Compositions and methods for nano-twin copper formation

Abstract

A copper electrolyte comprising a copper salt, a source of halide ions, and a reaction product of an amine or a sulfur-containing compound and 2, 3-epoxy-1-propanol, optionally in combination with one or more of a leveling agent or an accelerator, for producing nano-twin copper deposits. The copper electrolyte is used to initiate high density nano-twin copper deposits on various surfaces.

Description

[0001] Cross - reference to related applications

[0002] This application claims the benefit of U.S. Provisional Application No. 63 / 414,725, filed Oct. 10, 2022, the subject matter of which is incorporated herein by reference in its entirety. Technical field

[0003] The present invention generally relates to the electrodeposition of nanotwinned copper on various substrates and a copper electroplating bath for producing high - density nanotwinned copper deposits. Background art

[0004] Electrochemical deposition processes are well - established in integrated circuit manufacturing processes. In a method commonly referred to as "damascene" processing (pre - passivation metallization), copper wires can be formed by electroplating a metal into very thin, high aspect - ratio trenches and vias.

[0005] With the advancement of microelectronic devices, there is a continuing need to produce smaller and more dense interconnect features. Due to its high ductility and conductivity, copper is one of the most fundamental conductors in microelectronic devices. One approach towards this goal is to remove the solder between two separate substrates connecting copper vias, pads, bumps, or pillars, which can be replaced by (for example) Cu - Cu hybrid bonding.

[0006] To ensure the success of this method, which requires both high temperature and high pressure, it is highly desirable to produce (111) - oriented electroplated copper having >90% nanotwinned columnar copper (ntCu) grains.

[0007] Due to the combination of excellent mechanical properties, good electrical conductivity, and unique structure, the use of nanotwinned copper in microelectronics has attracted attention. When the grain size of a metal such as copper is reduced to the nanoscale level, the mechanical strength of the metal generally increases. Nanotwinned copper represents ultrafine - grained copper, the grains of which contain a high density of hierarchical nanotwins separated by coherent twin boundaries. By introducing nanoscale twins into the microstructure of copper, properties including mechanical strength, ductility, electromigration resistivity, and hardness can be improved.

[0008] Thin metal films at the nanoscale level can have exemplary mechanical properties. Thus, metals having nanotwinned crystalline properties can be suitable for applications such as through - silicon vias (TSVs), semiconductor chip interconnects, package substrate pin vias, metal interconnects (e.g., copper interconnects), and metal materials on substrates.

[0009] Nanotwinned copper can be obtained in several ways, including, for example, by sputtering and by electrolytic deposition using a copper electroplating composition that has been optimized to produce nanotwinned copper.

[0010] One of the advantages of sputtering is the high purity of the copper film, with the ability to conform to the preferred orientation of the grains. Sputtered (111)-oriented nanotwinned copper has been shown to have high thermal stability and strength.

[0011] On the other hand, direct current electrolytic electroplating has the advantage of being extremely compatible with high-volume industrial production. Electroplated nanotwinned copper can be divided into two groups - equiaxed grain nanotwinned copper and (111)-oriented nanotwinned copper.

[0012] Crystal defects can affect the mechanical, electrical, and optical properties of materials. Twinning occurs in materials in which two parts of the crystal structure are symmetrically related to each other. In a face-centered cubic (FCC) crystal structure containing copper, coherent twin boundaries can form as (111) mirror planes, and the typical stacking order of the (111) plane is reversed from this mirror plane. In other words, adjacent grains are mirror images across the coherent twin boundary in a layered (111)-structure. Twins grow in a layer-by-layer manner extending along the lateral (111) crystal plane, where the twin thickness is on the nanometer scale. Nanotwinned copper exhibits excellent mechanical and electrical properties and can be used in a wide range of applications in wafer-level packaging and advanced packaging designs.

[0013] Compared with copper exhibiting conventional grain boundaries, nanotwinned copper has strong mechanical properties, including high strength and high tensile ductility. For example, nanotwinned copper also exhibits high electrical conductivity (which can be attributed to twin boundaries), resulting in less significant electron scattering compared to grain boundaries. Nanotwinned copper also exhibits a high degree of thermal stability, which can be attributed to the twin boundaries having an excess energy that is lower by an order of magnitude than that of grain boundaries and being able to achieve a high copper atom diffusivity, which is useful for copper-copper direct bonding. In addition, nanotwinned copper also shows high resistance to electromigration, which may be the result of twin boundaries slowing down the electromigration-induced atomic diffusion. Nanotwinned copper exhibits strong resistance to seed etching, which may be important in applications of fine-line redistribution layers, and also shows low impurity incorporation, which results in fewer Kirkendall voids due to the welding reaction with nanotwinned copper.

[0014] In some aspects, nanotwinned copper enables direct copper-copper bonding, which can occur at low temperatures, medium pressures, and lower bonding forces / times. Typically, the deposition of copper structures results in a rough surface, and in some cases, electropolishing can be performed after the electrodeposition of nanotwinned copper before copper-copper bonding to achieve a smooth surface. Due to the smooth surface, nanotwinned copper structures can be used for copper-copper bonding, with shorter bonding times, lower temperatures, and fewer voids.

[0015] U.S. Patent No. 7,074,315 to Desmaison et al. (the entire subject matter of which is incorporated herein by reference) describes a copper electrolyte for depositing a matte copper layer. However, there is no suggestion of using Desmaison's copper electrolyte to deposit nanotwinned copper.

[0016] WO2020 / 092244 to Banik et al. (the entire subject matter of which is incorporated herein by reference) describes a copper structure having a high density of nanotwinned copper deposited on a substrate. Banik does not describe any specific electrolytic copper plating bath, but rather focuses on plating conditions, including applying a pulsed current waveform that alternates between a constant current and no current, where the duration of no current applied is substantially greater than the duration of the constant current applied.

[0017] U.S. Patent No. 10,566,314 to Yang (the entire subject matter of which is incorporated herein by reference) describes how the optimal copper grain structure for Cu-Cu metal-metal bonding is a columnar grain microstructure. The copper grain microstructure plated by the disclosed inhibitor-only system results in a columnar grain structure due to plating nanotwinned copper. Additionally, while columnar grains are mentioned, the (111) copper grain structure of nanotwinned copper is not mentioned.

[0018] Research has shown that very few materials can produce nanotwinned copper by electroplating, where the copper deposit exhibits a high degree of nanotwinning regardless of the underlying substrate.

[0019] There is still a need in the art for a copper electroplating solution for producing nanotwinned copper deposits, particularly a copper electroplating solution capable of producing nanotwinned copper deposits in the features of a microelectronic substrate and / or on a substrate that is not dominated by (111)-copper. SUMMARY OF THE INVENTION

[0020] One object of the present invention is to provide an improved copper electroplating solution.

[0021] Another object of the present invention is to provide a copper electroplating solution capable of producing high-density nanotwinned copper in a deposit.

[0022] Another object of the present invention is to provide a copper electroplating solution optimized to deposit nanotwinned copper in the features of a microelectronic substrate.

[0023] Yet another object of the present invention is to provide a copper electroplating solution that can initiate or produce a copper deposit exhibiting high-density nanotwinned copper on any surface.

[0024] Yet another object of the present invention is to provide a copper electroplating solution capable of producing a deposit exhibiting high-density nanotwinned copper on a surface that is not dominated by (111)-copper.

[0025] To this end, in one embodiment, the present invention generally relates to a copper electroplating solution, wherein the copper electroplating solution comprises:

[0026] a) a copper salt;

[0027] b) a source of halide ions; and

[0028] c) an inhibitor, wherein the inhibitor comprises a reaction product of a reactant and 2,3-epoxy-1-propanol, wherein the reactant comprises at least one of an amine and a sulfur-containing compound;

[0029] wherein the copper electroplating solution is configured to deposit high-density nanotwinned copper on a substrate.

[0030] In one embodiment, the copper electroplating solution may further optionally comprise one or more of the following:

[0031] a) an accelerator, wherein the accelerator comprises an organic sulfur compound; and

[0032] b) a leveling agent, wherein the leveling agent comprises a polymeric quaternary nitrogen substance.

[0033] In another embodiment, the present invention also generally relates to a method of depositing high-density nanotwinned copper on a substrate using the copper electroplating solution described herein, the substrate comprising a surface that is not dominated by (111)-copper. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 Depicts SEMs of copper deposited on (111)-dominated PVD copper and copper deposited on polycrystalline copper for a reference composition and a Compound 1 composition.

[0035] Figure 2 Depicts a 50K magnification of the transition layer of nanotwinned copper deposited from a Compound 1 composition on polycrystalline copper.

[0036] Figure 3 Depicts SEMs of copper deposited on (111)-dominated PVD copper and copper deposited on polycrystalline copper for a Compound 2A composition and a Compound 2B composition.

[0037] Figure 4 Depicts SEMs of copper deposited on (111)-dominated PVD copper, stainless steel, and PVD ruthenium surfaces for a reference composition and a Compound 1 composition.

[0038] Figure 5 Depicts a 20K magnification of the transition layer of nanotwinned copper deposited from a Compound 2A composition according to Example 3.

[0039] Figure 6Depicts a 20K magnification of the transition layer deposited from the Compound 2A composition according to Comparative Example 4.

[0040] Figure 7 Depicts a 20K magnification of the transition layer deposited from the Compound 2A composition according to Comparative Example 5.

[0041] Figure 8 Depicts a 20K magnification of the transition layer of nanotwinned copper deposited from the Compound 2A composition according to Example 6.

[0042] Figure 9 Depicts a 20K magnification of the transition layer of nanotwinned copper deposited from the Compound 2A composition according to Example 7. Detailed Description

[0043] As used herein, unless the context clearly dictates otherwise, the terms "a," "an," and "the" refer to both singular and plural referents.

[0044] As used herein, the term "about" refers to measurable values such as parameters, amounts, durations, etc., and is intended to include variations of + / −15% or less, preferably + / −10% or less, more preferably + / −5% or less, even more preferably + / −1% or less, and still more preferably + / −0.1% or less relative to the specifically recited value, so long as such variations are suitable for carrying out the invention described herein. Additionally, it should be understood that the value itself to which the modifier "about" refers is specifically disclosed herein.

[0045] As used herein, for ease of description, spatial relative terms such as "under," "below," "lower," "above," "upper," etc. are used to describe the relationship of one element or feature to another or other elements or features, as shown in the figures. It should also be understood that the terms "front" and "back" are not intended to be limiting and are intended to be interchangeable where appropriate.

[0046] As used herein, the term "comprising and / or containing" specifies the presence of the stated features, integers, steps, operations, elements, and / or components, but does not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0047] As used herein, if not otherwise defined specifically for a particular element or compound herein, the term "substantially free" or "essentially free" means that the given element or compound cannot be detected by ordinary analytical means for bath analysis known to those skilled in the art of metal plating. Such methods typically include atomic absorption spectroscopy, titration, UV-visible analysis, secondary ion mass spectrometry, and other commonly used analytical techniques.

[0048] As used herein, the term "feature" refers to vias, through-silicon vias (TSVs), trenches, pillars, pads, bumps, etc. that may be present on a microelectronic substrate.

[0049] As used herein, the term "high density" of nanotwinned copper refers to a copper deposit containing at least 75% or at least 80% or at least 85% or at least 90% or at least 95% of nanotwinned columnar copper grains in the deposit.

[0050] Unless otherwise indicated, all amounts are in weight percent. All numerical ranges are inclusive and combinable in any order, except where such numerical ranges are limited to a total of 100% which is logical. The term "average" is equivalent to the mean value of the sample.

[0051] The terms "plating" and "depositing" are used interchangeably throughout the specification.

[0052] The terms "composition" and "bath" and "electrolyte" and "solution" are used interchangeably throughout the specification.

[0053] Unless otherwise described in the specification as having substituent groups, the term "alkyl" means an organic chemical group consisting only of carbon and hydrogen and having the general formula C n H 2n+1 .

[0054] Studies have shown that very few materials are capable of producing nanotwinned copper (ntCu) or exhibiting highly nanotwinned copper deposits. One such material is poly(2,3-epoxy-1-propanol), which is a linear or branched polyhydroxy compound having a molecular weight of from about 200 to about 20,000, more preferably from about 500 to about 5,000, and even more preferably from about 1,000 to about 3,000.

[0055] It is also believed that the introduction of other organic electroplating compounds (such as accelerators, brighteners, carriers, wetting agents, and / or leveling agents) will destroy the ability of the polyhydroxy compound to produce nanotwinned copper.

[0056] Currently, it is extremely difficult to achieve high-density nanotwinned copper using polyhydroxy compounds, such as those described in U.S. Patent No. 11,384,446 to Richardson et al. and WO2023 / 014524, unless deposited on a PVD copper seed layer that exhibits a large amount of copper in a (111)-oriented grain structure.

[0057] It is desired to initiate high-density nanocrystalline twinned copper deposits on other surfaces, which include, for example, polycrystalline copper seed layers, stainless steel, and PVD ruthenium surfaces. To this end, the inventors of the present invention have developed means for optimizing copper electroplating solutions to deposit nanocrystalline twinned copper on various surfaces, which include, by way of example and not limitation, polycrystalline copper seed layers, stainless steel, and PVD ruthenium.

[0058] In one embodiment, the present invention generally relates to the electrodeposition of nanocrystalline twinned copper and a copper electroplating solution configured to produce copper deposits that exhibit high-density nanocrystalline twinned copper on various surfaces.

[0059] In one embodiment, the copper electroplating solution comprises:

[0060] a) a copper salt;

[0061] b) a source of halide ions; and

[0062] c) an inhibitor, wherein the inhibitor comprises the reaction product of a reactant and 2,3-epoxy-1-propanol,

[0063] wherein the reactant comprises at least one of an amine and a sulfur-containing compound.

[0064] In one embodiment, the copper electrolyte may also optionally comprise one or more of the following:

[0065] a) an accelerator, wherein the accelerator comprises an organic sulfur compound; and

[0066] b) a leveling agent, wherein the leveling agent comprises a polymeric quaternary nitrogen substance;

[0067] In a preferred embodiment, the copper salt includes copper sulfate. Other copper salts that can be used in the composition include copper methanesulfonate, copper pyrophosphate, copper propane sulfonate, and other similar compounds. The concentration of copper sulfate in the electroplating solution is generally in the range of about 1 g / L to 100 g / L, more preferably in the range of about 20 g / L to about 80 g / L, and even more preferably in the range of about 40 g / L to about 60 g / L.

[0068] Halide ions act as bridges to assist in the adsorption of certain organic additives to the substrate surface. Halide ions include, but are not limited to, chloride ions, bromide ions, iodide ions, and combinations thereof. In one embodiment, the halide ion includes chloride ions. The concentration of chloride ions in the electroplating solution is generally in the range of about 1 mg / L to 150 mg / L, more preferably about 30 mg / L to 120 mg / L, and most preferably about 45 mg / L to 75 mg / L.

[0069] In one embodiment, the electroplating composition contains an acid to control the conductivity of the plating bath, and suitable acids include sulfuric acid and methanesulfonic acid. In one embodiment, the acid is sulfuric acid. The concentration of the acid in the electroplating solution is generally in the range of about 0 g / L to 240 g / L, more preferably in the range of about 10 g / L to about 180 g / L, and even more preferably in the range of about 80 g / L to about 140 g / L. In one embodiment, the concentration of the acid is in the range of about 8 g / L to about 15 g / L, more preferably about 10 g / L. The inventors of the present invention have surprisingly found that the concentration of the acid can have a profound impact on the ability to develop nanotwins, and compositions containing a lower acid concentration tend to be more tolerant of ntCu formation than similar compositions containing a higher acid concentration.

[0070] In one embodiment, the inhibitor includes the reaction product of an amine or a sulfur-containing compound with 2,3-epoxy-1-propanol. The resulting linear or branched polyhydroxy compound generally has a molecular weight of about 200 g / mol to about 20,000 g / mol, more preferably about 500 g / mol to about 5,000 g / mol, and most preferably about 1,000 g / mol to about 3,000 g / mol.

[0071] Examples of suitable amines include ethanolamine, diethanolamine, triethanolamine, propanolamine, isopropanolamine, diisopropanolamine, triisopropanolamine, N-methyldiethanolamine, N-ethyldiethanolamine, N-propyldiethanolamine, methylmonoethanolamine, N,N-dimethylethanolamine, N,N-diethylethanolamine, N-propylmonoethanolamine, N-propyldiethanolamine, N-butylethanolamine, N-butyldiethanolamine, N,N-dibutylethanolamine, hydroxyethylmorpholine, 2-piperidylethanol, diethanolisopropanolamine, N-(2-hydroxyethyl)pyrrolidine, 4-pyridinemethanol, 4-pyridineethanol, 4-pyridinepropanol, 2-hydroxy-4-methylpyridine, 2-hydroxymethyl-1-methylimidazole, 4-hydroxymethyl-5-methylimidazole, choline chloride, b-methylcholine chloride, bis(2-hydroxyethyl)dimethylammonium chloride, tris(2-hydroxyethyl)methylammonium chloride, carnitine chloride, (2-hydroxyethyl)dimethyl(3-sulfopropyl)ammonium chloride, 1-(2-hydroxyethyl)-3-methylimidazolium chloride, and combinations of the foregoing items.

[0072] Other amines include tertiary amines such as 3-hydroxypropyl dimethylamine, n-butyl dimethylamine, bis(3-hydroxypropyl)methylamine, 2,3-dihydroxypropyl dimethylamine, 3-hydroxypropyl diethylenetriamine, 2-hydroxypropyl dimethylamine, 4-hydroxybutyl dimethylamine, 2-hydroxyethyl dimethylamine, n-propyl dimethylamine, 2-hydroxyethoxyethyl dimethylamine, bis(2-hydroxyethyl)methylamine, benzyl dimethylamine and 4-hydroxybenzyl dimethylamine, 4-methylpyridine, 3-ethylpyridine, 4-propylpyridine, 4-tert-butylpyridine, 4-cyanopyridine, 4-isopropylpyridine, 4-methoxypyridine, 3,4-dimethylpyridine, 3-methoxypyridine and 4-pyridinemethanol, 2-dimethylamino-1-ethanol, n-butyl dimethylamine and N,N-dimethylbenzylamine, 4-ethylpyridine and 1-methylimidazole, 1-benzylimidazole, N-methylmorpholine, 2-[2-(dimethylamino)ethoxy]ethanol.

[0073] Another suitable amine compound is bis(2-hydroxyethyl)dimethylammonium chloride.

[0074] Other similar amine compounds capable of reacting with 2,3-epoxy-1-propanol to produce a reaction compound can also be used as inhibitors of the present invention. Importantly, when used in a copper plating solution in a suitable composition, the reaction compound is a reaction compound capable of and / or configured to initiate copper deposits with high-density nanoscale twin copper on various substrates, including substrates that do not have a (111)-copper dominant surface.

[0075] Examples of suitable sulfur compounds include, but are not limited to, mercaptoacetic acid, thiomalic acid, sodium bisulfate, thiodiglycolic acid, thiodiethylene glycol, thiourea, N,N,N'N'-tetramethylthiourea, 2-mercaptoethanol, 3-mercaptopropanol, 2-mercaptoimidazole, 2-mercaptopyridine, 4-mercaptopyridine, 4-mercaptophenol, 3-mercapto-1-propanesulfonic acid, 3,6-dithia-1,8-octanediol, 2,2'-thiodiethanethiol, 2-hydroxyethyl disulfide, 3,3'-thiodipropanol and 2,2'-(ethylenedioxy)diethanethiol.

[0076] Other reactants capable of being used in a copper electrolyte to initiate copper deposits with high-density nanoscale twin copper on substrates that do not have a (111)-copper dominant surface include various pyridines and imidazoles. Similarly, such pyridines and / or imidazoles must be such that when used in a copper plating solution in a suitable composition, they are capable of and / or configured to initiate copper deposits with high-density nanoscale twin copper on various substrates (including substrates that do not have a (111)-copper dominant surface).

[0077] In one embodiment, a combination of reactants such as an amine and a sulfur-containing compound is used and the combination of reactants is reacted with 2,3-epoxy-1-propanol. For example, the inhibitor can include the reaction product of bis(2-hydroxyethyl)dimethylammonium chloride and 2,2'-thiobisethanol with 2,3-epoxy-1-propanol.

[0078] In one embodiment, the inhibitor compound comprises from 90.0 wt% to 99.9 wt% of 2,3-epoxy-1-propanol and from 0.1 wt% to 10.0 wt% of one or more reactants, more preferably from 95.0 wt% to 99.5 wt% of 2,3-epoxy-1-propanol and from 0.5 wt% to 5.0 wt% of one or more reactants, more preferably from 97.0 wt% to 99.0 wt% of 2,3-epoxy-1-propanol and from 2.0 wt% to 3.0 wt% of one or more reactants.

[0079] In one embodiment, the concentration of the linear or branched polyhydroxy inhibitor compound in the copper plating solution ranges from about 1 mg / L to about 10,000 mg / L, more preferably from about 10 mg / L to about 1000 mg / L, more preferably from about 50 mg / L to about 600 mg / L, more preferably from about 300 mg / L to about 500 mg / L.

[0080] In some embodiments, the copper plating solution may optionally include an accelerator and / or a leveling agent.

[0081] If used, the accelerator can include, for example, organic sulfur compounds, including organic sulfonium salts. Suitable organic sulfur compounds include, but are not limited to, bis-(3-sulfopropyl)-disulfide (SPS), 3-mercapto-1-propanesulfonic acid (MPS), 3-(benzothiazolyl-2-mercapto)-propanesulfonic acid (ZPS), N,N-dimethyldithiocarbamoylpropylsulfonic acid (DPS), propanesulfonic acid 3-S-isothiouronium (UPS), and (O-ethyldithiocarbonato)-S-(3-sulfopropyl) ester (OPX).

[0082] In one embodiment, the accelerator comprises ZPS or UPS. In another embodiment, the accelerator consists only of ZPS and / or UPS and the copper electrolyte is at least substantially free of any higher strength accelerators such as MPS or SPS.

[0083] The concentration of the accelerator depends in part on the specific accelerator used in the copper electrolytic solution, and a weaker accelerator can be used at a higher concentration than a stronger one. For example, ZPS and UPS can be used at a higher concentration than SPS in the copper electrolytic solution. In addition, using a stronger accelerator (such as SPS) as the accelerator may also require applying a high-density nanoscale twinned copper deposit as the base layer before depositing a subsequent layer using a copper electrolytic solution containing SPS. The concentration of the accelerator is preferably less than about 10 mg / L, more preferably in the range of about 1 mg / L to about 8 mg / L or in the range of about 1 mg / L to about 3 mg / L, depending in part on the specific inhibitor and accelerator combination.

[0084] If used, the leveling agent compound may include polymeric quaternary nitrogen substances such as those described in WO2018 / 057590, U.S. Patent No. 10,519,557, and U.S. Patent No. 10,294,574, the entire subject matter of each of which is incorporated herein by reference. Other leveling agent compounds include dipyridyl leveling agents such as those described in U.S. Patent No. 7,303,992 and U.S. Patent Publication No. 2005 / 0045488, the entire subject matter of each of which is incorporated herein by reference.

[0085] For example, the leveling agent may comprise the reaction product of an aliphatic di(tertiary amine) and a bifunctional alkylating agent corresponding to the following formula:

[0086]

[0087] wherein: G is selected from the group consisting of: a single covalent bond, -O-, O-((A) r -O) s and -((A) r -O) s -; A has the structure -CR 3 R 4 - or -C(R 3 )(R 4 )(R 33 )(R 34 )-; p and r are each independently an integer between 1 and 6 (inclusive), s is an integer between 1 and 10 (inclusive), q is an integer between 0 and 6 (inclusive); R 1 , R 2 , R 3 , R 4 , R 5 , R 6 and R 34 are each independently selected from the group consisting of hydrogen and substituted or unsubstituted aliphatic hydrocarbon groups containing 1 to 4 carbon atoms; R 33is a substituted or unsubstituted aliphatic hydrocarbon group having 1 to 4 carbon atoms, Y is a leaving group selected from the group consisting of: chlorine, bromine, iodine, tosyl, trifluoromethanesulfonate, sulfonate, methanesulfonate, methyl sulfate, fluorosulfonate, methyl tosylate, and p-bromobenzenesulfonate, Z is selected from the group consisting of: R 30 and a leaving group independently selected from the same groups as Y, and R 30 is selected from the group consisting of: aliphatic hydrocarbon group, hydroxy, alkoxy, cyano, carboxy, alkoxycarbonyl, and acylamino, and when -G- is not a single covalent bond, q is at least 1.

[0088] The leveling agent may further comprise an oligomer and / or a polymer compound selected from the group consisting of: salts containing cations having the following structures:

[0089]

[0090] wherein: G and A are as defined above; B has the following structure;

[0091]

[0092] D has the following structure;

[0093]

[0094] is the residue of an N,N'-dialkyl heterocyclic diamine, which binds at the respective tertiary amine sites to form a bis(quaternary ammonium) cationic structure with - (CR 1 R 2 ) p -G-(CR 5 R 6 ) q -;

[0095] p, r, t, u, w, and y are each an integer between 1 and 6 (inclusive), q, v, x, k, and z are each independently an integer between 0 and 6 (inclusive), s is an integer between 1 and 10 (inclusive), k is at least 1 when v or x is not 0, and q is at least 1 when G is not a single covalent bond; R 1 to R 6 , R 9 to R 19、 R 23 , R 25 and R 34 are each independently selected from the group consisting of hydrogen or a lower alkyl having 1 to 4 carbon atoms, R 7 , R 8 , R 20 , R 21 , R 22 , R24 and R 33 each independently selected from substituted or unsubstituted aliphatic hydrocarbon groups having 1 to 4 carbon atoms; and

[0096] n ranges from about 1 to about 30.

[0097] The leveling agent may further comprise a compound corresponding to the following formula:

[0098]

[0099] wherein: G, A, B and D are as defined above;

[0100]

[0101] is the residue of an N,N'-dialkyl heterocyclic diamine, which binds at each of its tertiary amine sites to form a bis(quaternary ammonium) cationic structure; p, r, t, u, w and y are each an integer between 1 and 6 (inclusive), q, v, x, k and z are each independently an integer between 0 and 6 (inclusive), s is an integer between 1 and 10 (inclusive), k is at least 1 when v or x is not 0, and q is at least 1 when G is not a single covalent bond; R 1 R 2 ) p -G-(CR 5 R 6 ) q - to form a bis(quaternary ammonium) cationic structure; p, r, t, u, w and y are each an integer between 1 and 6 (inclusive), q, v, x, k and z are each independently an integer between 0 and 6 (inclusive), s is an integer between 1 and 10 (inclusive), k is at least 1 when v or x is not 0, and q is at least 1 when G is not a single covalent bond; R 1 to R 6 、R 9 to R 19、 R 23 、R 25 and R 34 are each independently selected from the group consisting of hydrogen or lower alkyls containing 1 to 4 carbon atoms, R 7 、R 8 、R 20 、R 21 、R 22 、R 24 and R 33 are each independently selected from substituted or unsubstituted aliphatic hydrocarbon groups having 1 to 4 carbon atoms; and

[0102] R 30 is selected from the group consisting of aliphatic hydrocarbon groups, hydroxyl groups, alkoxy groups, cyano groups, carboxyl groups, alkoxycarbonyl groups and amido groups.

[0103] The leveling agent may further comprise a quaternized poly(epihalohydrin) comprising n repeating units corresponding to Structure 1N and p repeating units corresponding to Structure 1P:

[0104]

[0105] wherein Q has a structure corresponding to that obtainable by reacting the side methylene halide groups of a poly(epihalohydrin) with a tertiary amine selected from the group consisting of: (i) NR 1 R 2 R 3 , where R 1 、R 2 and R 3 are each independently selected from the group consisting of: substituted or unsubstituted alkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted alkynyl, substituted or unsubstituted cycloaliphatic, substituted or unsubstituted aralkyl, substituted or unsubstituted aryl, and substituted or unsubstituted heterocyclic; (ii) N-substituted and optionally further substituted heteroalicyclic amines, wherein the N-substituent is selected from the group consisting of: substituted or unsubstituted alkyl, substituted or unsubstituted cycloaliphatic, substituted or unsubstituted aralkyl, substituted or unsubstituted aryl, and substituted or unsubstituted heterocyclic; (iii) substituted or unsubstituted nitrogen-containing heteroaryl compounds;

[0106] n is an integer between 3 and 35, and p is an integer between 0 and 25;

[0107] X is a halogen substituent; and

[0108] X - is a monovalent anion.

[0109] Preferably, Q corresponds to structure IIA, IIB or IIC:

[0110]

[0111] wherein: (i) structure IIB is an N-substituted heterocyclic moiety; (ii) structure IIC is a heterocyclic moiety; (iii) R 1 、R 2 、R 3 and R 4 are each independently selected from the group consisting of: substituted or unsubstituted alkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted alkynyl, substituted or unsubstituted aralkyl, substituted or unsubstituted cycloaliphatic, substituted or unsubstituted aryl, and substituted or unsubstituted heterocyclic; and (iv) R 5 、R 6 、R 7 、R 8 and R 9 are each independently selected from the group consisting of: hydrogen, substituted or unsubstituted alkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted alkynyl, substituted or unsubstituted aralkyl, substituted or unsubstituted cycloaliphatic, substituted or unsubstituted aryl, and substituted or unsubstituted heterocyclic. Among R 1 to R 8When any of them is substituted, the substituent preferably does not contain an amino group.

[0112] The leveling agent may further comprise a substituted pyridyl compound, which may be, for example, a pyridinium compound, especially a quaternized pyridinium salt. Examples of these substituted pyridyl compounds include, but are not limited to, derivatives of vinylpyridine, such as derivatives of 2-vinylpyridine and 4-vinylpyridine, homopolymers of vinylpyridine, copolymers of vinylpyridine, quaternary salts of vinylpyridine, and quaternary salts of these homopolymers and copolymers. Specific examples of such compounds include, for example, poly(4-vinylpyridine), the reaction product of poly(4-vinylpyridine) and dimethyl sulfate, the reaction product of 4-vinylpyridine and 2-chloroethanol, the reaction product of 4-vinylpyridine and benzyl chloride, the reaction product of 4-vinylpyridine and allyl chloride, the reaction product of 4-vinylpyridine and 4-chloromethylpyridine, the reaction product of 4-vinylpyridine and 1,3-propanesultone, the reaction product of 4-vinylpyridine and methyl tosylate, the reaction product of 4-vinylpyridine and chloroacetone, the reaction product of 4-vinylpyridine and 2-methoxyethoxymethyl chloride, the reaction product of 4-vinylpyridine and 2-chloroethyl ether, the reaction product of 2-vinylpyridine and methyl tosylate, the reaction product of 2-vinylpyridine and dimethyl sulfate, the reaction product of vinylpyridine and a water-soluble initiator, poly(2-methyl-5-vinylpyridine), and 1-methyl-4-vinylpyridinium trifluoromethanesulfonate, etc.

[0113] Other polymeric quaternary nitrogen substances can also be used as leveling agents in the copper plating compositions described herein, provided that they are compatible with the inhibitor (and accelerator) and do not reduce the ability to initiate nanoscale twinned copper deposits on various substrates.

[0114] In one embodiment, suitable leveling agent substances include, but are not limited to, the reaction product of 4,4-bipyridine and 2-chloroethyl ether. The concentration of the leveling agent depends in part on the specific leveling agent used, as well as the specific inhibitor and accelerator and process conditions. In one embodiment, the leveling agent is present in the copper electrolyte at a concentration in the range of less than about 10 mg / L, or in the range of about 0.5 mg / L to about 10 mg / L, more preferably in the range of about 2 mg / L to about 5 mg / L.

[0115] It has been found that higher current densities (i.e., about 3 ASD to about 6 ASD, more preferably in the range of about 3 ASD to about 5 ASD) are beneficial for the purpose of producing nanoscale twinned copper. However, when overfilling copper in the features of a microelectronic substrate, a lower current density is preferred, such as in the range of about 0.5 ASD to about 2 ASD.

[0116] Thus, in one embodiment, the copper electroplating composition comprises a two-component copper electroplating bath or a three-component copper electroplating bath, which is used in a step current electroplating method to achieve through-hole filling with a nanotwinned copper microstructure. In one embodiment, a two-component copper electroplating bath comprising an inhibitor compound and a leveling agent described herein may be used, and the leveling agent comprises a polymeric quaternary nitrogen substance as described above. In another embodiment, a three-component copper electroplating bath that may be used comprises an inhibitor compound described herein, an accelerator comprising an organic sulfur compound (preferably UPS), and a leveling agent comprising a polymeric quaternary nitrogen substance.

[0117] Contrary to the step current variation, a ramp current in which the current slopes from high to low may also be applied to the two-component copper plating bath and the three-component copper plating bath to achieve through-hole filling with a nanotwinned copper microstructure.

[0118] As described herein, in one embodiment, the copper electroplating solution comprises:

[0119] A) about 40 g / L to about 60 g / L of copper ions;

[0120] B) about 80 g / L to about 140 g / L of sulfuric acid;

[0121] C) about 30 mg / L to about 120 mg / L of chloride ions;

[0122] D) about 300 mg / L to about 500 mg / L of the reaction product of an amine or a sulfur-containing compound with 2,3-epoxy-1-propanol;

[0123] E) optionally, about 0.5 mg / L to about 10 mg / L of a leveling agent, which comprises a polymeric quaternary nitrogen substance; and

[0124] F) optionally, about 1 mg / L to about 50 mg / L of an accelerator, which comprises an organic sulfur compound.

[0125] In another preferred embodiment, the copper electroplating solution consists essentially of the following:

[0126] A) about 40 g / L to about 60 g / L of copper ions;

[0127] B) about 80 g / L to about 140 g / L of sulfuric acid;

[0128] C) about 30 mg / L to about 120 mg / L of chloride ions;

[0129] D) about 300 mg / L to about 500 mg / L of the reaction product of an amine or a sulfur-containing compound with 2,3-epoxy-1-propanol; and

[0130] E) A leveling agent in an amount of from about 0.0 mg / L to about 10 mg / L, the leveling agent comprising a polymeric quaternary nitrogen substance.

[0131] In another preferred embodiment, the copper electroplating solution consists essentially of:

[0132] A) Copper ions in an amount of from about 40 g / L to about 60 g / L;

[0133] B) Sulfuric acid in an amount of from about 80 g / L to about 140 g / L;

[0134] C) Chloride ions in an amount of from about 30 mg / L to about 120 mg / L;

[0135] D) The reaction product of an amine or sulfur-containing compound and 2,3-epoxy-1-propanol in an amount of from about 300 mg / L to about 500 mg / L;

[0136] E) A leveling agent in an amount of from about 0.5 mg / L to about 10 mg / L, the leveling agent comprising a polymeric quaternary nitrogen substance;

[0137] and

[0138] F) A promoter in an amount of from about 0.0 mg / L to about 50 mg / L, the promoter comprising an organic sulfur compound.

[0139] In another embodiment, the copper electrolyte of the present invention contains a lower amount of sulfuric acid. For example, the copper electrolyte may contain:

[0140] A) Copper ions in an amount of from about 5 g / L to about 50 g / L;

[0141] B) Sulfuric acid in an amount of from about 8 g / L to about 15 g / L;

[0142] C) Chloride ions in an amount of from about 30 mg / L to about 120 mg / L;

[0143] D) The reaction product of an amine or sulfur-containing compound and 2,3-epoxy-1-propanol in an amount of from about 300 mg / L to about 500 mg / L;

[0144] E) Optionally, a leveling agent in an amount of from about 0.5 mg / L to about 10 mg / L, the leveling agent comprising a polymeric quaternary nitrogen substance; and

[0145] F) Optionally, a promoter in an amount of from about 1 mg / L to about 50 mg / L, the promoter comprising an organic sulfur compound.

[0146] In another preferred embodiment, the copper electroplating solution consists essentially of:

[0147] A) Copper ions in an amount of from about 5 g / L to about 50 g / L;

[0148] B) Sulfuric acid from about 8 g / L to about 15 g / L;

[0149] C) Chloride ions from about 30 mg / L to about 120 mg / L;

[0150] D) Reaction product of an amine or sulfur - containing compound from about 300 mg / L to about 500 mg / L with 2,3 - epoxy - 1 - propanol; and

[0151] E) A leveling agent from about 0.0 mg / L to about 5 mg / L, the leveling agent comprising a polymeric quaternary nitrogen substance.

[0152] In another preferred embodiment, the copper electroplating solution consists essentially of the following:

[0153] A) Copper ions from about 5 g / L to about 50 g / L;

[0154] B) Sulfuric acid from about 8 g / L to about 15 g / L;

[0155] C) Chloride ions from about 30 mg / L to about 120 mg / L;

[0156] D) Reaction product of an amine or sulfur - containing compound from about 300 mg / L to about 500 mg / L with 2,3 - epoxy - 1 - propanol;

[0157] E) A leveling agent from about 0.0 mg / L to about 5 mg / L, the leveling agent comprising a polymeric quaternary nitrogen substance;

[0158] And

[0159] F) A promoter from about 0.0 mg / L to about 50 mg / L, the promoter comprising an organic sulfur compound.

[0160] "Consists essentially of" means that the composition does not contain any additives that have an adverse effect on the ability of the composition to initiate copper deposits with high - density nanotwinned copper on a substrate, the substrate including a substrate that is a non - (111) copper substrate.

[0161] The present invention also generally relates to a method for electroplating high - density nanotwinned copper on a substrate, the method comprising the steps of:

[0162] A) Providing a substrate, at least one anode, and a copper plating bath as described herein;

[0163] B) Contacting the substrate and at least one anode with the copper bath respectively; and

[0164] C) Applying a voltage between the surface of the workpiece and at least one anode such that a cathode polarity is imposed on the substrate relative to at least one anode;

[0165] Wherein a copper structure with high - density nanotwins is deposited on the substrate.

[0166] The current density is typically in the range of about 0.01 ASD to about 50 ASD, more preferably about 0.5 ASD to about 20 ASD, and most preferably about 1 ASD to about 10 ASD. Additionally, it is preferred to stir the electroplating solution, and the electroplating solution is typically mixed at about 1 rpm to about 2,500 rpm, more preferably about 10 rpm to about 1,200 rpm, and most preferably about 50 rpm to about 400 rpm.

[0167] The anode can be an insoluble or soluble anode. An insoluble anode is preferred.

[0168] Copper is electrodeposited for a period of time to initiate a nanoscale twin copper deposit to a thickness of about 0.1 μm to about 1,000 μm, more preferably about 0.3 μm to about 200 μm, and most preferably about 1 μm to about 100 μm.

[0169] Substrates that can be coated with the copper electroplating solution described herein include printed wiring boards (PWBs), printed circuit boards (PCBs), and other electronic substrates that can include one or more posts, pads, wires, and vias, including surfaces that are not (111) copper, such as polycrystalline copper seed layers, stainless steel, and PVD ruthenium.

[0170] The presence of the nanoscale twin grain structure can be observed using any suitable microscopy technique such as electron microscopy techniques. The amount of the nanoscale twin grain structure in the copper deposit is preferably greater than about 80%, more preferably greater than about 90% nanoscale twin columnar copper grains, as estimated based on SEM cross-sections.

[0171] As shown in the following examples, the nanoscale twin copper structure can be characterized by multiple (111)-oriented crystalline copper grains that mostly contain nanoscale twins. In some specific embodiments, the multiple (111)-oriented crystalline copper grains contain a high density of nanoscale twins. As used herein, "high density of nanoscale twins" can refer to a copper structure having greater than about 80% nanoscale twins and even greater than about 90% nanoscale twins as observed using a suitable microscopy technique.

[0172] The crystal orientation of the crystalline copper grains can be characterized using suitable techniques such as electron backscatter diffraction (EBSD) analysis. In some specific embodiments, the crystal orientation mapping can be shown as an inverse pole figure (IPF) mapping. According to the present invention, it is preferred that the nanoscale twin copper structure mainly contains (111)-oriented grains.

[0173] The following inhibitor compounds were used in the examples:

[0174] Compound 1: The reaction product of 4-pyridinemethanol (1 wt%) and 2,3-epoxy-1-propanol (99 wt%) to form a polymer.

[0175] Compound 2A: 1 wt % of bis(2-hydroxyethyl)dimethylammonium chloride was reacted with 99 wt % of 2,3-epoxy-1-propanol to produce a polymer.

[0176] Compound 2B: 1 wt% of bis(2-hydroxyethyl)dimethylammonium chloride and 1 wt% of 2,2'-thiodiethanol were reacted with 98 wt% of 2,3-epoxy-1-propanol to produce a polymer.

[0177] The inhibitor compounds are prepared by reacting amines or sulfur-containing compounds with 2,3-epoxy-1-propanol. The general reaction procedure is as follows:

[0178] In a 1 L round bottom flask equipped with a thermometer, reflux condenser and magnetic stirrer, a methanol solution of boron trifluoride etherate (5 mmol) was added dropwise to a solution of 2,3-epoxy-1-propanol and an amine or sulfur-containing compound in the weight percentages listed to prepare each of Compound 1, Compound 2A and Compound 2B. The temperature was allowed to rise freely during the exotherm and heated at its maximum temperature for 30 minutes. The reaction was then cooled to less than 100°C, water was added to prepare a 20% w / w solution, and stirring was continued for 4 hours. The solution was then filtered and used as is.

[0179] Example 1 :

[0180] A copper electrolyte containing a solution of 40 g / L copper (II) ions, 10 g / L sulfuric acid, 50 mg / L chloride ions, and 400 mg / L amine polyhydroxy inhibitor was prepared (baseline composition), and a second copper electrolyte was prepared in a similar manner to the baseline composition, but substituting 400 mg / L Compound 1 (composition with Compound 1).

[0181] Intermediate nanotwinned Cu deposits were initiated from (111)-dominant PVD Cu seeds and polycrystalline Cu seeds at a constant current of 1 ASD using these two electrolytes.

[0182] like Figure 1 As shown, although both solutions are able to produce intermediate nanotwinned copper from copper seeds with (111) as the main component, the baseline composition cannot produce any nanotwinned copper on the polycrystalline copper seed layer at all, while the Compound 1 composition is able to produce intermediate nanotwinned copper from polycrystalline copper seeds.

[0183] Figure 2 A 50K magnification of a transition layer of Compound 1 composition plated on a polycrystalline copper seed is depicted. Figure 2 As shown, the Compound 1 composition is able to produce ntCu from polycrystalline copper seeds after 111 nm deposition to a total thickness of about 2.8 μm.

[0184] likeFigure 4 As shown, the compound 1 composition is capable of generating predominantly nanotwinned copper from stainless steel and ruthenium substrates, while the reference composition is not.

[0185] Example 2 :

[0186] Prepare a copper electrolyte by preparing a solution containing 40 g / L copper (II) ions, 10 g / L sulfuric acid, 50 mg / L chloride ions, and 400 mg / L of compound 2A, and prepare a second copper electrolyte in a similar manner but substituting 400 mg / L of compound 2B.

[0187] Use these two electrolytes to initiate intermediate nanotwinned copper deposits from (111)-dominant PVD copper seeds and polycrystalline copper seeds at a constant current of 1 ASD.

[0188] As Figure 3 shown, while both solutions are capable of generating intermediate nanotwinned copper from (111)-dominant copper seeds, the addition of a thiol compound in addition to the amine and reacting the two with 2,3-epoxy-1-propanol improves the ability to form nanotwinned copper on non-(111) Cu substrates.

[0189] As can be seen from Examples 1 and 2, the use of the above inhibitors (which comprise the reaction product of an amine or a sulfur-containing compound with 2,3-epoxy-1-propanol) in a copper plating solution enables the copper plating solution to initiate high-density nanotwinned copper deposition on various substrates (including non-(111) copper substrates) and to form nanotwinned copper in the features of the substrate.

[0190] Example 3 :

[0191] Prepare a copper electrolyte by preparing a solution containing 40 g / L copper (II) ions, 10 g / L sulfuric acid, 50 mg / L chloride ions, 1 mg / L SPS, and 400 mg / L of compound 2A. Plate a covered specimen block having a (111)-dominant PVD copper seed layer at 3 ASD and produce >90% nanotwinned copper.

[0192] Figure 5 A 20K magnification of the transition layer of the compound 2A composition plated on a (111)-dominant PVD copper seed layer is depicted. As Figure 5 shown, the compound 2A composition is capable of generating ntCu from (111)-dominant PVD copper seeds.

[0193] Example 3A :

[0194] A copper electrolyte was prepared in the same manner as in Example 3, except that 3 mg / L of SPS was added to the solution. A covered specimen block with a PVD copper seed layer dominated by (111) was plated at 3 ASD, and >90% of nanotwinned copper was produced.

[0195] Example 3B :

[0196] A copper electrolyte was prepared in the same manner as in Example 3, except that 8 mg / L of SPS was added to the solution and Compound 1 was used instead of Compound 2A. A covered specimen block with a PVD copper seed layer dominated by (111) was plated at 3 ASD, and >90% of nanotwinned copper was produced.

[0197] Example 3C :

[0198] An additional copper electrolyte was prepared in the same manner as in Example 3, except that 8 mg / L of SPS was added to the solution and Compound 2B was used instead of Compound 2A. A covered specimen block with a PVD copper seed layer dominated by (111) was plated at 3 ASD, and >90% of nanotwinned copper was produced.

[0199] Comparative Example 4 :

[0200] A copper electrolyte was prepared in the same manner as in Example 3, except that 28 mg / L of SPS was added to the solution. A covered specimen block with a PVD copper seed layer dominated by (111) was plated at 3 ASD, and no nanotwinned copper was produced.

[0201] Figure 6 A 20K magnification of the transition layer of the Compound 2A composition plated on a PVD copper seed layer dominated by (111) is depicted. As Figure 6 shown, the Compound 2A composition was able to produce ntCu from a PVD copper seed dominated by (111).

[0202] As can be seen from Comparative Example 4, increasing the amount of SPS in the copper electroplating solution from 1 mg / L to 28 mg / L resulted in the loss of nanotwinned copper.

[0203] Comparative Example 5 :

[0204] A copper electrolyte was prepared in the same manner as in Example 3, except that 50 g / L of copper(II) ions and 100 g / L of sulfuric acid were added to the solution. A covered specimen block with a PVD copper seed layer dominated by (111) was plated at 3 ASD, and no nanotwinned copper was produced.

[0205] Figure 7Depicts a 20K magnification of the transition layer of the Compound 2A composition plated on a (111)-dominant PVD copper seed layer. As Figure 7 shown, the Compound 2A composition is not capable of generating ntCu from a (111)-dominant PVD copper seed.

[0206] As can be seen from Comparative Example 5, increasing the amount of sulfuric acid in the copper electroplating solution from 10 mg / L to 100 g / L results in the loss of nanotwinned copper.

[0207] Example 6 :

[0208] Prepare a copper electrolyte for a solution containing 40 g / L copper(II) ions, 10 g / L sulfuric acid, 50 mg / L chloride ions, 1 mg / L SPS, 400 mg / L Compound 2A, and 3 mg / L leveling agent. Plate a covered specimen block with a (111)-dominant PVD copper seed layer at 3 ASD and produce >90% nanotwinned copper.

[0209] Figure 8 Depicts a 20K magnification of the transition layer of the Compound 2A composition plated on a (111)-dominant PVD copper seed layer. As Figure 8 shown, the Compound 2A composition is capable of generating ntCu from a (111)-dominant PVD copper seed.

[0210] Example 7 :

[0211] Prepare a copper electrolyte in the same manner as Comparative Example 4, except that 3 mg / L leveling agent is added to the solution. Plate a covered specimen block with a (111)-dominant PVD copper seed layer at 3 ASD and produce >90% nanotwinned copper.

[0212] Figure 9 Depicts a 20K magnification of the transition layer of the Compound 2A composition plated on a (111)-dominant PVD copper seed layer. As Figure 9 shown, the composition is capable of generating ntCu from a (111)-dominant PVD copper seed.

[0213] As can be seen from Example 7, when used in combination with low concentrations of sulfuric acid and added leveling agent, >90% nanotwinned copper can be produced even when using a high concentration of accelerator.

[0214] Finally, it should also be understood that the following claims are intended to cover all the general and specific features of the invention described herein and all statements that may fall within the scope of the invention between them in language.

Claims

1. A copper electroplating solution, the copper electroplating solution comprising: a) a copper salt; b) a source of halide ions; and c) an inhibitor, wherein the inhibitor comprises a reaction product of a reactant and 2,3-epoxy-1-propanol, wherein the reactant comprises at least one of an amine and a sulfur-containing compound; wherein a copper electrolyte is capable of depositing copper, and wherein the copper deposit exhibits greater than about 80% nanoscale twin columnar copper grains.

2. The copper electroplating solution according to claim 1, wherein the copper salt is copper sulfate.

3. The copper electroplating solution according to claim 1 or 2, the copper electroplating solution further comprising an acid, wherein the acid comprises sulfuric acid or methanesulfonic acid.

4. The copper electroplating solution according to any one of claims 1 to 3, wherein the copper electroplating composition comprises one or more of the following: (i) an accelerator, wherein the accelerator comprises an organic sulfur compound; and (ii) a leveling agent, wherein the leveling agent comprises a polymeric quaternary nitrogen substance.

5. The copper electroplating solution according to any one of claims 1 to 4, wherein the reactant comprises an amine compound selected from the group consisting of ethanolamine, diethanolamine, triethanolamine, propanolamine, isopropanolamine, diisopropanolamine, triisopropanolamine, N-methyldiethanolamine, N-ethyldiethanolamine, N-propyldiethanolamine, methylmonoethanolamine, N,N-dimethylethanolamine, N,N-diethylethanolamine, N-propylmonoethanolamine, N-propyldiethanolamine, N-butylethanolamine, N-butyldiethanolamine, N,N-dibutyldiethanolamine, hydroxyethylmorpholine, 2-piperidinoethanol, diethanolisopropanolamine, N-(2-hydroxyethyl)pyrrolidine, 4-pyridinemethanol, 4-pyridineethanol, 4-pyridinepropanol, 2-hydroxy-4-methylpyridine, 2-hydroxymethyl-1-methylimidazole, 4-hydroxymethyl-5-methylimidazole, choline chloride, b-methylcholine chloride, bis(2-hydroxyethyl)dimethylammonium chloride, tris(2-hydroxyethyl)methylammonium chloride, carnitine chloride, (2-hydroxyethyl)dimethyl(3-sulfopropyl)ammonium chloride, 1-(2-hydroxyethyl)-3-methylimidazolium chloride, bis(2-hydroxyethyl)dimethylammonium chloride, and combinations of the foregoing.

6. The copper electroplating solution according to any one of claims 1 to 4, wherein the reactant comprises a sulfur-containing compound, the sulfur-containing compound selected from the group consisting of 2,2'-thiobisethanol, mercaptoacetic acid, thiomalic acid, sodium bisulfate, thiodiglycolic acid, thiodiethylene glycol, thiourea, N,N,N'N'-tetramethylthiourea, 2-mercaptoethanol, 3-mercaptopropanol, 2-mercaptoimidazole, 2-mercaptopyridine, 4-mercaptopyridine, 4-mercaptophenol, 3-mercapto-1-propanesulfonic acid, 3,6-dithia-1,8-octanediol, 2,2'-thiobis(ethyl mercaptan), 2-hydroxyethyl disulfide, 3,3'-thiobispropanol, 2,2'-(ethylenedioxy)diethyl mercaptan, and combinations of one or more of the foregoing.

7. The copper electroplating solution according to claim 6, wherein the sulfur-containing compound comprises 2,2'-thiobisethanol.

8. The copper electroplating solution according to claim 4, wherein the accelerator is present and is selected from the group consisting of bis-(3-sulfopropyl)-disulfide, 3-mercapto-1-propanesulfonic acid, 3-(benzothiazolyl-2-mercapto)-propylsulfonic acid, N,N-dimethyldithiocarbamoylpropylsulfonic acid, 3-S-isothiouronium propylsulfonic acid, and (O-ethyl dithiocarbonate)-S-(3-sulfopropyl) ester.

9. The copper electroplating solution according to claim 4, wherein both the accelerator and the leveling agent are present in the composition.

10. The copper electroplating solution according to any one of claims 1 to 4, wherein the inhibitor comprises 90.0% to 99.9% by weight of the 2,3-epoxy-1-propanol reacted with 0.1% to 10.0% by weight of the reactant, or wherein the inhibitor comprises 95.0% to 99.5% by weight of the 2,3-epoxy-1-propanol reacted with 0.5% to 5.0% by weight of the reactant, or wherein the inhibitor comprises 97.0% to 99.0% by weight of the 2,3-epoxy-1-propanol reacted with 2.0% to 3.0% by weight of the reactant.

11. The copper electroplating solution according to claim 1, wherein the copper electroplating solution comprises: a. about 40 g / L to about 60 g / L of copper ions; b. about 80 g / L to about 140 g / L of sulfuric acid; c. about 30 mg / L to about 120 mg / L of chloride ions; d. about 300 mg / L to about 600 mg / L of the reaction product of an amine or a sulfur-containing compound with 2,3-epoxy-1-propanol.

12. The copper electroplating solution according to claim 1, wherein the copper electroplating solution comprises: a. about 5 g / L to about 50 g / L of copper ions; b. about 8 g / L to about 15 g / L of sulfuric acid; c. about 30 mg / L to about 120 mg / L of chloride ions; d. about 300 mg / L to about 600 mg / L of the reaction product of an amine or a sulfur-containing compound with 2,3-epoxy-1-propanol.

13. The copper electroplating solution according to claim 12, wherein the copper electroplating solution further comprises: a. about 0.01 mg / L to about 10 mg / L of the leveling agent, the leveling agent comprising a polymeric quaternary nitrogen substance; or b. about 0.1 mg / L to about 50 mg / L of the accelerator.

14. The copper electroplating solution according to claim 1, wherein the copper electroplating solution is at least substantially free of any accelerator, brightener, carrier, wetting agent or leveling agent, or any compound capable of acting as an accelerator, brightener, carrier, wetting agent or leveling agent.

15. A method for electroplating copper on a substrate, the method comprising the steps of: a. contacting the surface of the substrate and at least one anode with a copper electrolyte according to any one of claims 1 to 4; and b. applying a voltage between the surface of the substrate and the at least one anode such that a cathode polarity is imposed on the substrate relative to the at least one anode; A copper deposit having high-density nanotwinned columnar copper grains is initiated on the substrate.

16. The method according to claim 15, wherein the nanotwinned copper deposit is (111)-oriented.

17. The method according to claim 15 or 16, wherein the copper deposit comprises more than 90% nanotwinned columnar copper grains.

18. The method according to claim 15, wherein the substrate is a non-(111)-oriented copper substrate.

19. The method according to claim 18, wherein the substrate is selected from the group consisting of: polycrystalline copper seed, stainless steel, and PVD ruthenium.

20. The method according to claim 18 or 19, wherein the nanotwinned copper deposit is (111)-oriented.

21. A method for electrodepositing >80% nanotwinned copper on a non-(111)-oriented copper substrate using an aqueous copper electrolyte containing at least one organic additive.

22. The method according to claim 21, wherein the at least one organic additive comprises a reaction product of a reactant with 2,3-epoxy-1-propanol, wherein the reactant comprises at least one of an amine and a sulfur-containing compound.

23. The method according to claim 15, wherein a voltage is applied at a current density between about 1 ASD and about 8 ASD, more preferably between about 1 ASD and about 3 ASD.

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