Etchant compositions and related methods

Abstract

The invention provides an etchant composition for selectively etching silicon nitride in the presence of silicon oxide and polysilicon. The etchant composition can achieve passivation of at least one of silicon oxide, polysilicon, or any combination thereof in a single step by applying the etchant composition to a substrate while selectively etching silicon nitride. The etchant composition may include at least 60 wt% phosphoric acid based on the total weight of the etchant composition; at least 1% by weight of water based on the total weight of the etchant composition; and not more than 2% by weight of a metal oxidizing agent based on the total weight of the etchant composition.

Description

Technical Field

[0001] The present invention relates to an etchant composition for selective etching and related methods. Background Art

[0002] The fabrication of microelectronic devices involves the removal of materials by etching. The removal of these materials by etching can also result in the undesired removal of other materials. Summary of the Invention

[0003] Some embodiments relate to an etchant composition. In some embodiments, the etchant composition comprises at least 60 wt% phosphoric acid based on the total weight of the etchant composition. In some embodiments, the etchant composition comprises at least 3 wt% water based on the total weight of the etchant composition. In some embodiments, the etchant composition comprises no more than 2 wt% metal oxidant based on the total weight of the etchant composition.

[0004] Some embodiments relate to a method for selectively etching silicon nitride. In some embodiments, the method includes obtaining a substrate. In some embodiments, the substrate comprises a surface containing silicon nitride. In some embodiments, the substrate comprises a surface containing silicon oxide. In some embodiments, the substrate comprises a surface containing polysilicon. In some embodiments, the method includes obtaining an etchant composition. In some embodiments, the etchant composition comprises at least 60 wt% phosphoric acid based on the total weight of the composition. In some embodiments, the etchant composition comprises at least 3 wt% water based on the total weight of the composition. In some embodiments, the etchant composition comprises no more than 2 wt% metal oxidant based on the total weight of the composition. In some embodiments, the method includes contacting the substrate with the etchant composition.

[0005] Some embodiments relate to a method for preparing an etchant composition. In some embodiments, the method includes obtaining at least one of a metal oxidant, phosphoric acid, and water. In some embodiments, the method includes contacting the metal oxidant, the phosphoric acid, and the water to form an etchant composition. In some embodiments, the etchant composition comprises at least 60 wt% phosphoric acid based on the total weight of the composition. In some embodiments, the etchant composition comprises at least 3 wt% water based on the total weight of the composition. In some embodiments, the etchant composition comprises no more than 2 wt% metal oxidant based on the total weight of the composition. Brief Description of the Drawings

[0006] In this document, some embodiments of the present invention are described with reference to the accompanying drawings by way of example only. Now specifically referring to the figures in detail, it is emphasized that the illustrated embodiments are by way of example and for the purpose of an illustrative discussion of the embodiments of the present invention. In this regard, the description in conjunction with the figures will be apparent to those skilled in the art as to how to practice the embodiments of the present invention.

[0007] Figure 1 FIG. is a flowchart of a method for selectively etching silicon nitride according to some embodiments.

[0008] Figure 2 FIG. is a schematic diagram of a method for selectively etching silicon nitride according to some embodiments.

[0009] Figure 3 FIG. is a flowchart of a method for selectively etching silicon nitride according to some embodiments. DETAILED DESCRIPTION

[0010] Among the benefits and improvements already disclosed, other objects and advantages of the present invention will become apparent from the following description in conjunction with the accompanying drawings. Specific embodiments of the present invention are disclosed herein; however, it should be understood that the disclosed embodiments are only illustrative of the present invention which can be implemented in various forms. In addition, each of the examples given with respect to the various embodiments of the present invention is intended to be illustrative and not restrictive.

[0011] The entire text of any prior patents and publications referred to herein is incorporated by reference.

[0012] Throughout this specification and the claims, unless the context clearly dictates otherwise, the following terms are employed with the meanings specifically associated herewith. As used herein, the phrases "in one embodiment", "in an embodiment", and "in some embodiments" do not necessarily refer to the same embodiment, although they may. In addition, as used herein, the phrases "in another embodiment" and "in some other embodiments" do not necessarily refer to different embodiments, although they may. All embodiments of the present invention are intended to be combinable without departing from the scope or spirit of the present invention.

[0013] As used herein, the term "alkyl" refers to a hydrocarbon compound having 1 to 30 carbon atoms. An alkyl having n carbon atoms may be designated as "C n alkyl". For example, "C3 alkyl" may include n-propyl and isopropyl. An alkyl having a series of carbon atoms (such as 1 to 30 carbon atoms) may be designated as C1-C 30 alkyl. In some embodiments, the alkyl is straight-chain. In some embodiments, the alkyl is branched-chain. In some embodiments, the alkyl is substituted. In some embodiments, the alkyl is unsubstituted. In some embodiments, the alkyl includes or is selected from the group consisting of at least one of the following: C1-C 10Alkyl, C1-C9 alkyl, C1-C8 alkyl, C1-C7 alkyl, C1-C6 alkyl, C1-C5 alkyl, C1-C4 alkyl, C1-C3 alkyl, C2-C 10 alkyl, C3-C 10 alkyl, C4-C 10 alkyl, C5-C 10 alkyl, C6-C 10 alkyl, C7-C 10 alkyl, C8-C 10 alkyl, C2-C9 alkyl, C2-C8 alkyl, C2-C7 alkyl, C2-C6 alkyl, C2-C5 alkyl, C3-C5 alkyl, or any combination thereof. In some embodiments, the alkyl includes or is selected from the group consisting of at least one of the following: methyl, ethyl, n-propyl, 1-methylethyl (isopropyl), n-butyl, isobutyl, sec-butyl, n-pentyl, 1,1-dimethylethyl (tert-butyl), n-pentyl, isopentyl, n-hexyl, isohexyl, 3-methylhexyl, 2-methylhexyl, heptyl, octyl, nonyl, decyl, dodecyl, octadecyl, or any combination thereof.

[0014] As used herein, the term "alkenyl" refers to a hydrocarbon chain group having 1 to 10 carbon atoms and at least one carbon-carbon double bond. Examples of alkenyl include (but are not limited to) at least one of the following: vinyl, allyl, 1-methylethenyl, 1-propenyl, 1-butenyl, 2-butenyl, 3-butenyl, 1,3-butadienyl, 2-methyl-1-propenyl, 2-methyl-2-propenyl, 1-pentenyl, 2-pentenyl, 3-pentenyl, 4-pentenyl, 1,3-pentadienyl, 2,4-pentadienyl, 1,4-pentadienyl, 3-methyl-2-butenyl, 1-hexenyl, 2-hexenyl, 3-hexenyl, 1,3-hexadienyl, 1,4-hexadienyl, 2-methylpentenyl, 1-heptenyl, 3-heptenyl, 1-octenyl, 1,3-octadienyl, 1-nonenyl, 2-nonenyl, 3-nonenyl, 1-decenyl, 3-decenyl, 1-undecenyl, oleyl, linoleyl, linolenyl, or any combination thereof.

[0015] As used herein, the term "alkynyl" refers to a hydrocarbon chain group having 1 to 10 carbon atoms and at least one carbon-carbon triple bond. Examples of alkynyl include (but are not limited to) at least one of the following: ethynyl, propynyl, n-butynyl, n-pentynyl, 3-methyl-1-butynyl, n-hexynyl, methyl-pentynyl, or any combination thereof.

[0016] As used herein, the term "alkoxy" refers to a group of the formula -OR, where R is an alkyl group as defined herein. In some embodiments, the alkoxy may comprise, consist of, consist essentially of, or alternatively consist of at least one member selected from the group consisting of: methoxy, ethoxy, methoxy, ethoxy, n-propoxy, 1-methylethoxy (isopropoxy), n-butoxy, isobutoxy, sec-butoxy, tert-butoxy, or any combination thereof.

[0017] As used herein, the terms "amine", "alkylamino" and the like refer to a group of the formula -N(R a R b R c ), where R a , R b and R cEach is independently hydrogen or an alkyl group as defined herein. In some embodiments, the term "amine" includes an amino group as defined herein. In some embodiments, the amine may comprise, consist of, or consist essentially of a primary amine, a secondary amine, a tertiary amine, or a quaternary amine. In some embodiments, the amine may comprise, consist of, or consist essentially of an alkylamine, a dialkylamine, or a trialkylamine. In some embodiments, the amine may comprise, consist of, or consist essentially of, or alternatively may be selected from the group consisting of at least one of the following: methylamine, dimethylamine, ethylamine, diethylamine, isopropylamine, diisopropylamine, butylamine, sec-butylamine, tert-butylamine, di-sec-butylamine, isobutylamine, diisobutylamine, di-tert-pentylamine, ethylmethylamine, isopropyl-n-propylamine, or any combination thereof. Examples of alkylamines may include, but are not limited to, one or more of the following: primary alkylamines such as, for example and without limitation, methylamine, ethylamine, n-propylamine, isopropylamine, n-butylamine, sec-butylamine, isobutylamine, tert-butylamine, pentylamine, 2-aminopentane, 3-aminopentane, 1-amino-2-methylbutane, 2-amino-2-methylbutane, 3-amino-2-methylbutane, 4-amino-2-methylbutane, hexylamine, 5-amino-2-methylpentane, heptylamine, octylamine, nonylamine, decylamine, undecylamine, dodecylamine, tridecylamine, tetradecylamine, pentadecylamine, hexadecylamine, heptadecylamine, and octadecylamine; secondary alkylamines such as, for example and without limitation, dimethylamine, diethylamine, dipropylamine, diisopropylamine, dibutylamine, diisobutylamine, di-sec-butylamine, di-tert-butylamine, dipentylamine, dihexylamine, diheptylamine, dioctylamine, dinonylamine, didecylamine, methylethylamine, methylpropylamine, methylisopropylamine, methylbutylamine, methylisobutylamine, methylsec-butylamine, methyltert-butylamine, methylpentylamine, methylisopentylamine, ethylpropylamine, ethylisopropylamine, ethylbutylamine, ethylisobutylamine, ethylsec-butylamine, ethylamine, ethylisopentylamine, propylbutylamine, and propylisobutylamine; and tertiary alkylamines such as, for example and without limitation, trimethylamine, triethylamine, tripropylamine, tributylamine, tripentylamine, dimethylethylamine, methyldiethylamine, and methyldipropylamine. Examples of polyamines may include, but are not limited to, one or more of the following: ethylenediamine, propylenediamine, trimethylenediamine, tetramethylenediamine, 1,3-diaminobutane, 2,3-diaminobutane, pentamethylenediamine, 2,4-diaminopentane, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, N-methylethylenediamine, N,N-dimethylethylenediamine, trimethylethylenediamine, N-ethylethylenediamine, N,N-diethylethylenediamine, triethylethylenediamine, 1,2,3-triaminopropane, hydrazine, tris(2-aminoethyl)amine, tetrakis(aminomethyl)methane, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, heptaethylenooctamine, nonaethylenedecamine, and diazabicycloundecene.

[0018] As used herein, the term "cycloalkyl" refers to a non-aromatic carbocyclic group that is connected via a single bond and has 3 to 8 carbon atoms in the ring. The term includes monocyclic non-aromatic carbocycles and polycyclic non-aromatic carbocycles. For example, two or more cycloalkyl groups can be fused, bridged, or fused and bridged to obtain a polycyclic non-aromatic carbocycle. In some embodiments, the cycloalkyl can comprise, consist of, or consist essentially of, or alternatively be selected from the group consisting of: cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, or at least one of any combination thereof.

[0019] As used herein, the term "aryl" refers to a monocyclic or polycyclic aromatic hydrocarbon compound. The number of carbon atoms of the aryl can range from 5 carbon atoms to 100 carbon atoms. In some embodiments, the aryl has 5 to 20 carbon atoms. For example, in some embodiments, the aryl has 6 to 8 carbon atoms, 6 to 10 carbon atoms, 6 to 12 carbon atoms, 6 to 15 carbon atoms, or 6 to 20 carbon atoms. When used as a modifier, the term "monocyclic" refers to an aryl having a single aromatic ring structure. When used as a modifier, the term "polycyclic" refers to an aryl having more than one aromatic ring structure, which can be a fused, bridged, spiro-connected, or otherwise bonded ring structure. Examples of aryl include (but are not limited to) phenyl, biphenyl, naphthyl, and the like. In some embodiments, at least one carbon atom of the aryl (e.g., in the aromatic ring structure) is substituted with a heteroatom (including, for example and without limitation, at least one of O, N, etc.).

[0020] As used herein, the term "microelectronic device" (or "microelectronic device substrate" or simply "substrate") is used in a manner consistent with the general understanding of this term in the fields of electronic devices, microelectronic devices, and semiconductor manufacturing technologies, for example to refer to any one of the following various different types: semiconductor substrate; integrated circuit; solid-state memory device; rigid memory disk; read, write, and read / write heads and their mechanical or electronic components; flat panel display; phase change memory device; solar panel and other products comprising one or more solar cell devices; photovoltaics; and microelectromechanical systems (MEMS) fabricated for microelectronics, integrated circuit, energy harvesting, or computer chip applications. It should be understood that the term "microelectronic device" can refer to a microelectronic device or microelectronic device substrate in any process that contains or is prepared to contain functional electronic (current-carrying) structures, functional semiconductor structures, and insulating structures for ultimate electronic use in a microelectronic device or microelectronic assembly.

[0021] As used herein, the term "silicon nitride" means in accordance with the meaning of said term as used in the microelectronics and semiconductor manufacturing industries. Consistent therewith, silicon nitride refers to a material comprising a thin film prepared from amorphous silicon nitride, having commercially available low levels of other materials or impurities and some potential variation around the nominal stoichiometry of Si3N4. Silicon nitride can be present as part of a microelectronic device substrate as a functional feature of the device, e.g., as a barrier layer or an insulating layer, or can be present to function as a material facilitating a multi-step manufacturing method for preparing microelectronic devices.

[0022] As used herein, the term "silicon oxide" means in accordance with the meaning of said term as used in the microelectronics and semiconductor manufacturing industries. Consistent therewith, silicon oxide refers to thin films prepared from silicon oxide (SiOx) (e.g., SiO2), "thermal oxide" (ThOx), and the like. Silicon oxide can be deposited by any method, such as by chemical vapor deposition from tetraethyl orthosilicate (TEOS) or another source or can be placed on a substrate by thermal deposition. Silicon oxide can advantageously contain commercially available low levels of other materials or impurities. Silicon oxide can be present as part of a microelectronic device substrate as a feature of the microelectronic device, e.g., as an insulating layer.

[0023] As used herein, the term "polycrystalline silicon" or polycrystalline Si or poly-Si is understood by those skilled in the art to be the polycrystalline form comprising multiple small silicon crystals of silicon. It is typically deposited using low pressure chemical vapor deposition (LPCVD) and is typically doped with n-type polycrystalline silicon or p-type polycrystalline silicon. The degree of doping can vary from lightly doped (e.g., in the range of 1013 cm -3 to 1018 cm -3 to heavily doped (e.g., greater than 1018 cm -3 ), as is readily understood by those skilled in the art. Examples of p-doped materials include polycrystalline silicon doped with a dopant substance from Group IIIA of the periodic table (such as at least one of boron, aluminum, gallium, indium, or any combination thereof). The n-doped material can be, for example, polycrystalline silicon doped with a dopant substance from Group IV (silicon, germanium, or tin) or Group V (phosphorus, arsenic, antimony, or bismuth) of the periodic table.

[0024] As used herein, unless the context clearly dictates otherwise, the term "based on" is non-exclusive and allows for additional factors not described. Further, throughout this specification, the meanings of "a / an" and "the" include plural referents. The meaning of "in" includes "in" and "on".

[0025] The fabrication of microelectronic devices and the fabrication of semiconductors can involve the removal of materials via etching. Silicon nitride is an example of a material that is removed during the fabrication of microelectronic devices. For example, silicon nitride can be deposited as a thin layer, optionally a patterned thin layer, on a substrate by chemical vapor deposition. During the fabrication process, the silicon nitride layer is to be removed at least in part. An etchant can be used to remove at least a portion of the silicon nitride layer. However, in addition to removing silicon nitride, current etchants remove or otherwise damage other materials that are present, such as, for example and without limitation, silicon oxide and polysilicon. The removal or damage of these other materials, including silicon oxide and polysilicon, is undesirable.

[0026] Some embodiments relate to etchant compositions that can be used in the fabrication of microelectronics, including the fabrication of semiconductors. The etchant compositions disclosed herein exhibit high selectivity for silicon nitride over other materials, including silicon oxide and polysilicon. That is, for example, the etchant compositions disclosed herein are capable of removing silicon nitride without removing or otherwise damaging a layer or surface that comprises at least one of silicon oxide, polysilicon, or any combination thereof. The etchant compositions can also exhibit a dual functionality in a single application. That is, for example, a single application of the etchant compositions disclosed herein can passivate polysilicon while also etching silicon nitride at a sufficiently high etch rate and while leaving silicon oxide intact. In other words, the passivation and etching processes can be achieved in a single step of the process. These and other advantages will be apparent from the disclosure herein.

[0027] The etchant compositions disclosed herein can comprise one or more components. In some embodiments, the etchant composition is the result of a combination of one or more components. In some embodiments, the etchant composition is a composition that comprises one or more components. In some embodiments, the etchant composition is a mixture of one or more components. In some embodiments, the etchant composition is derived from a formulation. In some embodiments, the etchant composition is the reaction product of a formulation, wherein the formulation comprises one or more components that undergo a reaction. In some embodiments, the etchant composition is the dissolution product of a formulation, wherein the formulation comprises one or more components that undergo dissociation or solubilization (e.g., dissolution). In some embodiments, the formulation comprises one or more inert components, wherein the one or more inert components do not undergo any physical or chemical change.

[0028] The etchant composition may include a solution. In some embodiments, the etchant composition includes a liquid solution. In some embodiments, the etchant composition contains a liquid solution and at least one solid component. In some embodiments, the etchant composition includes a slurry. In some embodiments, the etchant composition includes a suspension. In some embodiments, the etchant composition includes an emulsion. In some embodiments, the etchant composition includes a solution of at least one dissolved component. In some embodiments, the etchant composition includes any of the foregoing.

[0029] In some embodiments, the one or more components may include a metal oxidizer. In some embodiments, the metal oxidizer includes at least one of the following metals: Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Hf, Ta, W, Re, Os, Ir, Pt, Au, Hg, Ac, Th, Pa, U, Np, Pu, Am, Cm, Bk, Cf, Es, Fm, Md, No, Lr, Rf, Db, Sg, Bh, Hs, Mt, Ds, Rg, Cn, or any combination thereof. In some embodiments, the metal oxidizer includes at least one of the following: metal sulfate, metal oxysulfate, metal oxide, metal phosphate, metal dihydrogen phosphate, metal halide, metal hydroxide, metal acid, metal nitrate, metal ammonium nitrate, metal carbonate, any hydrate thereof, or any combination thereof. Examples of metal oxidizers include (but are not limited to) at least one of the following: titanium(IV) oxysulfate, titanium(IV) sulfate hydrate, phosphomolybdic acid hydrate, silicomolybdic acid, molybdenum(VI) oxide, molybdic acid, lanthanum oxide, cerium(IV) sulfate, ammonium cerium nitrate, phosphotungstic acid, vanadium pentoxide, cobalt(III) acetylacetonate, or any combination thereof.

[0030] A metal oxidant may be present as a dissolution product in an etchant composition. For example, in some embodiments, the metal oxidant dissociates in the etchant composition into a metal oxidant. In some embodiments, the metal oxidant dissociates into a metal cation and an anion. In some embodiments, the metal oxidant comprises a metal cation of at least one of the following metals: Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Hf, Ta, W, Re, Os, Ir, Pt, Au, Hg, Ac, Th, Pa, U, Np, Pu, Am, Cm, Bk, Cf, Es, Fm, Md, No, Lr, Rf, Db, Sg, Bh, Hs, Mt, Ds, Rg, Cn, or any combination thereof. In some embodiments, the metal oxidant comprises a metal cation in the highest oxidation state. In some embodiments, the metal oxidant comprises a metal cation not in the highest oxidation state. Examples of metal oxidants include (but are not limited to) at least one of the following: Ti +3 、Ti +4 、V +2 、V +3 、V +4 、V +5 、Co +2 、Co +3 、Ni +2 、Ni +3 、Ni +4 、Mo + 、Mo +2 、Mo +3 、Mo +4 、Mo +5 、Mo +6 、Ce + 、Ce +2 、Ce +3 、Ce +4 、W +6 、Pt +4 、Rh + 、Rh +2 、Rh +3 、Rh +4 、Rh +5 、Gd +3 、or any combination thereof.

[0031] The etchant composition may comprise from 0.001 wt% to 2 wt% of a metal oxidizer, or any range or sub-range between 0.001% and 2%, based on the total weight of the etchant composition. For example, in some embodiments, the etchant composition comprises from 0.02 wt% to 2 wt%, from 0.03 wt% to 2 wt%, from 0.04 wt% to 2 wt%, from 0.05 wt% to 2 wt%, from 0.06 wt% to 2 wt%, from 0.07 wt% to 2 wt%, from 0.08 wt% to 2 wt%, from 0.09 wt% to 2 wt%, from 0.1 wt% to 2 wt%, from 0.2 wt% to 2 wt%, from 0.3 wt% to 2 wt%, from 0.4 wt% to 2 wt%, from 0.5 wt% to 2 wt%, from 0.6 wt% to 2 wt%, from 0.7 wt% to 2 wt%, from 0.8 wt% to 2 wt%, from 0.9 wt% to 2 wt%, from 1 wt% to 2 wt%, from 1.1 wt% to 2 wt%, from 1.2 wt% to 2 wt%, from 1.3 wt% to 2 wt%, from 1.4 wt% to 2 wt%, from 1.5 wt% to 2 wt%, from 1.6 wt% to 2 wt%, from 1.7 wt% to 2 wt%, from 1.8 wt% to 2 wt%, from 1.9 wt% to 2 wt%, from 0.01 wt% to 1.9 wt%, from 0.01 wt% to 1.8 wt%, from 0.01 wt% to 1.7 wt%, from 0.01 wt% to 1.6 wt%, from 0.01 wt% to 1.5 wt%, from 0.01 wt% to 1.4 wt%, from 0.01 wt% to 1.3 wt%, from 0.01 wt% to 1.2 wt%, from 0.01 wt% to 1.1 wt%, from 0.01 wt% to 1 wt%, from 0.01 wt% to 0.9 wt%, from 0.01 wt% to 0.8 wt%, from 0.01 wt% to 0.7 wt%, from 0.01 wt% to 0.6 wt%, from 0.01 wt% to 0.5 wt%, from 0.01 wt% to 0.4 wt%, from 0.01 wt% to 0.3 wt%, from 0.01 wt% to 0.2 wt%, from 0.01 wt% to 0.1 wt%, from 0.01 wt% to 0.09 wt%, from 0.01 wt% to 0.08 wt%, from 0.01 wt% to 0.07 wt%, from 0.01 wt% to 0.06 wt%, from 0.01 wt% to 0.05 wt%, from 0.01 wt% to 0.04 wt%, from 0.01 wt% to 0.03 wt%, or from 0.01 wt% to 0.02 wt% of a metal oxidizer. In some embodiments, the wt% is based on the total weight of the formulation.

[0032] The etchant composition may comprise from 0.01 wt% to 0.5 wt% of a metal oxidizer, or any range or sub-range between 0.01% and 0.5%, based on the total weight of the etchant composition. In some embodiments, the etchant composition comprises from 0.01 wt% to 0.5 wt%, from 0.01 wt% to 0.45 wt%, from 0.01 wt% to 0.4 wt%, from 0.01 wt% to 0.35 wt%, from 0.01 wt% to 0.3 wt%, from 0.01 wt% to 0.25 wt%, from 0.01 wt% to 0.2 wt%, from 0.01 wt% to 0.15 wt%, from 0.01 wt% to 0.1 wt%, from 0.01 wt% to 0.05 wt%, from 0.02 wt% to 0.5 wt%, from 0.03 wt% to 0.5 wt%, from 0.04 wt% to 0.5 wt%, from 0.05 wt% to 0.5 wt%, from 0.06 wt% to 0.5 wt%, from 0.07 wt% to 0.5 wt%, from 0.08 wt% to 0.5 wt%, from 0.09 wt% to 0.5 wt%, from 0.1 wt% to 0.5 wt%, from 0.15 wt% to 0.5 wt%, from 0.2 wt% to 0.5 wt%, from 0.25 wt% to 0.5 wt%, from 0.3 wt% to 0.5 wt%, from 0.35 wt% to 0.5 wt%, from 0.4 wt% to 0.5 wt%, or from 0.45 wt% to 0.5 wt% of a metal oxidizer. In some embodiments, the wt% is based on the total weight of the formulation.

[0033] The etchant composition may comprise no more than 2 wt% of a metal oxidizer based on the total weight of the etchant composition. For example, in some embodiments, the etchant composition comprises no more than 1.9 wt%, no more than 1.8 wt%, no more than 1.7 wt%, no more than 1.6 wt%, no more than 1.5 wt%, no more than 1.4 wt%, no more than 1.3 wt%, no more than 1.2 wt%, no more than 1.1 wt%, no more than 1 wt%, no more than 0.9 wt%, no more than 0.8 wt%, no more than 0.7 wt%, no more than 0.6 wt%, no more than 0.5 wt%, no more than 0.4 wt%, no more than 0.3 wt%, no more than 0.2 wt%, no more than 0.1 wt%, no more than 0.09 wt%, no more than 0.08 wt%, no more than 0.07 wt%, no more than 0.06 wt%, no more than 0.05 wt%, no more than 0.04 wt%, no more than 0.03 wt%, no more than 0.02 wt%, no more than 0.01 wt%, no more than 0.009 wt%, no more than 0.008 wt%, no more than 0.007 wt%, no more than 0.006 wt%, no more than 0.005 wt%, no more than 0.004 wt%, no more than 0.003 wt%, no more than 0.002 wt% of a metal oxidizer based on the total weight of the etchant composition.

[0034] The etchant composition may comprise from 0.001 wt% to 2 wt% of a metal oxidizer, or any range or sub-range between 0.001% and 2%, based on the total weight of the etchant composition. For example, in some embodiments, the etchant composition comprises from 0.001 wt% to 1 wt%, from 0.02 wt% to 2 wt%, from 0.03 wt% to 2 wt%, from 0.04 wt% to 2 wt%, from 0.05 wt% to 2 wt%, from 0.06 wt% to 2 wt%, from 0.07 wt% to 2 wt%, from 0.08 wt% to 2 wt%, from 0.09 wt% to 2 wt%, from 0.1 wt% to 2 wt%, from 0.2 wt% to 2 wt%, from 0.3 wt% to 2 wt%, from 0.4 wt% to 2 wt%, from 0.5 wt% to 2 wt%, from 0.6 wt% to 2 wt%, from 0.7 wt% to 2 wt%, from 0.8 wt% to 2 wt%, from 0.9 wt% to 2 wt%, from 1 wt% to 2 wt%, from 1.1 wt% to 2 wt%, from 1.2 wt% to 2 wt%, from 1.3 wt% to 2 wt%, from 1.4 wt% to 2 wt%, from 1.5 wt% to 2 wt%, from 1.6 wt% to 2 wt%, from 1.7 wt% to 2 wt%, from 1.8 wt% to 2 wt%, from 1.9 wt% to 2 wt%, from 0.01 wt% to 1.9 wt%, from 0.01 wt% to 1.8 wt%, from 0.01 wt% to 1.7 wt%, from 0.01 wt% to 1.6 wt%, from 0.01 wt% to 1.5 wt%, from 0.01 wt% to 1.4 wt%, from 0.01 wt% to 1.3 wt%, from 0.01 wt% to 1.2 wt%, from 0.01 wt% to 1.1 wt%, from 0.01 wt% to 1 wt%, from 0.01 wt% to 0.9 wt%, from 0.01 wt% to 0.8 wt%, from 0.01 wt% to 0.7 wt%, from 0.01 wt% to 0.6 wt%, from 0.01 wt% to 0.5 wt%, from 0.01 wt% to 0.4 wt%, from 0.01 wt% to 0.3 wt%, from 0.01 wt% to 0.2 wt%, from 0.01 wt% to 0.1 wt%, from 0.01 wt% to 0.09 wt%, from 0.01 wt% to 0.08 wt%, from 0.01 wt% to 0.07 wt%, from 0.01 wt% to 0.06 wt%, from 0.01 wt% to 0.05 wt%, from 0.01 wt% to 0.04 wt%, from 0.01 wt% to 0.03 wt%, or from 0.01 wt% to 0.02 wt% of the metal oxidizer. In some embodiments, the wt% is based on the total weight of the formulation.

[0035] The etchant composition may comprise from 0.01 wt% to 0.5 wt% of a metal oxidizer, or any range or sub-range between 0.01% and 0.5%, based on the total weight of the etchant composition. In some embodiments, the etchant composition comprises from 0.01 wt% to 0.5 wt%, from 0.01 wt% to 0.45 wt%, from 0.01 wt% to 0.4 wt%, from 0.01 wt% to 0.35 wt%, from 0.01 wt% to 0.3 wt%, from 0.01 wt% to 0.25 wt%, from 0.01 wt% to 0.2 wt%, from 0.01 wt% to 0.15 wt%, from 0.01 wt% to 0.1 wt%, from 0.01 wt% to 0.05 wt%, from 0.02 wt% to 0.5 wt%, from 0.03 wt% to 0.5 wt%, from 0.04 wt% to 0.5 wt%, from 0.05 wt% to 0.5 wt%, from 0.06 wt% to 0.5 wt%, from 0.07 wt% to 0.5 wt%, from 0.08 wt% to 0.5 wt%, from 0.09 wt% to 0.5 wt%, from 0.1 wt% to 0.5 wt%, from 0.15 wt% to 0.5 wt%, from 0.2 wt% to 0.5 wt%, from 0.25 wt% to 0.5 wt%, from 0.3 wt% to 0.5 wt%, from 0.35 wt% to 0.5 wt%, from 0.4 wt% to 0.5 wt%, or from 0.45 wt% to 0.5 wt% of a metal oxidizer. In some embodiments, the wt% is based on the total weight of the formulation.

[0036] The etchant composition may comprise from 0.001 wt% to 2 wt% of a metal oxidant, based on the total weight of the etchant composition, or any range or sub-range between 0.001% and 2%. For example, in some embodiments, the etchant composition comprises from 0.02 wt% to 2 wt%, from 0.03 wt% to 2 wt%, from 0.04 wt% to 2 wt%, from 0.05 wt% to 2 wt%, from 0.06 wt% to 2 wt%, from 0.07 wt% to 2 wt%, from 0.08 wt% to 2 wt%, from 0.09 wt% to 2 wt%, from 0.1 wt% to 2 wt%, from 0.2 wt% to 2 wt%, from 0.3 wt% to 2 wt%, from 0.4 wt% to 2 wt%, from 0.5 wt% to 2 wt%, from 0.6 wt% to 2 wt%, from 0.7 wt% to 2 wt%, from 0.8 wt% to 2 wt%, from 0.9 wt% to 2 wt%, from 1 wt% to 2 wt%, from 1.1 wt% to 2 wt%, from 1.2 wt% to 2 wt%, from 1.3 wt% to 2 wt%, from 1.4 wt% to 2 wt%, from 1.5 wt% to 2 wt%, from 1.6 wt% to 2 wt%, from 1.7 wt% to 2 wt%, from 1.8 wt% to 2 wt%, from 1.9 wt% to 2 wt%, from 0.01 wt% to 1.9 wt%, from 0.01 wt% to 1.8 wt%, from 0.01 wt% to 1.7 wt%, from 0.01 wt% to 1.6 wt%, from 0.01 wt% to 1.5 wt%, from 0.01 wt% to 1.4 wt%, from 0.01 wt% to 1.3 wt%, from 0.01 wt% to 1.2 wt%, from 0.01 wt% to 1.1 wt%, from 0.01 wt% to 1 wt%, from 0.01 wt% to 0.9 wt%, from 0.01 wt% to 0.8 wt%, from 0.01 wt% to 0.7 wt%, from 0.01 wt% to 0.6 wt%, from 0.01 wt% to 0.5 wt%, from 0.01 wt% to 0.4 wt%, from 0.01 wt% to 0.3 wt%, from 0.01 wt% to 0.2 wt%, from 0.01 wt% to 0.1 wt%, from 0.01 wt% to 0.09 wt%, from 0.01 wt% to 0.08 wt%, from 0.01 wt% to 0.07 wt%, from 0.01 wt% to 0.06 wt%, from 0.01 wt% to 0.05 wt%, from 0.01 wt% to 0.04 wt%, from 0.01 wt% to 0.03 wt%, or from 0.01 wt% to 0.02 wt% of a metal oxidant. In some embodiments, the wt% is based on the total weight of the formulation.

[0037] The etchant composition may comprise from 0.001 wt% to 0.5 wt% of a metal oxidizer, based on the total weight of the etchant composition, or any range or sub-range between 0.001% and 0.5%. For example, in some embodiments, the etchant composition comprises from 0.002 wt% to 0.5 wt%, from 0.004 wt% to 0.5 wt%, from 0.005 wt% to 0.5 wt%, from 0.006 wt% to 0.5 wt%, from 0.008 wt% to 0.5 wt%, from 0.01 wt% to 0.5 wt%, from 0.01 wt% to 0.45 wt%, from 0.01 wt% to 0.4 wt%, from 0.01 wt% to 0.35 wt%, from 0.01 wt% to 0.3 wt%, from 0.01 wt% to 0.25 wt%, from 0.01 wt% to 0.2 wt%, from 0.01 wt% to 0.15 wt%, from 0.01 wt% to 0.1 wt%, from 0.001 wt% to 0.05 wt%, from 0.002 wt% to 0.5 wt%, from 0.003 wt% to 0.5 wt%, from 0.004 wt% to 0.5 wt%, from 0.005 wt% to 0.5 wt%, from 0.006 wt% to 0.5 wt%, from 0.007 wt% to 0.5 wt%, from 0.008 wt% to 0.5 wt%, from 0.009 wt% to 0.5 wt%, from 0.01 wt% to 0.05 wt%, from 0.02 wt% to 0.5 wt%, from 0.03 wt% to 0.5 wt%, from 0.04 wt% to 0.5 wt%, from 0.05 wt% to 0.5 wt%, from 0.06 wt% to 0.5 wt%, from 0.07 wt% to 0.5 wt%, from 0.08 wt% to 0.5 wt%, from 0.09 wt% to 0.5 wt%, from 0.1 wt% to 0.5 wt%, from 0.15 wt% to 0.5 wt%, from 0.2 wt% to 0.5 wt%, from 0.25 wt% to 0.5 wt%, from 0.3 wt% to 0.5 wt%, from 0.35 wt% to 0.5 wt%, from 0.4 wt% to 0.5 wt%, or from 0.45 wt% to 0.5 wt% of the metal oxidizer. In some embodiments, the wt% is based on the total weight of the formulation.

[0038] In some embodiments, the one or more components may include phosphoric acid or its derivatives. In some embodiments, the phosphoric acid is an active component for etching silicon nitride. In some embodiments, the phosphoric acid includes solid phosphoric acid. In some embodiments, the phosphoric acid is provided as an aqueous phosphoric acid solution. In some embodiments, the aqueous phosphoric acid solution contains at least one of phosphoric acid, water, at least one additional component, or any combination thereof. In some embodiments, the aqueous phosphoric acid solution contains 50 wt% to 99 wt% phosphoric acid based on the total weight of the aqueous phosphoric acid solution, or any range or sub-range therebetween. In some embodiments, the aqueous phosphoric acid solution contains 80 wt% to 90 wt% phosphoric acid based on the total weight of the aqueous phosphoric acid solution. In some embodiments, the aqueous phosphoric acid solution contains 80 wt% to 85 wt% phosphoric acid based on the total weight of the aqueous phosphoric acid solution. In some embodiments, the remainder of the aqueous phosphoric acid solution contains water or at least one additional component.

[0039] The etchant composition may contain at least 50 wt% phosphoric acid based on the total weight of the etchant composition. For example, in some embodiments, the etchant composition contains at least 60 wt%, at least 65 wt%, at least 70 wt%, at least 75 wt%, at least 80 wt%, at least 85 wt%, at least 90 wt%, or at least 95 wt% phosphoric acid based on the total weight of the etchant composition. In some embodiments, the etchant composition contains 50 wt% to 99 wt%, 55 wt% to 99 wt%, 60 wt% to 99 wt%, 65 wt% to 99 wt%, 70 wt% to 99 wt%, 75 wt% to 99 wt%, 80 wt% to 99 wt%, 85 wt% to 99 wt%, 90 wt% to 99 wt%, 95 wt% to 99 wt%, 50 wt% to 95 wt%, 50 wt% to 90 wt%, 50 wt% to 85 wt%, 50 wt% to 80 wt%, 50 wt% to 75 wt%, 50 wt% to 70 wt%, 50 wt% to 65 wt%, 50 wt% to 60 wt%, 50 wt% to 55 wt%, 70 wt% to 95 wt%, 75 wt% to 95 wt%, 80 wt% to 95 wt%, 85 wt% to 95 wt%, 90 wt% to 95 wt%, 70 wt% to 90 wt%, 70 wt% to 85 wt%, 70 wt% to 80 wt%, 75 wt% to 90 wt%, 75 wt% to 85 wt%, 80 wt% to 90 wt%, or 85 wt% to 90 wt% phosphoric acid.

[0040] In some embodiments, the one or more components may include water or any of its derivatives. In some embodiments, water is added to adjust the selectivity to silicon nitride, increase the etching rate of silicon nitride, or any combination thereof. The etchant composition may comprise at least 5 wt% water based on the total weight of the etchant composition. For example, in some embodiments, the etchant composition comprises at least 1 wt%, at least 3 wt%, at least 5 wt%, at least 10 wt%, at least 15 wt%, at least 20 wt%, at least 25 wt%, at least 30 wt%, at least 35 wt%, at least 40 wt%, at least 40 wt% water based on the total weight of the etchant composition. In some embodiments, the etchant composition comprises no more than 50 wt% water based on the total weight of the etchant composition. For example, in some embodiments, the etchant composition comprises no more than 45 wt%, no more than 40 wt%, no more than 35 wt%, no more than 30 wt%, no more than 25 wt%, no more than 20 wt%, no more than 15 wt%, no more than 10 wt%, or no more than 5 wt% water based on the total weight of the etchant composition.

[0041] The etchant composition may comprise from 1 wt% to 50 wt% water based on the total weight of the etchant composition, or any range or sub-range between 1% and 50%. For example, in some embodiments, the etchant composition comprises from 1 wt% to 45 wt%, 1 wt% to 40 wt%, 1 wt% to 35 wt%, 1 wt% to 30 wt%, 1 wt% to 25 wt%, 1 wt% to 20 wt%, 1 wt% to 15 wt%, 1 wt% to 10 wt%, 1 wt% to 5 wt%, 5 wt% to 45 wt%, 5 wt% to 40 wt%, 5 wt% to 35 wt%, 5 wt% to 30 wt%, 5 wt% to 25 wt%, 5 wt% to 20 wt%, 5 wt% to 15 wt%, 5 wt% to 10 wt%, 10 wt% to 50 wt%, 15 wt% to 50 wt%, 20 wt% to 50 wt%, 25 wt% to 50 wt%, 30 wt% to 50 wt%, 35 wt% to 50 wt%, 40 wt% to 50 wt%, 45 wt% to 50 wt%, 5 wt% to 25 wt%, 6 wt% to 25 wt%, 8 wt% to 25 wt%, 10 wt% to 25 wt%, 12 wt% to 25 wt%, 14 wt% to 25 wt%, 15 wt% to 25 wt%, 16 wt% to 25 wt%, 18 wt% to 25 wt%, 20 wt% to 25 wt%, 22 wt% to 25 wt%, 24 wt% to 25 wt%, 5 wt% to 24 wt%, 5 wt% to 22 wt%, 5 wt% to 18 wt%, 5 wt% to 16 wt%, 5 wt% to 14 wt%, 5 wt% to water.

[0042] In some embodiments, the one or more components may include a fluoride compound or any derivative thereof. In some embodiments, the fluoride compound is added to adjust the selectivity to silicon nitride, increase the etching rate of silicon nitride, or any combination thereof. In some embodiments, the fluoride compound includes at least one of the following: hydrogen fluoride (HF), ammonium fluoride, tetrafluoroboric acid, hexafluorosilicic acid, a compound containing a boron-fluoride bond, a compound containing a silicon-fluoride bond, tetrabutylammonium tetrafluoroborate (TBA-BF4), tetraalkylammonium fluoride, or any combination thereof.

[0043] The etchant composition may contain from 0.0005 wt% (5 ppm) to 5 wt% of a fluoride compound based on the total weight of the etchant composition. For example, in some embodiments, the etchant composition contains from 0.0005% to 0.2%, from 0.0006% to 0.2%, from 0.0008% to 0.2%, from 0.001% to 0.2%, from 0.002% (20 ppm) to 0.2%, from 0.004% to 0.2%, from 0.006% to 0.2%, from 0.008% to 0.2%, from 0.01% to 0.2%, from 0.02% to 0.2%, from 0.0% to 0.2%, from 0.05% to 0.2%, from 0.06% to 0.2%, from 0.08% to 0.2%, from 0.1% to 0.2%, from 0.12% to 0.2%, from 0.14% to 0.2%, from 0.15% to 0.2%, from 0.16% to 0.2%, from 0.18% to 0.2%, from 0.0005% to 4.5%, from 0.0005% to 4%, from 0.0005% to 3.5%, from 0.0005% to 3%, from 0.0005% to 2.5%, from 0.0005% to 2%, from 0.0005% to 1.5%, from 0.0005% to 1%, from 0.0005% to 0.5%, from 0.0005% to 0.4%, from 0.0005% to 0.3%, from 0.0005% to 0.2%, from 0.0005% to 1%, from 0.0005% to 0.9%, from 0.0005% to 0.8%, from 0.0005% to 0.6%, from 0.0005% to 0.5%, from 0.0005% to 0.4%, from 0.0005% to 0.2%, from 0.0005% to 0.1%, from 0.0005% to 0.05%, from 0.0005% to 0.01%, from 0.0005% to 0.005%, from 0.0005% to 0.001%, or from 0.0005% to 0.0009%.

[0044] In some embodiments, the etchant composition does not contain a fluoride compound. In some embodiments, the etchant composition does not contain a detectable amount of a fluoride compound.

[0045] In some embodiments, the one or more components may include a silicon-containing compound or any derivative thereof. In some embodiments, the silicon-containing compound is added to adjust the selectivity of the etchant composition to silicon nitride, increase the etching rate of the etchant composition relative to silicon nitride, or any combination thereof. In some embodiments, the silicon-containing compound dissolves in the etchant composition, reacts with phosphoric acid to form a dissolved silicon-containing compound in the etchant composition, or any combination thereof. In some embodiments, the silicon-containing compound includes at least one of the following: silicon dioxide, tetraammonium methyl silicate (TMAS), tetraacetoxysilane, tetraalkoxysilane, tetraammonium methyl silicate, N-(3-trimethoxysilylpropyl)diethylenetriamine, N-(2-aminoethyl)-3-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropylsilanetriol, N-(3-trimethoxysilylpropyl)diethylenetriamine, N-(6-aminohexyl)aminopropyltrimethoxysilane, (3-aminopropyl)triethoxysilane, (3-aminopropyl)silanetriol, 3-aminopropylsilanetriol, tetramethoxysilane, tetraethoxysilane, any of its phosphate esters, or any combination thereof. The amount of the silicon-containing compound added to the etchant composition may include an amount that does not cause the silicon-containing compound to be supersaturated under etching conditions.

[0046] The etchant composition may comprise from 0.0005 wt% (5 ppm) to 1 wt% of a silicon-containing compound based on the total weight of the etchant composition. For example, in some embodiments, the etchant composition comprises from 0.0006 wt% to 1 wt%, from 0.0008 wt% to 1 wt%, from 0.001 wt% to 1 wt%, from 0.002 wt% to 1 wt%, from 0.004 wt% to 1 wt%, from 0.005 wt% to 1 wt%, from 0.006 wt% to 1 wt%, from 0.008 wt% to 1 wt%, from 0.01 wt% to 1 wt%, from 0.02 wt% to 1 wt%, from 0.04 wt% to 1 wt%, from 0.05 wt% to 1 wt%, from 0.06 wt% to 1 wt%, from 0.08 wt% to 1 wt%, from 0.1 wt% to 1 wt%, from 0.2 wt% to 1 wt%, from 0.4 wt% to 1 wt%, from 0.5 wt% to 1 wt%, from 0.6 wt% to 1 wt%, from 0.8 wt% to 1 wt%, from 0.0005 wt% to 0.8 wt%, from 0.0005 wt% to 0.6 wt%, from 0.0005 wt% to 0.5 wt%, from 0.0005 wt% to 0.4 wt%, from 0.0005 wt% to 0.2 wt%, from 0.0005 wt% to 0.1 wt%, from 0.0005 wt% to 0.08 wt%, from 0.0005 wt% to 0.06 wt%, from 0.0005 wt% to 0.05 wt%, from 0.0005 wt% to 0.04 wt%, from 0.0005 wt% to 0.02 wt%, from 0.0005 wt% to 0.01 wt%, from 0.0005 wt% to 0.008 wt%, from 0.0005 wt% to 0.006 wt%, from 0.0005 wt% to 0.005 wt%, from 0.0005 wt% to 0.004 wt%, from 0.0005 wt% to 0.002 wt%, from 0.0005 wt% to 0.001 wt%, or from 0.0005 wt% to 0.0008 wt% of a silicon-containing compound based on the total weight of the etchant composition.

[0047] The etchant composition may comprise from 0.1 wt% to 10 wt% of a silicon-containing compound based on the total weight of the etchant composition. For example, in some embodiments, the etchant composition comprises from 0.1% to 9%, from 0.1% to 8%, from 0.1% to 7%, from 0.1% to 6%, from 0.1% to 5%, from 0.1% to 4%, from 0.1% to 3%, from 0.1% to 2%, from 0.1% to 1%, from 0.5% to 10%, from 1% to 10%, from 2% to 10%, from 3% to 10%, from 4% to 10%, from 5% to 10%, from 6% to 10%, from 7% to 10%, from 8% to 10%, from 9% to 10%, or any combination thereof.

[0048] In some embodiments, the one or more components may include a compound of the following formula:

[0049]

[0050] or any of its derivatives,

[0051] wherein:

[0052] A is an aryl group;

[0053] each R 1 is independently hydrogen, hydroxy, hydroxy, alkyl, alkylamino, phenyl, benzyl, alkoxy, phenoxy or cycloalkyl;

[0054] x is 0 or 1;

[0055] y is 0 or 1 to 5;

[0056] y' is 0 or 1 to 5;

[0057] z is 1 to 3;

[0058] m is 1 to 3;

[0059] w is 0 or 1 to 4.

[0060] In some embodiments, each R 1 is independently hydrogen, hydroxy, hydroxy, C1-C 20 alkyl, C1-C 20 alkylamino, phenyl, benzyl, C1-C 20 alkoxy, phenoxy, or C3-C8 cycloalkyl.

[0061] In some embodiments, each R 1 is the same. In some embodiments, at least one R 1 is different. In some embodiments, each R 1 is different.

[0062] In some embodiments, y and y' are the same. In some embodiments, y and y' are different.

[0063] In some embodiments, m + z equals 4.

[0064] In some embodiments, the one or more components may include a compound of the following formula:

[0065]

[0066] or any of its derivatives,

[0067] wherein:

[0068] each R 2 is independently hydrogen, hydroxy, hydroxy, alkyl, alkylamino, phenyl, benzyl, alkoxy, phenoxy or cycloalkyl;

[0069] -M- is -NH- or -O-.

[0070] In some embodiments, each R 2 is independently hydrogen, hydroxy, hydroxy, C1-C 20 alkyl, C1-C 20 alkylamino, phenyl, benzyl, C1-C 20 alkoxy, phenoxy, or C3-C8 cycloalkyl.

[0071] In some embodiments, each R 2 is the same. In some embodiments, at least one R 2 is different. In some embodiments, each R 2 is different.

[0072] In some embodiments, the one or more components include a compound of the following formula:

[0073]

[0074] or any of its derivatives,

[0075] wherein:

[0076] Q is O or N;

[0077] R 3 to R 8 are each independently hydrogen, alkyl, alkoxy, alkenyl, cycloalkyl, aminoalkyl, aryl, alkylcarbonyl, alkylcarbonyloxy, or cyanoalkyl;

[0078] z is 0 or 1, with the proviso that when z is 0, at least two of R 3 to R 7 are alkoxy.

[0079] In some embodiments, R 3 to R 8 are each independently hydrogen, C1-C 20 alkyl, C1-C 20 alkoxy, C2-C 20 alkenyl, C3-C 20 cycloalkyl, C1-C 20 aminoalkyl, C6-C 20 aryl, C1-C 20 alkylcarbonyl, C1-C 20 alkylcarbonyloxy, or C1-C 10 cyanoalkyl.

[0080] In some embodiments, the one or more components may include at least one of the following: alkylbenzenesulfonic acid; alkyl diphenyl oxide disulfonic acid; the formula Si[phenyl-(-CH2-) xn (OR) m A compound, where n is from 1 to 3, m is from 1 to 3, x is 0 or from 1 to 3, m + n = 4, and each R is independently hydrogen or alkyl; a compound of the following formula:

[0081]

[0082] or any of its derivatives,

[0083] wherein:

[0084] R is alkyl (e.g., C1-C4 alkyl); or any combination thereof. The alkylbenzenesulfonic acid can be straight-chain or branched-chain. The alkyldiphenyloxide disulfonic acid can be C8-C 16 alkylbenzenesulfonic acid. The alkyldiphenyloxide disulfonic acid can be C6-C 12 alkyldiphenyloxide disulfonic acid. In some embodiments, the one or more components include at least one of the following: dodecylbenzenesulfonic acid, 4-octylbenzenesulfonic acid, hexyl diphenyloxide disulfonic acid, tetrapropyl-(sulfophenoxy)-benzenesulfonic acid, or any combination thereof.

[0085] In some embodiments, the one or more components can include a pyridine compound or any of its derivatives. In some embodiments, the pyridine compound includes 4-(3-phenylpropyl)pyridine.

[0086] Figure 1 is a flowchart of method 100 for selectively etching silicon nitride according to some embodiments. As Figure 1 shown, in some embodiments, method 100 can include at least one of the following steps: step 102 of obtaining a substrate; step 104 of obtaining an oxide removal composition; step 106 of obtaining an etchant composition; step 108 of contacting the substrate with the oxide removal composition; step 110 of contacting the substrate with the etchant composition; or any combination thereof.

[0087] ​In step 102, in some embodiments, a substrate is obtained. The substrate may comprise at least one of silicon nitride, silicon oxide, polysilicon, or any combination thereof. In some embodiments, the substrate comprises a surface containing silicon nitride. In some embodiments, the substrate comprises a surface containing silicon oxide. In some embodiments, the substrate comprises a surface containing polysilicon. The substrate may comprise other materials, including surfaces containing other materials. The substrate may contain other materials useful for microelectronic devices, such as one or more of insulating materials, barrier layers, conductive materials, semiconductor materials, metal silicides, or materials useful for processing microelectronic devices (e.g., photoresist, mask, in particular). Examples of substrates include those having a surface comprising at least one of silicon nitride, thermal oxide (ThOx), PECVD oxide (oxide deposited using plasma enhanced tetraethyl orthosilicate), polysilicon, or any combination thereof.

[0088] In some embodiments, the substrate comprises alternating thin film layers of silicon nitride. In some embodiments, the substrate comprises layers of silicon nitride alternating with at least one of a silicon oxide layer, a polysilicon layer, a semiconductor metal silicide layer, a dielectric (e.g., such as zirconia or alumina) layer, or any combination thereof. Prior to contact with the etchant composition, the substrate comprises alternating layers of silicon nitride positioned in openings between high aspect ratio silicon oxide structures.

[0089] In step 104, in some embodiments, an oxide removal composition is obtained. The oxide removal composition may comprise hydrogen fluoride (HF). In some embodiments, the hydrogen fluoride is present in the form of a dilute hydrogen fluoride solution.

[0090] In step 106, in some embodiments, an etchant composition is obtained. Any of the etchant compositions disclosed herein may be used. For example, in some embodiments, the etchant composition comprises at least 60 wt% phosphoric acid based on the total weight of the composition; at least 5 wt% water based on the total weight of the composition; and no more than 2 wt% metal oxidant based on the total weight of the composition. It should be understood that other etchant compositions disclosed herein may be used without departing from the present invention.

[0091] In step 108, in some embodiments, the substrate is contacted with an oxide removal composition. The oxide removal composition can be used to remove surface oxides from the substrate and, in particular, from a silicon nitride surface. That is, in some embodiments, a thin oxidized surface is present on the silicon nitride surface or film. The presence of the surface oxide can reduce the etching rate of the silicon nitride. Thus, in some embodiments, the substrate is contacted with an oxide removal composition. As mentioned above, in some embodiments, the oxide removal composition comprises hydrogen fluoride. In some embodiments, the oxide removal composition comprises diluted hydrogen fluoride. After contacting the substrate with the oxide removal composition, the excess oxide removal composition and other substances can be rinsed, washed, or otherwise removed from the surface with water (e.g., deionized water) at a temperature in the range of 20 °C to 90 °C or any range or sub-range therebetween, and then dried (e.g., spin-dried, contacted with nitrogen (N2), air-dried, etc.).

[0092] In step 110, in some embodiments, the substrate is contacted with an etchant composition. The contacting can include applying the etchant composition to the surface by at least one of the following: spraying the etchant composition onto the surface; dipping the substrate (in a static or dynamic volume of the etchant composition) into the etchant composition; contacting the surface with another material (e.g., a pad or fibrous absorbent applicator element on which the etchant composition is adsorbed); contacting the substrate with a quantity of the etchant composition in a circulation bath; immersing the substrate in the etchant composition, or any combination thereof, particularly techniques for contacting the etchant composition with the surface of a silicon-containing microelectronic substrate for removal. The application can be used for dynamic or static cleaning in a batch or single-wafer apparatus.

[0093] Selective etching of silicon nitride with an etchant composition can be carried out in the presence of silicon oxide and polysilicon, as mentioned above. In addition to silicon oxide and polysilicon, selective etching of silicon nitride with an etchant composition can be carried out in the presence of other materials while still maintaining selectivity to silicon nitride. Examples of these other materials include (but are not limited to) at least one of a conductive material, a semiconductor material, an insulating material, a processing material, or any combination thereof. In some embodiments, metal silicide is present during the selective etching of silicon nitride. In some embodiments, metal silicide is present but not exposed during the selective etching of silicon nitride.

[0094] The contacting conditions may include at least one of duration, temperature, or any combination thereof. The duration should be sufficient to selectively remove silicon nitride. The duration of exposure to the etchant composition and the temperature of the etchant composition may be selected based on the desired amount of silicon nitride to be removed from the substrate surface. The duration of contact should balance process control and quality with process efficiency and throughput of the etching process and the semiconductor manufacturing line. Examples of suitable durations may be in the range of 5 minutes to 300 minutes, or any range or sub-range therebetween, such as 10 minutes to 60 minutes. Examples of suitable temperatures are in the range of 100 °C to 250 °C (e.g., 100 °C to 180 °C, 150 °C to 180 °C) or any range or sub-range of temperatures therebetween. These contact times and temperatures are illustrative, and other suitable contact time and temperature conditions may be used herein without departing from the present invention.

[0095] By contacting the substrate with the etchant composition, the etchant composition may passivate at least one of a surface comprising polysilicon, a surface comprising silicon oxide, or any combination thereof. In some embodiments, passivating the surface includes modifying the surface to reduce the reactivity of the surface, e.g., when there are substances for etching silicon nitride. In some embodiments, when there is a surface comprising polysilicon, the metal oxidant modifies or is configured to modify the surface comprising polysilicon so as to reduce the reactivity of the surface comprising polysilicon. In some embodiments, when there is a surface comprising silicon oxide, the metal oxidant modifies or is configured to modify the surface comprising silicon oxide so as to reduce the reactivity of the surface comprising silicon oxide. In some embodiments, the etchant composition passivates surfaces other than silicon nitride.

[0096] The etchant composition may exhibit a selectivity of at least 150, at least 200, at least 500, at least 1000, at least 2000, at least 4000, or greater for silicon nitride relative to polysilicon. In some embodiments, for example, the etchant composition exhibits a selectivity of 10:1 to 7000:1 or any range or sub-range therebetween for silicon nitride relative to polysilicon. The etchant composition may exhibit a selectivity of at least 150, at least 200, at least 500, at least 1000, at least 2000, at least 4000, or greater for silicon nitride relative to silicon oxide. In some embodiments, for example, the etchant composition exhibits a selectivity of 10:1 to 7000:1 or any range or sub-range therebetween for silicon nitride relative to silicon oxide. In some embodiments, the etchant composition has the same or similar selectivity for silicon nitride relative to polysilicon and silicon oxide. In some embodiments, the etchant composition has different selectivity for silicon nitride relative to polysilicon and silicon oxide.

[0097] After contacting the substrate with the etchant composition, the excess etchant composition and other substances can be rinsed, washed, or otherwise removed from the surface using water (e.g., deionized water) at a temperature in the range of 20°C to 90°C or any range or sub-range therebetween, followed by drying (e.g., spin drying, contacting with nitrogen gas (N2), air drying, etc.).

[0098] Figure 2 FIG. 200 is a schematic diagram of a method for selectively etching silicon nitride according to some embodiments. As Figure 2 shown, in some embodiments, substrate 202 includes silicon nitride 204, polysilicon 206, and silicon oxide 208. The substrate 202 also includes surface oxide 210. In step 220, the surface oxide 210 is removed. In step 240, the polysilicon 206 is passivated and the silicon nitride 204 is etched without etching the polysilicon 206 (e.g., passivated polysilicon) or at least etching less than 5% of the surface of the polysilicon 206.

[0099] Figure 3 FIG. 300 presents an illustration of a process flow that shows a structure having polysilicon at the bottom of a channel and also containing silicon oxide and silicon nitride surfaces. The combined passivation and etching steps according to the present invention involve the incorporation of cerium(IV) sulfate Ce(IV)SO4 into the etchant composition (such as Entegris PlanarEX 2155).

[0100] Figure 3 FIG. 300 is a flow chart of a method for forming an etchant composition according to some embodiments. As Figure 3 shown, in some embodiments, the method 300 for forming the etchant composition includes at least one of the following steps: obtaining a metal oxidizer, phosphoric acid, and water in step 302; contacting the metal oxidizer, phosphoric acid, and water to form an etchant composition in step 304; or any combination thereof. In some embodiments, the contacting is carried out at a temperature in the range of 20°C to 200°C or any range or sub-range therebetween. In some embodiments, the contacting includes mixing, combining, adding, or otherwise bringing into close or immediate proximity to form an etchant composition. It should be understood that any one of the one or more components disclosed herein can be included in the etchant composition without departing from the present invention.

[0101] Example 1

[0102] Base formulation

[0103] A base formulation is prepared. The base formulation includes about 82 wt% phosphoric acid, about 14 wt% water, about 4 wt% 3-aminopropylsilanetriol, and about 0.1 wt% tetramethylammonium silicate. The wt% is based on the total weight of the base formulation.

[0104] Example 2

[0105] Comparative formulation (metal-free oxidant)

[0106] The base formulation of Example 1 was exposed to a coated silicon nitride (SiN) film and a phosphorus-doped polysilicon film at a temperature of 160 °C. The thickness changes of the coated silicon nitride (SiN) film and the phosphorus-doped polysilicon film were measured by spectroscopic ellipsometry. The SiN etching rate and the polysilicon etching rate were calculated from the measured thickness changes over time periods of 10 minutes and 120 minutes, respectively. The results are summarized in Table 1 below.

[0107] Example 3

[0108] Formulation A

[0109] Approximately 0.1 wt% of phosphomolybdic acid hydrate was added to the base formulation of Example 1 to form Formulation A. Formulation A was exposed to a coated silicon nitride (SiN) film and a phosphorus-doped polysilicon film at a temperature of 160 °C. The thickness changes of the coated silicon nitride (SiN) film and the phosphorus-doped polysilicon film were measured by spectroscopic ellipsometry. The SiN etching rate and the polysilicon etching rate were calculated from the measured thickness changes over time periods of 10 minutes and 120 minutes, respectively. The results are summarized in Table 1 below. The wt% is based on the total weight of the base formulation.

[0110] Example 4

[0111] Formulation B

[0112] Approximately 0.1 wt% of silicomolybdic acid was added to the base formulation of Example 1 to form Formulation B. Formulation B was exposed to a coated silicon nitride (SiN) film and a phosphorus-doped polysilicon film at a temperature of 160 °C. The thickness changes of the coated silicon nitride (SiN) film and the phosphorus-doped polysilicon film were measured by spectroscopic ellipsometry. The SiN etching rate and the polysilicon etching rate were calculated from the measured thickness changes over time periods of 10 minutes and 120 minutes, respectively. The results are summarized in Table 1 below. The wt% is based on the total weight of the base formulation.

[0113] Example 5

[0114] Formulation C

[0115] Approximately 0.1 wt% of molybdenum(VI) oxide was added to the base formulation of Example 1 to form Formulation C. Formulation C was exposed to a coated silicon nitride (SiN) film and a phosphorus-doped polysilicon film at a temperature of 160 °C. The thickness changes of the coated silicon nitride (SiN) film and the phosphorus-doped polysilicon film were measured by spectroscopic ellipsometry. The SiN etching rate and the polysilicon etching rate were calculated from the measured thickness changes over time periods of 10 minutes and 120 minutes, respectively. The results are summarized in Table 1 below. The wt% is based on the total weight of the base formulation.

[0116] Example 6

[0117] Formulation D

[0118] Approximately 0.1 wt% cerium(IV) sulfate was added to the base formulation of Example 1 to form Formulation D. Formulation D was exposed to a coated silicon nitride (SiN) film and a phosphorus-doped polysilicon film at a temperature of 160 °C. The thickness changes of the coated silicon nitride (SiN) film and the phosphorus-doped polysilicon film were measured by spectroscopic ellipsometry. The SiN etching rate and the polysilicon etching rate were calculated from the measured thickness changes over times of 10 minutes and 120 minutes, respectively. The results are summarized in Table 1 below. The wt% is based on the total weight of the base formulation.

[0119] Example 7

[0120] Formulation E

[0121] Approximately 0.05 wt% cerium(IV) sulfate was added to the base formulation of Example 1 to form Formulation E. Formulation E was exposed to a coated silicon nitride (SiN) film and a phosphorus-doped polysilicon film at a temperature of 160 °C. The thickness changes of the coated silicon nitride (SiN) film and the phosphorus-doped polysilicon film were measured by spectroscopic ellipsometry. The SiN etching rate and the polysilicon etching rate were calculated from the measured thickness changes over times of 10 minutes and 120 minutes, respectively. The results are summarized in Table 1 below. The wt% is based on the total weight of the base formulation.

[0122] Example 8

[0123] Formulation F

[0124] Approximately 0.05 wt% La2O3 was added to the base formulation of Example 1 to form Formulation F. Formulation F was exposed to a coated silicon nitride (SiN) film and a phosphorus-doped polysilicon film at a temperature of 160 °C. The thickness changes of the coated silicon nitride (SiN) film and the phosphorus-doped polysilicon film were measured by spectroscopic ellipsometry. The SiN etching rate and the polysilicon etching rate were calculated from the measured thickness changes over times of 10 minutes and 120 minutes, respectively. The results are summarized in Table 1 below. The wt% is based on the total weight of the base formulation.

[0125] Example 9

[0126] Formulation G

[0127] Approximately 0.25 wt% nitric acid was added to the base formulation of Example 1 to form formulation G. Formulation G was exposed to a coated silicon nitride (SiN) film and a phosphorus-doped polysilicon film at a temperature of 160 °C. The thickness changes of the coated silicon nitride (SiN) film and the phosphorus-doped polysilicon film were measured by spectroscopic ellipsometry. The SiN etch rate and the polysilicon etch rate were calculated from the measured thickness changes over time periods of 10 minutes and 120 minutes, respectively. The results are summarized in Table 1 below. The wt% is based on the total weight of the base formulation.

[0128] Table 1: Polysilicon etch rate, SiN etch rate, and selectivity for formulations A to G

[0129]

[0130] Aspect

[0131] The following describes various aspects. It should be understood that any one or more of the features detailed in the following aspects may be combined with any one or more other aspects.

[0132] Aspect 1. An etchant composition comprising:

[0133] At least 60 wt% phosphoric acid based on the total weight of the etchant composition;

[0134] At least 1 wt% water based on the total weight of the etchant composition; and

[0135] No more than 2 wt% metal oxidant based on the total weight of the etchant composition,

[0136] wherein when a surface comprising polysilicon is present, the metal oxidant is configured to modify the surface comprising polysilicon so as to reduce the reactivity of the surface comprising polysilicon with the phosphoric acid.

[0137] Aspect 2. The etchant composition of Aspect 1, wherein the etchant composition comprises:

[0138] 80 wt% to 95 wt% of the phosphoric acid based on the total weight of the etchant composition.

[0139] Aspect 3. The etchant composition according to any one of Aspects 1 to 2, wherein the etchant composition comprises:

[0140] 1 wt% to 25 wt% of the water based on the total weight of the etchant composition.

[0141] Aspect 4. The etchant composition according to any one of Aspects 1 to 3, wherein the etchant composition comprises:

[0142] 0.001 wt% to 1 wt% of the metal oxidant, based on the total weight of the etchant composition.

[0143] Aspect 5. The etchant composition according to any one of Aspects 1 to 4, wherein the etchant composition comprises:

[0144] 0.001 wt% to 0.1 wt% of the metal oxidant, based on the total weight of the etchant composition.

[0145] Aspect 6. The etchant composition according to any one of Aspects 1 to 5, wherein the metal oxidant comprises cations of at least one of the following: Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Hf, Ta, W, Re, Os, Ir, Pt, Au, Hg, Ac, Th, Pa, U, Np, Pu, Am, Cm, Bk, Cf, Es, Fm, Md, No, Lr, Rf, Db, Sg, Bh, Hs, Mt, Ds, Rg, Cn, or any combination thereof.

[0146] Aspect 7. The etchant composition according to any one of Aspects 1 to 6, wherein the metal oxidant is at least one of the following: Ce +3 , Ce +4 , V +2 、V +3 、V +4 、V +5 、Mo +2 、Mo +3 、Mo +4 、Mo +5 、Mo +6 、or any combination thereof.

[0147] Aspect 8. The etchant composition according to any one of Aspects 1 to 7, wherein the metal oxidant is a dissolved product of a metal oxidant.

[0148] Aspect 9. The etchant composition according to Aspect 8, wherein the metal oxidant comprises at least one of the following: titanium(IV) oxysulfate, titanium(IV) sulfate hydrate, phosphomolybdic acid hydrate, silicomolybdic acid, molybdenum(VI) oxide, molybdic acid, lanthanum oxide, cerium(IV) sulfate, ammonium cerium(IV) nitrate, phosphotungstic acid, vanadium pentoxide, cobalt(III) acetylacetonate, or any combination thereof.

[0149] Aspect 10. The etchant composition according to any one of Aspects 1 to 8, further comprising at least one of the following: a fluoride compound, a silicon-containing compound, an alkylbenzenesulfonic acid, an alkyldiphenyloxide disulfonic acid, a pyridine compound, or any combination thereof.

[0150] Aspect 11. The etchant composition according to any one of Aspects 1 to 9, wherein the etchant composition exhibits a selectivity of silicon nitride to polysilicon in the range of 10:1 to 7000:1.

[0151] Aspect 12. A method, comprising:

[0152] obtaining a substrate comprising:

[0153] a surface comprising silicon nitride,

[0154] a surface comprising silicon oxide, and

[0155] a surface comprising polysilicon;

[0156] obtaining an etchant composition comprising:

[0157] at least 60 wt% phosphoric acid based on the total weight of the etchant composition;

[0158] at least 1 wt% water based on the total weight of the etchant composition; and

[0159] no more than 2 wt% metal oxidant based on the total weight of the etchant composition;

[0160] contacting the substrate with the etchant composition,

[0161] wherein the etchant composition removes at least a portion of the surface comprising silicon nitride,

[0162] wherein the etchant composition removes less than 5% of the surface comprising polysilicon.

[0163] Aspect 13. The method according to Aspect 12, wherein the etchant composition comprises:

[0164] 80 wt% to 95 wt% of the phosphoric acid based on the total weight of the etchant composition.

[0165] Aspect 14. The method according to any one of Aspects 12 to 13, wherein the etchant composition comprises:

[0166] 1 wt% to 25 wt% of the water based on the total weight of the etchant composition.

[0167] Aspect 15. The method according to any one of Aspects 12 to 14, wherein the etchant composition comprises:

[0168] 0.001 wt% to 1 wt% of the metal oxidant, based on the total weight of the etchant composition.

[0169] Aspect 16. The method according to any one of aspects 12 to 15, wherein the etchant composition comprises:

[0170] 0.001 wt% to 0.1 wt% of the metal oxidant, based on the total weight of the etchant composition.

[0171] Aspect 17. The method according to any one of aspects 12 to 16, wherein the metal oxidant comprises cations of at least one of the following: Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Hf, Ta, W, Re, Os, Ir, Pt, Au, Hg, Ac, Th, Pa, U, Np, Pu, Am, Cm, Bk, Cf, Es, Fm, Md, No, Lr, Rf, Db, Sg, Bh, Hs, Mt, Ds, Rg, Cn, or any combination thereof.

[0172] Aspect 18. The method according to any one of aspects 12 to 17, wherein the etchant composition further comprises at least one of the following: a fluoride compound, a silicon-containing compound, an alkylbenzenesulfonic acid, an alkyldiphenyloxide disulfonic acid, a pyridine compound, or any combination thereof.

[0173] Aspect 19. The method according to any one of aspects 12 to 18, wherein the etchant composition exhibits a selectivity of silicon nitride to polysilicon in the range of 10:1 to 7000:1.

[0174] Aspect 20. A method comprising:

[0175] Obtaining phosphoric acid;

[0176] Obtaining water;

[0177] Obtaining a metal oxidant;

[0178] Contacting the phosphoric acid, the water, and the metal oxidant to form an etchant composition comprising:

[0179] At least 60 wt% phosphoric acid, based on the total weight of the etchant composition;

[0180] At least 1 wt% water, based on the total weight of the etchant composition; and

[0181] A metal oxidizer that is no more than 2% by weight based on the total weight of the etchant composition,

[0182] wherein when a surface containing polysilicon is present, the metal oxidizer is configured to modify the surface containing polysilicon so as to reduce the reactivity of the surface containing polysilicon with the phosphoric acid.

Claims

1. An etchant composition comprising: at least 60 wt% phosphoric acid based on the total weight of the etchant composition; at least 1 wt% water based on the total weight of the etchant composition; and no more than 2 wt% metal oxidizer based on the total weight of the etchant composition, wherein when a surface comprising polysilicon is present, the metal oxidizer is configured to modify the surface comprising polysilicon to reduce the reactivity of the surface comprising polysilicon with the phosphoric acid.

2. The etchant composition according to claim 1, wherein the etchant composition comprises: 80 wt% to 95 wt% of the phosphoric acid based on the total weight of the etchant composition.

3. The etchant composition according to claim 1, wherein the etchant composition comprises: 1 wt% to 25 wt% of the water based on the total weight of the etchant composition.

4. The etchant composition according to claim 1, wherein the etchant composition comprises: 0.001 wt% to 1 wt% of the metal oxidizer based on the total weight of the etchant composition.

5. The etchant composition according to claim 1, wherein the etchant composition comprises: 0.001 wt% to 0.1 wt% of the metal oxidizer based on the total weight of the etchant composition.

6. The etchant composition according to claim 1, wherein the metal oxidizer comprises a cation of at least one of the following: Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Hf, Ta, W, Re, Os, Ir, Pt, Au, Hg, Ac, Th, Pa, U, Np, Pu, Am, Cm, Bk, Cf, Es, Fm, Md, No, Lr, Rf, Db, Sg, Bh, Hs, Mt, Ds, Rg, Cn, or any combination thereof.

7. The etchant composition according to claim 1, wherein the metal oxidizer is at least one of the following: Ce +3 , Ce +4 , V +2 , V +3 , V +4 , V +5 , Mo +2 , Mo +3 , Mo +4 , Mo +5 , Mo +6 , or any combination thereof.

8. The etchant composition according to claim 1, wherein the metal oxidizer is a dissolved product of a metal oxidizer.

9. The etchant composition according to claim 8, wherein the metal oxidizer comprises at least one of the following: titanium(IV) oxysulfate, titanium(IV) sulfate hydrate, phosphomolybdic acid hydrate, silicomolybdic acid, molybdenum(VI) oxide, molybdic acid, lanthanum oxide, cerium(IV) sulfate, ammonium cerium(IV) nitrate, phosphotungstic acid, vanadium pentoxide, cobalt(III) acetylacetonate, or any combination thereof.

10. The etchant composition according to claim 1, further comprising at least one of the following: a fluoride compound, a silicon-containing compound, an alkylbenzenesulfonic acid, an alkyl diphenyloxide disulfonic acid, a pyridine compound, or any combination thereof.

11. The etchant composition according to claim 1, wherein the etchant composition exhibits a selectivity of silicon nitride to polysilicon in the range of 10:1 to 7000:

1.

12. A method comprising: Obtain a substrate, the substrate comprising: A surface comprising silicon nitride, A surface comprising silicon oxide, and A surface comprising polysilicon; Obtain an etchant composition, the etchant composition comprising: At least 60 wt% phosphoric acid based on the total weight of the etchant composition; At least 1 wt% water based on the total weight of the etchant composition; And No more than 2 wt% metal oxidizer based on the total weight of the etchant composition; Contact the substrate with the etchant composition, Wherein the etchant composition removes at least a portion of the surface comprising silicon nitride, Wherein the etchant composition removes less than 5% of the surface comprising polysilicon.

13. The method according to claim 12, wherein the etchant composition comprises: 80 wt% to 95 wt% of the phosphoric acid based on the total weight of the etchant composition.

14. The method according to claim 12, wherein the etchant composition comprises: 1 wt% to 25 wt% of the water based on the total weight of the etchant composition.

15. The method according to claim 12, wherein the etchant composition comprises: 0.001 wt% to 1 wt% of the metal oxidizer based on the total weight of the etchant composition.

16. The method according to claim 12, wherein the etchant composition comprises: 0.001 wt% to 0.1 wt% of the metal oxidizer based on the total weight of the etchant composition.

17. The method according to claim 12, wherein the metal oxidizer comprises a cation of at least one of the following: Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Hf, Ta, W, Re, Os, Ir, Pt, Au, Hg, Ac, Th, Pa, U, Np, Pu, Am, Cm, Bk, Cf, Es, Fm, Md, No, Lr, Rf, Db, Sg, Bh, Hs, Mt, Ds, Rg, Cn, or any combination thereof.

18. The method according to claim 12, wherein the etchant composition further comprises at least one of the following: a fluoride compound, a silicon-containing compound, an alkylbenzenesulfonic acid, an alkyldiphenyloxide disulfonic acid, a pyridine compound, or any combination thereof.

19. The method according to claim 12, wherein the etchant composition exhibits a selectivity of silicon nitride to polysilicon in the range of 10:1 to 7000:

1.

20. A method, comprising: Obtain phosphoric acid; Obtain water; Obtain a metal oxidizer; Contact the phosphoric acid, the water, and the metal oxidizer to form an etchant composition, the etchant composition comprising: At least 60 wt% phosphoric acid based on the total weight of the etchant composition; At least 1 wt% water based on the total weight of the etchant composition; And A metal oxidizing agent that is no greater than 2% by weight based on the total weight of the etchant composition, wherein when a surface comprising polysilicon is present, the metal oxidizing agent is configured to modify the surface comprising polysilicon so as to reduce the reactivity of the surface comprising polysilicon with the phosphoric acid.

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