or station temperature, purge conditions and timing, wafer temperature, RF power level, RF frequency, substrate, pedestal, chuck and / or susceptor position, and other parameters of a particular process performed by the multi-station processing tool 500. The system control software 558 may be configured in any suitable way. For example, it may describe subroutines or control objects of various process tool components to control the operation of the process tool components necessary to perform various processing tool processes according to the disclosed method. The system control software 558 may be coded in any suitable computer-readable programming language.

[0184] In some embodiments, the system control software 558 may include input / output control (IOC) sequence instructions for controlling the various parameters described above. For example, each stage of the PEALD process may include one or more instructions executed by the system controller 550.

[0185] In some embodiments, other computer software and / or programs stored in the mass storage device 554 and / or memory device 556 associated with the system controller 550 may be employed. Examples of programs or parts of programs for this purpose include substrate positioning programs, process gas control programs, pressure control programs, heater control programs, and plasma control programs.

[0186] The substrate positioning program may include program code for process tool components used to mount the substrate onto the base 518 and to control the spacing between the substrate and other components of the multi-station processing tool 500.

[0187] The process gas control program may include code for controlling the gas composition and flow rate, and optionally for introducing gas into one or more process stations before deposition, in order to stabilize the pressure within the process stations. The process gas control program may include code for controlling the gas composition and flow rate within any disclosed range. The pressure control program may include code for controlling the pressure within the process stations by adjusting, for example, the throttle valve of the process station's exhaust system, the gas flow into the process station, etc. The pressure control program may include code for maintaining the pressure within the process stations within any disclosed pressure range.

[0188] The heater control program may include code for controlling the current to the heating unit used to heat the substrate. Alternatively, the heater control program may control the supply of a heat transfer gas (such as helium) to the substrate. The heater control program may include instructions for maintaining the substrate temperature within any disclosed range.

[0189] The plasma control program may include code for setting the RF power level and frequency applied to process electrodes in one or more process stations, for example, using one of the RF power levels disclosed herein. The plasma control program may also include code for controlling the duration of each plasma exposure.

[0190] In some embodiments, a user interface associated with the system controller 550 may be present. The user interface may include a display screen, a graphic software display of the device and / or process conditions, and user input devices such as a pointing device, keyboard, touchscreen, and microphone.

[0191] In some embodiments, the parameters adjusted by the system controller 550 may relate to process conditions. Non-limiting examples include process gas composition and flow rate, temperature, pressure, plasma conditions (RF power level, frequency, and exposure time, etc.). These parameters may be provided to the user in the form of a recipe that can be entered using a user interface.

[0192] Signals for monitoring the process may be provided by analog and / or digital input connections from various process tool sensors to the system controller 550. Signals for controlling the process may be output to the analog and digital output connections of the multi-station processing tool 500. Non-limiting examples of process tool sensors that can be monitored include mass flow controllers, pressure sensors (such as pressure gauges), and thermocouples. Appropriately programmed feedback and control algorithms may be used in conjunction with data from these sensors to maintain process conditions.

[0193] The disclosed embodiments may be implemented using any suitable chamber. Examples of deposition systems include, but are not limited to, the ATLUS®, VECTOR®, and / or SPEED® product lines, available from Lam Research Corp., Fremont, California, or a variety of other commercially available processing systems. Two or more stations may perform the same function. Similarly, two or more stations may perform different functions. Each station can be designed / configured to perform a specific function / method as desired.

[0194] Figure 6 is a block diagram of a processing system suitable for carrying out a thin film deposition process according to a particular embodiment. The system 600 includes a transport module 603. The transport module 603 provides a clean pressurized environment to minimize the risk of contamination as the substrate moves between various reactor modules during the process. Mounted on the transport module 603 are two multi-station reactors 609 and 610, each capable of performing atomic layer deposition (ALD) and / or chemical vapor deposition (CVD) according to a particular embodiment. In other embodiments, one reactor may include a station configured to perform ALD and another reactor may include a station configured to perform etching. The multi-station reactors 609 and 610 may include a plurality of stations 611, 613, 615, and 617 that can perform operations sequentially or non-sequentially according to the disclosed embodiments. The stations may include a heated base or substrate support, one or more gas inlets or showerheads or dispersion plates.

[0195] Mounted on the transport module 603 may also be one or more single or multi-station modules 607 capable of performing plasma or chemical (non-plasma) pre-cleaning, or any other processes described in relation to the disclosed methods. In some cases, the multi-station modules 607 may be used for various processes, for example, to prepare substrates for deposition processes. The multi-station modules 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 in which wafers are stored before and after processing. An atmospheric robot (not shown) in the atmospheric transport chamber 619 may first remove the wafer from the wafer source module 601 to the load lock 621. A wafer transport device (typically a robotic arm unit) in the transport module 603 moves the wafer from the load lock 621 to modules mounted on the transport module 603, and between modules.

[0196] In various embodiments, the 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. The processor may include a CPU or computer, analog and / or digital input / output connections, a stepping motor controller board, and the like.

[0197] The controller 629 may control all activities of the deposition apparatus. The controller 629 runs system control software that includes an instruction set for controlling timing, gas mixing, chamber pressure, chamber temperature, wafer temperature, radio frequency (RF) power level, wafer chuck or pedestal position, and other parameters of a particular process. In some embodiments, other computer programs stored in a memory device associated with the controller 629 may be employed.

[0198] Typically, a user interface will be associated with the controller 629. The user interface may include a display screen, a graphic software display of the device and / or process conditions, and user input devices such as a pointing device, keyboard, touchscreen, and microphone.

[0199] The system control logic may be configured in any suitable way. Generally, this logic can be designed or configured in hardware and / or software. Instructions for controlling the driving electrical circuits may be hardcoded or provided as software. Instructions may be provided by “programming.” Such programming is understood to include any form of logic, including hardcoded logic in digital signal processors, application-specific integrated circuits, and other devices with specific algorithms implemented as hardware. Programming is also understood to include software or firmware instructions that can be executed on a general-purpose processor. The system control software may be coded in any suitable computer-readable programming language.

[0200] Computer program code for controlling germanium-containing reducing agent pulses, hydrogen flow, tungsten-containing precursor pulses, and other processes in the process sequence can be written in any conventional computer-readable programming language, such as assembly language, C, C++, Pascal, Fortran, etc. The compiled object code or script is executed by the processor to perform tasks specified within the program. Alternatively, as mentioned above, the program code may be hardcoded.

[0201] Controller parameters relate to process conditions such as process gas composition and flow rate, temperature, pressure, cooling gas pressure, substrate temperature, and chamber wall temperature. These parameters may be provided to the user in the form of a recipe and may be entered using a user interface. Signals for monitoring the process may be provided by the analog and / or digital input connections of the system controller 629. Signals for controlling the process are output to the analog and digital output connections of the system 600.

[0202] The system software may be designed or configured in various ways. For example, various chamber component subroutines or control objects may be described to control the operation of the chamber components necessary to perform the deposition process (and, in some cases, other processes) according to the disclosed embodiments. Examples of programs or parts of programs for this purpose include substrate positioning code, process gas control code, pressure control code, and heater control code.

[0203] In some implementations, the controller 629 is part of a system that may be part of the examples described above. Such a system may include semiconductor processing equipment such as one or more processing tools, one or more chambers, one or more processing platforms, and / or specific processing components (wafer pedestals, gas flow systems, etc.). These systems may be integrated with electronic equipment for controlling the operation of the system before, during, and after processing semiconductor wafers or substrates. This electronic equipment may be referred to as a “controller” capable of controlling various components or sub-components of one or more systems. Depending on the processing requirements and / or the type of system, the controller 629 may be programmed to control any of the processes disclosed herein, such as supplying processing gases, setting temperature (e.g., heating and / or cooling), setting pressure, setting vacuum, setting power, setting radio frequency (RF) generators in some systems, setting RF matching circuits, setting frequency, setting flow rate, setting fluid supply, setting position and operation, loading and unloading wafers into and out of tools, and loading and unloading wafers into and out of other transport tools and / or load locks connected to or interlocked with a particular system.

[0204] Broadly speaking, a controller may be defined as an electronic device having various integrated circuits, logic, memory, and / or software that, for example, receive and issue commands, control operations, enable cleaning operations, and enable endpoint measurement. 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 (e.g., software) that execute program instructions. Program instructions are instructions transmitted to the controller in the form of various individual settings (or program files) that define operational parameters for performing a specific process on or for a semiconductor wafer, or for a system. In some embodiments, operational parameters may be part of a recipe defined by a process engineer to achieve one or more processing steps in the manufacture of one or more layers, materials, metals, oxides, silicon, silicon dioxide, planes, circuits, and / or wafer types.

[0205] In several implementations, the controller may be integrated into the system, coupled to it, networked to the system, or a combination of these, being part of or coupled to a computer. For example, the controller may be in the “cloud” or all or part of a host computer system in a manufacturing plant that enables remote access to wafer processing. This computer, by enabling remote access to the system, can monitor the current progress of an assembly operation, review the history of past assembly operations, examine trends or performance metrics from multiple assembly operations, modify parameters of the current process, set up subsequent processing steps for the current process, or start a new process. In some examples, a remote computer (e.g., a server) can provide process recipes to the system over a network that may include a local network or the internet. The remote computer may include a user interface that allows input or programming of parameters and / or settings, which are then transmitted from the remote computer to the system. In some examples, the controller receives instructions in the form of data that define the parameters of each processing step performed during one or more operations. It should be understood that these parameters may be specific to the type of process being performed and the type of tool to which the controller is configured to interface or control. Therefore, as described above, the controllers may be distributed by including one or more separate controllers that are networked together and work toward a common purpose such as the processes and control described herein. An example of controllers distributed for such purposes is one or more integrated circuits on the chamber that are combined to control a process on the chamber and communicate with one or more integrated circuits that are remotely located (e.g., at the platform level or as part of a remote computer).

[0206] Exemplary systems, though not limited to them, may include plasma etching chambers or modules, deposition chambers or modules, spin rinse chambers or modules, metal plating chambers or modules, clean chambers or modules, bevel edge etching chambers or modules, physical vapor deposition (PVD) chambers or modules, chemical vapor deposition (CVD) chambers or modules, atomic layer deposition (ALD) chambers or modules, atomic layer etching (ALE) chambers or modules, ion implantation chambers or modules, track chambers or modules, and any other semiconductor processing systems associated with or used in the assembly and / or manufacture of semiconductor wafers.

[0207] As described above, depending on one or more process steps performed by the tool, the controller may communicate with one or more other tool circuits or modules, other tool components, cluster tools, other tool interfaces, adjacent tools, neighboring tools, tools located throughout the factory, a main computer, other controllers, or one or more tools used for material handling to move wafer containers to tool locations and / or into and out of load ports within the semiconductor manufacturing plant.

[0208] The apparatus and processes described herein may be used in combination with lithography patterning tools or processes for, for example, the assembly or manufacture of semiconductor devices, displays, LEDs, photovoltaic panels, etc. Typically, such apparatus and processes are used or carried out together in a common assembly facility, though not necessarily. Lithography patterning of films typically includes some or all of the following steps, each step of which is performed with several possible tools: (1) coating of photoresist onto a workpiece (i.e., a substrate) using a spin-on or spray-on tool; (2) curing of the photoresist using a hot plate, furnace, or UV curing tool; (3) exposure of the photoresist to visible light, ultraviolet light, or X-rays using a tool such as a wafer stepper; (4) patterning of the resist using a tool such as a wet bench by growing the resist to selectively remove it; (5) transfer of the resist pattern to the underlying film or workpiece using a dry etching tool or plasma-assisted etching tool; and (6) removal of the resist using a tool such as an RF or microwave plasma resist stripper.

[0209] conclusion While the embodiments described above have been explained in some detail for clarity, it will be apparent that certain changes and modifications can be made within the scope of the appended claims. It should be noted that many alternative methods exist for realizing the processes, systems, and apparatus of these embodiments. Therefore, these embodiments are considered illustrative and not restrictive, and are not limited to the details shown herein. This disclosure may be implemented in the following forms: [Form 1] A method for processing a substrate, This includes performing spacer-on-spacer patterning on a semiconductor substrate using at least one spacer containing tin oxide. method. [Form 2] The method according to Embodiment 1, wherein spacer-on-spacer patterning is performed The first conformal spacer material is deposited on top of the patterned core material, A first spacer including the first conformal spacer material is formed by selectively etching the patterned core material. A second conformal spacer material is deposited on top of the first spacer, A second spacer comprising the second conformal spacer material is formed by selectively etching the first spacer, Etching the target layer using the aforementioned second spacer as a mask and Includes, The first conformal spacer material contains tin oxide, or the second conformal spacer material contains tin oxide. method. [Form 3] A method according to Embodiment 2, wherein the first conformal spacer material comprises tin oxide, and the first spacer is selectively etched by being removed using hydrogen gas. [Form 4] A method according to Embodiment 2, wherein at least one of the first conformal spacer material and the second conformal spacer material comprises tin oxide, and the other of the first conformal spacer material and the second conformal spacer material is selected from the group consisting of titanium oxide, silicon oxide, silicon nitride, hafnium oxide, and lead oxide. [Form 5] A method for processing a substrate, A substrate having a patterned core material is provided, A first material selected from the group consisting of silicon oxide, silicon nitride, titanium oxide, and lead oxide is conformally deposited on the sidewall of the patterned core material, A first spacer is formed by selectively removing the patterned core material, Conformally depositing a spacer material containing tin oxide onto the side wall of the first spacer, By selectively removing the first spacer, a second spacer containing tin oxide is formed. A method that includes this. [Form 6] A method for processing a substrate, A substrate having a patterned core material is provided, Conformally depositing tin oxide material onto the sidewalls of the core material from above the patterned core material, A tin oxide spacer is formed by selectively removing the patterned core material, A second spacer material is deposited on top of the tin oxide spacer, on the side wall of the tin oxide spacer, A second spacer is formed by selectively removing the tin oxide spacer, A method that includes this. [Form 7] A method for processing a substrate, Conformally depositing removable material on top of a core material, By selectively removing the horizontal region of the removable material and removing the core material, a spacer containing the removable material is formed. The method includes depositing a complementary material on a spacer containing the removable material, wherein the removable material is selectively etchable with respect to the complementary material. method. [Form 8] A method according to Embodiment 7, wherein at least one of the removable material and the complementary material comprises tin oxide, and the other of the removable material and the complementary material is selected from the group consisting of titanium oxide, silicon oxide, silicon nitride, hafnium oxide, and lead oxide. [Form 9] A method according to Embodiment 7, further comprising removing the spacer containing the removable material using hydrogen gas. [Form 10] A method according to any of forms 1 to 9, wherein the tin oxide is deposited using tin halides, organometallic tin-containing compounds, chlorinated organometallic tin-containing compounds, and combinations thereof.

Claims

1. A method for processing a substrate, The method includes performing spacer-on-spacer patterning on a semiconductor substrate using at least one spacer containing tin oxide, Performing the aforementioned spacer-on-spacer patterning is, A first spacer having the first conformal spacer material is formed by selectively etching a patterned core material from a substrate having the first conformal spacer material formed on the patterned core material, wherein the first conformal spacer material is selected from the group consisting of titanium oxide, silicon oxide, silicon nitride, and lead oxide. The present invention relates to forming a second spacer having a second conformal spacer material using the first spacer, wherein the second conformal spacer material contains tin, method.

2. The method according to claim 1, wherein spacer-on-spacer patterning is performed. The first conformal spacer material is deposited on top of the patterned core material, The first spacer, which includes the first conformal spacer material, is formed by selectively etching the patterned core material. The second conformal spacer material is deposited on top of the first spacer, The second spacer, which includes the second conformal spacer material, is formed by selectively etching the first spacer. Etching the target layer using the aforementioned second spacer as a mask and including, method.

3. A method for processing a substrate, A substrate having a patterned core material is provided, A first material selected from the group consisting of silicon oxide, silicon nitride, titanium oxide, and lead oxide is conformally deposited on the sidewall of the patterned core material, The first spacer is formed by selectively removing the patterned core material, Conformally depositing a spacer material containing tin oxide onto the side wall of the first spacer, By selectively removing the first spacer, a second spacer containing tin oxide is formed. A method that includes this.

4. A method for processing a substrate, A substrate having a patterned core material selected from the group consisting of silicon dioxide, silicon nitride, titanium dioxide, and lead oxide is provided. Conformally depositing tin oxide material onto the sidewalls of the core material from above the patterned core material, A tin oxide spacer is formed by selectively removing the patterned core material, A second spacer material is deposited on top of the tin oxide spacer, on the side wall of the tin oxide spacer, A second spacer is formed by selectively removing the tin oxide spacer, A method that includes this.

5. A method for processing a substrate, Conformally depositing removable material on top of a core material, By selectively removing the horizontal region of the removable material and removing the core material, a spacer containing the removable material is formed. The method includes depositing a complementary material on a spacer containing the removable material, wherein the removable material is selectively etchable with respect to the complementary material. The complementary material comprises tin oxide, and the removable material is selected from the group consisting of titanium oxide, silicon oxide, silicon nitride, hafnium oxide, and lead oxide. method.

6. A method according to claim 5, further comprising removing the spacer containing the removable material using hydrogen gas.

7. A method according to any one of claims 1 to 3, wherein the second spacer is deposited using at least one of tin halides, organometallic tin-containing compounds, chlorinated organometallic tin-containing compounds, and combinations thereof.

8. In the method according to any one of claims 1 to 2, A method wherein the first conformal spacer material is deposited at a temperature lower than the temperature at which the patterned core material is deposited.

9. In the method according to claim 5, A method wherein the removable material is deposited at a temperature lower than the temperature at which the core material is deposited.

10. In the method according to any one of claims 1 to 3, A method for passivating the substrate using an oxygen plasma flash operation.

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