Copper electroplating bath

Abstract

The invention relates to an aqueous acidic electroplating bath for electrodeposition of copper and copper alloys in the manufacture of printed circuit boards, IC substrates, semiconductors and glass devices for electronic applications. The electroplating bath according to the invention comprises copper ions, at least one acid and a urethanylene polymer. The electroplating bath is particularly suitable for filling recessed structures with copper and building up columnar bump structures.

Description

TECHNICAL FIELD

[0001] The present invention relates to electroplating baths for the electrodeposition of copper or copper alloys. The electroplating baths are suitable for the manufacture of printed circuit boards, IC substrates and the like, and for the metallization of semiconductor and glass substrates. BACKGROUND

[0002] Aqueous acidic electroplating baths for the electrolytic deposition of copper are used for the manufacture of printed circuit boards and IC substrates, wherein fine structures such as trenches, through-holes (TH), blind micro-vias (BMV) and pillar bumps have to be filled or built up with copper. Another application of such electrolytic deposition of copper is the filling of recessed structures such as through-silicon vias (TSV), and dual damascene plating or forming of redistribution layers (RDL) and pillar bumps in or on semiconductor substrates. Yet another increasingly demanding application is the filling of glass vias, i.e. holes and associated recessed structures in glass substrates, with copper or copper alloys by electroplating.

[0003] The patent application EP 1 069 211 A2 discloses an aqueous acidic copper electroplating bath comprising a copper ion source, an acid, a carrier additive, a brightener additive and a leveler additive, which can be poly[bis(2-chloroethyl) ether-alternate-1,3-bis[3-(dimethylamino)propyl]urea (CAS No. 68555-36-2) with at least one terminal end containing an organically bound halogen atom (e.g. a covalent C-Cl bond) (see comparative preparation example 1).

[0004] Zinc electroplating baths each containing a large amount of urethanylic polymers are disclosed in WO 201 1 / 029781 A1 and US 2009 / 205969 A1.

[0005] EP 2 518 187 A1 teaches copper electroplating baths containing ruthenium-based levelers. These leveler additives in acidic copper electroplating baths are not suitable to meet current and future requirements for the manufacture of advanced printed circuit boards, IC substrates and the metallization of semiconductor and glass substrates. Depending on the circuit layout, BMVs in printed circuit boards and IC substrates have to be completely filled with copper rather than just conformally filled. Typical requirements for BMV filling are, for example: obtaining a completely filled BMV while depositing no more than 10 to 15 pm of copper on adjacent flat substrate areas, and while creating no more than 0 to 10 pm of a crater on the outer surface of the filled BMV.

[0006] In the metallization of semiconductor wafers, TSV filling has to result in a complete and void-free filling with copper while creating no more than 1 / 5 of the via diameter of overplated copper on adjacent flat areas. Similar requirements apply for the filling of glass vias with copper.

[0007] OBJECTIVE OF THE INVENTION

[0008] It is therefore an object of the present invention to provide an aqueous acidic copper electroplating bath for the electrolytic deposition of copper or copper alloys which meets the requirements of the above mentioned applications, in particular in the field of printed circuit board and / or IC substrate manufacturing, and more particularly in the metallization of semiconductor substrates, such as TSV filling, dual damascene plating, deposition of redistribution layers or pillar bumping and / or filling of glass vias. SUMMARY

[0009] It is an object of the present invention to solve the above mentioned problems with an aqueous acidic copper electroplating bath comprising a source of copper ions, an acid and at least one ureylene-based polymer selected from the group consisting of polymers according to formula (I), (II) and / or (III):

[0010]

[0011]

[0012]

[0013] wherein

[0014] n denotes an integer, preferably from 1 to 40, more preferably from 1 to 10, and

[0015] A denotes a unit derived from a diamino compound of formula (IV), (V), (VI) and / or (VII)

[0016]

[0017]

[0018]

[0019]

[0020] wherein

[0021] R1, R2, R5, R6are independently selected from the group consisting of substituted or unsubstituted hydrocarbon residues having 1 to 10 carbon atoms, preferably methyl, ethyl, hydroxyethyl, or -CH2CH2(OCH2CH2) a -OH, wherein a is an integer from 0 to 4, preferably from 1 to 4, and

[0022] R3, R4are independently selected from the group consisting of (CH2) p groups, wherein p is an integer from 2 to 12, preferably ethylene or propylene, or -[CH2CH2O] m -CH2CH2- groups, wherein m is an integer from 1 to 40, preferably -(CH2)2-O-(CH2)2- or -(CH2)2-O(CH2)2-O-(CH2)2- groups,

[0023] Z can be the same or different and denotes O or S, preferably Z is the same, most preferably Z is O,

[0024] x and y are integers, which can be the same or different, and are preferably integers selected from 1, 2 and 3, more preferably both x and y are 2,

[0025] R7and R8are independently selected from the group of (CH2) p wherein p is an integer from 1 to 12, preferably methylene, ethylene or propylene or -[CH2CH2O] m -CH2CH2- groups, wherein m is an integer from 1 to 40, preferably -(CH2)2-O-(CH2)2- or -(CH2)2-O(CH2)2-O-(CH2)2- groups,

[0026] R7, R8in formula VII can be meta or para bound to the nitrogen atom comprised in the pyridine ring relative to the pyridine moiety,

[0027] the single units A can be the same or different,

[0028] wherein B and B' denote units derived from compounds of the following formula (VIII), (IX), (X) or (XI):

[0029]

[0030]

[0031]

[0032]

[0033] wherein

[0034] R5, R6are independently selected from the group consisting of substituted or unsubstituted hydrocarbon residues having 1 to 10 carbon atoms, preferably methyl, ethyl, hydroxyethyl or -CH2CH2(OCH2CH2) a -OH, wherein a is an integer from 0 to 4, and

[0035] R3is selected from the group of (CH2) p wherein p is an integer from 2 to 12, preferably ethylene or propylene or -[CH2CH2O] m -CH2CH2- groups, wherein m is an integer from 1 to 40, preferably -(CH2)2-O-(CH2)2- or -(CH2)2-O(CH2)2-O-(CH2)2- groups,

[0036] Z denotes O or S, preferably Z is O,

[0037] x is an integer, preferably an integer selected from 1, 2 and 3, more preferably x is 2,

[0038] R7is selected from the group (CH2) p wherein p is an integer from 1 to 12, preferably methylene, ethylene or propylene or -[CH2CH2O] m -CH2CH2- group, wherein m is an integer from 1 to 40, preferably a -(CH2)2-0-(CH2)2- or -(CH2)2-0(CH2)2-0-(CH2)2- group, wherein R7in formula XI can be bound meta or para to the nitrogen atom comprised by the pyridine ring relative to the pyridine moiety,

[0039] R9is selected from the group consisting of hydrogen, a linear or branched, substituted or unsubstituted hydrocarbon residue having 1 to 10 carbon atoms, preferably an alkyl group, more preferably a methyl, ethyl, propyl, butyl, pentyl, hexyl, octyl, hydroxyethyl group, a -OR10and -CH2CH2(OCH2CH2) a -(OCH2CHCH3) b -OR10, wherein a is an integer from 0 to 10 and b is an integer from 0 to 10 and R10is selected from the group consisting of a linear or branched, substituted or unsubstituted hydrocarbon residue having 1 to 10 carbon atoms, preferably a methyl, ethyl, propyl, butyl, pentyl, hexyl, octyl, hydroxyethyl group,

[0040] or wherein R9and / or R10is selected from the group consisting of an aryl or alkylaryl residue, which can be substituted or unsubstituted, preferably a substituted or unsubstituted phenyl or benzyl group, and which can contain one or more heteroatoms, preferably N, S or O,

[0041] wherein the single units B can be the same or different, and

[0042] wherein B and B’ are different,

[0043] wherein L is a divalent unit selected from the group consisting of:

[0044] -R 11 - XII

[0045]

[0046] wherein

[0047] R11is selected from the group consisting of an alkylene-(CH2) c -, wherein c is an integer from 2 to 10, preferably from 2 to 6, and a xylyl group,

[0048] each R12 is independently selected from the group consisting of hydrogen, alkyl, aryl, alkylaryl,

[0049] M is an integer from 0 to 3, φ is an integer in the range of 1 to 100, and K is an integer in the range of 1 to 3,

[0050] wherein the single units L can be the same or different.

[0051] Recess structures such as trenches, blind micro vias (BMV), through silicon vias (TSV) and through glass vias can be filled with copper deposited from the aqueous acidic copper electroplating bath according to the present application. The copper filled recess structures are preferably void free, or at least contain less voids, and have an acceptable pit, that is to say a flat or almost flat surface. Furthermore, the building of pillar bump structures is feasible.

[0052] With the urethine polymers of the present application a uniform reaction product is obtained, in principle, hydrophobic groups such as hexyl or aromatic groups can also be introduced at both ends of the polymer or oligomer. This has shown to be beneficial in the copper plating examples shown, especially preferred for filling BMV. DETAILED DESCRIPTION

[0053] In the following description, the "urethine polymer" is also referred to as "polymer".

[0054] The polymer according to formula (I) has a unit B at one end of the polymer chain, the polymer according to formula (II) has a unit B at both ends of the polymer chain and the polymer according to formula (III) has a unit B at one end of the polymer chain and a unit B' at the other end of the polymer chain, wherein B and B' are selected from compounds of formula (VIII), (IX), (X) or (XI) and wherein B and B' are different.

[0055] Since both B and B' represent a unit derived from a compound of formula (VIII), (IX), (X) or (XI), a polymer having B' at both ends is equivalent to a polymer having B at both ends, i.e. a polymer according to formula (II).

[0056] If one or more of R1, R2, R5 or R6 is substituted by a hydrocarbon residue, it is preferably substituted by a C1-C6 alkyl group (straight chain or branched, preferably -CH3, -CH2CH3), an aryl group (preferably phenyl) or an aralkyl group (preferably benzyl).

[0057] In a preferred embodiment, R1, R2, R5 and R6 in formula (IV) are independently selected from the group consisting of methyl, ethyl, hydroxyethyl and -CH2CH2(OCH2CH2) a -OH, wherein a is an integer from 1 to 4.

[0058] In a preferred embodiment, R5and R6in formula (VIII) are independently selected from the group consisting of methyl, ethyl, hydroxyethyl and -CH2CH2(OCH2CH2) a -OH, wherein a is an integer from 1 to 4.

[0059] In a preferred embodiment, R3and R4in formula (IV), (V) and / or (VI) are independently selected from the group consisting of ethylene, propylene, -(CH2)2-0-(CH2)2- and -(CH2)2-0-(CH2)2-0-(CH2)2-.

[0060] In a preferred embodiment, R3in formula (VIII), (IX) and / or (X) is selected from the group consisting of ethylene, propylene, -(CH2)2-0-(CH2)2- and -(CH2)2-0-(CH2)2-0-(CH2)2-.

[0061] In a preferred embodiment, R7and R8in formula (VII) are independently selected from the group consisting of methylene, ethylene, propylene, a -(CH2)2-0-(CH2)2- group or a -(CH2)2-0-(CH2)2-0-(CH2)2- group.

[0062] In a preferred embodiment, R7in formula (XI) is selected from the group consisting of methylene, ethylene, propylene, a -(CH2)2-0-(CH2)2- group or a -(CH2)2-0-(CH2)2-0-(CH2)2- group.

[0063] In a preferred embodiment, R9and / or R10in formula (VIII), (IX), (X) and / or (XI) are independently selected from methyl, ethyl, propyl, butyl, pentyl, hexyl, octyl, wherein R9and / or R10may be straight-chained or, if possible, branched, hydroxyethyl, phenyl or benzyl.

[0064] The term "polymer" must be understood in a broad sense in connection with the present application. It comprises any compound of formula (I), (II) or (III) wherein n = 1.

[0065] The term "polymer" does indeed comprise compounds which are designated as oligomers, in particular, for example compounds of formula (I), (II) or (III) wherein n is from 1 to 5.

[0066] The ureylene-based polymers of formula (I), (II) and (III) can be obtained by reacting one or more diamino compounds of formula (IV), (V), (VI) and / or (VII) with one or more compounds of formula (XIIa) or (XIIIa) below,

[0067] LG-R 11 -LG XIIa

[0068]

[0069] wherein LG in formula XIIa or formula XIIIa can be the same or different and is a leaving group which can be displaced in a substitution reaction by the N atom of a compound of formula (IV), (V), (VI) or (VII), or by the N atom of a compound of formula (VIII), (IX), (X) or (XI). In this substitution reaction, a polymer of formula (I), (II) and / or (III) is formed.

[0070] In the polymer, the linkage between unit A and L, or B and L (or B' and L) occurs via a fourth ammonium group which is formed by connecting the bivalent residue L with a third amino group of a compound of formula (IV), (V), (VIII) or (IX),

[0071] or via an imidazolyl moiety,

[0072]

[0073] said imidazolyl moiety is formed by connecting the bivalent residue L with a third amino group of a compound of formula (VI) or (X),

[0074] or via a pyridyl moiety,

[0075]

[0076] said pyridyl moiety is formed by connecting the bivalent residue L with a nitrogen in the pyridyl ring of a compound of formula (VII) or (XI).

[0077] The polymer is a positively charged ureylenic polymer and the counter ion LG- is present.

[0078] Preferably, LG is selected from halogen or pseudohalogen, preferably from mesylate, triflate, nonaflate, alkylsulfonate, e.g. mesylate, arylsulfonate, tosylate or halide (preferably CI or Br).

[0079] The class of the obtained polymer can be controlled mainly by the following parameters:

[0080] i) the molar ratio (n A ) of the total amount of the substance (precursor of unit A in the polymer) of formula (IV), (V), (VI) and / or (VII) to the total amount of the substance (precursor of unit L in the polymer) of formula (XIIa) and / or (XIIIa) (n L ) and An L ) to the total amount of the substance (precursor of (terminal) unit B or B' in the polymer) of the compound of formula (VIII), (IX), (X) or (XI) (n

[0081] ii) the molar ratio (n A ) of the total amount of the substance (precursor of unit A in the polymer) of the compound of formula (IV), (V), (VI) and / or (VII) (n B ) to the total amount of the substance (precursor of (terminal) unit B or B' in the polymer) of the compound of formula (VIII), (IX), (X) or (XI) (n A :n B ) to the total amount of the substance (precursor of (terminal) unit B or B' in the polymer) of the compound of formula (VIII), (IX), (X) or (XI) (n

[0082] iii) when at least two of the compounds of formula (VIII), (IX), (X) or (XI) are selected: the molar ratio (n B ) of the first compound of formula (IV), (V), (VI) or (VII) (n B’ ) to the second compound of formula (IV), (V), (VI) or (VII) (n B :n B’ ) wherein the second compound is different from the first compound.

[0083] Parameter i) influences, for example, the (average) chain length and the (average) molar mass of the polymer, or the structure of the intermediate polymer as shown below.

[0084] Parameter ii) influences, for example, the ratio between polymer (I) and polymer (II). The higher n B , the more polymer (II) is formed. A

[0085] Parameter iii) influences, for example, the ratio between polymer (II) and polymer (III). The relationship n B’ equal to n B facilitates the formation of polymer (III).

[0086] In the process for producing a polymer, the molar ratio (n A ) of the total amount of the substance (precursor of unit A in the polymer) of the compound of formula (IV), (V), (VI) and / or (VII) (n L ) to the total amount of the substance (precursor of (terminal) unit B or B' in the polymer) of the compound of formula (XIIa) and / or (XIIIa) (n A :n L ) is preferably in the range of 1 :2 to 1 :1.

[0087] In the process for producing a polymer, the molar ratio (n A ​) with a total amount (n B ) of the compound of formula (XIIa) and / or (XIIIa) in a molar ratio (n A :n B ) preferably in the range of 1 : 1 to 3 : 1.

[0088] When adding (for example) the compound of formula (IV), (V), (VI) and / or (VII) (precursor of unit A) and the compound of formula (VIII), (IX), (X) or (XI) (precursor of unit B, B') to the compound of formula (XIIa) and / or (XIIIa) (or vice versa, as shown in the examples), these molar ratios are preferably used in a non-sequential process.

[0089] These processes for obtaining the polymers (I), (II) and (III) are not to be understood as exhaustive. For example, a sequential process is possible, wherein in a first step, an intermediate polymer consisting of units A and L is formed, and in a second step, this intermediate polymer is reacted with B, or with B and B'.

[0090] The ureylene polymer of formula (I) can be obtained by reacting one or more diaminic compounds of formula (IV), (V), (VI) and / or (VII) (molar amount n A ) with one or more compounds of formula (XIIa) and / or (XIIIa) (molar amount n L ), wherein the compound of formula (IV), (V), (VI) and / or (VII) is used in a total amount (n A ) of the compound of formula (XIIa) and / or (XIIIa) in a molar ratio (n L :n A :n L ) of 1 : 1. The obtained intermediate polymer has the formula (XIV), wherein n denotes an integer, preferably 1 to 40, more preferably 1 to 10.

[0091]

[0092] The ureylene polymer according to formula (II) is further reacted with a compound according to formula (VIII), (IX), (X) or (XI) to obtain a ureylene polymer according to formula (I).

[0093] The ureylene polymer according to formula (II) can be obtained by reacting one or more diaminic compounds of formula (IV), (V), (VI) and / or (VII) (molar amount n A ) with one or more compounds of formula (XIIa) and / or (XIIIa) (molar amount n L) of the total amount of substance (n A ) of the compounds of formula (XIIa) and / or (XIIIa) is at least 1 : 1.1, more preferably at least 1 : 1.3, and most preferably at least 1 : 1.5. The intermediate polymer obtained has the formula (XV), wherein n denotes an integer, preferably 1 to 40, more preferably 1 to 10. L ) of the total amount of substance (n A :n L ) of the total amount of substance (n

[0094]

[0095] The intermediate uretdione polymer according to formula (XV) is further reacted with one compound according to formula (VIII), (IX), (X) or (XI) to obtain a uretdione polymer according to formula (II), or with two different compounds according to formula (VIII), (IX), (X) or (XI) to obtain a uretdione polymer according to formula (III).

[0096] The uretdione polymers of formula (I), (II) and (III) preferably have a weight average molecular weight Mw W .

[0097] The reaction for forming the uretdione polymer can preferably be carried out in an aqueous or aqueous-alcoholic solution or in a solvent-free substance at a temperature of preferably 20 to 100 °C.

[0098] The uretdione polymers of formula (I), (II) and (III) preferably do not contain any organically bound halogen, such as covalent C-Cl moieties.

[0099] The concentration of the at least one uretdione polymer according to formula (I), (II) and / or (III) in the aqueous acidic copper electroplating bath is preferably in the range of 0.001 mg / l to 200 mg / l, more preferably 0.005 mg / l to 100 mg / l and most preferably 0.01 mg / l to 50 mg / l.

[0100] The term acidic means a pH value below 7. The aqueous acidic copper electroplating bath preferably has a pH value of < 2, more preferably < 1.

[0101] The aqueous acidic copper electroplating bath further contains at least one source of copper ions, which is preferably selected from the group comprising copper sulfate and copper alkylsulfonate (e.g. copper methanesulfonate). The concentration of copper ions in the aqueous acidic copper electroplating bath is preferably in the range of 4 g / l to 90 g / l.

[0102] The aqueous acidic copper electroplating bath further contains at least one acid source, which is preferably selected from the group comprising sulfuric acid, fluoroboric acid, phosphoric acid and methanesulfonic acid, and is preferably added in a concentration of 10 g / l to 400 g / l, more preferably 20 g / l to 300 g / l.

[0103] The aqueous acidic copper electroplating bath preferably further contains at least one accelerator-brightener additive selected from the group consisting of organic thiol-, sulfide-, disulfide- and polysulfide-compounds. Preferred accelerator-brightener additives are selected from the group comprising 3-(benzothiazol-2-yl-sulfanyl)-propylsulfonic acid, 3- mercaptopropane-1 -sulfonic acid, ethylenedithiodipropylsulfonic acid, bis-(p-sulfophenyl)- disulfide, bis-(ω-sulfobutyl)-disulfide, bis-(ω-sulfohydroxypropyl)-disulfide, bis-(ω- sulfopropyl)-disulfide, bis-(ω-sulfopropyl)-sulfide, methyl-(ω-sulfopropyl)-disulfide, methyl-(ω-sulfopropyl)-trisulfide, O-ethyl-dithiocarbonic acid-S-(ω-sulfopropyl)-ester, mercaptoacetic acid, thiophosphonic acid-O-ethyl-bis-(ω-sulfopropyl)-ester, thiophosphonic acid- para-(ω-sulfopropyl)-ester and their corresponding salts. The concentration of all accelerator- brightener additives optionally present in the aqueous acidic copper bath is preferably in the range of 0.01 mg / l to 100 mg / l, more preferably 0.05 mg / l to 10 mg / l.

[0104] The aqueous acidic copper electroplating bath optionally further contains at least one carrier-inhibitor additive, which is preferably selected from the group comprising polyvinyl alcohol, carboxymethyl cellulose, polyethylene glycol, polypropylene glycol, polyethylene glycol stearate, alkoxylated naphthol, polyethylene glycol oleate, polyethylene glycol stearyl ether, polyethylene glycol nonylphenyl ether, octyl polyalkylene glycol ether, octyldiol-bis-(polyalkylene glycol ether), poly(ethylene glycol-random-propylene glycol), poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) and poly(propylene glycol)-block-poly(ethylene glycol)-block-poly(propylene glycol). More preferably, the optional carrier-inhibitor additive is selected from the group comprising polyethylene glycol, polypropylene glycol, poly(ethylene glycol-random-propylene glycol), poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) and poly(propylene glycol)-block-poly(ethylene glycol)-block-poly(propylene glycol). The concentration of the optional carrier-inhibitor additive is preferably in the range of 0.005 g / l to 20 g / l, more preferably 0.01 g / l to 5 g / l.

[0105] Optionally, the aqueous acidic copper electroplating bath contains, in addition to the urethine polymer according to formula (I), (II) or (III), at least one further leveler additive selected from the group comprising nitrogen-containing organic compounds (such as polyethyleneimine, alkoxylated polyethyleneimine, alkoxylated lactams and polymers thereof, diethylenetriamine and hexamethylenetetramine), organic dyes (such as Genasol green B, Bismarck brown Y and acid violet 7), sulfur-containing amino acids (such as cysteine, phenazinium salts and derivatives thereof). The preferred further leveler additive is selected from nitrogen-containing organic compounds. The optional leveler additive is added to the aqueous acidic copper electroplating bath in an amount of 0.1 mg / l to 100 mg / l.

[0106] The aqueous acidic copper electroplating bath optionally further contains at least one halide source or halide, preferably chloride, in an amount of preferably 20 mg / l to 200 mg / l, more preferably 30 mg / l to 60 mg / l. Suitable halide sources are, for example, alkali halides, such as sodium chloride.

[0107] When the counter ion is a halide, the optional halide can be provided alone or in part by the urethine polymer according to formula (I), (II) or (III).

[0108] In another aspect, the present invention provides a method for depositing copper on a substrate, comprising the following steps in this order:

[0109] a. providing a substrate, and

[0110] b. contacting the substrate with an aqueous acidic copper electroplating bath as described before,

[0111] c. applying an electric current between the substrate and at least one anode,

[0112] and thereby depositing copper on the substrate.

[0113] The substrate can be selected from the group comprising printed circuit boards, IC substrates, semiconductor wafers and glass substrates.

[0114] The copper can be deposited within a recessed structure selected from the group comprising trenches, blind micro-vias, through-silicon vias and through-glass vias.

[0115] The aqueous acidic copper electroplating bath is preferably operated in a temperature range of 15 °C to 50 °C, more preferably in a temperature range of 25 °C to 40 °C, by applying an electric current to the substrate and at least one anode according to the method of the present invention. Preferably, a cathodic current density in the range of 0.0005 A / dm 2 to 12 A / dm 2 , more preferably 0.001 A / dm 2 to 7 A / dm 2 is applied.

[0116] The electroplating bath according to the present application can be used for DC electroplating and reverse pulse electroplating. Both inert and soluble anodes can be utilized when depositing copper from the electroplating bath according to the present application.

[0117] In one embodiment of the present application, a redox couple (e.g. Fe 2+ / 3+ ions) is added to the electroplating bath. This redox couple is particularly useful if reverse pulse electroplating is combined with an inert anode for copper deposition. Suitable processes for copper plating using a redox couple in combination with reverse pulse electroplating and an inert anode are disclosed, for example, in US 5,976,341 and US 6,099,711.

[0118] The aqueous acidic copper electroplating bath according to the present application can be used in conventional vertical or horizontal electroplating equipment.

[0119] The aqueous acidic copper electroplating bath according to the present application is essentially free of zinc ions. "Essentially free" is defined herein as "not intentionally added". "Not intentionally added" means that the bath does not contain zinc ions, but can contain very small amounts of zinc ions inserted as contamination. Thus, the aqueous acidic copper electroplating bath according to the present application does contain less than 2 ppm zinc ions, preferably less than 0.5 ppm zinc ions, or does not contain zinc ions.

[0120] The metal layer obtained by electroplating from the aqueous acidic copper electroplating bath is a copper or copper alloy layer. Thus, because the bath does not contain zinc ions, a zinc and zinc alloy layer cannot be obtained from the aqueous acidic copper electroplating bath.

[0121] The present application will now be illustrated by reference to the following non-limiting examples.

[0122] Example

[0123] The weight average molecular weight Mw of the ureylene polymers W was determined by gel permeation chromatography (GPC) using a GPC device from SECurity GPC system PSS equipped with a RI sensor and an Agilent 1260 pump, Tosoh TSK 2500+3000 columns, and M W = 400 to 40000 g / mol Pullulan and PEG standards. The solvent used was Millipore water with 0.5% acetic acid and 0.1 M Na2S04.

[0124] 1. Preparation of urethine polymers

[0125] 1.1 Manufacturing Example 1

[0126] Dissolve 23.04 g (100 mmol) of 1,3-bis(3-(dimethylaminopropyl)urea and 4.84 g (33.33 mmol) of 1-(3-(dimethylaminopropyl)urea in 61 mL of distilled water and dissolve and heat to 80°C over 10 minutes. After a clear solution is obtained, add 32.2 g (100 mmol) of triethylene glycol dimethanesulfonate dropwise over one hour and stir the mixture at 80°C for 10 hours. Then cool the reaction mixture to 25°C.

[0127] 1.2 Manufacturing Example 2

[0128] Dissolve 5.61 g (33.33 mmol) of 1-(3-(1H-imidazol-1-yl)propylurea and 27.63 g (100 mmol) of 1,3-bis(3-(1H-imidazol-1-yl)propylurea in 67 mL of distilled water and heat to 80°C over 10 minutes. After a clear solution is obtained, add 32.2 g (100 mmol) of triethylene glycol dimethanesulfonate dropwise over 43 minutes and stir the mixture at 80°C for an additional 93 hours. Then stir and cool the reaction mixture to 25°C.

[0129] Obtain 127.8 g of an orange polymer solution in water (48.3 wt%) (Mw = 1150 Da).

[0130] 1.3 Manufacturing Example 3

[0131] Dissolve 2.52 g (16.67 mmol) of 1-(pyridin-3-ylmethyl)urea and 12.11 g (50 mmol) of 1,3-bis(pyridin-3-ylmethyl)urea in 29 mL of distilled water and heat to 80°C over 10 minutes. After a clear solution is obtained, add 16.12 g (50 mmol) of triethylene glycol dimethanesulfonate dropwise over 7 minutes and stir the mixture at 80°C for an additional 20 hours. Then cool the reaction mixture to 25°C.

[0132] Obtain 60 g of an orange polymer solution in water (51.8 wt%) (Mw = 1580 Da).

[0133] 1.4 Manufacturing Example 4

[0134] Dissolve 13.79 g (59.9 mmol) of 1,3-bis(3-(dimethylaminopropyl)urea and 8.70 g (59.9 mmol) of 1-(3-(dimethylaminopropyl)urea in 47.3 mL of distilled water and heat to 80°C over 10 minutes. After a clear solution is obtained, add 29 g (90 mmol) of triethylene glycol dimethanesulfonate dropwise over one hour and stir the mixture at 80°C for 10 hours. Then cool the reaction mixture to 25°C.

[0135] A 100 g solution of the orange polymer in water (51.3 wt%) was obtained. (Mw = 1130 Da).

[0136] 1.5 Manufacturing Example 5

[0137] A 7.51 g (32.6 mmol) of 1,3-bis(3-(dimethylaminopropyl)urea and 2.49 g (10.87 mmol) of 1-(3-(dimethylaminopropyl)-3-hexylurea were dissolved in 20 mL of distilled water and heated to 80°C over 10 minutes. After a clear solution was obtained, 10.5 g (32.6 mmol) of triethylene glycol dimethanesulfonate was added dropwise over 32 minutes and the mixture was stirred at 80°C for 5 hours. The reaction mixture was then cooled to 25°C.

[0138] A 40 g solution of the orange polymer in water (49.9 wt%) was obtained. (Mw = 1510 Da).

[0139] 1.6 Manufacturing Example 6

[0140] A 7.55 g (32.8 mmol) of 1,3-bis(3-(dimethylaminopropyl)urea and 2.42 g (10.87 mmol) of 1-(3-(dimethylaminopropyl)-3-phenylurea were dissolved in 20 mL of distilled water and heated to 80°C over 10 minutes. After a clear solution was obtained, 10.6 g (32.8 mmol) of triethylene glycol dimethanesulfonate was added dropwise over 12 minutes and the mixture was stirred at 80°C for 5 hours. The reaction mixture was then cooled to 25°C.

[0141] A 40 g solution of the orange polymer in water (49.3 wt%) was obtained. (Mw = 1390 Da).

[0142] 1.7 Manufacturing Example 7

[0143] A 5.06 g (21.95 mmol) of 1,3-bis(3-(dimethylaminopropyl)urea and 4.86 g (21.95 mmol) of 1-(3-(dimethylaminopropyl)-3-phenylurea were dissolved in 20 mL of distilled water and heated to 80°C over 10 minutes. After a clear solution was obtained, 10.62 g (32.9 mmol) of triethylene glycol dimethanesulfonate was added dropwise over 9 minutes and the mixture was stirred at 80°C for 5 hours. The reaction mixture was then cooled to 25°C.

[0144] A 40 g solution of the orange polymer in water (47.9 wt%) was obtained. (Mw = 1250 Da).

[0145] 2. Application Examples

[0146] Equipment: A miniature distributor assembly with a volume of 2.5L, a pump-stirred bath, no air injection, and titanium anodes coated with iridium oxide.

[0147] Using a solution containing 60g / l Cu 2+ Ions (added as copper sulfate), 50 g / L sulfuric acid, 45 mg / L Cl - A copper plating bath stock solution containing ions, 300 mg / L polyethylene glycol as a carrier-inhibitor additive, and 1.0 ml / L of an organic brightener additive. A ureidyl polymer is added to the stock solution (Application Examples 1 to 6).

[0148] Apply 1.9A / dm throughout application instances 1 through 6 2 The current density was [value missing]. The average thickness of the copper plated on the top surface of the substrate was 15 μm. The plating time was 45 min. The test tray was cleaned and rinsed before copper plating.

[0149] The test discs used throughout Application Examples 1 through 6 comprised BMVs (depth x diameter: 70 x 75 μm and 70 x 100 μm). The dimensions of the test discs were 8.6 x 9.6 cm.

[0150] Comparison examples:

[0151] -Mirapol Solvay is a polymer derived from N,N'-bis[3-(dimethylamino)propyl]urea and 1,1'-oxybis[2-chloroethane].

[0152] Examples of this invention show that it is better than Mirapol Significantly better results, because the examples of the present invention result in pits with reduced depth.

[0153] The results are shown in the table below.

[0154] Table 1

[0155]

[0156] Table 2

[0157]

Claims

1. An aqueous acidic copper electroplating bath comprising a source of copper ions, an acid and at least one ureylenic polymer selected from the group consisting of polymers according to formula (I), (II) and / or (III): wherein n denotes an integer from 1 to 40, and A denotes a unit derived from a diamino compound of the following formula (IV), (V), (VI) and / or (VII): wherein Z can be the same or different and denotes O or S, x and y are integers and can be the same or different, the single units A can be the same or different, wherein B and B' denote a unit derived from a compound of the following formula (VIII), (IX), (X) or (XI): wherein Z denotes O or S, x is an integer, or wherein R9or R10is selected from the group consisting of aryl or alkylaryl residues, which can be substituted or unsubstituted, and which can contain one or more heteroatoms, wherein B and B' are different, wherein L is a divalent unit selected from the group consisting of: wherein each R12is independently from each other selected from the group consisting of hydrogen, alkyl, aryl, alkylaryl, M is an integer from 0 to 3, φ is an integer in the range of 1 to 100, and K is an integer in the range of 1 to 3, wherein the single units L can be the same or different one or more diamino compounds of formula (IV), (V), (VI) and / or (VII) are reacted with one or more compounds of the following formula (XIIa) or (XIIIa): wherein LG in formula XIIa or in formula Xllla can be the same or different and is a leaving group which can be displaced in a substitution reaction by a N atom of the compound of formula (IV), (V), (VI) or (VII), or a N atom of the compound of formula (VIII), (IX), (X) or (XI). and / or 3. The aqueous acidic copper electroplating bath according to any one of the preceding claims, wherein in formula (IV), (V) and / or (VI), R3and R4are independently selected from the group consisting of ethylene, propylene, -(CH2)2-0-(CH2)2- and -(CH2)2-0-(CH2)2-0-(CH2)2-, and / or wherein in formula (VIII), (IX) and / or (X), R3is selected from the group consisting of ethylene, propylene, -(CH2)2-0-(CH2)2- and -(CH2)2-0-(CH2)2-0-(CH2)2-. R1, R2, R5, R6are independently selected from the group consisting of substituted or unsubstituted hydrocarbon residues having 1 to 10 carbon atoms or -CH2CH2(OCH2CH2) a -OH, wherein a is an integer from 0 to 4, and R3, R4are independently selected from the group (CH2) p wherein p is an integer from 2 to 12, or -[CH2CH2O] m -CH2CH2- group, wherein m is an integer from 1 to 40, 4. The aqueous acidic copper electroplating bath according to claim 1 or 2, wherein in formula (VII), R7and R8are independently selected from the group consisting of methylene, ethylene, propylene, a -(CH2)2-0-(CH2)2- group or a -(CH2)2-0(CH2)2-0-(CH2)2- group, and / or R7and R8are independently selected from the group (CH2) p wherein p is an integer from 1 to 12, or -[CH2CH2O] m -CH2CH2- groups, wherein m is an integer from 1 to 40, wherein R7, R8in formula VII can be bound in meta or para position to the nitrogen atom comprised in the pyridyl moiety, wherein in formula (XI), R7is selected from the group consisting of methylene, ethylene, propylene, a -(CH2)2-0-(CH2)2- group or a -(CH2)2-0(CH2)2-0-(CH2)2- group. ​ ​ R5, R6are independently selected from the group consisting of substituted or unsubstituted hydrocarbon residues having 1 to 10 carbon atoms, and -CH2CH2(OCH2CH2) a -OH, wherein a is an integer from 0 to 4, and R3is selected from the group (CH2) p wherein p is an integer from 2 to 12, or -[CH2CH2O] m -CH2CH2- group, wherein m is an integer from 1 to 40, ​ ​ R7is selected from the group (CH2) p wherein p is an integer from 1 to 12, or -[CH2CH2O] m -CH2CH2- group, wherein m is an integer from 1 to 40, wherein R7in formula XI can be bound meta or para to the nitrogen atom comprised in the pyridyl moiety, R9is selected from the group consisting of hydrogen, a straight-chained or branched substituted or unsubstituted hydrocarbon residue having 1 to 10 carbon atoms, -CH2CH2(OCH2CH2) a -OR10and -CH2CH2(OCH2CH2) a -(OCH2CHCH3) b -OR10, wherein a is an integer from 0 to 10 and b is an integer from 0 to 10 and R10is a radical selected from straight-chained or branched substituted or unsubstituted hydrocarbon residues having 1 to 10 carbon atoms, ​ ​ ​ - R 11 - XII ​ R11is selected from the group consisting of alkylene-(CH2) c - wherein c is an integer from 2 to 10, and a xylyl group, ​ ​ ​ LG-R 11 —LG XIIa ​ 2. The aqueous acidic copper electroplating bath of claim 1, wherein in formula (IV), R1, R2, R5, and R6 are independently selected from the group consisting of methyl, ethyl, hydroxyethyl, and -CH2CH2(OCH2CH2) a -OH, wherein a is an integer from 1 to 4. ​ wherein in formula (VIII), R5and R6are independently selected from the group consisting of methyl, ethyl, hydroxyethyl, and -CH2CH2(OCH2CH2) a -OH, wherein a is an integer from 1 to 4. ​ ​ ​ ​ ​ ​ 5. The aqueous acidic copper electroplating bath according to claim 1 or 2, wherein in formula (VIII), (IX), (X) and / or (XI), R9and / or R10are independently selected from methyl, ethyl, propyl, butyl, pentyl, hexyl, octyl, hydroxyethyl, phenyl or benzyl.

6. The aqueous acidic copper electroplating bath according to claim 1 or 2, wherein the urethmyl-based polymer according to formula (I), (II) and (III) does not have covalently C-bound halogen.

7. The aqueous acidic copper electroplating bath according to claim 1 or 2, wherein the aqueous acidic copper electroplating bath is essentially free of zinc ions.

8. The aqueous acidic copper electroplating bath of claim 1 or 2, wherein the urethmylene polymer of formula (I), (II) and (III) has a weight average molecular weight Mw in the range of 1000 to 20000 Da W .

9. The aqueous acidic copper electroplating bath according to claim 1 or 2, wherein the concentration of the urethmyl-based polymer according to formula (I), (II) and / or (III) is in the range of 0.001 mg / l to 200 mg / l.

10. The aqueous acidic copper electroplating bath according to claim 1 or 2, wherein the aqueous acidic copper electroplating bath further comprises a halide source or halide ions.

11. The aqueous acidic copper electroplating bath according to claim 10, wherein the concentration of halide ions is in the range of 20 mg / l to 200 mg / l.

12. The aqueous acidic copper electroplating bath according to claim 1 or 2, wherein the aqueous acidic copper electroplating bath further comprises an accelerator-brightener additive selected from the group comprising organic mercapto-, sulfido-, disulfido- and polysulfido-compounds.

13. A method for depositing copper on a substrate, comprising the following steps in this order: a. providing a substrate, and b. contacting the substrate with an aqueous acidic copper electroplating bath according to any one of claims 1 to 12, c. applying an electric current between the substrate and at least one anode, and thereby depositing copper on the substrate.

14. The method for depositing copper on a substrate according to claim 13, wherein the substrate is selected from the group comprising printed circuit boards, IC substrates, semiconductor wafers and glass substrates.

15. The method for depositing copper on a substrate according to claim 13 or 14, wherein copper is deposited within a recessed structure selected from the group comprising trenches, blind micro-vias, through-silicon-vias and through-glass-vias.

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