Polishing compositions and methods of use thereof

Abstract

To effectively remove ruthenium and / or hard mask materials while minimizing copper corrosion.SOLUTION: A polishing composition includes an abrasive, a pH adjuster, a barrier film removal rate enhancer, a low-k removal rate inhibitor, an azole-containing corrosion inhibitor, and a ruthenium removal rate enhancer. A method of polishing a substrate includes the steps of: applying the polishing composition described herein to a surface of a substrate, where the surface comprises ruthenium or a hard mask material; and bringing a pad into contact with the surface of the substrate and moving the pad in relation to the substrate.SELECTED DRAWING: None

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority from U.S. Provisional Application No. 62 / 975,829, filed February 13, 2020, the contents of which are incorporated herein by reference in their entirety. [Background technology]

[0002] The semiconductor industry is constantly under pressure to improve chip performance by further miniaturizing devices through innovations in processes, materials, and integration. Previous material innovations include the introduction of copper, replacing aluminum as the conductive material in interconnect structures, and the use of tantalum (Ta) / tantalum nitride (TaN) as a diffusion barrier to isolate the Cu conductive material from non-conductive / insulating dielectric materials. Copper (Cu) was chosen as the interconnect material due to its low resistivity and excellent resistance to electromigration.

[0003] However, as the features of newer chip generations shrink, multilayer Cu / barrier / dielectric stacks must become thinner and more conformal to maintain effective interconnect resistance in the back end of the line (BEOL). Thinner Cu and Ta / TaN barrier film schemes face challenges in resistivity and flexibility in deposition. For example, resistivity rapidly deteriorates at smaller dimensions and advanced manufacturing nodes, and transistor circuit speed improvements (at the front end of the line (FEOL)) are halved by delays from conductive Cu / barrier interconnects (BEOL). Ruthenium (Ru) has emerged as a leading candidate for use as a liner material, barrier layer, and conductive layer. Ruthenium has excellent Cu diffusion resistance in dielectric layers, but can also facilitate direct copper electrical filling into small-dimension trenches without a copper seed layer. Furthermore, ruthenium is also being investigated as a VIA material to replace traditional tungsten (W) metal. Summary of the Invention [Means for solving the problem]

[0004] This Summary is provided to introduce a selection of concepts that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in limiting the scope of the claimed subject matter.

[0005] As defined in this disclosure, unless otherwise specified, all percentages given should be understood to be weight percents based on the total weight of the polishing composition.

[0006] In one aspect, embodiments described herein relate to a polishing composition comprising an abrasive; a pH adjuster; a barrier film removal rate enhancer; a low-k removal rate inhibitor; an azole-containing corrosion inhibitor; and a ruthenium removal rate enhancer.

[0007] In another aspect, embodiments described herein relate to a polishing composition comprising an abrasive; a pH adjuster; an organic acid or its salt; a nonionic surfactant; an azole-containing corrosion inhibitor; and a compound selected from the group consisting of ammonium salts, thiocyanates, halide salts, nitrates, nitric acid, and mixtures thereof.

[0008] In yet another aspect, embodiments described herein relate to a method of polishing a substrate (e.g., a substrate comprising ruthenium), comprising applying a polishing composition described herein to a surface of a substrate, wherein the surface comprises ruthenium or a hard mask material; and contacting a pad with the surface of the substrate and moving the pad relative to the substrate.

[0009] Other aspects and advantages of the claimed subject matter will become apparent from the following description and appended claims. DETAILED DESCRIPTION OF THE INVENTION

[0010] Embodiments described herein generally relate to compositions and methods of using the compositions to polish substrates comprising at least a ruthenium portion and / or a hard mask portion (e.g., tungsten, carbides, nitride ceramics (e.g., TiN) and their doped derivatives), and more specifically, substrates that may comprise at least a ruthenium portion, a hard mask portion, and a copper portion. The compositions described herein can effectively remove ruthenium and / or hard mask material while minimizing copper corrosion (e.g., minimizing surface roughness). For example, the compositions described herein can effectively remove ruthenium and / or hard mask material from copper, ruthenium liners, hard mask materials (e.g., titanium and its doped derivatives, tungsten and its doped derivatives (e.g., WB), carbides (e.g., BC, BC, TiC, SiC, and WC), boron-containing materials (e.g., BO, BCN, and AlMgB). 14 ), nitride ceramic materials (e.g., SiN, TiN, BN), barrier materials (e.g., Ta, TaN), and dielectric materials (e.g., TEOS, low-k, ultra low-k, etc.).

[0011] Many currently available CMP slurries are specifically designed to remove materials more common in older chip designs, such as the aforementioned copper and tungsten. However, in back-end (BEOL) applications in the semiconductor industry, ruthenium is used as a liner material because it has good electrical conductivity, deposition properties, and is resistant to Cu diffusion. Unlike other materials, such as cobalt and copper, ruthenium is relatively chemically stable and therefore does not degrade during polishing, which can make it difficult to remove. Furthermore, ruthenium is often used in conjunction with copper, a conductive layer. As mentioned above, copper is a relatively soft material and is easy to remove. Copper is essential for the function of many semiconductor devices, and the use of CMP slurries can easily strip or damage copper layers or inlays, adversely affecting the performance of the finished device. Because copper is more susceptible to chemical attack, older CMP slurries may not be able to effectively remove ruthenium without causing harmful and unacceptable defects in the copper. As a result, less advanced slurries can result in unacceptable erosion, wafer topography, and / or removal rate selectivity for one or more components of the multi-component substrate being polished. Additionally, more complex integration schemes may use a hard mask as an etch mask along with a Ru liner and Cu conductive layer, which introduces yet another material that the polishing slurry must be able to effectively remove.

[0012] With the increasing use and shrinking size of multi-component integration schemes in semiconductor manufacturing, there is a market need for CMP slurries that can effectively polish substrates containing ruthenium, copper, and hard mask materials with minimal copper corrosion, while providing favorable removal rates and selectivities to all other components.

[0013] In one or more embodiments, the polishing composition described herein comprises an abrasive; a pH adjuster; a barrier film removal rate enhancer; a low-k removal rate suppressor; an azole-containing corrosion inhibitor; and a ruthenium removal rate enhancer. In one or more embodiments, the polishing composition may also comprise a chelating agent and / or an oxidizing agent. In one or more embodiments, the polishing composition according to the present disclosure may comprise from about 0.1 wt % to about 50 wt % of an abrasive, from about 0.01 wt % to about 10 wt % of a pH adjuster, from about 0.002 wt % to about 4 wt % of a barrier film removal rate enhancer, from about 0.0005 wt % to about 5 wt % of a low-k removal rate suppressor, from about 0.0001 wt % to about 1 wt % of an azole-containing corrosion inhibitor, from about 0.0001 wt % to about 5 wt % of a ruthenium removal rate enhancer, and the remaining wt % (e.g., from about 20 wt % to about 99 wt %) of a solvent (e.g., deionized water). In one or more embodiments, the polishing composition can further comprise about 0.001 wt % to about 1 wt % of a chelating agent and / or about 0.001 wt % to about 5 wt % of an oxidizing agent.

[0014] In one or more embodiments, the present disclosure provides a concentrated polishing composition that can be diluted up to 2-fold, or up to 4-fold, or up to 6-fold, or up to 8-fold, or up to 10-fold with water before use. In other embodiments, the present disclosure provides a point-of-use (POU) polishing composition for use on a ruthenium-containing substrate, comprising the polishing composition, water, and optionally an oxidizing agent.

[0015] In one or more embodiments, the POU polishing composition can include about 0.1 wt% to about 12 wt% abrasive, about 0.01 wt% to about 5 wt% pH adjuster, about 0.002 wt% to about 2 wt% barrier film removal rate enhancer, about 0.0005 wt% to about 0.5 wt% low-k removal rate inhibitor, about 0.0001 wt% to about 0.1 wt% azole-containing corrosion inhibitor, about 0.0001 wt% to about 0.5 wt% ruthenium removal rate enhancer, optionally about 0.001 wt% to about 5 wt% oxidizer, and about 80 wt% to about 99 wt% solvent (e.g., deionized water). In one or more embodiments, the POU polishing composition can further include 0.001 wt% to 0.1 wt% chelating agent.

[0016] In one or more embodiments, the concentrated polishing composition can include about 1 wt % to about 50 wt % abrasive, about 0.1 wt % to about 10 wt % pH adjuster, about 0.02 wt % to about 4 wt % barrier film removal rate enhancer, about 0.005 wt % to about 5 wt % low-k removal rate inhibitor, about 0.001 wt % to about 1 wt % azole-containing corrosion inhibitor, about 0.001 wt % to about 5 wt % ruthenium removal rate enhancer, and the remaining wt % (e.g., about 20 wt % to about 98.5 wt %) solvent (e.g., deionized water). In one or more embodiments, the concentrated polishing composition can further include about 0.01 wt % to about 1 wt % chelating agent and / or about 0.001 wt % to about 5 wt % oxidizing agent.

[0017] In one or more embodiments, the polishing composition described herein may comprise at least one abrasive (e.g., two or three). In some embodiments, the at least one abrasive is selected from the group consisting of cationic abrasives, substantially neutral abrasives, and anionic abrasives. In one or more embodiments, the at least one abrasive is selected from the group consisting of alumina, silica, titania, ceria, zirconia, co-formed products thereof (i.e., co-formed products of alumina, silica, titania, ceria, or zirconia), coated abrasives, surface-modified abrasives, and mixtures thereof. In some embodiments, the at least one abrasive does not comprise ceria. In some embodiments, the at least one abrasive may be highly pure and contain less than about 100 ppm alcohol, less than about 100 ppm ammonia, and less than about 100 parts per billion (ppb) alkali cations, such as sodium cations. The abrasive can be present in an amount from about 0.1% to about 12% (eg, from about 0.5% to about 10%), based on the total weight of the POU polishing composition, or any subrange thereof.

[0018] In some embodiments, the at least one abrasive is present in an amount of about 0.1 wt % or more (e.g., about 0.5 wt % or more, about 1 wt % or more, about 2 wt % or more, about 4 wt % or more, about 5 wt % or more, about 10 wt % or more, about 12 wt % or more, about 15 wt % or more, or about 20 wt % or more) to about 50 wt % or less (e.g., about 45 wt % or less, about 40 wt % or less, about 35 wt % or less, about 30 wt % or less, about 25 wt % or less, about 20 wt % or less, about 15 wt % or less, about 12 wt % or less, about 10 wt % or less, or about 5 wt % or less) relative to the polishing composition described herein.

[0019] In one or more embodiments, the polishing composition described herein can include at least one (e.g., two or three) pH adjuster. In some embodiments, the at least one pH adjuster is selected from the group consisting of ammonium hydroxide, sodium hydroxide, potassium hydroxide, cesium hydroxide, monoethanolamine, diethanolamine, triethanolamine, methylethanolamine, methyldiethanolamine, tetrabutylammonium hydroxide, tetrapropylammonium hydroxide, tetraethylammonium hydroxide, tetramethylammonium hydroxide, ethyltrimethylammonium hydroxide, diethyldimethylammonium hydroxide, dimethyldipropylammonium hydroxide, benzyltrimethylammonium hydroxide, tris(2-hydroxyethyl)methylammonium hydroxide, choline hydroxide, and any combination thereof.

[0020] In some embodiments, the at least one pH adjuster is present in an amount of about 0.01 wt % or more (e.g., about 0.05 wt % or more, about 0.1 wt % or more, about 0.5 wt % or more, about 1 wt % or more, about 2 wt % or more, about 4 wt % or more, about 5 wt % or more, about 6 wt % or more, or about 8 wt % or more) to about 10 wt % or less (e.g., about 9 wt % or less, about 8 wt % or less, about 7 wt % or less, about 6 wt % or less, about 5 wt % or less, about 4 wt % or less, about 3 wt % or less, about 2 wt % or less, about 1 wt % or less, about 0.5 wt % or less, about 0.2 wt % or less, or about 0.1 wt % or less) relative to the polishing composition described herein.

[0021] In some embodiments, the pH value of the polishing composition can range from about 7 or more (e.g., about 7.5 or more, about 8 or more, about 8.5 or more, about 9 or more, about 9.5 or more, about 10 or more, about 10.5 or more, about 11 or more, about 11.5 or more, or about 12 or more) to about 14 or less (e.g., about 13.5 or less, about 13 or less, about 12.5 or less, about 12 or less, about 11.5 or less, about 11 or less, about 10.5 or less, about 10 or less, about 9.5 or less, or about 9 or less). Without wishing to be bound by theory, it is believed that polishing compositions having a pH less than 7 will significantly increase copper removal rate and corrosion, while polishing compositions having a pH greater than 14 may affect the stability of the suspended abrasive, significantly increasing roughness and reducing the overall quality of films polished with such compositions. To achieve the desired pH, the relative concentrations of the components in the polishing compositions described herein can be adjusted.

[0022] In one or more embodiments, the polishing composition described herein may include at least one (e.g., two or three) barrier film removal rate enhancing agent. In some embodiments, the at least one barrier film removal rate enhancing agent is an organic acid (e.g., a carboxylic acid, an amino acid, a sulfonic acid, or a phosphonic acid) or a salt thereof. In some embodiments, the barrier film removal rate enhancing agent may be an organic acid or a salt thereof selected from the group consisting of gluconic acid, lactic acid, citric acid, tartaric acid, malic acid, glycolic acid, malonic acid, formic acid, oxalic acid, acetic acid, propionic acid, peracetic acid, succinic acid, lactic acid, aminoacetic acid, phenoxyacetic acid, bicine, diglycolic acid, glyceric acid, tricine, alanine, histidine, valine, phenylalanine, proline, glutamine, aspartic acid, glutamic acid, arginine, lysine, tyrosine, benzoic acid, salts thereof, and mixtures thereof. Without wishing to be bound by theory, it is believed that an organic acid or its salt (e.g., as described above) can be used as an effective barrier film removal rate enhancer in the polishing composition described herein to improve the removal rate of a barrier film (e.g., a Ta film or a TaN film) in a semiconductor substrate.

[0023] In some embodiments, the barrier film removal rate enhancing agent is present in an amount of about 0.002 wt % or more (e.g., about 0.005 wt % or more, about 0.01 wt % or more, about 0.05 wt % or more, about 0.1 wt % or more, about 0.15 wt % or more, about 0.2 wt % or more, about 0.5 wt % or more, about 1 wt % or more, about 1.5 wt % or more, or about 2 wt % or more) to about 4 wt % or less (e.g., about 3.5 wt % or less, about 3 wt % or less, about 2.5 wt % or less, about 2 wt % or less, about 1.5 wt % or less, or about 1 wt % or less) relative to the polishing composition described herein.

[0024] In one or more embodiments, the polishing composition described herein can include at least one (e.g., two or three) low-k removal rate inhibitor. In some embodiments, the at least one low-k removal rate inhibitor is a nonionic surfactant. In one or more embodiments, the nonionic surfactant is selected from the group consisting of alcohol alkoxylates, alkylphenol alkoxylates, tristyrylphenol alkoxylates, sorbitan ester alkoxylates, polyalkoxylates, polyalkylene oxide block copolymers, tetrahydroxy oligomers, alkoxylated diamines, and mixtures thereof. In one or more embodiments, the nonionic surfactant is a polymer having a number average molecular weight of about 500 g / mol or greater, or about 1000 g / mol or greater, or about 2500 g / mol or greater, or about 5000 g / mol or greater, or about 7500 g / mol or greater, or about 10000 g / mol or greater. In one or more embodiments, the nonionic surfactant is a polymer having a number average molecular weight of about 1,000,000 g / mol or less, or about 750,000 g / mol or less, or about 500,000 g / mol or less, or about 250,000 g / mol or less, or about 100,000 g / mol or less. In one or more embodiments, the alkoxylate group of the alkoxylated nonionic surfactant is an ethoxylate group, a propoxylate group, or a combination of an ethoxylate group and a propoxylate group. Without wishing to be bound by theory, it is surprising that a nonionic surfactant (such as those described above) can be used as a low-k removal rate inhibitor in the polishing composition described herein to reduce or minimize the removal rate of a low-k film (e.g., a carbon-doped silicon oxide film) in a semiconductor substrate.

[0025] In some embodiments, the low-k removal rate inhibitor is present in an amount of about 0.0005 wt % or more (e.g., about 0.001 wt % or more, about 0.005 wt % or more, about 0.01 wt % or more, about 0.05 wt % or more, about 0.1 wt % or more, about 0.5 wt % or more, about 1 wt % or more, about 1.5 wt % or more, about 2 wt % or more, or about 3 wt % or more) to about 5 wt % or less (e.g., about 4.5 wt % or less, about 4 wt % or less, about 3.5 wt % or less, about 3 wt % or less, about 2.5 wt % or less, about 2 wt % or less, about 1.5 wt % or less, about 1 wt % or less, about 0.5 wt % or less, or about 0.1 wt % or less) relative to the polishing composition described herein.

[0026] In one or more embodiments, the polishing composition described herein can include at least one (e.g., two or three) azole-containing corrosion inhibitor. In some embodiments, the at least one azole-containing corrosion inhibitor is selected from the group consisting of substituted or unsubstituted triazole, substituted or unsubstituted tetrazole, substituted or unsubstituted benzotriazole, substituted or unsubstituted pyrazole, and substituted or unsubstituted imidazole. In one or more embodiments, the azole-containing corrosion inhibitor is selected from the group consisting of 1,2,4-triazole, 1,2,3-triazole, tetrazole, benzotriazole, tolyltriazole, ethylbenzotriazole (e.g., 1-methylbenzotriazole, 4-methylbenzotriazole, and 5-methylbenzotriazole), ethylbenzotriazole (e.g., 1-ethylbenzotriazole), propylbenzotriazole (e.g., 1-propylbenzotriazole), butylbenzotriazole (e.g., 1-butylbenzotriazole and 5-butylbenzotriazole), pentylbenzotriazole (e.g., 1-pentylbenzotriazole), hexylbenzotriazole, ... The anticorrosive agent may be selected from the group consisting of benzotriazoles (e.g., 1-hexylbenzotriazole and 5-hexylbenzotriazole), dimethylbenzotriazoles (e.g., 5,6-dimethylbenzotriazole), chlorobenzotriazoles (e.g., 5-chlorobenzotriazole), dichlorobenzotriazoles (e.g., 5,6-dichlorobenzotriazole), chloromethylbenzotriazoles (e.g., 1-(chloromethyl)-1-H-benzotriazole), chloroethylbenzotriazole, phenylbenzotriazole, benzylbenzotriazole, aminotriazole, aminobenzimidazole, aminotetrazole, and mixtures thereof. In one or more embodiments, the composition may include benzotriazole and benzotriazole derivatives (e.g., substituted benzotriazoles). Without wishing to be bound by theory, it is believed that azole-containing anticorrosive agents (e.g., as described above) can significantly reduce or minimize the removal rate of copper in semiconductor substrates.

[0027] In some embodiments, the azole-containing corrosion inhibitor is present in an amount of about 0.0001 wt % or more (e.g., about 0.0002 wt % or more, about 0.0005 wt % or more, about 0.001 wt % or more, about 0.002 wt % or more, about 0.005 wt % or more, about 0.01 wt % or more, about 0.02 wt % or more, about 0.05 wt % or more, about 0.1 wt % or more, about 0.2 wt % or more, or about 0.5 wt % or more) to about 1 wt % or less (e.g., about 0.8 wt % or less, about 0.6 wt % or less, about 0.5 wt % or less, about 0.4 wt % or less, about 0.2 wt % or less, about 0.1 wt % or less, about 0.05 wt % or less, about 0.02 wt % or less, about 0.01 wt % or less, or about 0.005 wt % or less) relative to the polishing composition described herein.

[0028] In one or more embodiments, the polishing composition described herein can include at least one (e.g., two or three) ruthenium removal rate enhancing agent. In some embodiments, the at least one ruthenium removal rate enhancing agent can include an ammonium salt, a thiocyanate, nitric acid or a salt thereof, and a halide salt. In some embodiments, the at least one ruthenium removal rate enhancing agent is selected from the group consisting of ammonium hydroxide, ammonium chloride, ammonium fluoride, ammonium bromide, ammonium sulfate, ammonium carbonate, ammonium bicarbonate, ammonium nitrate, ammonium phosphate, ammonium acetate, ammonium thiocyanate, potassium thiocyanate, sodium thiocyanate, nitric acid, sodium nitrate, potassium nitrate, rubidium nitrate, cesium nitrate, sodium fluoride, potassium fluoride, rubidium fluoride, cesium fluoride, sodium chloride, potassium chloride, rubidium chloride, cesium chloride, and mixtures thereof.

[0029] In some embodiments, the ruthenium removal rate enhancing agent is present in an amount of about 0.0001 wt. % to about 5 wt. % of the composition. In one or more embodiments, the ruthenium removal rate enhancing agent is present in an amount of about 0.0001 wt. % or more (e.g., about 0.0002 wt. % or more, about 0.0005 wt. % or more, about 0.001 wt. % or more, about 0.002 wt. % or more, about 0.005 wt. % or more, about 0.01 wt. % or more, about 0.02 wt. % or more, about 0.05 wt. % or more, about 0.1 wt. % or more, about 0.2 ... % or more, or about 0.5% by weight or more) to about 5% by weight or less (e.g., about 4% by weight or less, about 3% by weight or less, about 2% by weight or less, about 1% by weight or less, about 0.8% by weight or less, about 0.6% by weight or less, about 0.5% by weight or less, about 0.4% by weight or less, about 0.2% by weight or less, about 0.1% by weight or less, about 0.05% by weight or less, about 0.02% by weight or less, about 0.01% by weight or less, or about 0.005% by weight or less).

[0030] In one or more embodiments, the polishing composition described herein can optionally contain at least one (e.g., two or three) chelating agent. In some embodiments, the at least one optional chelating agent can be an amino-containing carboxylic acid (e.g., a polyaminopolycarboxylic acid) or a phosphonic acid. In some embodiments, the chelating agent is selected from the group consisting of ethylenediaminetetraacetic acid, iminodiacetic acid, N-hydroxyethyl-ethylenediaminetriacetic acid, nitrilotriacetic acid, diethylenetriaminepentaacetic acid, hydroxyethylethylenediaminetriacetic acid, triethylenetetraaminehexaacetic acid, diaminocyclohexanetetraacetic acid, nitrilotrimethylphosphonic acid, ethylenediaminetetra(methylenephosphonic acid), 1-hydroxyethylidene-1,1-diphosphonic acid, diethylenetriaminepenta(methylenephosphonic acid), and combinations thereof. Without wishing to be bound by theory, it is believed that including a chelating agent (e.g., those described above) in the polishing composition described in the present disclosure can significantly reduce or minimize defects observed on semiconductor substrates (e.g., defects on the surface of copper wafers).

[0031] In some embodiments, the chelating agent is present in an amount of about 0.001 wt % or more (e.g., about 0.002 wt % or more, about 0.005 wt % or more, about 0.01 wt % or more, about 0.02 wt % or more, about 0.05 wt % or more, about 0.1 wt % or more, about 0.2 wt % or more, or about 0.5 wt % or more) to about 1 wt % or less (e.g., about 0.8 wt % or less, about 0.6 wt % or less, about 0.5 wt % or less, about 0.4 wt % or less, about 0.2 wt % or less, about 0.1 wt % or less, about 0.05 wt % or less, about 0.02 wt % or less, about 0.01 wt % or less, or about 0.005 wt % or less) relative to the polishing composition described herein.

[0032] An optional oxidizer (or oxidizing agent) can be added when the concentrated slurry is diluted to form the POU slurry. The oxidizer can be selected from the group consisting of hydrogen peroxide, orthoperiodic acid, metaperiodic acid, dimesoperiodic acid, diorthoperiodic acid, ammonium periodate, potassium periodate, sodium periodate, ammonium persulfate, iodic acid, iodate salts, perchloric acid, perchlorate salts, hydroxylamine and hydroxylamine salts, and any combination thereof. In one or more embodiments, the oxidizer can be hydrogen peroxide.

[0033] In some embodiments, the oxidizing agent is present in an amount of about 0.001 wt. % or more (e.g., about 0.002 wt. % or more, about 0.004 wt. % or more, about 0.005 wt. % or more, about 0.01 wt. % or more, about 0.025 wt. % or more, about 0.05 wt. % or more, about 0.075 wt. % or more, about 0.1 wt. % or more, about 0.5 wt. % or more, about 1 wt. % or more, or about 2 wt. % or more) to about 5 wt. % or less (e.g., about 4.5 wt. % or less, about 4 wt. % or less, about 3.5 wt. % or less, about 3 wt. % or less, about 2.5 wt. % or less, about 2 wt. % or less, about 1.5 wt. % or less, about 1 wt. % or less, about 0.5 wt. % or less, or about 0.1 wt. % or less) relative to the polishing composition described herein. In some embodiments, without wishing to be bound by theory, it is believed that the oxidizing agent can aid in the removal of hard mask material from a hard mask-containing substrate.

[0034] In some embodiments, the polishing composition described herein can include a solvent (e.g., a primary solvent) such as water. In some embodiments, the solvent (e.g., water) is present in an amount of about 20% by weight or more (e.g., about 25% by weight or more, about 30% by weight or more, about 35% by weight or more, about 40% by weight or more, about 45% by weight or more, about 50% by weight or more, about 55% by weight or more, about 60% by weight or more, about 65% by weight or more, about 70% by weight or more, about 75% by weight or more, about 80% by weight or more, about 85% by weight or more, about 90% by weight or more, about 92% by weight or more, about 94% by weight or more, about 95% by weight or more, or about 97% by weight or more) to about 99% by weight or less (e.g., about 98% by weight or less, about 96% by weight or less, about 94% by weight or less, about 92% by weight or less, about 90% by weight or less, about 85% by weight or less, about 80% by weight or less, about 75% by weight or less, about 70% by weight or less, or about 65% by weight or less).

[0035] In one or more embodiments, an optional secondary solvent (e.g., an organic solvent) can be used in the polishing composition (e.g., POU or concentrated polishing composition) of the present disclosure to aid in dissolving the azole-containing corrosion inhibitor. In one or more embodiments, the secondary solvent can be one or more alcohols, alkylene glycols, or alkylene glycol ethers. In one or more embodiments, the secondary solvent comprises one or more solvents selected from the group consisting of ethanol, 1-propanol, 2-propanol, n-butanol, propylene glycol, 2-methoxyethanol, 2-ethoxyethanol, propylene glycol propyl ether, dimethyl sulfoxide, and ethylene glycol.

[0036] In some embodiments, the secondary solvent is present in an amount of about 0.0025 wt % or more (e.g., about 0.005 wt % or more, about 0.01 wt % or more, about 0.02 wt % or more, about 0.05 wt % or more, about 0.1 wt % or more, about 0.2 wt % or more, about 0.4 wt % or more, about 0.6 wt % or more, about 0.8 wt % or more, or about 1 wt % or more) to about 5 wt % or less (e.g., about 4 wt % or less, about 3 wt % or less, about 2 wt % or less, about 1 wt % or less, about 0.8 wt % or less, about 0.6 wt % or less, about 0.5 wt % or less, or about 0.1 wt % or less) relative to the polishing composition described herein.

[0037] In one or more embodiments, the polishing composition described herein can contain, for example, an organic solvent, a pH adjuster, a quaternary ammonium compound (e.g., a salt or hydroxide), an amine, an alkali base (e.g., an alkali hydroxide), a fluorine-containing compound, a silicon-containing compound such as a silane (e.g., an alkoxysilane), an imine (e.g., an amidine such as 1,8-diazabicyclo[5.4.0]-7-undecene (DBU) and 1,5-diazabicyclo[4.3.0]non-5-ene (DBN)), a salt (e.g., a halide salt or a gold salt ... silane (e.g., an alkoxysilane), a silane (e.g., an alkoxysilane), a silane (e.g., an alkoxysilane), a silane (e.g., an alkoxysilane), a silane (e.g., an alkoxysilane), a silane (e.g., an alkoxysilane), a silane (e.g., an alkoxysilane), a silane (e.g., an alkoxysilane), a silane (e.g., an alkoxysilane), a silane (e.g., an alkoxysilane), a silane (e.g., an alkoxysilane), a silane (e.g., an alkoxysilane), a silane The polishing composition may be substantially free of one or more specific components, such as metal salts, polymers (e.g., cationic polymers or anionic polymers), surfactants (e.g., cationic surfactants, anionic surfactants, or nonionic surfactants), plasticizers, oxidizers (e.g., periodic acid), corrosion inhibitors (e.g., azole or non-azole corrosion inhibitors), and / or specific abrasives (e.g., ceria abrasives, nonionic abrasives, surface-modified abrasives, or negatively / positively charged abrasives). Halide salts that can be excluded from the polishing composition include alkali metal halides (e.g., sodium or potassium halides) or ammonium halides (e.g., ammonium chloride), and may be fluorides, chlorides, bromides, or iodides. As used in this disclosure, a component that is "substantially free" from the polishing composition refers to a component that is not intentionally added to the polishing composition. In some embodiments, the polishing compositions described herein may have about 1000 ppm or less (e.g., about 500 ppm or less, about 250 ppm or less, about 100 ppm or less, about 50 ppm or less, about 10 ppm or less, or about 1 ppm or less) of one or more of the above components that are substantially absent from the polishing composition. In some embodiments, the polishing compositions described herein may be completely free of one or more of the above components.

[0038] The present disclosure also contemplates methods of using any of the above-described polishing compositions (e.g., concentrates or POU slurries). For concentrates, the method can include diluting the concentrate (e.g., by a factor of 2 or more) to form a POU slurry, and then contacting a surface at least partially comprising ruthenium and / or a hard mask material with the POU slurry. In some embodiments, an oxidizer can be added to the slurry before, after, or during the dilution. For POU slurries, the method can include contacting the surface at least partially comprising ruthenium and / or a hard mask material with the slurry.

[0039] In one or more embodiments, the present disclosure features a polishing method that can include applying a polishing composition according to the present disclosure to a substrate (e.g., a wafer) having at least ruthenium and / or a hard mask material on its surface; and contacting a pad with the surface of the substrate and moving the pad relative to the substrate. In some embodiments, when the substrate includes at least one or more silicon oxides, ruthenium, copper, a hard mask material, and / or a barrier material (e.g., Ta, TaN), the method can effectively polish the substrate without significant corrosion or undesirable removal rate selectivity. In one or more embodiments, the copper removal rate is less than about 500 Å / min, or less than about 400 Å / min, or less than about 300 Å / min, or less than about 200 Å / min, or less than about 150 Å / min, or less than about 125 Å / min, or less than about 100 Å / min, or less than about 90 Å / min, or less than about 80 Å / min, or less than about 70 Å / min. In one or more embodiments, the static etch rate (SER) of a 2 cm x 2 cm copper coupon incubated in a polishing composition according to the present disclosure at 45°C for 5 minutes is less than about 10 Å / min, or less than about 8 Å / min, or less than about 6 Å / min, or less than about 5 Å / min, or less than about 4 Å / min, or less than about 3.5 Å / min, or less than about 2 Å / min, or less than about 2.5 Å / min. In one or more embodiments, the ruthenium removal rate is about 3 Å / min or more, or about 5 Å / min or more, or about 15 Å / min or more, or about 25 Å / min or more, or about 35 Å / min or more, or about 45 Å / min or more, or about 55 Å / min or more. In one or more embodiments, the ratio of copper polishing rate to ruthenium polishing rate (Cu:Ru) is about 35:1 or less, or about 30:1 or less, or about 25:1 or less, or about 20:1 or less, or about 15:1 or less, or about 10:1 or less, or about 5:1 or less, or about 4:1 or less, or about 3:1 or less, or about 2.5:1 or less, or about 2:1 or less, or about 1.5:1 or less, or about 1:1 or less.

[0040] The term "silicon oxide" as used herein is intended to include both undoped and doped silicon oxides. For example, in one or more embodiments, the silicon oxide may be doped with at least one dopant selected from carbon, nitrogen (for silicon oxide), oxygen, hydrogen, and any other known dopant for silicon oxide. Some examples of types of silicon oxide films include TEOS (tetraethyl orthosilicate), SiOC, SiOCN, SiOCH, SiOH, and SiON.

[0041] In some embodiments, the method of using the polishing composition described herein can further include manufacturing a semiconductor device from a substrate treated with the polishing composition by one or more processes. For example, photolithography, ion implantation, dry / wet etching, plasma etching, deposition (e.g., PVD, CVD, ALD, ECD), wafer mounting, die cutting, packaging, and testing can be used to manufacture a semiconductor device from a substrate treated with the polishing composition described herein.

[0042] The following specific examples are to be construed as merely illustrative, and not limitative of the remainder of the disclosure in any way whatsoever. Without further elaboration, it is believed that one skilled in the art can, based on the description herein, utilize the present invention to its fullest extent. [Example]

[0043] In these examples, polishing was performed using two polishing systems. The first polishing system used an Ebara CMP polisher with a Fujibo soft pad, a downforce pressure of 105 hPa, and a slurry flow rate of 100 mL / min to 500 mL / min to polish 300 mm wafers. The second polishing system used an AMAT Mirra CMP polisher with a Fujibo soft pad, a downforce pressure of 1.5 psi, and a slurry flow rate of 100 mL / min to 400 mL / min to polish 200 mm wafers.

[0044] The general compositions used in the following examples are set forth below in Table 1. Specific details regarding the differences in the compositions tested are explained in more detail when each example is described.

[0045] [Table 1]

[0046] Example 1 Table 2 below shows the removal rates of Ru, Cu, and black diamond (BD-1) blanket wafers when polished with Compositions 1-6. Compositions 1-6 contained the same components in the same concentrations, except for the differences noted below and in Table 2. The BD-1 blanket wafer is a low-k dielectric material (i.e., carbon-doped silicon oxide) coated on a silicon wafer.

[0047] Composition 1 contained a Cu removal rate inhibitor (Cu RRI), which was an azole-containing corrosion inhibitor. Compositions 2-5 each contained a ruthenium removal rate enhancer (Ru RRE) at a different concentration, as shown in Table 2. Compositions 6 and 7 contained a Ru RRE and two Cu removal rate inhibitors (i.e., Cu RRI-1 and Cu RRI-2), both of which were azole-containing corrosion inhibitors. Composition 8 contained a Ru RRE and only one of the Cu RRIs.

[0048] The results surprisingly showed that the addition of the Ru RRE increased the Ru removal rate to an acceptable range of approximately 30 Å / min. Furthermore, the Cu removal rate increased with the addition of the Ru RRE, but could be adequately controlled by adding a second Cu RRI. In addition, these results showed that the removal rate of BD-1 was not significantly affected by the addition of the Ru RRE and Cu-RRI-2.

[0049] [Table 2]

[0050] While only a few exemplary embodiments have been described in detail above, those skilled in the art will readily appreciate that many modifications can be made therein without substantially departing from the invention, and accordingly, all such modifications are intended to be included within the scope of the present disclosure, as defined in the following claims. (Addendum) The present disclosure includes the following aspects. Section 1: abrasives; pH adjuster; Barrier film removal rate enhancer; low-k removal rate inhibitor; Azole-containing corrosion inhibitors; and Ruthenium removal rate enhancer 1. A polishing composition comprising: Section 2: Item 1. The polishing composition according to item 1, wherein the abrasive is selected from the group consisting of alumina; silica; titania; ceria; zirconia; a co-formed product of alumina, silica, titania, ceria, or zirconia; coated abrasives; surface-modified abrasives; and mixtures thereof. Section 3: Item 2. The polishing composition according to Item 1, wherein the abrasive is present in an amount of about 0.1% by weight to about 50% by weight of the composition. Section 4: Item 2. The polishing composition according to Item 1, wherein the barrier film removal rate increasing agent is an organic acid or a salt thereof selected from the group consisting of gluconic acid, lactic acid, citric acid, tartaric acid, malic acid, glycolic acid, malonic acid, formic acid, oxalic acid, acetic acid, propionic acid, peracetic acid, succinic acid, lactic acid, potassium acetate, potassium citrate, aminoacetic acid, phenoxyacetic acid, bicine, diglycolic acid, glyceric acid, tricine, alanine, histidine, valine, phenylalanine, proline, glutamine, aspartic acid, glutamic acid, arginine, lysine, tyrosine, benzoic acid, salts thereof, and mixtures thereof. Section 5: Item 2. The polishing composition according to Item 1, wherein the barrier film removal rate increasing agent is present in an amount of about 0.002% by weight to about 4% by weight of the composition. Item 6: Item 2. The polishing composition according to item 1, wherein the low-k removal rate inhibitor is a nonionic surfactant. Section 7: Item 7. The polishing composition according to item 6, wherein the nonionic surfactant is selected from the group consisting of alcohol alkoxylates, alkylphenol alkoxylates, tristyrylphenol alkoxylates, sorbitan ester alkoxylates, polyalkoxylates, polyalkylene oxide block copolymers, tetrahydroxy oligomers, alkoxylated diamines, and mixtures thereof. Section 8: Item 2. The polishing composition according to item 1, wherein the low-k removal rate inhibitor is present in an amount of about 0.0005% to about 5% by weight of the composition. Section 9: Item 2. The polishing composition according to item 1, wherein the azole-containing corrosion inhibitor is selected from the group consisting of triazole, tetrazole, benzotriazole, tolyltriazole, 1,2,4-triazole, ethylbenzotriazole, propylbenzotriazole, butylbenzotriazole, pentylbenzotriazole, hexylbenzotriazole, dimethylbenzotriazole, chlorobenzotriazole, dichlorobenzotriazole, chloromethylbenzotriazole, chloroethylbenzotriazole, phenylbenzotriazole, benzylbenzotriazole, aminotriazole, aminobenzimidazole, pyrazole, imidazole, aminotetrazole, and mixtures thereof. Section 10: Item 2. The polishing composition according to Item 1, wherein the azole-containing anticorrosive is present in an amount of about 0.0001% by weight to about 1% by weight of the composition. Section 11: Item 2. The polishing composition according to item 1, wherein the pH adjuster is selected from the group consisting of ammonium hydroxide, sodium hydroxide, potassium hydroxide, cesium hydroxide, monoethanolamine, diethanolamine, triethanolamine, methylethanolamine, methyldiethanolamine, tetrabutylammonium hydroxide, tetrapropylammonium hydroxide, tetraethylammonium hydroxide, tetramethylammonium hydroxide, ethyltrimethylammonium hydroxide, diethyldimethylammonium hydroxide, dimethyldipropylammonium hydroxide, benzyltrimethylammonium hydroxide, tris(2-hydroxyethyl)methylammonium hydroxide, choline hydroxide, and any combination thereof. Section 12: Item 2. The polishing composition according to Item 1, wherein the pH adjuster is present in an amount of about 0.01% by weight to about 10% by weight of the composition. Section 13: Item 2. The polishing composition according to item 1, wherein the ruthenium removal rate enhancing agent is selected from the group consisting of ammonium hydroxide, ammonium chloride, ammonium fluoride, ammonium bromide, ammonium sulfate, ammonium carbonate, ammonium bicarbonate, ammonium nitrate, ammonium phosphate, ammonium acetate, ammonium thiocyanate, potassium thiocyanate, sodium thiocyanate, nitric acid, sodium nitrate, potassium nitrate, rubidium nitrate, cesium nitrate, sodium fluoride, potassium fluoride, rubidium fluoride, cesium fluoride, sodium chloride, potassium chloride, rubidium chloride, cesium chloride, and mixtures thereof. Section 14: Item 2. The polishing composition according to item 1, wherein the ruthenium removal rate enhancing agent is present in an amount of about 0.0001% by weight to about 5% by weight of the composition. Section 15: Item 1. The polishing composition according to item 1, further comprising a chelating agent selected from the group consisting of ethylenediaminetetraacetic acid, iminodiacetic acid, N-hydroxyethyl-ethylenediaminetriacetic acid, nitrilotriacetic acid, diethylenetriaminepentaacetic acid, hydroxyethylethylenediaminetriacetic acid, triethylenetetraaminehexaacetic acid, diaminocyclohexanetetraacetic acid, nitrilotrimethylphosphonic acid, ethylenediaminetetra(methylenephosphonic acid), 1-hydroxyethylidene-1,1-diphosphonic acid, diethylenetriaminepenta(methylenephosphonic acid), and combinations thereof. Section 16: Item 16. The polishing composition according to Item 15, wherein the chelating agent is present in an amount of about 0.001% by weight to about 1% by weight of the composition. Section 17: Item 1. The polishing composition according to item 1, further comprising an oxidizing agent selected from the group consisting of hydrogen peroxide, orthoperiodic acid, metaperiodic acid, dimesoperiodic acid, diorthoperiodic acid, ammonium periodate, potassium periodate, sodium periodate, ammonium persulfate, iodic acid, iodate salts, perchloric acid, perchlorate salts, hydroxylamine and hydroxylamine salts, and any combination thereof. Section 18: The composition comprises: the abrasive in an amount of about 0.1% to about 50% by weight of the composition; the pH adjuster in an amount of about 0.01% to about 10% by weight of the composition; the barrier film removal rate enhancing agent in an amount of about 0.002% to about 4% by weight of the composition; the low-k removal rate inhibitor in an amount of about 0.0005% to about 5% by weight of the composition; the azole-containing corrosion inhibitor in an amount of about 0.0001% to about 1% by weight of the composition; and the ruthenium removal promoter in an amount of about 0.0001% to about 5% by weight of the composition; Item 1. The polishing composition according to item 1, comprising: Section 19: Item 2. The polishing composition according to Item 1, wherein the pH of the composition is about 7 to about 14. Section 20: abrasives; pH adjuster; organic acids or their salts; nonionic surfactants; Azole-containing corrosion inhibitors; and A compound selected from the group consisting of ammonium salts, thiocyanates, halide salts, nitrates, nitric acid, and mixtures thereof. 1. A polishing composition comprising: Section 21: Applying the polishing composition of item 1 to a surface of a substrate, wherein the surface contains ruthenium or a hard mask material; and contacting a pad with the surface of the substrate and moving the pad relative to the substrate; 1. A method for polishing a substrate, comprising:

Claims

1. abrasives; pH adjuster; low-k removal rate inhibitors; Azole-containing corrosion inhibitors; and Ruthenium removal rate enhancer Including, the ruthenium removal rate enhancing agent is selected from the group consisting of ammonium hydroxide, ammonium chloride, ammonium fluoride, ammonium bromide, ammonium sulfate, ammonium carbonate, ammonium bicarbonate, ammonium nitrate, ammonium phosphate, ammonium acetate, ammonium thiocyanate, potassium thiocyanate, sodium thiocyanate, nitric acid, sodium nitrate, potassium nitrate, rubidium nitrate, cesium nitrate, sodium fluoride, potassium fluoride, rubidium fluoride, cesium fluoride, sodium chloride, potassium chloride, rubidium chloride, cesium chloride, and mixtures thereof; A polishing composition having a pH of 7 to 14.

2. 2. The polishing composition of claim 1, wherein the abrasive is selected from the group consisting of alumina; silica; titania; ceria; zirconia; a co-formed product of alumina, silica, titania, ceria, or zirconia; a coated abrasive; a surface-modified abrasive; and mixtures thereof.

3. 10. The polishing composition of claim 1, wherein the abrasive is in an amount of 0.1% to 50% by weight of the polishing composition.

4. The polishing composition of claim 1 , further comprising a barrier film removal rate enhancing agent.

5. 5. The polishing composition of claim 4, wherein the barrier film removal rate increasing agent is an organic acid or a salt thereof selected from the group consisting of gluconic acid, lactic acid, citric acid, tartaric acid, malic acid, glycolic acid, malonic acid, formic acid, oxalic acid, acetic acid, propionic acid, peracetic acid, succinic acid, potassium acetate, potassium citrate, aminoacetic acid, phenoxyacetic acid, bicine, diglycolic acid, glyceric acid, tricine, alanine, histidine, valine, phenylalanine, proline, glutamine, aspartic acid, glutamic acid, arginine, lysine, tyrosine, benzoic acid, salts thereof, and mixtures thereof.

6. 5. The polishing composition of claim 4, wherein the barrier film removal rate enhancing agent is present in an amount of 0.002% to 4% by weight of the polishing composition.

7. 2. The polishing composition of claim 1, wherein the low-k removal rate inhibitor is a nonionic surfactant.

8. 8. The polishing composition of claim 7, wherein the nonionic surfactant is selected from the group consisting of alcohol alkoxylates, alkylphenol alkoxylates, tristyrylphenol alkoxylates, sorbitan ester alkoxylates, polyalkoxylates, polyalkylene oxide block copolymers, tetrahydroxy oligomers, alkoxylated diamines, and mixtures thereof.

9. 10. The polishing composition of claim 1, wherein the low-k removal rate inhibitor is in an amount of 0.0005% to 5% by weight of the polishing composition.

10. 2. The polishing composition of claim 1, wherein the azole-containing corrosion inhibitor is selected from the group consisting of triazole, tetrazole, benzotriazole, tolyltriazole, 1,2,4-triazole, ethylbenzotriazole, propylbenzotriazole, butylbenzotriazole, pentylbenzotriazole, hexylbenzotriazole, dimethylbenzotriazole, chlorobenzotriazole, dichlorobenzotriazole, chloromethylbenzotriazole, chloroethylbenzotriazole, phenylbenzotriazole, benzylbenzotriazole, aminotriazole, aminobenzimidazole, pyrazole, imidazole, aminotetrazole, and mixtures thereof.

11. 10. The polishing composition of claim 1, wherein the azole-containing corrosion inhibitor is in an amount of 0.0001% to 1% by weight of the polishing composition.

12. 2. The polishing composition of claim 1, wherein the pH adjuster is selected from the group consisting of ammonium hydroxide, sodium hydroxide, potassium hydroxide, cesium hydroxide, monoethanolamine, diethanolamine, triethanolamine, methylethanolamine, methyldiethanolamine, tetrabutylammonium hydroxide, tetrapropylammonium hydroxide, tetraethylammonium hydroxide, tetramethylammonium hydroxide, ethyltrimethylammonium hydroxide, diethyldimethylammonium hydroxide, dimethyldipropylammonium hydroxide, benzyltrimethylammonium hydroxide, tris(2-hydroxyethyl)methylammonium hydroxide, choline hydroxide, and any combination thereof.

13. 10. The polishing composition of claim 1, wherein the pH adjuster is in an amount of 0.01% to 10% by weight of the polishing composition.

14. 2. The polishing composition of claim 1, wherein the ruthenium removal rate enhancing agent is in an amount of 0.0001% to 5% by weight of the polishing composition.

15. 2. The polishing composition of claim 1, further comprising a chelating agent selected from the group consisting of ethylenediaminetetraacetic acid, iminodiacetic acid, N-hydroxyethyl-ethylenediaminetriacetic acid, nitrilotriacetic acid, diethylenetriaminepentaacetic acid, hydroxyethylethylenediaminetriacetic acid, triethylenetetraaminehexaacetic acid, diaminocyclohexanetetraacetic acid, nitrilotrimethylphosphonic acid, ethylenediaminetetra(methylenephosphonic acid), 1-hydroxylethylidene-1,1-diphosphonic acid, diethylenetriaminepenta(methylenephosphonic acid), and combinations thereof.

16. 16. The polishing composition of claim 15, wherein the chelating agent is in an amount of 0.001% to 1% by weight of the polishing composition.

17. 2. The polishing composition of claim 1, further comprising an oxidizing agent selected from the group consisting of hydrogen peroxide, orthoperiodic acid, metaperiodic acid, dimesoperiodic acid, diorthoperiodic acid, ammonium periodate, potassium periodate, sodium periodate, ammonium persulfate, iodic acid, iodate salts, perchloric acid, perchlorate salts, hydroxylamine and hydroxylamine salts, and any combination thereof.

18. The polishing composition comprises: the abrasive in an amount of 0.1% to 50% by weight of the polishing composition; the pH adjuster in an amount of 0.01 wt % to 10 wt % of the polishing composition; the low-k removal rate inhibitor in an amount of 0.0005% to 5% by weight of the polishing composition ； the azole-containing corrosion inhibitor in an amount of 0.0001 wt % to 1 wt % of the polishing composition; and the ruthenium removal rate enhancing agent in an amount of 0.0001% to 5% by weight of the polishing composition. The polishing composition of claim 1 , comprising:

19. 20. The polishing composition of claim 18, further comprising a barrier film removal rate enhancing agent in an amount of 0.002 wt % to 4 wt % of the polishing composition.

20. abrasives; pH adjuster; organic acids or their salts; nonionic surfactants; Azole-containing corrosion inhibitors; and A compound selected from the group consisting of ammonium hydroxide, ammonium chloride, ammonium fluoride, ammonium bromide, ammonium sulfate, ammonium carbonate, ammonium bicarbonate, ammonium nitrate, ammonium phosphate, ammonium acetate, ammonium thiocyanate, potassium thiocyanate, sodium thiocyanate, nitric acid, sodium nitrate, potassium nitrate, rubidium nitrate, cesium nitrate, sodium fluoride, potassium fluoride, rubidium fluoride, cesium fluoride, sodium chloride, potassium chloride, rubidium chloride, cesium chloride, and mixtures thereof. Including, A polishing composition having a pH of 7 to 14.

21. applying the polishing composition of claim 1 to a surface of a substrate, wherein the surface comprises ruthenium or a hard mask material; and contacting a pad with the surface of the substrate and moving the pad relative to the substrate; 1. A method for polishing a substrate, comprising:

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