Composition for cobalt or cobalt alloy electroplating

Abstract

The present invention relates to a cobalt electroplating composition comprising (a) cobalt ions, (b) an ammonium compound of formula (NR1R2R3H +) n Xn-wherein R1, R2, R3 are independently selected from H and a linear or branched C1 to C6 alkyl group, X is selected from an n-valent inorganic or organic counter ion, n is an integer selected from 1, 2 or 3.

Description

[0001] This application is a divisional application of patent application with application number 201980033847.0. The application date of the original application is April 5, 2019, and the name of the invention is “Composition for cobalt or cobalt alloy electroplating”.

[0002] The present invention relates to compositions for electroplating of cobalt or cobalt alloys. Background of the Invention

[0004] Filling small features, such as vias and trenches, by metal electroplating is an essential component of the semiconductor manufacturing process. It is well known that the presence of organic substances as additives in the electroplating bath is crucial to achieve uniform metal deposition on the substrate surface and avoid defects within the metal lines, such as voids and seams.

[0005] Filling interconnects with copper becomes particularly challenging as the aperture size of recessed features such as vias or trenches decreases further, also because depositing copper seeds by physical vapor deposition (PVD) prior to copper electrodeposition can exhibit non-uniformity and non-conformality and thus further reduce the aperture size, particularly at the top of the hole. In addition, there is increasing interest in replacing copper with cobalt, as cobalt exhibits less electromigration into the electrolyte.

[0006] WO 2017 / 004424 discloses a composition for electroplating cobalt into interconnect features, comprising an acetylenic inhibitor compound and preferably a buffer. The preferred buffer is boric acid. The only example also comprises boric acid.

[0007] DE 10 2014 019753 A1 discloses a boric acid-free nickel electroplating bath which contains ammonium chloride.

[0008] JP 62-103387A discloses an electroplating bath for depositing metals such as Ni, Co, Fe, etc., which contains a buffer. The Co composition in Example 10 contains citrate as a buffer.

[0009] On the other hand, cobalt may also replace copper in other applications such as under bump metallization. In this case much larger structures containing micrometer-scale aperture sizes are used. In this application, in addition to no void filling, it is particularly important that all features are equally filled with cobalt so that all bumps on which solder is to be deposited exhibit substantially the same height.

[0010] One disadvantage of existing cobalt electrodeposition baths is the significant inhomogeneity of the electrodeposited cobalt layer.

[0011] There remains a great need for a cobalt electroplating bath that provides substantially planarity over fill features in addition to void-free fill of submicron-scale interconnects. There is also a great need for a cobalt electroplating bath that provides cobalt under-bump metallization that exhibits low non-uniformity over fill features.

[0012] It is therefore an object of the present invention to provide a composition useful for cobalt electrodeposition which improves the non-uniformity of cobalt deposition on a wafer. SUMMARY OF THE INVENTION

[0014] It has been discovered that it is possible to reduce non-uniformity in cobalt electroplating compositions using specific ammonium compounds as described below, particularly if applied to substrates containing micron-sized solder bump features.

[0015] Therefore, the present invention provides a composition comprising

[0016] (a) cobalt ions,

[0017] (b) Formula (NR 1 R 2 R 3 H + ) n X n- Ammonium compounds

[0018] in

[0019] R 1 , R 2 , R 3 independently selected from H and straight or branched C1 to C6 alkyl,

[0020] X is selected from n-valent inorganic or organic counterions,

[0021] n is an integer selected from 1, 2 or 3.

[0022] The invention further relates to the use of a metal electroplating composition as defined herein for depositing cobalt into interconnect features or for providing cobalt under-bump metallization.

[0023] The present invention further relates to a method for depositing a cobalt-containing layer on a substrate, the substrate comprising features having pore sizes ranging from 1 nanometer to 100 micrometers, the method comprising:

[0024] a) contacting a composition as defined herein with a substrate, and

[0025] b) applying a current density to the substrate for a period of time sufficient to deposit a metal layer onto the substrate.

[0026] By using the ammonium compounds according to the invention, the non-uniformity of cobalt deposition on the wafer is significantly improved. Another advantage of the present invention is that by using the ammonium compounds described herein, the use of boric acid is avoided, which is a huge advantage from health, safety and environmental reasons. Therefore, another object of the present invention is to provide a composition that can be used for cobalt electrodeposition without boric acid. DETAILED DESCRIPTION OF THE INVENTION

[0028] The composition according to the invention comprises cobalt ions, and an ammonium compound as described below.

[0029] Ammonium compounds

[0030] The cobalt or cobalt alloy electroplating composition comprises the formula (NR 1 R 2 R 3 H + ) n X n- of ammonium compounds.

[0031] In this paper, R 1 , R 2 and R 3 is independently selected from H, linear or branched C1 to C6 alkyl. 1 , R 2 and R 3 R is independently selected from H and straight or branched C1 to C4 alkyl, in particular methyl and ethyl. 1 , R 2 and R 3 At least one of is H, and even more preferably, R 1 , R 2 and R 3 At least two of are H. Most preferably, R 1 , R 2 and R 3 It's H.

[0032] X is an n-valent inorganic or organic counterion. Typical inorganic counterions are, but are not limited to, chloride, sulfate (including hydrogen sulfate), phosphate (including hydrogen phosphate and dihydrogen phosphate) and nitrate. Typical organic counterions are, but are not limited to, C1 to C6 alkyl sulfonate, preferably methane sulfonate, C1 to C6 carboxylate, preferably acetate or citrate, phosphonate, sulfamate, etc. Inorganic counterions are preferred. Chloride is the most preferred counterion X because the non-uniformity of cobalt deposition on the wafer can be further improved by using chloride in combination with ammonium cations.

[0033] n is an integer selected from 1, 2 or 3, depending on the valency of the counterion. For example, for chloride and hydrogen sulfate, n is 1, for sulfate or hydrogen phosphate, n is 2, and for phosphate, n is 3.

[0034] Preferred ammonium compounds are ammonium sulfate, ammonium chloride or ammonium methanesulfonate.

[0035] Depending on the pH of the composition, the amine compound may be fully or partially protonated or deprotonated.

[0036] The cobalt or cobalt alloy electroplating composition preferably contains substantially no boric acid. As used herein, "substantially no boric acid" means that the boric acid content is less than 0.1 g / l, preferably less than 100 mass ppm, and most preferably the boric acid content is below the detection limit.

[0037] Inhibitors

[0038] The electroplating composition may further comprise one or more inhibiting agents, also referred to as suppressors.

[0039] Without limitation, typical inhibitors are selected from the group consisting of carboxymethyl cellulose, nonylphenol polyglycol ether, polyethylene glycol dimethyl ether, octanol bis(polyalkylene glycol ether), octanol polyalkylene glycol ether, oleic acid polyglycol esters, polyethylene propylene glycol, polyethylene glycol, polyethyleneimine, polyethylene glycol dimethyl ether, polyoxypropylene glycol, polypropylene glycol, polyvinyl alcohol, stearic acid polyglycol esters, stearyl alcohol polyglycol ethers, polyethylene oxide, ethylene oxide-propylene oxide copolymers, butanol-ethylene oxide-propylene oxide copolymers, 2-mercapto-5-benzimidazole sulfonic acid, 2-mercaptobenzimidazole (MBI), benzotriazole, and combinations thereof.

[0040] In some embodiments, the inhibitor includes one or more nitrogen atoms, such as an amine group or an imine group. In some embodiments, the inhibitor is a polymeric or oligomeric compound containing amine groups separated by carbon aliphatic spacers such as CH2CH2 or CH2CH2CH2. In a specific embodiment, the inhibitor is polyethyleneimine (PEI, also known as polyethylenimine, poly[imino(1,2-ethylenediyl)] or poly(iminoethylene)). As shown in the experimental results included herein, PEI has shown excellent bottom-up filling properties in the case of cobalt deposition.

[0041] Particularly preferred inhibitors are those of formula I

[0042] R1-≡-R2 (S1)

[0043] To fill pores having nanometer or micrometer sizes, in particular pore sizes of 100 nanometers or less, 20 nm or less, 15 nm or less, or even 7 nm or less.

[0044] In this paper, R 1 is selected from XY, wherein X is selected from a linear or branched C1 to C 10Alkanediyl, straight or branched C2 to C 10 Alkenyl, linear or branched C2 to C 10 Alkynediyl and (C2H3R 6 -O) m m is an integer selected from 1 to 30, preferably from 1 to 15, more preferably from 1 to 10, and most preferably from 1 to 5.

[0045] In a preferred embodiment, X is selected from a linear or branched C1 to C6 alkanediyl group, preferably from a C1 to C4 alkanediyl group.

[0046] In a preferred embodiment, X is selected from methanediyl, ethane-1,1-diyl and ethane-1,2-diyl. In a second preferred embodiment, X is selected from propane-1,1-diyl, butane-1,1-diyl, pentane-1,1-diyl and hexane-1,1-diyl. In a third preferred embodiment, X is selected from propane-2,2-diyl, butane-2,2-diyl, pentane-2,2-diyl and hexane-2,2-diyl.

[0047] In a fourth preferred embodiment, X is selected from propane-1,2-diyl, butane-1,2-diyl, pentane-1,2-diyl and hexane-1,2-diyl. In a fifth preferred embodiment, X is selected from propane-1,3-diyl, butane-1,3-diyl, pentane-1,3-diyl and hexane-1,3-diyl.

[0048] Y is a monovalent group and may be selected from OR 3 , where R 3 Selected from (i) H, (ii) C5 to C 20 Aryl, preferably C5, C6 and C 10 Aryl, (iii) C1 to C 10 Alkyl, preferably C1 to C6 alkyl, most preferably C1 to C4 alkyl, (iv) C6 to C 20 Arylalkyl, preferably C6 to C 10 Arylalkyl, (v) C6 to C 20 alkylaryl, all of which may be substituted with OH, SO3H, COOH or a combination thereof, and (vi) (C2H3R 6 -O) n In a preferred embodiment, R 3 It can be C1 to C6 alkyl or H. 6 It can be selected from H and C1 to C5 alkyl, preferably selected from H and C1 to C4 alkyl, most preferably H, methyl or ethyl.

[0049] In another preferred embodiment, R 3 In another preferred embodiment, R3 Selected from the formula (C2H3R 6 -O) n -H polyoxyalkylene group. 6 is selected from H and C1 to C5 alkyl, preferably selected from H and C1 to C4 alkyl, most preferably selected from H, methyl or ethyl. Typically, n can be an integer from 1 to 30, preferably from 1 to 15, most preferably from 1 to 10. In a particular embodiment, polyoxymethylene, polyoxypropylene or polyoxymethylene-co-oxypropylene can be used. In another preferred embodiment, R 3 Can be selected from C1 to C 10 The alkyl group is preferably selected from C1 to C6 alkyl groups, most preferably methyl and ethyl groups.

[0050] In addition, Y can be an amine group NR 3 R 4 , where R 3 and R 4 The same or different and may have the above pair OR 3 Description R 3 meaning.

[0051] In a preferred embodiment, R 3 and R 4 In another preferred embodiment, R 3 and R 4 At least one, preferably both, of the formula (C2H3R 6 -O) n -H polyoxyalkylene group. 6 is selected from H and C1 to C5 alkyl, preferably selected from H and C1 to C4 alkyl, most preferably H, methyl or ethyl. In another preferred embodiment, R 3 and R 4 At least one, preferably both, selected from C1 to C 10 The alkyl group is preferably selected from C1 to C6 alkyl groups, most preferably methyl and ethyl groups.

[0052] R 3 and R 4 They can also form a ring system, which can be O or NR 7 Insert. R 7 Can be selected from R 6 and Such ring systems may preferably contain 4 or 5 carbon atoms to form a 5- or 6-membered carbocyclic ring system. In such carbocyclic ring systems, one or two carbon atoms may be replaced by oxygen atoms.

[0053] In addition, Y can be a positively charged ammonium group N + R 3 R 4 R5 . R 3 , R 4 , R 5 The same or different and may have the above pair OR 3 and NR 3 R 4 Description R 3 In a preferred embodiment, R 3 , R 4 and R 5 Independently selected from H, methyl or ethyl.

[0054] m may be an integer selected from 1 to 30, preferably from 1 to 15, even more preferably from 1 to 10, most preferably from 1 to 5.

[0055] In the additive of formula S1, R 2 It can be R as mentioned above 1 or R 3 If R 2 YesR 1 , you can choose R 1 To form a symmetrical compound (two R 1 s are the same) or asymmetric compounds (two R 1 s are different).

[0056] In a preferred embodiment, R 2 It's H.

[0057] Particularly preferred aminoalkynes are those wherein

[0058] (a)R 1 It is X-NR 3 R 4 And R 2 It is H;

[0059] (b)R 1 It is X-NR 3 R 4 And R 2 It is X-NR 3 R 4 , wherein X is selected from a linear C1 to C4 alkanediyl group and a branched C3 to C6 alkanediyl group;

[0060] Particularly preferred hydroxyalkynes or alkoxyalkynes are those wherein

[0061] (a)R 1 It's X-OR 3 And R 2 It is H;

[0062] (b)R 1 It's X-OR 3 And R 2It's X-OR 3 , wherein X is selected from a linear C1 to C4 alkanediyl group and a branched C3 to C6 alkanediyl group;

[0063] Particularly preferred alkynes containing an amino group and a hydroxy group are those in which R 1 It's X-OR 3 , especially X-OH, R 2 It is X-NR 3 R 4 , wherein X is independently selected from those of linear C1 to C4 alkanediyl and branched C3 to C6 alkanediyl;

[0064] The amine groups in the additive may be selected from primary (R 3 , R 4 is H), Zhong (R 3 or R 4 is H) and a tertiary amine group (R 3 and R 4 Not all H).

[0065] The alkyne may comprise one or more terminal triple bonds or one or more non-terminal triple bonds (alkyne functional groups). Preferably, the alkyne comprises one or more terminal triple bonds, in particular 1 to 3 terminal triple bonds, most preferably one terminal triple bond.

[0066] Particularly preferred specific primary aminoalkynes are:

[0067]

[0068] Particularly preferred specific secondary aminoalkynes are:

[0069]

[0070] Particularly preferred specific tertiary aminoalkynes are:

[0071]

[0072]

[0073] Other preferred additives are those wherein the remaining R 3 and R 4 Can be formed together with optional O or NR 3 Preferably, the remaining R 3 and R 4 Together they form a C5 or C6 divalent group, in which one or two, preferably one, carbon atom may be replaced by O or NR 7 Replace, where R 7 is selected from hydrogen, methyl or ethyl.

[0074] An example of such a compound is:

[0075]

[0076] The first can be obtained by reaction of propargylamine with formaldehyde and morpholine, and the second and third can be obtained by reaction of propargyl alcohol with formaldehyde and piperidine or morpholine, respectively.

[0077] Another preferred additive comprising a saturated heterocyclic system is:

[0078]

[0079] In this case, R 3 and R 4 Together they form two NR 3 The ring system into which the group is inserted, wherein R 3 Selected from CH2-C≡CH. This additive contains three terminal triple bonds.

[0080] The amino groups in the additives can be further quaternized by reaction with an alkylating agent, for example but not limited to dialkyl sulfates, such as DMS, DES or DPS, benzyl chloride or chloromethylpyridine. Particularly preferred quaternized additives are:

[0081]

[0082] Particularly preferred specific pure hydroxyalkynes are:

[0083]

[0084] Particularly preferred specific aminoalkynes containing OH groups are:

[0085]

[0086] In this case the remaining R 3 and R 4 It can also be formed together with O or NR 3 Preferably, the remaining R 3 and R 4 Together they form a C5 or C6 divalent group, in which one or two, preferably one, carbon atom may be replaced by O or NR 7 Replace, where R 7 is selected from hydrogen, methyl or ethyl.

[0087] Examples of such compounds are:

[0088]

[0089] These can be obtained by reaction of propargyl alcohol with formaldehyde and piperidine or morpholine, respectively.

[0090] By partial reaction with the alkylating agent, a mixture of additives can be formed. In one embodiment, such a mixture can be obtained by the reaction of 1 mol of diethylaminopropyne and 0.5 mol of epichlorohydrin, 1 mol of diethylaminopropyne and 0.5 mol of benzyl chloride, 1 mol of diethylaminopropyne and 0.9 mol of dimethyl sulfate, 1 mol of dimethylpropargylamine and 0.33 mol of dimethyl sulfate, or 1 mol of dimethylpropargylamine and 0.66 mol of dimethyl sulfate. In another embodiment, such a mixture can be obtained by the reaction of 1 mol of dimethylpropargylamine and 1.5, 1.9 or 2.85 mol of dimethyl sulfate, 1 mol of dimethylpropargylamine and 0.5 mol of epichlorohydrin, 1 mol of dimethylpropargylamine and 2.85 diethyl sulfate, or 1 mol of dimethylpropargylamine and 1.9 mol of dipropyl sulfate.

[0091] In further embodiments, the inhibitor may be substituted with a SO3H (sulfonate) group or a COOH (carboxyl) group. Specific sulfonated additives may be, but are not limited to, butynyloxyethanesulfonic acid, propynyloxyethanesulfonic acid, 1,4-di-(β-sulfoethoxy)-2-butyne, 3-(β-sulfoethoxy)-propyne.

[0092] In general, the total amount of inhibitor in the electroplating bath is 0.5ppm to 10000ppm of the total weight of the electroplating bath. The inhibitor is usually used in a total amount of about 0.1ppm to about 1000ppm, more usually 1 to 100ppm of the total weight of the electroplating bath, although a larger or smaller amount can be used. The preferred concentration range is, for example, between about 10-60ppm, or between about 15-60ppm, or between about 30-60ppm. In this regard, parts per million (ppm) is the mass fraction of inhibitor molecules in the electrolyte. In some cases, the inhibitor may have a concentration of at least about 10ppm, or at least about 15ppm, or at least about 20ppm, or at least about 30ppm, or at least about 50ppm. In these or other cases, the inhibitor may have a concentration of about 1,000ppm or less, such as about 500ppm or less, about 100ppm or less, about 75ppm or less, about 60ppm or less, or about 50ppm or less.

[0093] Leveling agent

[0094] The electroplating composition may further comprise one or more levelers.

[0095] Preferred levelers are those of formula L1 to L4

[0096] [B] n [A] p (L1)

[0097]

[0098] It has the following substituents.

[0099] As used herein, "aryl" refers to a C6 to C 14 Carbocyclic or C3 to C 10 A nitrogen- or oxygen-containing heterocyclic aromatic ring system which may be unsubstituted or substituted with up to 3 C1 to C 12 Alkyl or substituted with up to 2 OH, NH2 or NO2 groups.

[0100] In all embodiments, R in formulas L1 to L4 1 Can be selected from X 1 -CO-OR 11 , X 1 -SO2-OR 11 , X 1 -PO(OR 11 )2 and X 1 -SO-OR 11 . R 1 Also referred to herein as "functional groups".

[0101] X 1 It can be a chemical bond, which means the functional group -CO-OR 11 、-SO2-OR 11 、-PO(OR 11 )2 and -SO-OR 11 Directly bonded to the polymer backbone in formula L1, the vinyl group in formula L2, or the aromatic system in formulas L3a, L3b, and L4. "Chemical bond" as used herein means that the respective moieties do not exist, but bridge adjacent moieties to form a direct chemical bond between these adjacent moieties. For example, if the Y moiety in XYZ is a chemical bond, the adjacent moieties X and Z together form a group XZ.

[0102] In an alternative, X 1 is a divalent aromatic group. Preferred divalent aromatic groups are phenylene, naphthalene, pyridine or imidazole, especially 1,4-phenylene.

[0103] In another alternative, X 1 It is a two-price C1 to C 12 Alkanediyl, which may be interrupted by an O atom. x " means that the respective group contains x C atoms. For example, the term "C x To C y "Alkanediyl" and C x To C y Alkyl refers to an alkane(di)yl group having from x to y carbon atom numbers, and includes straight chain, branched (if > C3) and cyclic alkanediyl groups (if > C4).

[0104] In yet another alternative, X 1 is a divalent arylalkyl-X 11 -X 12 -, where X 11 are C1 to C2 groups bonded to the polymer backbone, vinyl or aromatic system, respectively. 15 Alkanediyl, X 12 is a divalent aromatic group bonded to a functional group. Preferred arylalkyl groups may be, but are not limited to, benzyl (ortho, meta or para form) and 1, 2 or 3-methylpyridine. The alkanediyl moiety X 11 Preferably, it may be methanediyl, propanediyl or butanediyl. The aryl moiety X 12 Preference may be given to phenylene, naphthalene, pyridine or imidazole, in particular 1,4-phenylene.

[0105] In another alternative, X 1 is a divalent alkyl aryl-X 12 -X 11 -, where X 12 is a divalent aromatic group bonded to the polymer backbone, vinyl or aromatic system, respectively, X 11 is bonded to the C1 to C 15 Preferred arylalkyl groups may be, but are not limited to, toluoyl (ortho, meta or para form) and 1, 2 or 3-methylpyridine. Alkanediyl moiety X 11 Preferably, it may be methanediyl, propanediyl or butanediyl. The alkanediyl moiety X 11 Preference may be given to phenylene, naphthalene, pyridine or imidazole, in particular 1,4-phenylene.

[0106] In yet another alternative, X 1 It is a divalent (poly) alkylene oxide spacer -(C2H3R 12 -O) m -, where R 12 is selected from H and C1 to C4 alkyl, preferably H or methyl, and m is an integer from 1 to 10, preferably from 1 to 5.

[0107] Preferably, X 1 Selected from a chemical bond, a C1 to C4 alkanediyl group or a phenylene group.

[0108] In a preferred embodiment, R 11 is selected from H and C1 to C4 alkyl, preferably H or methyl, most preferably H.

[0109] In a first embodiment, in formula L1 A is a comonomer unit derived from vinyl alcohol or acrylamide which may optionally be (poly)ethoxylated and B is a monomer unit of formula L1a

[0110]

[0111] In formulae L1a and L2 of the first and second embodiments, R 2 Selected from

[0112] (i) H,

[0113] (ii) aryl, preferably C6 to C 10 carbocyclic aryl or C3 to C8 heterocyclic aryl containing up to two N atoms, most preferably phenyl or pyridyl,

[0114] (iii) C1 to C 10 Alkyl, preferably C1 to C6 alkyl, more preferably C1 to C4 alkyl, most preferably C1 to C3 alkyl,

[0115] (iv) arylalkyl, preferably C7 to C 15 carbocyclic arylalkyl or C4 to C8 heterocyclic arylalkyl containing up to two N atoms, more preferably C4 to C8 arylalkyl, most preferably benzyl or 1, 2 or 3-methylpyridine,

[0116] (v) alkylaryl, preferably C7 to C 15 carbocyclic alkylaryl or C4 to C8 heterocyclic alkylaryl containing up to two N atoms, more preferably C4 to C8 alkylaryl, most preferably toluoyl (ortho, meta or para form) and 1, 2 or 3-methylpyridine, or

[0117] (vi) (Poly) alkylene oxide substituent -(O-C2H3R 12 ) m -OH, wherein m is an integer from 1 to 50, preferably from 1 to 30, more preferably from 1 or 2 to 20, most preferably from 1 or 2 to 10, and R 12 .

[0118] In formulas L1a and L2, R 3 Selected from R 1 and R 2 . R 4 Selected from R 2 , and only in R 3 Not R 1 In the case of R 3 It can also be R 1 In other words: Formula L1a and L2 may contain one or two functional groups R 1 Therefore, the leveler of L2 having two functional groups can be relative to the functional group R 1 It has cis and trans configurations.

[0119] In a preferred embodiment, R 2 , R 3 and R 4is selected from H, methyl, ethyl or propyl, most preferably H. In another preferred embodiment, R 2 and R 3 or R 4 is selected from H, methyl, ethyl or propyl, most preferably H, another group R 3 or R 4 Selected from R 1 .

[0120] In Formula L1, n is an integer from 2 to 10,000, and p may be 0 or an integer from 1 to 10,000.

[0121] If p is 0, the leveler of formula L1 can be a homopolymer, such as but not limited to polyacrylic acid, polysulfonic acid, polyphosphonic acid, etc., wherein R 2 =R 3 =R 4 =H, or polymaleic acid, where R 2 =R 4 =H and R 3 =R 1 or R 2 =R 3 =H and R 4 =R 1 Alternatively, the leveler of formula L1 can be a copolymer, such as but not limited to poly(acrylic acid-co-maleic acid), poly(acrylic acid-co-2-methacrylic acid), poly(sulfonic acid-co-maleic acid), poly(phosphonic acid-co-maleic acid), etc., to adjust the amount of functional groups present in the leveler.

[0122] Alternatively, if p>0, the polymeric leveler may be a copolymer of the above mentioned monomers with another monomer, such as vinyl alcohol and its ethoxylated or polyethoxylated derivatives or acrylamide. In this case, the sum of n and p is the total degree of polymerization.

[0123] The degree of polymerization n+p in formula L1 is an integer from 2 to 10,000. n+p is preferably an integer from 10 to 5,000, most preferably from 20 to 5,000.

[0124] If copolymers are used, such copolymers may have a block, random, alternating or gradient structure, with a random structure being preferred. "Random" as used herein means that the respective comonomers are polymerized from a mixture and are therefore arranged in a statistical manner according to their copolymerization parameters. "Block" as used herein means that the respective comonomers are polymerized successively with one another to form blocks of the respective comonomers in any predetermined order.

[0125] The molecular weight M of the polymeric leveler of formula L1 is wIt can be from about 500 to about 500000 g / mol, preferably from about 1000 to about 350000 g / mol, and most preferably from about 2000 to about 300000 g / mol. In a particular embodiment, the molecular weight M w In another embodiment, the molecular weight M w In yet another embodiment, the molecular weight Mw is from about 100,000 to about 300,000 g / mol.

[0126] If copolymers are used, the ratio between the two monomers B or between comonomer A and monomer B in the leveler of formula L1 may be 5:95 to 95:5% by weight, preferably 10:90 to 90:10 by weight, most preferably 20:80 to 80:40 by weight. Terpolymers comprising two monomers B and comonomer A may also be used.

[0127] Particularly preferred polymeric levelers of formula L1 are polyacrylic acid, maleic acid acrylic acid copolymers, acrylic acid-2-methacrylic acid copolymers, polyphosphonic acid and polysulfonic acid. Most preferred are polyacrylic acid, maleic acid acrylic acid copolymers and acrylic acid-2-methacrylic acid copolymers. In the case of maleic acid acrylic acid copolymers, a ratio p:n of 20:80 to 60:40 is particularly preferred. In the case of 2-methacrylic acid acrylic acid copolymers, a ratio p:n of 20:80 to 80:20 is particularly preferred.

[0128] The following specific copolymer levelers of formula L1b to L1d are particularly preferred:

[0129]

[0130] It is a terpolymer of acrylic acid, maleic acid and ethoxylated vinyl alcohol, wherein q and r are integers, the sum of q+r corresponds to p in formula 1, and the ratio q / r is from 10:90 to 90:10, preferably from 20:80 to 80:40, most preferably from 40:60 to 60:40; and

[0131]

[0132] It is a terpolymer of acrylic acid, maleic acid and vinylphosphonic acid, wherein q and r are integers, the sum of q+r corresponds to p in formula 1, and the ratio q / r is 10:90 to 90:10, preferably 20:80 to 80:40, most preferably 40:60 to 60:40.

[0133] Particularly preferred monomeric levelers of formula L2 are acrylic acid, vinylphosphonic acid and vinylsulfonic acid.

[0134] In a third embodiment comprising a polymeric leveler of formula L3a or L3b (also collectively referred to as L3), R 31 Typically, R may be as defined above. 1 ,H,OR 5 and R 5 Preferably, R 31 is H or OH. Such polymers are commercially available in the form of naphthalenesulfonic acid condensation products, Na salts and phenolsulfonic acid condensation products, Na salts, for example from BASF.

[0135] In the leveler of formula L3, X 2 is (i) a chemical bond or (ii) a methanediyl group. Preferably, X 2 It is methanediyl.

[0136] The degree of polymerization o in the leveler of formula L3 is from 2 to 1000. o is preferably an integer from 5 to 500, most preferably from 10 to 250.

[0137] Molecular weight M of polymer leveler L3 w It can be from about 500 to about 400000 g / mol, preferably from about 1000 to about 300000 g / mol, and most preferably from about 3000 to about 250000 g / mol. In a particular embodiment, the molecular weight M w In another embodiment, the molecular weight M w In yet another embodiment, the molecular weight Mw is from about 100,000 to about 300,000 g / mol.

[0138] In a fourth embodiment, in the leveler of formula L4, C6 to C 14 Carbocyclic groups or C3 to C 10 A nitrogen- or oxygen-containing heterocyclic aromatic group which may be unsubstituted or substituted with up to 3 C1 to C 12 alkyl or up to 2 OH, NH2 or NO2 groups. The heteroaryl is preferably a 5- or 6-membered ring system with up to 2, preferably 1, N atoms.

[0139] Preferred groups Those of formula L4a

[0140]

[0141] Where R 5 , R 6 , R 7 , R 8 and R 9is independently selected from (i) H and (ii) C1 to C6 alkyl. Preferably, R 5 , R 6 , R 8 and R 9 R is independently selected from H, methyl, ethyl or propyl, most preferably H. 7 Preferably it is selected from H, methyl, ethyl or propyl, most preferably from methyl or ethyl.

[0142] In certain embodiments, the leveler may be present at a concentration of about 1-10,000 ppm, or about 10-1,000 ppm, or about 10-500 ppm. In some cases, the concentration of the leveler may be at least about 1 ppm or at least about 100 ppm. In these or other cases, the concentration of the leveler may be about 500 ppm or less, or about 1000 ppm or less.

[0143] In one embodiment, a single leveler may be used in the cobalt electroplating bath, ie, the bath is substantially free of any other levelers as described in the next section. In another embodiment, two or more levelers are used in combination.

[0144] Other levelers typically contain one or more nitrogen, amine, amide or imidazole, and may also contain sulfur functional groups. Certain levelers include one or more five-membered and six-membered rings and / or conjugated organic compound derivatives. The nitrogen group may form part of the ring structure. In amine-containing levelers, the amine may be a primary, secondary or tertiary alkyl amine. In addition, the amine may be an aryl amine or a heterocyclic saturated or aromatic amine. Exemplary amines include, but are not limited to, dialkylamines, trialkylamines, arylalkylamines, triazoles, imidazoles, triazoles, tetrazoles, benzimidazoles, benzotriazoles, piperidines, morpholines, piperazines, pyridines, Azoles, benzo azoles, pyrimidines, quinolines and isoquinolines. Imidazoles and pyridines are available in some cases. Other examples of levelers include Janus Green B and Prussian Blue. Leveler compounds may also include ethoxy groups. For example, the leveler may include a general backbone similar to that present in polyethylene glycol or polyethylene oxide, with amine segments functionally inserted into the chain (e.g., Janus Green B). Exemplary epoxides include, but are not limited to, epihalohydrins, such as epichlorohydrin and epibromohydrin, and polyepoxide compounds. Polyepoxide compounds having two or more epoxy moieties linked together by ether-containing bonds are available in some cases. Some leveler compounds are polymeric, while others are not. Exemplary polymeric leveler compounds include, but are not limited to, polyethylene imine, polyamidoamines, and reaction products of amines with various oxygen epoxides or sulfides. An example of a non-polymeric leveler is 6-mercapto-hexanol. Another exemplary leveler is polyvinyl pyrrolidone (PVP).

[0145] Additional levelers that are particularly useful in the case of cobalt are, but are not limited to: alkylated polyalkyleneimines; polyethylene glycols; organic sulfonates; 4-mercaptopyridine; 2-mercaptothiazoline; ethylenethiourea; thiourea; 1-(2-hydroxyethyl)-2-imidazolidinthione; sodium naphthalene 2-sulfonate; acrylamide; substituted amines; imidazole; triazole; tetrazole; piperidine; morpholine; piperazine; pyridine; azole; benzo Azole; quinoline; isoquinoline; coumarin and its derivatives.

[0146] Accelerator

[0147] The electroplating composition may further comprise one or more accelerating agents (also referred to as accelerators), preferably in combination with a suppressor.

[0148] Exemplary accelerators that can be used to deposit cobalt include, but are not limited to: N,N-dimethyldithiocarbamic acid (-3-sulfopropyl) ester; 3-mercapto-propyl sulfonic acid (3-sulfopropyl) ester; 3-sulfanyl-1-propanesulfonate; carbonic acid-dithio-o-ethyl ester-s-ester, with 3-mercapto-1-propanesulfonic acid potassium salt; bis-sulfopropyl disulfide; 3-(benzothiazolyl-s-thio)propyl sulfonic acid sodium salt; pyridine Propyl sulfobetaine; 1-sodium-3-mercaptopropane-1-sulfonate; N,N-dimethyl-dithiocarbamic acid-(3-sulfoethyl) ester; 3-mercapto-ethylpropylsulfonic acid (3-sulfoethyl) ester; 3-mercapto-ethylsulfonic acid sodium salt; Carbonic acid-dithio-o-ethyl ester-s-ester; Pyridine Ethyl sulfobetaine; and thiourea. In some cases, a combination of these accelerators is used. In a particular embodiment, the accelerator is 3-sulfanyl-1-propanesulfonate (commonly known as MPS or 3-mercapto-1-propanesulfonic acid sodium salt) and / or thiourea (TU). The selected accelerator may include, in some cases, a sulfonic acid component and / or an ester component and / or a thiol group.

[0149] In some embodiments, the accelerator is present in the electrolyte at a concentration of about 1-10,000ppm, for example, about 150-500ppm or about 150-400ppm. In some embodiments, the concentration of the accelerator is at least about 100ppm, at least about 150ppm, at least about 200ppm or at least about 300ppm. In these or other cases, the concentration of the accelerator may be about 1,000ppm or less, or about 500ppm or less, or about 400ppm or less. The optimal accelerator concentration may depend on what the accelerator used is. In various embodiments, the accelerator is MPS and is present in the electrolyte at a concentration that satisfies one or more of the restrictions listed in this paragraph. In other embodiments, the accelerator is thiourea and is present in the electrolyte at a concentration that satisfies one or more of the restrictions listed in this paragraph.

[0150] In one embodiment, the cobalt electroplating composition does not contain any accelerator. The composition preferably does not contain any sulfur-containing compounds.

[0151] Other additives

[0152] A wide variety of other additives may be used in the bath to provide the desired surface finish to the cobalt plated metal. Typically more than one additive is used, each additive providing a desired function. Advantageously, the electroplating bath may contain one or more wetting agents or surfactants, such as or (available from BASF) to remove entrapped air or hydrogen bubbles etc. Further components added are grain refiners, stress reducers, levelers and mixtures thereof.

[0153] The bath may also contain a cobalt ion complexing agent such as, but not limited to, sodium acetate, sodium citrate, EDTA, sodium tartrate, or ethylenediamine.

[0154] Further additives are disclosed in Journal of The Electrochemical Society, 156 (8) D301-D309 2009 "Superconformal Electrodeposition of Co and Co-Fe Alloys Using 2-Mercapto-5-benzimidazolesulfonic Acid", which is incorporated herein by reference.

[0155] In a further embodiment, a surfactant may be present in the electroplating composition to improve wetting.The wetting agent may be selected from nonionic surfactants, anionic surfactants, and cationic surfactants.

[0156] In a preferred embodiment, nonionic surfactants are used. Typical nonionic surfactants are fluorinated surfactants, polyglocols or molecules containing polyoxyethylene and / or oxypropylene.

[0157] In a preferred embodiment, the cobalt or cobalt alloy electroplating composition consists essentially of cobalt ions (and respective counterions and precursors), an ammonium compound, a suppressor, a leveler, and optionally an acid other than boric acid.

[0158] Electrolytes

[0159] In one embodiment, a generally aqueous electroplating bath for void-free filling of cobalt or cobalt alloys may contain a source of cobalt ions such as, but not limited to, cobalt sulfate, cobalt chloride, or cobalt sulfamate.

[0160] The cobalt ion concentration in the electroplating solution may be in the range of 0.01 to 1 mol / l. In one specific example, the ion concentration may have a range of 0.1 to 0.6 mol / l. In another specific example, the range may be 0.3 to 0.5 mol / l. In yet another specific example, the range may be 0.03 to 0.1 mol / l.

[0161] In a preferred embodiment, the composition is substantially free of chloride ions. Substantially free of chloride ions means that the chloride ion content is less than 1 ppm, especially less than 0.1 ppm.

[0162] During the deposition process, the pH of the electroplating bath can be adjusted to have a high Faradaic efficiency while avoiding co-deposition of cobalt hydroxide. To this end, a pH range of 1 to 6 can be used. In one specific example, a pH range of 2 to 5.5 can be used. In another specific example, a pH range of 3 to 5.5 can be used. The pH is preferably below 5, and most preferably below 4.

[0163] In a preferred embodiment, boric acid may be used as a supporting electrolyte in the cobalt electroplating bath. Boric acid may be incorporated into the composition at a concentration of about 5 to about 50 g / l, such as about 15 to about 40 g / l.

[0164] The electrodeposition composition is preferably free of nickel ions and iron ions. If nickel ions or iron ions are present, the molar ratio of nickel ions to cobalt ions, the molar ratio of iron ions to cobalt ions, and the molar ratio of the sum of nickel ions and iron ions to cobalt ions are preferably no greater than about 0.01, or between about 0.00001 and about 0.01.

[0165] The electrodeposition composition is also preferably substantially free of copper ions. Although it may be difficult to avoid very slight copper contamination, it is particularly preferred that the bath has a copper ion content of no more than 20 ppb, such as in the range of 0.1 ppb to 20 ppb.

[0166] The electrodeposition composition preferably does not contain any functional concentration effective to convert cobaltous ions (Co 2+ ) is reduced to metallic cobalt (Co 0 Functional concentration refers to any concentration of a reagent that is effective in reducing cobaltous ions in the absence of an electrolytic current or is activated by an electrolytic current or electrolytic field to react with cobaltous ions.

[0167] method

[0168] An electrolytic bath comprising cobalt ions and the at least one additive according to the present invention is prepared. For interconnection, a dielectric substrate having a seed layer is placed in the electrolytic bath, wherein the electrolytic bath contacts the at least one outer surface and, in the case of a dielectric substrate, a three-dimensional pattern of the seed layer. A counter electrode is placed in the electrolytic bath and an electric current is passed through the electrolytic bath between the seed layer on the substrate and the counter electrode. At least a portion of the cobalt is deposited into at least a portion of the three-dimensional pattern, wherein the deposited cobalt is substantially free of voids.

[0169] The present invention can be used to deposit cobalt-containing layers on various substrates, particularly substrates having micron and / or nanometer-sized pores, particularly pores of various sizes. For example, the present invention is particularly suitable for depositing cobalt on integrated circuit substrates, such as semiconductor devices, having small diameter through holes, trenches or other pores. In one embodiment, semiconductor devices are plated according to the present invention. Such semiconductor devices include, but are not limited to, wafers used to manufacture integrated circuits. In addition, the present invention is particularly suitable for depositing cobalt for under-bump metallization applications.

[0170] In order to be able to deposit on a substrate comprising a dielectric surface, a seed layer needs to be applied to the surface. Such a seed layer can be composed of cobalt, iridium, osmium, palladium, platinum, rhodium and ruthenium or an alloy comprising these metals. Preferably, it is deposited on a cobalt seed. For example, the seed layer is described in detail in US20140183738 A.

[0171] The seed layer may be deposited or grown by chemical vapor deposition (CVD), atomic layer deposition (ALD), physical vapor deposition (PVD), electroplating, electroless plating, or other suitable methods of depositing conformal thin films. In one embodiment, a cobalt seed layer is deposited to form a high-quality conformal layer that fully and uniformly covers all exposed surfaces within the openings and top surfaces. In one embodiment, a high-quality seed layer may be formed by depositing a cobalt seed material at a slow deposition rate to uniformly and consistently deposit a conformal seed layer. By forming the seed layer in a conformal manner, the compatibility of subsequently formed fill materials with underlying structures may be improved. Specifically, the seed layer may assist the deposition process by providing an appropriate surface energy for deposition thereon.

[0172] The substrate preferably comprises submicron features and cobalt is deposited to fill the submicron features. Most preferably, the submicron features have an (effective) pore size of 10 nm or less and / or an aspect ratio of 4 or more. More preferably, these features have a pore size of 7 nanometers or less, most preferably 5 nanometers or less.

[0173] The pore size according to the present invention refers to the minimum diameter or gap distance of the feature before electroplating, ie after seed deposition. The terms "pore" and "opening" are used synonymously herein.

[0174] The electrodeposition current density should be selected to promote void-free, especially bottom-up filling behavior. 0.1 to 40 mA / cm 2 In one specific example, the current density may be 1 to 10 mA / cm 2 In another specific example, the current density may be 5 to 15 mA / cm 2 .

[0175] General requirements for a method for electrodepositing cobalt on a semiconductor integrated circuit substrate are described in US 2011 / 0163449 A1.

[0176] Typically, the substrate is electroplated by contacting the substrate with the electroplating bath of the present invention. The substrate typically serves as a cathode. The electroplating bath contains a soluble or insoluble anode. Optionally, the cathode and anode may be separated by a membrane. A potential is typically applied to the cathode. Sufficient current density is applied and electroplating is performed for a time sufficient to deposit a metal layer, such as a cobalt layer, of the desired thickness on the substrate. Suitable current densities include, but are not limited to, 1 to 250 mA / cm 2 Typically, when used to deposit cobalt in the manufacture of integrated circuits, the current density is between 1 and 60 mA / cm 2 The specific current density depends on the substrate to be plated, the selected leveler, etc. Such current density selection is within the ability of those skilled in the art. The applied current can be direct current (DC), pulse current (PC), pulse reverse current (PRC) or other suitable current.

[0177] In general, when the present invention is used to deposit metal on a substrate, such as a wafer for manufacturing an integrated circuit, the plating bath is agitated during use. The present invention may use any suitable agitation method and these methods are well known in the art. Suitable agitation methods include, but are not limited to, bubbling with an inert gas or air, agitation of the workpiece, impact, etc. These methods are known to those skilled in the art. When the present invention is used to electroplating an integrated circuit substrate, such as a wafer, the wafer can be rotated, such as 1 to 300 RPM, and the plating solution contacts the rotating wafer, such as by pumping or spraying. In an alternative, if the flow of the plating bath is sufficient to provide the desired metal deposition, the wafer does not need to be rotated.

[0178] According to the present invention, cobalt is deposited in the pores without substantially forming voids within the metal deposit.

[0179] As used herein, void-free filling may be ensured by extremely significant bottom-up cobalt growth while perfectly suppressing sidewall cobalt growth (leading to a flat growth front and thus providing essentially defect-free trench / via filling) (so-called bottom-up filling), or by so-called V-type filling.

[0180] As used herein, the term "substantially free of voids" means that at least 95% of the plated holes are free of voids. Preferably, at least 98% of the plated holes are free of voids, and most preferably, all plated holes are free of voids. As used herein, the term "substantially free of seams" means that at least 95% of the plated holes are free of seams. Preferably, at least 98% of the plated holes are free of seams, and most preferably, all plated holes are free of seams.

[0181] Electroplating equipment for electroplating semiconductor substrates is well known. The electroplating equipment comprises an electroplating tank, which contains a Co electrolyte and is made of a suitable material, such as plastic or other materials that are inert to the electrolytic plating solution. The tank can be cylindrical, especially for wafer electroplating. The cathode is horizontally placed on the upper part of the tank and can be any type of substrate, such as a silicon wafer with openings, such as grooves and through holes. The wafer substrate is usually coated with a seed layer or a metal-containing layer of Co or other metals to initiate electroplating thereon. The anode for wafer electroplating is also preferably circular and horizontally placed in the lower part of the tank to form a space between the anode and the cathode. The anode is usually a soluble anode.

[0182] These bath additives can be used in conjunction with membrane technology developed by various tool manufacturers. In such systems, the anode is isolated from the organic bath additives by a membrane. The purpose of separating the anode and the organic bath additives is to minimize oxidation of the organic bath additives.

[0183] The cathode substrate and the anode are electrically connected by wiring and are connected to a rectifier (power supply) respectively. The cathode substrate for direct current or pulse current has a net negative charge so that the Co ions in the solution are reduced at the cathode substrate to form plated Co metal on the cathode surface. Oxidation reaction occurs at the anode. The cathode and anode can be arranged horizontally or vertically in the tank.

[0184] Although the method of the present invention has been generally described with respect to semiconductor manufacturing, it will be appreciated that the present invention can be used in any electrolytic process requiring a substantially void-free cobalt deposit. Such processes include printed wiring board manufacturing. For example, the present electroplating bath can be used to plate through-holes, pads or traces on a printed wiring board, and for bump plating on a wafer. Other suitable processes include packaging and interconnect manufacturing. Accordingly, suitable substrates include lead frames, interconnects, printed wiring boards, etc.

[0185] Unless otherwise indicated, all percentages, ppm or equivalent values ​​refer to weight relative to the total weight of the respective composition. All cited documents are incorporated herein by reference.

[0186] The following examples shall further illustrate the present invention without limiting the scope of the present invention. Example

[0187] Experimental methods

[0188] Experiments were performed using 300 mm silicon segments (available from IMAT, Inc., Vancouver, WA, USA) with 56 μm thick patterned photoresist and multiple copper seeded 50 micron open vias.

[0189] The electroplated cobalt was studied by 3D laser scanning microscopy (3D LSM). The height of the cobalt layer deposited on the bumps was determined visually.

[0190] The non-uniformity is measured from the height of 82 bumps:

[0191] (a) 70 bumps at two locations in a dense area:

[0192] (i) 35 bumps in the center of the dense zone with a pitch size of 100 μm and an open bump area of ​​19.6%, and

[0193] (ii) 35 bumps at the edge of the dense area with a pitch size of 150 μm and an open bump area of ​​8.7%,

[0194] and

[0195] (b) 12 bumps in a discrete area with a pitch size of 250 μm and 3.1% open bump area.

[0196] From these heights the non-uniformity is calculated using the following formula:

[0197]

[0198] in

[0199] The “maximum bump height” and “minimum bump height” are the cobalt deposition heights in the bumps with the highest and lowest deposited cobalt layers, respectively.

[0200] "Mean height" means the arithmetic mean of all heights.

[0201] Example 1 (comparative)

[0202] A cobalt electroplating bath was prepared containing 1.02 mol / l CoSO4*7H2O in deionized water. The pH of the solution was 5.3.

[0203] The substrate was placed in contact at 25 °C and rotated at 100 rpm and 100 mA / cm 2 Cobalt was electroplated from the electroplating bath onto the wafer with a current of 1.50 s for 360 s.

[0204] The non-uniformity of the Co film is 52.2%.

[0205] Example 2 (Comparative)

[0206] A cobalt electroplating bath containing 1.02 mol / l CoSO4*7H2O, 0.49 mol / l H3BO3 in deionized water was prepared. The pH of the solution was 3.9.

[0207] The substrate was placed in contact at 25 °C and rotated at 100 rpm and 100 mA / cm 2 Cobalt was electroplated from the electroplating bath onto the wafer with a current of 1.50 s for 360 s.

[0208] The non-uniformity of the Co film was 39.8%, which was only slightly reduced compared with Comparative Example 1.

[0209] Example 3

[0210] A cobalt electroplating bath containing 1.02 mol / l CoSO4*7H2O, 0.50 mol / l NH4Cl in deionized water was prepared. The pH of the solution was 4.1.

[0211] The substrate was placed in contact at 25 °C and rotated at 100 rpm and 100 mA / cm 2 Cobalt was electroplated from the electroplating bath onto the wafer with a current of 1.50 s for 360 s.

[0212] The non-uniformity of the Co film was 21.6%. By using NH4Cl, the non-uniformity was reduced by about 60% compared to Comparative Example 1 (no additive) and by about 46% compared to Comparative Example 2 (using boric acid).

[0213] Example 4

[0214] A cobalt electroplating bath containing 1.02 mol / l CoSO4*7H2O, 0.50 mol / l NH4CH3COO in deionized water was prepared. The pH of the solution was 5.8.

[0215] The substrate was placed in contact at 25 °C and rotated at 100 rpm and 100 mA / cm 2 Cobalt was electroplated from the electroplating bath onto the wafer with a current of 1.50 s for 360 s.

[0216] The non-uniformity of the Co film was 30.2%. By using NH4CH3COO, the non-uniformity was reduced by about 42% compared to Comparative Example 1 (no additive) and by about 24% compared to Comparative Example 2 (using boric acid).

Claims

1. A composition comprising (a) cobalt ions, (b) Formula (NR 1 R 2 R 3 H + ) n X n- Ammonium compounds in R 1 , R 2 , R 3 independently selected from H and straight or branched C1 to C6 alkyl, X is selected from n-valent inorganic or organic counterions, n is an integer selected from 1, 2 or 3.

2. A composition according to claim 1, wherein R 1 , R 2 and R 3 Independently selected from H and straight or branched C1 to C4 alkyl.

3. A composition according to claim 1 or 2, wherein R 1 , R 2 and R 3 At least two of them are H, preferably R 1 , R 2 and R 3 All are H.

4. The composition according to any one of the preceding claims, wherein X is an inorganic counterion, in particular chloride, sulfate, hydrogensulfate, phosphate, hydrogenphosphate, dihydrogenphosphate and nitrate.

5. A composition according to any one of the preceding claims, wherein X is chloride.

6. A composition according to any one of claims 1 to 3, wherein X is an organic counterion, in particular C1 to C6 alkylsulfonate, C1 to C6 carboxylate, phosphonate and sulfamate.

7. A composition according to any one of the preceding claims, further comprising an inhibitor of formula S1 in R 1 Selected from XY; R 2 Selected from R 1 and R 3 ; X is selected from a linear or branched C1 to C 10 Alkanediyl, straight or branched C2 to C 10 Alkenyl, linear or branched C2 to C 10 Alkynediyl and (C2H3R 6 -O) m -H; Y is selected from OR 3 , NR 3 R 4 , N + R 3 R 4 R 5 and NH-(C=O)-R 3 ; R 3 , R 4 , R 5 are the same or different and are selected from (i) H, (ii) C5 to C 20 Aryl, (iii) C1 to C 10 Alkyl, (iv) C6 to C 20 Arylalkyl, (v) C6 to C 20 Alkylaryl, which may be substituted by OH, SO3H, COOH or a combination thereof, and (vi) (C2H3R 6 -O)nH, and where R 3 and R 4 Can be formed together with O or NR 7 Inserted ring system; m, n are integers independently selected from 1 to 30; R 6 Selected from H and C1 to C5 alkyl; R 7 Selected from R 6 and 8. The composition according to any one of the preceding claims, further comprising a leveler comprising a structure of formula L1 [B]n[A]p(L1) Or having a structure of formula L2 or a structure comprising formula L3a or L3b Or having a structure of formula L4 and their salts, in R 1 Choice X 1 -CO-OR 11 , X 1 -SO2-OR 11 , X 1 -PO(OR 11 )2, X 1 -SO-OR 11 ; R 2 independently selected from (i) H, (ii) aryl, (iii) C1 to C 10 alkyl, (iv) arylalkyl, (v) alkylaryl and (vi) -(O-C2H3R 12 ) m -OH, R 3 Selected from R 1 and R 2 ; R 4 Selected from R 2 and in R 3 YesR 2 In the case of R 4 It can also be R 1 , C6 to C 14 Carbocyclic groups or C3 to C 10 A nitrogen- or oxygen-containing heterocyclic aromatic group which may be unsubstituted or substituted with up to 3 C1 to C 12 Alkyl or substituted with up to 2 OH, NH2 or NO2 groups, R 31 Selected from R 1 , H, OR 5 and R 5 , X 1 is a divalent group selected from (i) a chemical bond, (ii) an aromatic group, (iii) a C1 to C 12 Alkanediyl, which may be interrupted by an O atom, (iv) arylalkyl-X 11 -X 12 -, (v) alkylaryl-X 12 -X 11 - and (vi) -(O-C2H3R 12 ) m O-, X 2 is (i) a chemical bond or (ii) a methanediyl group, R 11 is selected from H and C1 to C4 alkyl, R 12 is selected from H and C1 to C4 alkyl, X 12 is a divalent aromatic group, X 11 It is a two-price C1 to C 15 Alkanediyl, A is a comonomer selected from vinyl alcohol and acrylamide, which may optionally be (poly)ethoxylated, B is selected from the formula L1a n is an integer from 2 to 10,000, m is an integer from 2 to 50, o is an integer from 2 to 1000, p is 0 or an integer from 1 to 10,000.

9. The composition according to claim 8, wherein the leveler is selected from the group consisting of polyacrylic acid, maleic acid acrylic acid copolymer, polyphosphonic acid, polysulfonic acid, acrylic acid, vinylphosphonic acid, vinylsulfonic acid and p-toluenesulfonate.

10. The composition according to any one of the preceding claims, wherein the composition further comprises an inhibitor selected from hydroxyalkyne, C1 to C6 alkoxyalkyne or aminoalkyne.

11. A composition according to any preceding claim, wherein the composition is substantially free of boric acid.

12. Use of a composition according to any one of the preceding claims for depositing cobalt into interconnect features or for providing cobalt under bump metallization.

13. A method of depositing cobalt on a semiconductor substrate, the substrate comprising a recessed feature having a pore size of 1 nanometer to 100 micrometers, the method comprising: a) contacting a composition according to any one of claims 1 to 11 with a semiconductor substrate, b) applying the potential for a time sufficient to fill the recessed features with cobalt.

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