TW202415813A - Composition and method for nanotwinned copper formation - Google Patents

Abstract

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

Description

Composition and method for forming nano-twinned copper

[Cross-reference to related applications]

This application claims priority to U.S. Provisional Patent Application No. 63/414,725 filed on October 10, 2022, the subject matter of which is incorporated herein by reference in its entirety.

The present invention generally relates to the electrodeposition of nanobicrystalline copper on various substrates, and copper electroplating baths for producing high density nanobicrystalline copper deposits.

Electrochemical deposition processes are well established in integrated circuit manufacturing. Copper lines can be formed by electroplating metal into very fine, high aspect ratio trenches and vias in a process commonly referred to as "damascene" processing (pre-passivation metallization).

As microelectronics develop, there is a continuous need to create smaller and denser interconnect features. Copper is one of the most important conductors in microelectronic devices due to its high ductility and conductivity. One approach toward this goal is to remove the solder between two separate substrates that connect copper vias, pads, bumps, or pillars, which can be replaced by, for example, Cu-Cu hybrid bonding.

To ensure the success of this method (which requires both high temperatures and high pressures), it is particularly preferred to produce electroplated copper with >90% nanotwin columnar copper (ntCu) grains in a (111) orientation.

Nanotwin copper has attracted attention for use in microelectronics due to its combination of excellent mechanical properties, good electrical conductivity, and unique structure. The mechanical strength of metals such as copper generally increases as the grain size is reduced to the nanoscale. Nanotwin copper represents ultrafine crystalline copper whose grains contain a high density of layered nanoscale twin crystals separated by coherent twin boundaries. By introducing nanotwins into the copper microstructure, properties including mechanical strength, ductility, electromigration resistance, and hardness can be improved.

Nanoscale metal films may have exemplary mechanical properties. Therefore, metals having nanobicrystalline properties may be suitable for applications such as through-silicon vias (TSVs), semiconductor chip interconnects, package substrate lead vias, metal interconnects (e.g., copper interconnects), and metal materials on substrates.

Nanocrystal copper can be achieved in several ways, including, for example, by sputtering and by electrolytic deposition using a copper plating composition that has been optimized to produce nanocrystal copper.

One of the advantages of sputter deposition is the high purity of the copper film, together with the ability to track a better grain orientation. It has been shown that sputter deposited (111) oriented nanobi-crystalline copper has high thermal stability and strength.

On the other hand, direct current electrolytic plating has the advantage of being extremely compatible with industrial mass production. Electroplated nano-twin copper can be divided into two categories: equiaxed nano-twin copper and (111) oriented nano-twin copper.

Crystal defects can affect the mechanical, electrical, and optical properties of materials. Twinning occurs where two parts of the crystal structure of a material are symmetrically related to each other. In face-centered cubic (FCC) crystal structures including copper, coherent twin boundaries can form as (111) mirror planes, which is the opposite of the typical stacking sequence of (111) planes. In other words, adjacent grains in the layered (111) structure are mirror images of each other across the coherent twin boundaries. Twins grow in a layer-by-layer manner extending along the lateral (111) crystal planes, with twin thicknesses on the order of a few nanometers. Nanocrystalline copper exhibits excellent mechanical and electrical properties and can be used in a wide variety of applications in wafer-level packaging and advanced packaging designs.

Compared to copper that exhibits conventional grain boundaries, nanotwin copper has robust mechanical properties, including high strength and high tensile ductility. For example, nanotwin copper exhibits high electrical conductivity, which can be attributed to the twin boundaries, which in turn lead to less significant electron scattering than grain boundaries. Nanotwin copper also exhibits high thermal stability (which can be attributed to the excess energy of the twin boundaries being orders of magnitude lower than that of the grain boundaries) and achieves high copper atomic diffusivity (which is suitable for direct copper-to-copper bonding). In addition, nanotwin copper shows high electromigration resistance, which can be the result of the twin boundaries slowing down the atomic diffusion induced by electromigration. Nano-bi-crystal copper exhibits strong resistance to seed etching (which can be important in fine-line redistribution layer applications) and also shows low impurity incorporation (which results in fewer Kirkendall voids due to soldering reactions with nano-bi-crystal copper).

In some embodiments, nano-twin copper achieves direct copper-copper bonding, which can occur at low temperature, moderate pressure, and low bonding force/time. Generally speaking, the deposition of copper structures results in a rough surface, and in some cases, the electrodeposition of nano-twin copper can be followed by electropolishing to achieve a smooth surface before copper-copper bonding. When a smooth surface is achieved, nano-twin copper structures can be used in copper-copper bonding with shorter bonding times, lower temperatures, and fewer voids.

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 that the copper electrolyte of Desmaison et al. can be used to deposit nanobicrystalline copper.

WO2020/092244 to Banik et al., the subject matter of which is incorporated herein by reference in its entirety, describes a copper structure having a high density of nanobicrystalline copper deposited on a substrate. Banik does not describe any particular electrolytic copper plating bath, but rather focuses on plating conditions including a pulsed current waveform that alternates between a constant current and no current, wherein the duration of no current being applied is substantially greater than the duration of the constant current being applied.

U.S. Patent No. 10,566,314 to Yang, the entirety of which is incorporated herein by reference, describes how the best copper grain structure for Cu-Cu metal-to-metal bonding is a columnar grain microstructure. The copper grain microstructure plated by the disclosed suppressor-only system produces a columnar grain structure as a result of the electroplating of nanobicrystalline copper. Furthermore, although columnar grains are mentioned, the (111) copper grain structure of the nanobicrystalline copper is not mentioned.

Studies have shown that few materials can be used to produce nanotwinned copper by electroplating, where the copper deposits show a high degree of nanotwinning regardless of the underlying substrate.

There is still a need in the art for a copper electroplating solution for producing nano-twin copper deposits, and in particular, a copper electroplating solution capable of producing nano-twin copper in features of microelectronic substrates and/or on substrates that are not dominated by (111) copper.

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

Another object of the present invention is to provide a copper electroplating solution capable of producing high-density nano-twinned copper in a deposit.

Another object of the present invention is to provide a copper electroplating solution optimized for depositing nanobicrystalline copper in features of microelectronic substrates.

Yet another object of the present invention is to provide a copper electroplating solution that can initiate or produce copper deposits exhibiting high density nano-twinned copper on any surface.

Yet another object of the present invention is to provide a copper electroplating solution capable of producing deposits exhibiting high density nano-twinned copper on surfaces not dominated by (111) copper.

To this end, in one embodiment, the present invention generally relates to a copper electroplating solution, wherein the copper electroplating solution comprises: a)    a copper salt; b)    a halide ion source; 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 compound and a sulfur-containing compound; wherein the copper electroplating solution is configured to deposit high-density nano-twin copper on a substrate.

In one embodiment, the copper plating solution may optionally also include one or more of the following: a)    an accelerator, wherein the accelerator comprises an organic sulfur compound; and b)    a leveler, wherein the leveler comprises a polymerized quaternary nitrogen species.

In another embodiment, the present invention also generally relates to a method of depositing high density nanobicrystalline copper on a substrate (including a surface that is not dominated by (111) copper) using the copper electroplating solution described herein.

As used herein, “a”, “an” and “the” refer to both the singular and the plural, unless the context clearly requires otherwise.

As used herein, the term "about" refers to measurable values, such as parameters, amounts, time durations, and the like, 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 of the specifically recited value, such that such variations are suitable for use in the practice of the invention as described herein. In addition, it is also to be understood that the value to which the modifier "about" refers is itself expressly disclosed herein.

As used herein, spatially relative terms such as "beneath," "below," "lower," "above," "upper," and the like are used for ease of description to describe the relationship of one element or feature to another (or multiple) elements or features, as depicted in the drawings. It should be further understood that the terms "front" and "back" are not intended to be limiting and are intended to be interchangeable where appropriate.

As used herein, the terms “comprise” and “comprising” specifically specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

As used herein, unless otherwise defined herein with respect to a particular element or compound, the term "substantially free" or "essentially free" means that a given element or compound cannot be detected by conventional analytical means for bath analysis, which are well known to those of ordinary skill in the art of metal plating technology. Such methods generally include atomic absorption spectroscopy, titration, UV-Vis analysis, secondary ion mass spectrometry, and other commonly available analytical techniques.

As used herein, the term "feature" refers to a via, through-silicon via (TSV), trench, pillar, pad, bump, etc. that may be present on a microelectronic substrate.

As used herein, the term "high density" nanotwin 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% nanotwin columnar copper grains in the deposit.

Unless otherwise noted, all amounts are percentages by weight. All numerical ranges are inclusive and combinable in any order, except where such numerical ranges are logically limited to where they total 100%. The term "average" is equivalent to the mean value of a sample.

The terms "plating" and "deposit" or "deposition" are used interchangeably throughout this specification.

The terms "composition", "bath", "electrolyte", and "solution" are used interchangeably throughout this specification.

Unless otherwise described as having a substituent in this specification, the term "alkyl" refers to an organic chemical group containing only carbon and hydrogen and having the following general formula: C _n H _2n+1 .

Studies have shown that few materials can produce nanotwin copper (ntCu) or copper deposits that exhibit a highly nanotwin phenomenon. One such material is poly(2,3-epoxy-1-propanol), which is a linear or branched polyhydroxy compound having a molecular weight of about 200 to about 20,000, more preferably about 500 to about 5,000, and even more preferably about 1,000 to about 3,000.

It is also believed that the introduction of other organic electroplating compounds, such as accelerators, brighteners, carriers, wetting agents, and/or levelers, will destroy the ability of polyhydroxy compounds to produce nanocrystalline twin copper.

Currently for polyhydroxy compounds, such as described in U.S. Patent Nos. 11,384,446 and WO2023/014524 to Richardson et al. (the entirety of each of which is incorporated herein by reference), high-density nanobicrystalline copper is difficult to achieve unless the deposition is performed on a PVD copper seed layer (which exhibits a large amount of copper in a (111) oriented grain structure).

It would be desirable to initiate high density nanobicrystalline copper deposits on other surfaces, including, 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 nanobicrystalline copper on various surfaces, including, by way of example and not limitation, polycrystalline copper seed layers, stainless steel, and PVD ruthenium.

In one embodiment, the present invention generally relates to the electrodeposition of nanobicrystalline copper, and a copper electroplating solution configured to produce copper deposits exhibiting a high density of nanobicrystalline copper on various surfaces.

In one embodiment, the copper plating solution comprises: a)    copper salt; b)    halide ion source; and c)    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 compound and a sulfur-containing compound.

In one embodiment, the copper electrolyte may optionally also include one or more of the following: a)    an accelerator, wherein the accelerator includes an organic sulfur compound; and b)    a leveler, wherein the leveler includes a polymerized quaternary nitrogen species; In a preferred embodiment, the copper salt includes copper sulfate. Other copper salts that may be used in the composition include copper methanesulfonate, copper pyrophosphate, copper propanesulfonate, and other similar compounds. The concentration of copper sulfate in the electroplating solution is generally in the range of about 1 to 100 g/L, more preferably in the range of about 20 to about 80 g/L, and more preferably in the range of about 40 to about 60 g/L.

Halide ions serve as bridges to assist certain organic additives in adsorbing onto 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 ions include chloride ions. The concentration of chloride ions in the electroplating solution is generally in the range of about 1 to 150 mg/L, more preferably about 30 to 120 mg/L, and most preferably about 45 to 75 mg/L.

In one embodiment, the plating 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 plating solution is generally in the range of about 0 to 240 g/L, more preferably in the range of about 10 to about 180 g/L, and more preferably in the range of about 80 to about 140 g/L. In one embodiment, the concentration of the acid is in the range of about 8 to about 15 g/L, and more preferably about 10 g/L. The inventors of the present invention have unexpectedly discovered that the concentration of acid can have a significant impact on the ability to develop nanotwinning phenomena, and that compositions containing lower acid concentrations tend to be more permissive to ntCu formation than similar compositions containing higher acid concentrations.

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

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, hydroxyethyl 1-(2-hydroxyethyl)-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-methylimidazole chloride, and combinations thereof.

Other amine compounds include tertiary amines such as 3-hydroxypropyldimethylamine, n-butyldimethylamine, di(3-hydroxypropyl)methylamine, 2,3-dihydroxypropyldimethylamine, 3-hydroxypropyldiethylamine, 2-hydroxypropyldimethylamine, 4-hydroxybutyldimethylamine, 2-hydroxyethyldimethylamine, n-propyldimethylamine, 2-hydroxyethoxyethyldimethylamine, di(2-hydroxyethyl)methylamine, benzyldimethylamine, and 4-hydroxybenzyldimethylamine, 4-methylpyridine, 3-ethylpyridine, 4-propylpyridine, 4-tertiary butylpyridine, 4-cyanopyridine, 4-isopropylpyridine, 4-methoxypyridine, 3,4 -dimethylpyridine, 3-methoxypyridine, 4-pyridinemethanol, 2-dimethylamino-1-ethanol, n-butyldimethylamine, N,N-dimethylbenzylamine, 4-ethylpyridine, 1-methylimidazole, 1-benzylimidazole, N-methyl phenoxyethanol, 2-[2-(dimethylamino)ethoxy]ethanol.

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

Other similar amine compounds that react with 2,3-epoxy-1-propanol to produce reactive compounds can also be used as inhibitors in the present invention. Importantly, when used in a suitable composition in a copper plating solution, the reactive compound is capable and/or configured to initiate copper deposits having high density nanobicrystalline copper on a variety of substrates, including surfaces that are not dominated by (111) copper.

Examples of suitable sulfur compounds include, but are not limited to, thioglycolic acid, thiomalonic acid, sodium hydrogen sulfide, thiodiglycolic acid, thiodiethylene glycol, thiourea, N,N,N'N'-tetramethylthiourea, 2-butylethanol, 3-butylpropanol, 2-butylimidazole, 2-butylpyridine, 4-butylpyridine, 4-butylphenol, 3-butyl-1-propanesulfonic acid, 3,6-dithio-1,8-octanediol, 2,2'-thiodiethanethiol, 2-hydroxyethyl disulfide, 3,3'-thiodipropanol, and 2,2'-(ethylenedioxy)diethanethiol.

Other reactants that can be used in copper electrolytes to initiate copper deposits with high density nanotwinned copper on substrates that are not dominated by (111) copper include various pyridines and imidazoles. Again, when used in a suitable composition in a copper plating solution, such pyridines and/or imidazoles must be capable and/or configured to initiate copper deposits with high density nanotwinned copper on a variety of substrates, including substrates that are not dominated by (111) copper.

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

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

In one embodiment, the concentration of the linear or branched polyhydroxy inhibitor compound in the copper electroplating solution is in the range of about 1 to about 10,000 mg/L, more preferably about 10 to about 1,000 mg/L, more preferably about 50 to about 600 mg/L, more preferably about 300 to about 500 mg/L.

In some embodiments, the copper plating solution may optionally include an accelerator and/or a leveler.

If used, the accelerator may include, for example, an organic sulfur compound, including an organic sulfur salt. Suitable organic sulfur compounds include, but are not limited to, bis-(3-sulfopropyl) disulfide (SPS), 3-butyl-1-propanesulfonic acid (MPS), 3-(benzothiazolyl-2-butyl)-propylsulfonic acid (ZPS), N,N-dimethyldithiocarbamate methylpropanesulfonic acid (DPS), 3-S-isothiourea propylsulfonate (UPS), and (O-ethyldithiocarbonate)-S-(3-sulfopropyl) ester (OPX).

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 accelerator, such as MPS or SPS.

The concentration of the accelerator depends in part on the specific accelerator used in the copper plating solution, and weaker accelerators can be used at higher concentrations than stronger accelerators. For example, ZPS and UPS can be used in copper plating solutions at higher concentrations than SPS. In addition, using stronger accelerators (such as SPS) as an accelerator may also require applying a high-density nanotwin copper deposit as a base layer, followed by depositing a subsequent layer using a copper plating solution containing SPS. Depending in part on the particular inhibitor and accelerator combination, the concentration of the accelerator is preferably less than about 10 mg/L, more preferably in the range of about 1 to about 8 mg/L, or in the range of about 1 to about 3 mg/L.

If used, the leveler compound may include polymeric quaternary nitrogen species, such as those described in WO2018/057590, U.S. Pat. No. 10,519,557, and U.S. Pat. No. 10,294,574, each of which is incorporated herein by reference in its entirety. Other leveler compounds include dipyridyl levelers, such as those described in U.S. Pat. No. 7,303,992 and U.S. Patent Publication No. 2005/0045488, the entirety of which is each incorporated herein by reference.

For example, the leveler may comprise the reaction product of an aliphatic di(t-amine) and a difunctional alkylating agent corresponding to the following formula: 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 a structure of -CR ³ R ⁴ - or -C(R ³ )(R ⁴ )C(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), and 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 a substituted or unsubstituted aliphatic hydrocarbon group containing 1 to 4 carbon atoms; R ^R33 is a substituted or unsubstituted aliphatic hydrocarbon group having 1 to 4 carbon atoms, Y is a detached group selected from the group consisting of chloride, bromide, iodide, p-toluenesulfonyl, trifluoromethanesulfonate, sulfonate, methanesulfonate, methyl sulfate, fluorosulfonate, methyl p-toluenesulfonate, and p-bromobenzenesulfonate; Z is selected from the group consisting of ^R30 and a detached group (which is independently selected from the same group as Y), and ^R30 is selected from the group consisting of an aliphatic hydrocarbon group, a hydroxyl group, an alkoxy group, a cyano group, a carboxyl group, an alkoxycarbonyl group, and an amide group; and when -G- is not a single covalent bond, q is at least one.

The leveler may also comprise an oligomer and/or polymer compound selected from the group consisting of a salt comprising a cation having the following structure: or Wherein: G and A are as defined above; B has the following structure; D has the following structure; The above structure is a residue of an N,N'-dialkyl heterocyclic diamine bonded to -(CR ¹ R ² ) _p -G-(CR ⁵ R ⁶ ) _q ]- at each t-amine site to form a di(quaternary ammonium) cation structure; each of p, r, t, u, w and y is an integer between 1 and 6 (inclusive), wherein each of q, v, x, k, and z is independently an integer between 0 and 6 (inclusive), s is an integer between 1 and 10 (inclusive), when v or x is not 0, k is at least one, and when G is not a single covalent bond, q is at least one. Each of ^R1 to ^R6 , ^R9 to ^R19 , ^R23 , ^R25 , and ^R34 is independently selected from the group consisting of hydrogen or an alkyl group containing 1 to 4 carbon atoms, each of ^R7 , ^R8 , ^R20 , ^R21 , ^R22 , ^R24 , and ^R33 is independently selected from the group consisting of a substituted or unsubstituted aliphatic hydrocarbon group having 1 to 4 carbon atoms; and n is between about 1 and about 30.

The leveler may also include a compound corresponding to the following formula: or Wherein: G, A, B, and D are as described above;

The above structure is a residue of an N,N'-dialkyl heterocyclic diamine bonded to -(CR ¹ R ² ) _p -G-(CR ⁵ R ⁶ ) _q ]- at each t-amine site to form a di(quaternary ammonium) cation structure; each of p, r, t, u, w and y is an integer between 1 and 6 (inclusive), wherein each of q, v, x, k and z is independently an integer between 0 and 6 (inclusive), s is an integer between 1 and 10 (inclusive), when v or x is not 0, k is at least one, and when G is not a single covalent bond, q is at least one. Each of ^R1 to ^R6 , ^R9 to ^R19 , ^R23 , ^R25 , and ^R34 is independently selected from the group consisting of hydrogen or an alkyl group containing 1 to 4 carbon atoms, each of ^R7 , ^R8 , ^R20 , ^R21 , ^R22 , ^R24 , and ^R33 is independently selected from the group consisting of a substituted or unsubstituted aliphatic hydrocarbon group having 1 to 4 carbon atoms; and ^R30 is selected from the group consisting of an aliphatic hydrocarbon group, a hydroxyl group, an alkoxy group, a cyano group, a carboxyl group, an alkoxycarbonyl group, and an amide group.

The leveler may also include a quaternary ammonium poly(halogenated epoxypropane) comprising n repeating units corresponding to structure 1N and p repeating units corresponding to structure 1P: wherein Q has a structure corresponding to a structure obtainable by reacting a pendant methylene halide group of a poly(halogenated epoxypropane) with a tertiary amine, wherein the tertiary amine is selected from the group consisting of: (i) NR ¹ R ² R ³ , wherein each of R ¹ , R ² , and R ³ is independently selected from the group consisting of substituted or unsubstituted alkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted alkynyl, substituted or unsubstituted alicyclic, 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 alicyclic, substituted or unsubstituted aralkyl, substituted or unsubstituted aryl, and substituted or unsubstituted heterocyclic; and (iii) substituted or unsubstituted nitrogen-containing heteroaryl compounds; n is an integer between 3 and 35, p is an integer between 0 and 25; X is a halogen substituent; and ^X- is a monovalent anion.

Preferably, Q corresponds to structure IIA, IIB, or IIC: or (IIC) wherein: (i) Structure IIB is an N-substituted heterocyclic moiety; (ii) Structure IIC is a heterocyclic moiety; (iii) each of R ¹ , R ² , R ³ , and R ⁴ is 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 alicyclic, substituted or unsubstituted aryl, and substituted or unsubstituted heterocyclic; and (iv) R ⁵ , R ⁶ , R ⁷ , R ⁸ , and R Each of R 1 to ^{R 8} is independently selected from the group consisting of: hydrogen, substituted or unsubstituted alkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted alkenyl, substituted or unsubstituted aralkyl, substituted or unsubstituted alicyclic, substituted or unsubstituted heterocyclic, and substituted or unsubstituted heterocyclic. When any one of R ¹ to R ⁸ is substituted, the substituent preferably does not include an amino group.

The leveler may also include substituted pyridyl compounds, such as pyridinium compounds, and in particular quaternary ammonium pyridinium salts. Examples of such substituted pyridyl compounds include, but are not limited to, derivatives of vinyl pyridine, such as derivatives of 2-vinyl pyridine, derivatives of 4-vinyl pyridine, homopolymers of vinyl pyridine, copolymers of vinyl pyridine, quaternary ammonium salts of vinyl pyridine, and quaternary ammonium salts of such 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 chlorotoluene, the reaction product of 4-vinylpyridine and chloropropylene, 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 p-toluenesulfonate. reaction product, reaction product of 4-vinylpyridine and chloroacetone, reaction product of 4-vinylpyridine and 2-methoxyethoxymethyl chloride, reaction product of 4-vinylpyridine and 2-chloroethyl ether, reaction product of 2-vinylpyridine and methyl p-toluenesulfonate, reaction product of 2-vinylpyridine and dimethyl sulfate, reaction product of vinylpyridine and a water-soluble initiator, poly(2-methyl-5-vinylpyridine), and 1-methyl-4-vinylpyridinium trifluoromethanesulfonate, etc.

Other polymeric quaternary nitrogen species may also be used as levelers in the copper electroplating compositions described herein, provided they are compatible with the inhibitors (and accelerators) and do not adversely affect the ability to initiate nanobi-crystalline copper deposits on a variety of substrates.

In one embodiment, suitable leveler species include, but are not limited to, the reaction product of 4,4-bipyridyl and 2-chloroethyl ether. The concentration of the leveler depends in part on the specific leveler used, as well as the specific inhibitors and accelerators, and the process conditions. In one embodiment, the leveler 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 to about 10 mg/L, more preferably about 2 to about 5 mg/L.

It has been found that higher current densities (i.e., about 3 to about 6 ASD, more preferably in the range of about 3 to about 5 ASD) are beneficial for the purpose of producing nano-bicrystalline copper. However, when superfilling copper in features of microelectronic substrates, lower current densities, such as in the range of about 0.5 to about 2 ASD, are preferred.

Thus, in one embodiment, the copper plating composition comprises a two- or three-component copper plating bath, which is used in a step-current plating method to achieve nano-bicrystalline copper microstructures by filling. In one embodiment, a two-component copper plating bath can be used, which comprises an inhibitor compound described herein and a leveler comprising a polymerized quaternary nitrogen species as described above. In another embodiment, a three-component copper plating bath can be used, which comprises: an inhibitor compound described herein, an accelerator comprising an organic sulfur compound (preferably UPS), and a leveler comprising a polymerized quaternary nitrogen species.

A ramped current (where the current ramps from high to low, as opposed to a step current change) can also be applied to the 2-component and 3-component copper plating baths to accomplish via filling with nanobicrystalline copper microstructures.

As described herein, in one embodiment, a copper plating solution comprises: A)   about 40 to about 60 g/L of copper ions; B)   about 80 to about 140 g/L of sulfuric acid; C)   about 30 to about 120 mg/L of chloride ions; D)   about 300 to about 500 mg/L of a reaction product of an amine compound or a sulfur-containing compound and 2,3-epoxy-1-propanol; E)   optionally, about 0.5 to about 10 mg/L of a leveler comprising a polymeric quaternary nitrogen species; and F)   optionally, about 1 to about 50 mg/L of an accelerator comprising an organic sulfur compound.

In another preferred embodiment, the copper plating solution consists essentially of: A)   about 40 to about 60 g/L of copper ions; B)   about 80 to about 140 g/L of sulfuric acid; C)   about 30 to about 120 mg/L of chloride ions; D)   about 300 to about 500 mg/L of a reaction product of an amine compound or a sulfur-containing compound and 2,3-epoxy-1-propanol; and E)   about 0.0 to about 10 mg/L of a leveler comprising a polymeric quaternary nitrogen species.

In another preferred embodiment, the copper plating solution consists essentially of: A)   about 40 to about 60 g/L of copper ions; B)   about 80 to about 140 g/L of sulfuric acid; C)   about 30 to about 120 mg/L of chloride ions; D)   about 300 to about 500 mg/L of a reaction product of an amine compound or a sulfur-containing compound and 2,3-epoxy-1-propanol; E)   about 0.5 to about 10 mg/L of a leveler comprising a polymeric quaternary nitrogen species; and F)   about 0.0 to about 50 mg/L of an accelerator comprising an organic sulfur compound.

In another embodiment, the copper electrolyte of the present invention contains a relatively small amount of sulfuric acid. For example, the copper electrolyte may contain: A)   about 5 to about 50 g/L of copper ions; B)   about 8 to about 15 g/L of sulfuric acid; C)   about 30 to about 120 mg/L of chloride ions; D)   about 300 to about 500 mg/L of a reaction product of an amine compound or a sulfur-containing compound and 2,3-epoxy-1-propanol; E)   optionally, about 0.5 to about 10 mg/L of a leveler, the leveler comprising a polymeric quaternary nitrogen species; and F)   optionally, about 1 to about 50 mg/L of an accelerator, the accelerator comprising an organic sulfur compound.

In another preferred embodiment, the copper plating solution consists essentially of: A)   about 5 to about 50 g/L of copper ions; B)   about 8 to about 15 g/L of sulfuric acid; C)   about 30 to about 120 mg/L of chloride ions; D)   about 300 to about 500 mg/L of a reaction product of an amine compound or a sulfur-containing compound and 2,3-epoxy-1-propanol; and E)   about 0.0 to about 5 mg/L of a leveler comprising a polymeric quaternary nitrogen species.

In another preferred embodiment, the copper plating solution consists essentially of: A)   about 5 to about 50 g/L of copper ions; B)   about 8 to about 15 g/L of sulfuric acid; C)   about 30 to about 120 mg/L of chloride ions; D)   about 300 to about 500 mg/L of the reaction product of an amine compound or a sulfur-containing compound and 2,3-epoxy-1-propanol; E)   about 0.0 to about 5 mg/L of a leveler comprising a polymeric quaternary nitrogen species; and F)   about 0.0 to about 50 mg/L of an accelerator, the dry accelerator comprising an organic sulfur compound.

“Consisting essentially of” means that the composition does not contain any additives that would adversely affect the ability of the composition to initiate copper deposits having high density nanobi-crystalline copper on substrates, including substrates other than (111) copper substrates.

The present invention also generally relates to a method for electroplating nanobicrystalline copper on a substrate, the method comprising the following steps: A)   providing a substrate, at least one anode, and a copper electroplating bath as described herein; B)   contacting the substrate and the at least one anode with the copper bath respectively; and C)   applying a voltage between the surface of the workpiece and the at least one anode so that the cathode polarity is applied to the substrate relative to the at least one anode; wherein a copper structure having a high density of nanobicrystalline is deposited on the substrate.

The current density is generally in the range of about 0.01 to about 50 ASD, more preferably about 0.5 to about 20 ASD, and most preferably about 1 to about 10 ASD. In addition, the plating solution is preferably stirred, and the plating solution is generally mixed at about 1 to about 2,500 rpm, more preferably about 10 to about 1,200 rpm, and most preferably about 50 to about 400 rpm.

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

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

Substrates that may be plated using the copper plating solutions described herein include printed wiring boards (PWBs), printed circuit boards (PCBs), and other electronic substrates that may include one or more posts, pads, lines, and vias, including non-(111) copper surfaces such as polycrystalline copper seed layers, stainless steel, and PVD ruthenium.

The presence of nanotwinned grain structures can be observed using any suitable microscopic technique, such as electron microscopy. The amount of nanotwinned grain structures in the copper deposit is preferably greater than about 80%, more preferably greater than about 90% nanotwinned columnar copper grains, as assessed based on SEM cross-sections.

As described in the following examples, the nanotwinned copper structure can be characterized by a plurality of (111) oriented copper grains containing a majority of nanotwins. In some embodiments, the plurality of (111) oriented copper grains contain a high density of nanotwins. As used herein, "high density of nanotwins" can refer to a copper structure having greater than about 80% nanotwins, and even greater than about 90% nanotwins, as observed using appropriate microscopy techniques.

The crystal orientation of the copper grains can be characterized using suitable techniques such as electron backscatter diffraction (EBSD) analysis. In some embodiments, the crystal orientation map can be displayed in an anti-pole figure (IPF). According to the present invention, it is preferred that the nano-bicrystalline copper structure mainly contains (111) oriented grains.

In the examples, the following inhibitor compounds were used: Compound 1: the reaction product of 4-pyridinemethanol (1 wt.%) and 2,3-epoxy-1-propanol (99 wt.%) to produce a polymer.

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.

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.

The inhibitor compound is prepared by reacting an amine compound or a sulfur-containing compound with 2,3-epoxy-1-propanol. The general reaction procedure is as follows: In a 1 L round-bottom flask equipped with a thermometer, a reflux condenser, and a magnetic stirrer, a solution of boron trifluoride etherate (5 mmol) in methanol is added dropwise to a solution of 2,3-epoxy-1-propanol and an amine compound or a sulfur-containing compound in the weight percentages listed to produce each of Compound 1, Compound 2A, and Compound 2B. The temperature is allowed to increase freely during the exotherm, and heating is continued at its maximum temperature for 30 minutes. The reaction is then allowed to cool to less than 100°C, whereupon water is added to make a 20% w/w solution, and the solution is stirred for 4 hours. This solution is then filtered and used as is. Example 1:

A copper electrolyte containing 40 g/L copper (II) ions, 10 g/L sulfuric acid, 50 mg/L chloride ions, and 400 mg/L amino polyhydroxy inhibitor was prepared (baseline composition), and a second copper electrolyte was prepared in the same manner as the baseline composition, but with 400 mg/L Compound 1 substituted (composition with Compound 1).

Using two electrolytes at a constant current of 1 ASD, intermediate nanobicrystalline Cu deposits were initiated from (111) dominated PVD Cu seeds and polycrystalline Cu seeds.

As shown in Figure 1, although both solutions can generate intermediate nano-twin copper from (111)-dominated copper seeds, the baseline composition is completely unable to generate any nano-twin copper on the polycrystalline copper seed layer, while the compound 1 composition can generate intermediate nano-twin copper from polycrystalline copper seeds.

Figure 2 depicts a 50K magnified image of the transition layer of Compound 1 composition deposited on a polycrystalline copper seed. As can be seen from Figure 2, after 111 nm deposition, Compound 1 composition is able to generate ntCu from the polycrystalline copper seed to a total thickness of approximately 2.8 µm.

As shown in Figure 4, the compound 1 composition can produce a large amount of nano-twin copper from stainless steel and ruthenium substrates, while the baseline composition cannot do so. Example 2:

A copper electrolyte containing 40 g/L copper (II) ions, 10 g/L sulfuric acid, 50 mg/L chloride ions, and 400 mg/L compound 2A was prepared, and a second copper electrolyte was prepared in the same manner, but with 400 mg/L compound 2B instead.

Using two electrolytes at a constant current of 1 ASD, intermediate nanobicrystalline Cu deposits were initiated from (111) dominated PVD Cu seeds and polycrystalline Cu seeds.

As shown in Figure 3, although both solutions are capable of generating intermediate nanobicrystalline copper from (111)-dominated copper seeds, adding a thiol compound in addition to the amine and reacting both with 2,3-epoxy-1-propanol improves the nanobicrystalline copper capability on non-(111) Cu substrates.

As can be seen from Examples 1 and 2, the use of the inhibitor described above (which comprises the reaction product of an amine compound or a sulfur-containing compound and 2,3-epoxy-1-propanol) in a copper electroplating solution enables the copper electroplating solution to initiate high-density nano-twin copper deposition on various substrates (including non-(111) copper substrates) and generate nano-twin copper in the features of the substrate. Example 3:

A copper electrolyte 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 compound 2A was prepared. Blanket coupons with (111)-dominated PVD copper seed layers were electroplated at 3 ASD and produced >90% nano-twin copper.

FIG5 depicts a 20K magnified image of the transition layer of the compound 2A composition coated on the (111)-dominated PVD copper seed layer. As can be seen from FIG5, the compound 2A composition is able to produce ntCu from the (111)-dominated PVD copper seed. Example 3A:

The copper electrolyte was prepared in the same manner as in Example 3, but 3 mg/L of SPS was added to the solution. A blanket coupon with a (111)-dominated PVD copper seed layer was plated at 3 ASD and produced >90% nano-twinned copper. Example 3B:

The copper electrolyte was prepared in the same manner as in Example 3, but 8 mg/L of SPS was added to the solution and Compound 1 was used instead of Compound 2A. A blanket coupon with a (111)-dominated PVD copper seed layer was electroplated at 3 ASD and produced >90% nanobi-crystalline copper. Example 3C:

An additional copper electrolyte was prepared in the same manner as Example 3, but 8 mg/L of SPS was added to the solution and Compound 2B was used instead of Compound 2A. A blanket coupon with a (111)-dominated PVD copper seed layer was plated at 3 ASD and produced >90% nanotwin copper. Comparative Example 4:

The copper electrolyte was prepared in the same manner as in Example 3, but 28 mg/L of SPS was added to the solution. The covered coupon with the (111)-dominated PVD copper seed layer was electroplated at 3 ASD, but no nano-twinned copper was produced.

Figure 6 depicts a 20K magnified image of the transition layer of compound 2A deposited on a (111)-dominated PVD copper seed layer. As shown in Figure 6, compound 2A cannot generate ntCu from a (111)-dominated PVD copper seed.

From Comparative Example 4, it can be seen that increasing the amount of SPS from 1 to 28 mg/L in the copper electroplating solution causes the loss of nano-twin copper. Comparative Example 5:

A copper electrolyte was prepared in the same manner as in Example 3, but 50 g/L of copper (II) ions and 100 g/L of sulfuric acid were added to the solution. A blanket coupon with a (111)-dominated PVD copper seed layer was electroplated at 3 ASD, but nano-twin copper was not produced.

Figure 7 depicts a 20K magnified image of the transition layer of compound 2A deposited on a (111)-dominated PVD copper seed layer. As shown in Figure 7, compound 2A cannot generate ntCu from a (111)-dominated PVD copper seed.

From Comparative Example 5, it can be seen that increasing the amount of sulfuric acid from 10 to 100 g/L in the copper electroplating solution causes the loss of nano-twin copper. Example 6:

A copper electrolyte containing 40 g/L of Cu(II) ions, 10 g/L of sulfuric acid, 50 mg/L of chloride ions, 1 mg/L of SPS, 400 mg/L of compound 2A, and 3 mg/L of leveler was prepared. A covered wafer with a (111)-dominated PVD copper seed layer was electroplated at 3 ASD and produced >90% nano-twinned copper.

FIG8 depicts a 20K magnified image of the transition layer of the compound 2A composition coated on the (111)-dominated PVD copper seed layer. As can be seen from FIG8, the compound 2A composition is able to generate ntCu from the (111)-dominated PVD copper seed. Example 7:

The copper electrolyte was prepared in the same manner as in Comparative Example 4, but 3 mg/L of the leveler was added to the solution. A blanket coupon with a (111) dominated PVD copper seed layer was plated at 3 ASD and produced >90% nanobi-crystalline copper.

Figure 9 depicts a 20K magnified image of the transition layer of the compound 2A composition deposited on the (111) dominated PVD copper seed layer. As can be seen from Figure 9, the composition is able to produce ntCu from the (111) dominated PVD copper seed.

As can be seen from Example 7, when used in combination with low concentration sulfuric acid and a leveling agent, even with a high concentration of accelerator, >90% nano-twin copper can be produced.

Finally, it is also to be understood that the following claims are intended to cover all generic and specific features of the invention described herein, as well as all statements of the scope of the invention which in terms of language may fall therebetween.

without

[Figure 1] SEM images of copper deposited by the baseline composition and the compound 1 composition on (111)-dominated PVD copper and on polycrystalline copper. [Figure 2] A 50K magnified image of the transition layer of nanobicrystalline copper deposited by the compound 1 composition on polycrystalline copper. [Figure 3] SEM images of copper deposited by the compound 2A composition and the compound 2B composition on (111)-dominated PVD copper and on polycrystalline copper. [Figure 4] SEM images of copper deposited by the baseline composition and the compound 1 composition on (111)-dominated PVD copper, stainless steel, and PVD ruthenium surfaces. [Figure 5] depicts a 20K magnified image of a transition layer of nano-twin copper deposited from the compound 2A composition according to Example 3. [Figure 6] depicts a 20K magnified image of a transition layer deposited from the compound 2A composition according to Comparative Example 4. [Figure 7] depicts a 20K magnified image of a transition layer deposited from the compound 2A composition according to Comparative Example 5. [Figure 8] depicts a 20K magnified image of a transition layer of nano-twin copper deposited from the compound 2A composition according to Example 6. [Figure 9] depicts a 20K magnified image of a transition layer of nano-twin copper deposited from the compound 2A composition according to Example 7.

Claims (23)

A copper electroplating solution comprising: a)     a copper salt; b)     a halide ion source; 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 compound and a sulfur-containing compound; wherein the copper electrolyte is capable of depositing copper, wherein the copper deposit exhibits greater than about 80% nano-twin columnar copper grains. The copper electroplating solution of claim 1, wherein the copper salt is copper sulfate. The copper electroplating solution of claim 1 or 2, further comprising an acid, wherein the acid comprises sulfuric acid or methanesulfonic acid. A copper electroplating solution as claimed in 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 leveler, wherein the leveler comprises a polymerized quaternary nitrogen species. A copper electroplating solution as claimed in any one of claims 1 to 4, wherein the reactant comprises an amine compound, and the amine compound is 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-dibutylethanolamine, hydroxyethyl , 2-piperidinylethanol, 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-methylimidazole chloride, bis(2-hydroxyethyl)dimethylammonium chloride, and combinations thereof. A copper electroplating solution as claimed in any one of claims 1 to 4, wherein the reactant comprises a sulfur-containing compound, and the sulfur-containing compound is selected from the group consisting of: 2,2'-thiodiethanol, thioglycolic acid, thiomalonic acid, sodium hydrogen sulfide, thiodiglycolic acid, thiodiethylene glycol, thiourea, N,N,N'N'-tetramethylthiourea, 2-butylethanol, 3-butylpropanol, 2-butylimidazole, 2-butylpyridine, 4-butylpyridine, 4-butylphenol, 3-butyl-1-propanesulfonic acid, 3,6-dithio-1,8-octanediol, 2,2'-thiodiethanethiol, 2-hydroxyethyl disulfide, 3,3'-thiodipropanol, 2,2'-(ethylenedioxy)diethanethiol, and a combination of one or more of the foregoing. A copper electroplating solution as claimed in claim 6, wherein the sulfur-containing compound comprises 2,2'-thiodiethanol. A copper electroplating solution as claimed in claim 4, wherein the accelerator is present and is selected from the group consisting of: bis-(3-sulfopropyl) disulfide, 3-butyl-1-propanesulfonic acid, 3-(benzothiazolyl-2-butyl)-propylsulfonic acid, N,N-dimethyldithiocarbamate propylsulfonic acid, 3-S-isothiourea propylsulfonate, and (O-ethyldithiocarbonic acid)-S-(3-sulfopropyl) ester. A copper electroplating solution as claimed in claim 4, wherein both the accelerator and the leveler are present in the composition. A copper electroplating solution as claimed in any one of claims 1 to 4, wherein the inhibitor comprises 90.0 to 99.9 wt.% of the 2,3-epoxy-1-propanol reacted with 0.1 to 10.0 wt.% of the reactant(s), or wherein the inhibitor comprises 95.0 to 99.5 wt.% of the 2,3-epoxy-1-propanol reacted with 0.5 to 5.0 wt.% of the reactant(s), or wherein the inhibitor comprises 97.0 to 99.0 wt.% of the 2,3-epoxy-1-propanol reacted with 2.0 to 3.0 wt.% of the reactant(s). The copper electroplating solution of claim 1, wherein the copper electroplating solution comprises: a.     About 40 to about 60 g/L of copper ions; b.     About 80 to about 140 g/L of sulfuric acid; c.     About 30 to about 120 mg/L of chloride ions; d.     About 300 to about 600 mg/L of a reaction product of an amine compound or a sulfur-containing compound and 2,3-epoxy-1-propanol. The copper electroplating solution of claim 1, wherein the copper electroplating solution comprises: a.     About 5 to about 50 g/L of copper ions; b.     About 8 to about 15 g/L of sulfuric acid; c.     About 30 to about 120 mg/L of chloride ions; d.     About 300 to about 600 mg/L of a reaction product of an amine compound or a sulfur-containing compound and 2,3-epoxy-1-propanol. The copper plating solution of claim 12 further comprises: a.     About 0.01 to about 10 mg/L of the leveler, the leveler comprising a polymeric quaternary nitrogen species; or b.     About 0.1 to about 50 mg/L of the accelerator. A copper electroplating solution as claimed in claim 1, wherein the copper electroplating solution is at least substantially free of any accelerator, brightener, carrier, wetting agent, or leveler, or any compound that can act as an accelerator, brightener, carrier, wetting agent, or leveler. A method for electro-depositing copper on a substrate, the method comprising the following steps: a.     contacting a surface of the substrate and at least one anode with a copper electrolyte as in any one of claims 1 to 4; and b.     applying a voltage between the surface of the substrate and the at least one anode so that a cathode with polarity relative to the at least one anode is applied to the substrate; wherein a copper deposit having a high density of nano-twin columnar copper grains is initially formed on the substrate. The method of claim 15, wherein the nano-bicrystalline copper deposit is oriented in a (111) direction. The method of claim 15 or 16, wherein the copper deposit comprises greater than 90% nano-twinned columnar copper grains. The method of claim 15, wherein the substrate is a non-(111) oriented copper substrate. The method of claim 18, wherein the substrate is selected from the group consisting of: polycrystalline copper seed, stainless steel, and PVD ruthenium. The method of claim 18 or 19, wherein the nano-bicrystalline copper deposit is oriented in a (111) direction. A method for electrodepositing >80% nanobi-crystalline copper on a non-(111) oriented copper substrate using an aqueous copper electrolyte containing at least one organic additive. The method of claim 21, wherein the at least one organic additive comprises a reaction product of a reactant and 2,3-epoxy-1-propanol, wherein the reactant comprises at least one of an amine compound and a sulfur-containing compound. The method of claim 15, wherein the voltage is applied at a current density between about 1 and about 8 ASD, more preferably between about 1 and about 3 ASD.