Compositions containing leveling agents for electroplating cobalt

Abstract

A cobalt electrodeposition composition comprising cobalt ions and a specific leveling agent, wherein the leveling agent comprises X 1 ‑CO‑O‑R 11 , X 1 ‑SO 2 ‑O‑R 11 , X 1 ‑PO(OR 11 ) 2 , X 1 ‑SO‑O‑R 11 Functional group, where X 1 is a divalent group selected from the following: (i) a chemical bond, (ii) an aromatic group, (iii) a C group which may be interrupted by an O atom 1 ‑C 12 Alkanediyl, (iv) aralkyl-X 11 ‑X 12 ‑, (v) alkylaryl‑X 12 ‑X 11 ‑and (vi)‑(O‑C 2 H 3 R 12 ) m O‑, R 11 Selected from H and C 1 ‑C 4 Alkyl, R 12 Selected from H and C 1 ‑C 4 Alkyl, X 12 is a divalent aromatic group, X 11 For divalent C 1 ‑C 15 Alkanediyl.

Description

[0001] The present invention relates to a composition for electroplating cobalt, comprising cobalt ions and a leveling agent. Background of the Invention

[0003] Filling of small features such as vias and trenches by metal electroplating is an essential part of the semiconductor manufacturing process. It is well known that the presence of organic substances as additives in the electroplating bath is critical to obtaining uniform metal deposition on the substrate surface and avoiding defects such as voids and seams within the metal lines.

[0004] With further reductions in hole size of recessed features such as vias or trenches, filling of interconnects with copper becomes particularly challenging, also because copper seed deposition by physical vapor deposition (PVD) prior to copper electrodeposition may exhibit non-uniformity and inconsistency, thus further reducing the hole size, especially at the top of the hole. In addition, replacing copper with cobalt is becoming more and more of a concern, as cobalt exhibits less electromigration into the dielectric.

[0005] For electroplating of cobalt, several additives have been proposed to ensure void-free filling of submicron-sized features.

[0006] US 2011 / 0163449 A1 discloses a cobalt electrodeposition process using a bath containing a cobalt deposition inhibiting additive such as saccharin, coumarin or polyethyleneimine (PEI).

[0007] US 2009 / 0188805 A1 discloses a cobalt electrodeposition process using a bath comprising at least one accelerating, inhibiting or depolarizing additive selected from polyethyleneimine and 2-mercapto-5-benzimidazolesulfonic acid.

[0008] WO2017 / 004424 discloses a composition for cobalt electrodeposition comprising SPS as an accelerator and an acetylenic inhibitor such as propargyl alcohol and alkoxylated propargyl alcohol.

[0009] PCT / EP2017 / 066896 discloses alkynols and alkynamines as inhibitors.

[0010] EP1323848A1 discloses a nickel electroplating solution containing: a) nickel ions and b) at least two chelating agents selected from amino polycarboxylic acids, polycarboxylic acids and polyphosphonic acids, wherein the pH of the nickel electroplating solution is 4-9, and the ratio of nickel ions to chloride ions (Ni +2 / Cl -1 ) is 1 or less.

[0011] US2016 / 273117A1 discloses a method for electroplating cobalt into a recessed component on a substrate, the method comprising: receiving a substrate in an electroplating chamber, the substrate comprising a recessed component having a cobalt seed layer thereon, the cobalt seed layer having a thickness of about 50A or less, and a width of the recessed component of about 10-150nm; immersing the substrate in an electrolyte comprising boric acid, halide ions, cobalt ions, and an organic additive for achieving seamless bottom-up filling in the recessed component; and electroplating cobalt into the component under conditions that provide bottom-up filling.

[0012] A disadvantage of existing cobalt electrodeposition baths is the strong heave effect on densely packed components.

[0013] There remains a strong need for a cobalt electroplating bath that, in addition to void-free filling of sub-micron-sized interconnect features, provides a substantially planar surface of the filled features.

[0014] It is therefore an object of the present invention to provide a cobalt electroplating additive having good leveling properties, in particular a leveling agent capable of providing a substantially flat metal layer and filling nano- and micro-scale features with a cobalt electroplating bath without substantially forming defects such as, but not limited to, voids.

[0015] Another object of the present invention is to provide a cobalt electroplating bath capable of depositing low-impurity metal layers.

[0016] Brief description of the invention

[0017] In the case of specific vinyl-based, polyethylene-based or aromatic leveling agents described below, the present invention provides a new class of highly effective leveling agents that result in reduced ridges on recessed features that are fully filled with cobalt, particularly on substrates containing nano-sized interconnected features, especially if there are regions of different feature density and width.

[0018] Therefore, the present invention provides a composition comprising the following components:

[0019] (a) metal ions consisting essentially of cobalt ions, and

[0020] (b) a leveling agent comprising a structure of formula L1:

[0021] [B] n [A] p (L1)

[0022] Or having the structure of formula L2:

[0023]

[0024] Or comprising the structure of formula L3a or L3b:

[0025]

[0026] Or having the structure of formula L4:

[0027]

[0028] and their salts,

[0029] in:

[0030] R 1 Selected from X 1 -CO-OR 11 , X 1 -SO 2 -OR 11 , X 1 -PO(OR 11 ) 2 , X 1 -SO-OR 11 ; R 2 , R 3 , R 4 Independently selected from R 1 and (i) H, (ii) aryl, (iii) C 1 -C 10 alkyl, (iv) aralkyl, (v) alkaryl and (vi) -(OC 2 H 3 R 12 ) m -OH, provided that if R 2 , R 3 or R 4 One of the selected R 1 , then other groups R 2 , R 3 or R 4 Different from R 1 ,

[0031] C 6 -C 14 Carbon ring or C 3 -C 10 A nitrogen or oxygen-containing heterocyclic aromatic group which may be unsubstituted or substituted with up to 3 C 1 -C 12 Alkyl or up to 2 OH, NH 2 or NO 2 Group substitution,

[0032] R 31 Selected from R 1 ,H,OR 5 and R 5 ,

[0033] R 32Selected from (i) H and (ii) C 1 -C 6 alkyl,

[0034] X 1 is a divalent group selected from the following: (i) a chemical bond, (ii) an aromatic group, (iii) a C group which may be interrupted by an O atom 1 -C 12 Alkanediyl, (iv) aralkyl-X 11 -X 12 -, (v) alkylaryl-X 12 -X 11 - and (vi)-(OC 2 H 3 R 12 ) m O-,

[0035] X 2 is (i) a chemical bond or (ii) a methanediyl group,

[0036] R 11 Selected from H and C 1 -C 4 alkyl,

[0037] R 12 Selected from H and C 1 -C 4 alkyl,

[0038] X 12 is a divalent aromatic group,

[0039] X 11 For divalent C 1 -C 15 Alkanediyl,

[0040] A is a comonomer selected from vinyl alcohol and acrylamide, which may be optionally (poly)ethoxylated,

[0041] B is selected from the formula L1a:

[0042]

[0043] n is an integer from 2 to 10,000,

[0044] m is an integer from 2 to 50,

[0045] o is an integer from 2 to 1000, and

[0046] p is 0 or an integer from 1 to 10,000, and wherein the composition does not contain any dispersed particles.

[0047] In another embodiment, the present invention provides a composition comprising the following components: (a) metal ions consisting essentially of cobalt ions, and (b) a leveling agent comprising the structure of formula L1:

[0048] [B] n [A] p (L1)

[0049] Or having the structure of formula L2:

[0050]

[0051] Or comprising the structure of formula L3a or L3b:

[0052]

[0053] Or having the structure of formula L4:

[0054]

[0055] and their salts,

[0056] in:

[0057] R 1 Selected from X 1 -CO-OR 11 , X 1 -SO 2 -OR 11 , X 1 -PO(OR 11 ) 2 , X 1 -SO-OR 11 ; R 2 is selected from (i) H, (ii) aryl, (iii) C 1 -C 10 alkyl, (iv) aralkyl, (v) alkaryl and (vi) -(OC 2 H 3 R 12 ) m -OH,

[0058] R 3 Selected from R 1 and R 2 ;

[0059] R 4 Selected from R 2 , and in R 3 For R 2 In the case of R 4 Can also be R 1 ,

[0060] C 6 -C 14 Carbon ring or C 3 -C 10 A nitrogen or oxygen-containing heterocyclic aromatic group which may be unsubstituted or substituted with up to 3 C 1 -C 12 Alkyl or up to 2 OH, NH 2 or NO 2 Group substitution,

[0061] R 31 Selected from R 1 ,H,OR 5 and R 5 ,

[0062] R 32 Selected from (i) H and (ii) C 1 -C 6 alkyl,

[0063] X 1 is a divalent group selected from the following: (i) a chemical bond, (ii) an aromatic group, (iii) a C group which may be interrupted by an O atom 1 -C 12 Alkanediyl, (iv) aralkyl-X 11 -X 12 -, (v) alkylaryl-X 12 -X 11 - and (vi)-(OC 2 H 3 R 12 ) m O-,

[0064] X 2 is (i) a chemical bond or (ii) a methanediyl group,

[0065] R 11 Selected from H and C 1 -C 4 alkyl,

[0066] R 12 Selected from H and C 1 -C 4 alkyl,

[0067] X 12 is a divalent aromatic group,

[0068] X 11 For divalent C 1 -C 15 Alkanediyl,

[0069] A is a comonomer selected from vinyl alcohol and acrylamide which may be optionally (poly)ethoxylated, and B is selected from the formula L1a:

[0070]

[0071] n is an integer from 2 to 10,000,

[0072] m is an integer from 2 to 50,

[0073] o is an integer from 2 to 1000, and

[0074] p is 0 or an integer from 1 to 10,000,

[0075] The composition is free of any dispersed particles.

[0076] The invention further relates to the use of a metal plating bath comprising a composition as defined herein for depositing cobalt on a substrate, wherein the substrate comprises recessed features having a pore size of 100 nanometers or less, in particular 20 nm or less, 15 nm or less or even 7 nm or less.

[0077] The present invention further relates to a method for depositing a layer comprising cobalt on a substrate comprising components having a pore size of less than 100 nm, preferably less than 50 nm, by the following steps:

[0078] a) contacting a composition as defined herein with a substrate, and

[0079] b) applying a current density to the substrate for a time sufficient to deposit a metal layer onto the substrate.

[0080] In this way an additive is provided which causes less ridges on the wafer above the completely filled recessed features. DETAILED DESCRIPTION OF THE INVENTION

[0082] The composition of the present invention comprises cobalt ions and a leveling agent of formula L1 to L4 described below.

[0083] Leveling agent of the present invention

[0084] As used herein, "leveling agent" refers to an organic compound that is capable of providing a substantially flat metal layer on a substrate in addition to any additional functionality. The terms "leveling agent" and "leveling additive" are used interchangeably throughout this specification.

[0085] In a first embodiment, the leveling agent used in the electroplating composition comprises a polymeric structure of formula L1:

[0086] [B] n [A] p (L1)

[0087] In a second embodiment, the leveling agent used in the electroplating composition comprises a monomer structure of formula L2:

[0088]

[0089] In a third embodiment, the leveling agent used in the electroplating composition comprises a polymeric structure of formula L3a or L3b:

[0090]

[0091] In a fourth embodiment, the leveling agent used in the electroplating composition comprises a monomer structure of formula L4:

[0092]

[0093] wherein the substituents are described below.

[0094] As used herein, "aryl" refers to a C 6 -C 14 Carbon ring or C 3 -C 10 A nitrogen or oxygen-containing heterocyclic aromatic ring system which may be unsubstituted or substituted with up to 3 C 1 -C 12 Alkyl or up to 2 OH, NH 2 or NO 2 Group substitution.

[0095] In all embodiments, R in formulas L1 to L4 1 Can be selected from X 1 -CO-OR 11 , X 1 -SO 2 -OR 11 , X 1 -PO(OR 11 ) 2 and X 1 -SO-OR 11 . R 1 Also referred to herein as a "functional group".

[0096] X 1 Can be a chemical bond, which means the functional group -CO-OR 11 、-SO 2 -OR 11 、-PO(OR 11 ) 2 AND-SO-OR 11Directly 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 corresponding moieties do not exist, but adjacent moieties are bridged so as to form a direct chemical bond between these adjacent moieties. For example, if the moiety Y in XYZ is a chemical bond, the adjacent moieties X and Z together form a group XZ.

[0097] In the alternative, X 1 is a divalent aromatic group. Preferred divalent aromatic groups are phenylene, naphthalene, pyridine or imidazole, particularly 1,4-phenylene.

[0098] In another alternative, X 1 is a divalent C 1 -C 12 As used herein, "C x " means that the corresponding group contains x number of C atoms. For example, the term "C x -C y Alkanediyl" and "C x -C y "Alkyl" means an alkane (alkanedi) group having from x to y number of carbon atoms and includes straight chain, branched (if >C 3 ) and cycloalkanediyl (if >C 4 ).

[0099] In yet another alternative, X 1 is a divalent aralkyl-X 11 -X 12 -, where X 11 are C groups bonded to the polymer backbone, vinyl or aromatic system, respectively. 1 -C 15 alkanediyl, and X 12 is a divalent aromatic group bonded to a functional group. Preferred aralkyl groups may be, but are not limited to, benzyl (ortho, meta or para form) and 1-methylpyridine, 2-methylpyridine or 3-methylpyridine. The alkanediyl moiety X 11 Preferably, it may be methanediyl, propanediyl or butanediyl. The aryl moiety X 12 Preferred are phenylene, naphthalene, pyridine or imidazole, particularly 1,4-phenylene.

[0100] In another alternative, X 1 is a divalent alkylaryl-X 12 -X 11 -, where X 12 is a divalent aromatic group bonded to the polymer backbone, vinyl or aromatic system, respectively, and X 11 is the C bonded to the functional group 1 -C 15Alkanediyl. Preferred aralkyl groups may be, but are not limited to, toluoyl (o, m or p form) and 1-methylpyridine, 2-methylpyridine or 3-methylpyridine. Alkanediyl moiety X 11 Preferably, it may be methanediyl, propanediyl or butanediyl. The alkanediyl moiety X 11 Preferred may be phenylene, naphthalene, pyridine or imidazole, particularly 1,4-phenylene.

[0101] In yet another alternative, X 1 is a divalent (poly)oxyalkylene spacer -(C 2 H 3 R 12 -O) m -, where R 12 Selected from H and C 1 -C 4 The alkyl group is preferably H or methyl, and m is an integer of 1-10, preferably 1-5.

[0102] X 1 Preferably selected from chemical bonds, C 1 -C 4 Alkanediyl and phenylene.

[0103] In a preferred embodiment, R 11 Selected from H and C 1 -C 4 Alkyl, preferably H or methyl, most preferably H.

[0104] In a first embodiment, in formula L1, A is a comonomer unit derived from vinyl alcohol or acrylamide which may be optionally (poly)ethoxylated, and B is a monomer unit of formula L1a

[0105]

[0106] In general, in formulae L1a and L2 of the first and second embodiments, R 2 , R 3 and R 4 Independently selected from R 1 and group R R , where R R Selected from:

[0107] (i) H,

[0108] (ii) aryl, preferably C 6 -C 10 A carbocyclic aromatic group or a C 3 -C 8 Heterocyclic aryl, most preferably phenyl or pyridyl,

[0109] (iii)C 1 -C10 Alkyl, preferably C 1 -C 6 Alkyl, more preferably C 1 -C 4 Alkyl, most preferably C 1 -C 3 alkyl,

[0110] (iv) Arylalkyl, preferably C 7 -C 15 Carbocyclic aralkyl or C containing up to 2 N atoms 4 -C 8 Heterocyclic aralkyl, more preferably C 4 -C 8 Aralkyl, most preferably benzyl or 1-methylpyridine, 2-methylpyridine or 3-methylpyridine,

[0111] (v) an alkylaryl group, preferably C 7 -C 15 Carbocyclic alkylaryl or C containing up to 2 N atoms 4 -C 8 Heterocycloalkylaryl, more preferably C 4 -C 8 Alkaryl, most preferably tolyl (o-, m- or p-form) and 1-, 2- or 3-methylpyridine, or

[0112] (vi) (Poly)oxyalkylene substituents - (OC 2 H 3 R 12 ) m -OH, wherein m is an integer of 1 to 50, preferably 1 to 30, more preferably 1 or 2 to 20, most preferably 1 or 2 to 10, and R 12 Selected from H and C 1 -C 4 alkyl.

[0113] Since only R 2 , R 3 and R 4 One of the groups may contain a group R 1 , so if R 2 , R 3 and R 4 One of the selected R 1 , then other groups R 2 , R 3 and R 4 Different from R 1 .

[0114] In certain embodiments, in formulae L1a and L2 of the first and second embodiments, R 2 Selected from:

[0115] (i) H,

[0116] (ii) aryl, preferably C 6 -C 10 A carbocyclic aromatic group or a C 3 -C 8 Heterocyclic aryl, most preferably phenyl or pyridyl,

[0117] (iii)C 1 -C 10 Alkyl, preferably C 1 -C 6 Alkyl, more preferably C 1 -C 4 Alkyl, most preferably C 1 -C 3 alkyl,

[0118] (iv) Arylalkyl, preferably C 7 -C 15 Carbocyclic aralkyl or C containing up to 2 N atoms 4 -C 8 Heterocyclic aralkyl, more preferably C 4 -C 8 Aralkyl, most preferably benzyl or 1-methylpyridine, 2-methylpyridine or 3-methylpyridine,

[0119] (v) an alkylaryl group, preferably C 7 -C 15 Carbocyclic alkylaryl or C containing up to 2 N atoms 4 -C 8 Heterocycloalkylaryl, more preferably C 4 -C 8 Alkaryl, most preferably tolyl (o-, m- or p-form) and 1-, 2- or 3-methylpyridine, or

[0120] (vi) (Poly)oxyalkylene substituents - (OC 2 H 3 R 12 ) m -OH, wherein m is an integer of 1 to 50, preferably 1 to 30, more preferably 1 or 2 to 20, most preferably 1 or 2 to 10, and R 12 Selected from H and C 1 -C 4 alkyl.

[0121] In certain embodiments, in formula L1a and L2, R 3 Selected from R 1 and R R . R 4Selected from R R And only in R 3 Not for R 1 In the case of R 4 Can also be R 1 In other words: Formula L1a and L2 may contain one or two functional groups R 1 Therefore, the L2 leveling agent having two functional groups may have a relative functional group R 1 It has cis and trans configurations.

[0122] In another specific embodiment, R 2 Selected from R 1 And R 3 and R 4 Selected from R R .

[0123] In a preferred embodiment, R 2 , R 3 and R 4 is 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, and the other groups R 3 or R 4 Selected from R 1 In another preferred embodiment, R 2 Selected from R 1 And R 3 and R 4 It is selected from H, methyl, ethyl or propyl, most preferably H.

[0124] In Formula L1, n is an integer of 2 to 10,000 and P may be 0 or an integer of 1 to 10,000.

[0125] If p is 0, the leveling agent of formula L1 may 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, wherein R 2 =R 4 =H and R 3 =R 1 or R 2 =R 3 =H and R 4 =R 1 ; or polyitaconic acid, wherein R 3 =R 4 =H and R 2 =R 1Alternatively, the leveling agent of formula L1 may be a copolymer, such as but not limited to poly(acrylic acid-co-maleic acid), poly(acrylic acid-co-itaconic acid), poly(acrylic acid-co-2-methylacrylic acid), poly(sulfonic acid-co-maleic acid), poly(sulfonic acid-co-itaconic acid), poly(phosphonic acid-co-maleic acid), poly(phosphonic acid-co-itaconic acid), poly(phosphonic acid-co-sulfonic acid), etc., so as to adjust the type and amount of functional groups present in the leveling agent.

[0126] Alternatively, if p>0, the polymer leveling agent may be a copolymer of the above monomers with other monomers 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.

[0127] The degree of polymerization n+p in formula L1 is preferably an integer of 2 to 10,000. n+p is most preferably an integer of 10 to 5000, most preferably an integer of 20 to 5000.

[0128] If a copolymer is used, the copolymer may have a block, random, alternating or gradient structure, preferably a random structure. "Random" as used herein means that the corresponding comonomers are polymerized from a mixture and are therefore distributed in a statistical manner depending on the copolymerization parameters. "Block" as used herein means that the corresponding comonomers are polymerized successively to each other to form blocks of the corresponding comonomers in any predetermined order.

[0129] The molecular weight M of the polymer leveling agent of formula L1 w It can be about 500 to about 500,000 g / mol, preferably about 1,000 to about 350,000 g / mol, and most preferably about 2000 to about 300,000 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.

[0130] If a copolymer is used, the ratio between the two monomers B or the comonomer A and the monomer B in the leveling agent of formula L1 can be 5:95 wt % to 95:5 wt %, preferably 10:90 wt % to 90:10 wt %, most preferably 20:80 wt % to 80:40 wt %. Terpolymers comprising two monomers B and one comonomer A can also be used.

[0131] Particularly preferred polymer leveling agents of formula L1 are polyacrylic acid, polyitaconic acid, maleic acid acrylic acid copolymer, itaconic acid acrylic acid copolymer, acrylic acid 2-methacrylic acid copolymer, polyphosphonic acid and polysulfonic acid. Most preferably, polyacrylic acid, maleic acid acrylic acid copolymer and acrylic acid 2-methacrylic acid copolymer are used. In the case of maleic acid acrylic acid copolymer or itaconic acid acrylic acid copolymer, the ratio p:n is preferably 20:80% to 60:40% by weight. In the case of 2-methacrylic acid acrylic acid copolymer, the ratio p:n is preferably 20:80% to 80:20% by weight.

[0132] Particularly preferred are the specific copolymer leveling agents of the following formulae L1b to L1d:

[0133]

[0134] It is a terpolymer of acrylic acid, maleic acid and ethoxylated vinyl alcohol, wherein q and r are integers, the sum 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

[0135]

[0136] It is a terpolymer of acrylic acid, maleic acid and vinylphosphonic acid, wherein q and r are integers, the sum 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.

[0137] Particularly preferred monomeric leveling agents of formula L2 are acrylic acid, vinylphosphonic acid and vinylsulfonic acid.

[0138] In a third embodiment comprising a polymeric leveling agent of formula L3a or L3b (also collectively referred to as L3), R 31 Typically, R may be as defined above. 1 ,H,OR 32 and R 32 . R 31 Preferred is H or OH. These polymers are commercially available as naphthalenesulfonic acid condensation products, Na salts and phenolsulfonic acid condensation products, Na salts, for example from BASF.

[0139] In the leveling agent of formula L3, X 2 is (i) a chemical bond or (ii) a methanediyl group. 2 Methanediyl is preferred.

[0140] The degree of polymerization o in the leveling agent of formula L3 is 2-1000. o is preferably an integer of 5-500, and most preferably 10-250.

[0141] The molecular weight of polymer leveling agent L3 is M w It can be about 500 to about 400,000 g / mol, preferably about 1,000 to about 300,000 g / mol, and most preferably about 3000 to about 250,000 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.

[0142] In a fourth embodiment, the leveling agent of formula L4, C 6 -C 14 Carbon ring or C 3 -C 10 A nitrogen or oxygen-containing heterocyclic aromatic group which may be unsubstituted or substituted with up to 3 C 1 -C 12 Alkyl or up to 2 OH, NH 2 or NO 2 Heterocyclic aryl is preferably a 5-membered or 6-membered ring system having up to 2, preferably 1, N atoms.

[0143] Preferred groups is a group of formula L4a:

[0144]

[0145] Where R 5 , R 6 , R 7 , R 8 and R 9 independently selected from (i) H and (ii) C 1 -C 6 Alkyl. 5 , R 6 , R 8 and R 9 Preferably, they are independently selected from H, methyl, ethyl or propyl, and most preferably H. 7 Preferably it is selected from H, methyl, ethyl or propyl, most preferably from methyl or ethyl.

[0146] In certain embodiments, the leveling agent 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 leveling agent may be at least about 1 ppm, or at least about 100 ppm. In these or other cases, the concentration of the leveling agent may be about 500 ppm or less, or about 1,000 ppm or less.

[0147] In one embodiment, a single leveling agent may be used in the cobalt electroplating bath, ie, the bath is substantially free of any other leveling agent as described in the following section. In another embodiment, two or more leveling agents are used in combination.

[0148] Other leveling agents

[0149] The plating composition may further comprise one or more other leveling agents.

[0150] Other leveling agents typically contain one or more nitrogen, amine, imide or imidazole, and may also contain sulfur functional groups. Certain leveling agents include one or more five-membered rings and six-membered rings and / or conjugated organic compound derivatives. The nitrogen group may constitute a part of the ring structure. In amine-containing leveling agents, the amine may be a primary, secondary or tertiary alkylamine. In addition, the amine may be an arylamine or a heterocyclic saturated or aromatic amine. Exemplary amines include, but are not limited to, dialkylamines, trialkylamines, arylalkylamines, triazoles, imidazoles, triazoles, tetrazoles, benzimidazoles, benzotriazoles, piperidine, morpholine, piperazine, pyridine, oxazole, benzoxazole, pyrimidine, quinoline and isoquinoline. Imidazole and pyridine may be applicable to some situations. Other examples of leveling agents include Janus Green B and Prussian Blue. The leveling agent compound may also contain an ethoxylate group. For example, the leveling agent may contain a general backbone similar to that found 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 epoxide moieties linked together via ether-containing linkages may be suitable for some situations. Some leveling agent compounds are polymers, while other leveling agent compounds are not polymers. Exemplary polymeric leveling agent compounds include, but are not limited to, polyethyleneimines, polyamidoamines, and reaction products of amines with various oxygen epoxides or sulfides. One example of a non-polymeric leveling agent is 6-mercapto-hexanol. Another exemplary leveling agent is polyvinylpyrrolidone (PVP).

[0151] Exemplary leveling agents that may be particularly useful in the context of cobalt deposition in combination with the leveling agents of the present invention include, but are not limited to, alkylated polyalkyleneimines, polyethylene glycols, organic sulfonates, 4-mercaptopyridine, 2-mercaptothiazoline, ethylenethiourea, thiourea, 1-(2-hydroxyethyl)-2-imidazolinethione, sodium naphthalene 2-sulfonate, acrylamide, substituted amines, imidazoles, triazoles, tetrazoles, piperidine, morpholine, piperazine, pyridine, oxazole, benzoxazole, quinoline, isoquinoline, coumarin, and derivatives thereof.

[0152] Inhibitors

[0153] The plating composition may further comprise and preferably comprises one or more inhibitors. In particular, if the semiconductor substrate to be plated comprises a recessed feature with a pore size below 100 nm, particularly below 50 nm, and even more particularly, if the aspect ratio of the recessed feature is 4 or greater, then it is generally necessary to use an inhibitor.

[0154] As used herein, "inhibitor" refers to an organic compound that reduces the plating rate of an electroplating bath on at least a portion of a substrate. In particular, the inhibitor is an additive that suppresses the plating rate on the substrate on any recessed feature. Depending on diffusion and adsorption, the inhibitor reduces the plating rate at the upper sidewall of the recessed feature. The terms "inhibitor" and "inhibiting agent" are used interchangeably throughout this specification.

[0155] As used herein, "member" refers to a cavity on a substrate, such as, but not limited to, a channel and a via. "Hole" refers to a recessed member, such as a via and a channel. Unless the context clearly indicates otherwise, the term "plating" as used herein refers to metal electroplating. "Deposition" and "plating" are used interchangeably throughout this specification.

[0156] The "hole size" of the present invention means the minimum diameter or free distance of the recessed component before plating, i.e. after seed deposition. Depending on the geometry of the component (channel, through hole, etc.), the terms "width", "diameter", "hole" and "opening" are used synonymously in this article.

[0157] As used herein, "aspect ratio" means the ratio of the depth of a recessed feature to the hole size.

[0158] Without limitation, typical inhibitors are selected from the group consisting of carboxymethyl cellulose, nonoxyphenol polyethylene glycol ether, polyethylene glycol dimethyl ether, caprylyl glycol bis(polyalkylene glycol ether), capryl alcohol polyalkylene glycol ether, polyethylene glycol oleate, polyethylene propylene glycol, polyethylene glycol, polyethylene imine, polyethylene glycol dimethyl ether, polyoxypropylene glycol, polypropylene glycol, polyvinyl alcohol, stearic acid polyethylene glycol ester, stearyl alcohol polyethylene glycol ether, polyethylene oxide, ethylene oxide-propylene oxide copolymer, butanol-ethylene oxide-propylene oxide copolymer, 2-mercapto-5-benzimidazole sulfonic acid, 2-mercaptobenzimidazole (MBI), benzotriazole, and combinations thereof.

[0159] In some embodiments, the inhibitor contains one or more nitrogen atoms, such as an amino or imine group. In some embodiments, the inhibitor is a carbon aliphatic spacer such as CH 2 CH 2 or CH 2 CH 2 CH 2 In certain embodiments, the inhibitor is polyethyleneimine (PEI, also known as polyaziridine, poly[imino(1,2-ethylenediyl)] or poly(iminoethylene)). PEI has shown excellent bottom-up filling properties in the case of cobalt deposition, as shown in the experimental results included herein.

[0160] Particularly preferred inhibitors are those of formula S1:

[0161]

[0162] In order to fill nano- or micro-sized pore sizes, in particular pore sizes of 100 nanometers or less, 20 nm or less, 15 nm or less, or even 7 nm or less.

[0163] Here, R 1 is selected from XY, wherein X is selected from a linear or branched C 1 -C 10 Alkanediyl, straight chain or branched C 2 -C 10 Alkenyl, straight chain or branched C 2 -C 10 Alkynediyl and (C 2 H 3 R 6 -O) m m is an integer selected from 1-30, preferably 1-15, even more preferably 1-10, most preferably 1-5.

[0164] In a preferred embodiment, X is selected from a linear or branched C 1 -C 6 Alkanediyl, preferably C 1 -C 4 Alkanediyl.

[0165] 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. 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.

[0166] Y is a monovalent group and can be selected from OR 3 , where R 3 Selected from (i) H; (ii) C 5 -C 20 Aryl, preferably C 5 , C 6 and C 10 Aryl; (iii) C 1 -C 10 Alkyl, preferably C 1 -C 6 Alkyl, most preferably C 1 -C 4 Alkyl; (iv) C 6 -C 20 Arylalkyl, preferably C 6 -C 10 Aralkyl; (v) C 6 -C 20 Alkyl groups, all of which can be OH, SO 3 H, COOH or a combination thereof; and (vi) (C 2 H 3 R 6 -O) n -H. In a preferred embodiment, R 3 Can be C 1 -C 6 Alkyl or H. R 6 Can be selected from H and C 1 -C 5 Alkyl, preferably H and C 1 -C 4 Alkyl, most preferably H, methyl or ethyl.

[0167] In another preferred embodiment, R 3 In another preferred embodiment, R 3 Selected from the formula (C 2 H3 R 6 -O) n -H polyoxyalkylene. 6 Selected from H and C 1 -C 5 Alkyl, preferably H and C 1 -C 4 alkyl, most preferably H, methyl or ethyl. In general, n can be an integer from 1 to 30, preferably from 1 to 15, and most preferably from 1 to 10. In a specific embodiment, polyoxymethylene, polyoxypropylene or polyoxymethylene-co-oxypropylene can be used. In another preferred embodiment, R 3 Can be selected from C 1 -C 10 Alkyl, preferably C 1 -C 6 Alkyl groups, most preferably methyl and ethyl groups.

[0168] In addition, Y can be an amino group NR 3 R 4 , where R 3 and R 4 The same or different and may have the above for OR 3 The R 3 meaning.

[0169] In a preferred embodiment, R 3 and R 4 Select H to form NH 2 In another preferred embodiment, R 3 and R 4 At least one, preferably both, are selected from the formula (C 2 H 3 R 6 -O) n -H polyoxyalkylene. 6 Selected from H and C 1 -C 5 Alkyl, preferably H and C 1 -C 4 In another preferred embodiment, R 3 and R 4 At least one, preferably both, are selected from C 1 -C 10 Alkyl, preferably C 1 -C 6 Alkyl groups, most preferably methyl and ethyl groups.

[0170] R 3 and R 4 It can also be formed together with O or NR 7 The ring system of R7 Can be selected from R 6 and The ring system may preferably contain 4 or 5 carbon atoms to form a 5-membered carbocyclic ring system or a 6-membered carbocyclic ring system. In the carbocyclic ring system, one or two carbon atoms may be replaced by oxygen atoms.

[0171] In addition, Y can be a positively charged ammonium group N + R 3 R 4 R 5 . R 3 , R 4 , R 5 The same or different and may have the above for OR 3 and NR 3 R 4 Described by R 3 In a preferred embodiment, R 3 , R 4 and R 5 Independently selected from H, methyl or ethyl.

[0172] m may be an integer selected from 1-30, preferably 1-15, even more preferably 1-10, most preferably 1-5.

[0173] In the additive of formula S1, R 2 Can be selected from R as described above 1 or R 3 If R 2 For R 1 , then you can select R 1 To form a symmetrical compound (two R 1 same) or asymmetric compounds (two R 1 different).

[0174] In a preferred embodiment, R 2 For H.

[0175] Particularly preferred aminoalkynes are those which are:

[0176] (a)R 1 For X-NR 3 R 4 And R 2 is H;

[0177] (b)R 1 For X-NR 3 R 4 , R 2 For X-NR 3 R 4 and X is selected from a linear C 1 -C 4 Alkanediyl and branched C3 -C 6 Alkanediyl.

[0178] Particularly preferred hydroxyalkynes or alkoxyalkynes are those:

[0179] (a)R 1 X-OR 3 And R 2 is H;

[0180] (b)R 1 X-OR 3 , R 2 X-OR 3 and X is selected from a linear C 1 -C 4 Alkanediyl and branched C 3 -C 6 Alkanediyl.

[0181] Particularly preferred alkynes containing an amino group and a hydroxy group are those in which R 1 X-OR 3 , especially X-OH and R 2 For X-NR 3 R 4 and X is independently selected from a linear C 1 -C 4 Alkanediyl and branched C 3 -C 6 Alkanediyl.

[0182] The amino group in the additive can be selected from primary amino groups (R 3 , R 4 H), secondary amino group (R 3 , R 4 H) and tertiary amino group (R 3 , R 4 None of them are H).

[0183] The alkyne may contain one or more terminal triple bonds or one or more non-terminal triple bonds (alkyne functional groups). The alkyne preferably contains one or more terminal triple bonds, in particular 1 to 3 triple bonds, most preferably 1 terminal triple bond.

[0184] Particularly preferred specific primary aminoalkynes are:

[0185]

[0186] Particularly preferred specific secondary aminoalkynes are:

[0187]

[0188] Particularly preferred specific tertiary aminoalkynes are:

[0189]

[0190] Other preferred additives are those wherein the remaining R 3 and R 4 Can be formed together with optional spacer O or NR 3 The remaining R 3 and R 4 Preferably one or both of them are formed together, preferably one carbon atom can be formed by O or NR 7 Exchange C 5 or C 6 A divalent group, wherein R 7 is selected from hydrogen, methyl or ethyl.

[0191] Examples of such compounds are:

[0192]

[0193] The first can be received by reaction of propargylamine with formaldehyde and morpholine, the second and third by reaction of propargyl alcohol with formaldehyde and piperidine or morpholine, respectively.

[0194] Another preferred additive comprising a saturated heterocyclic system is:

[0195]

[0196] In this case, R 3 and R 4 There are two NRs forming a spacer together 3 The ring system of the group, in which R 3 Selected from CH 2 -C≡CH. The additive contains three terminal triple bonds.

[0197] The amino groups in the additives can be further diquaternized by reaction with an alkylating agent, such as, but not limited to, dialkyl sulfates such as DMS, DES or DPS, benzyl chloride or chloromethylpyridine. Particularly preferred quaternized additives are:

[0198]

[0199] Particularly preferred specific pure hydroxyalkynes are:

[0200]

[0201] Particularly preferred aminoalkynes containing specific OH groups are:

[0202]

[0203] Also in this case, the remaining R 3 and R 4Can be formed together with optional spacer O or NR 3 The remaining R 3 and R 4 Preferably one or both of them are formed together, preferably one carbon atom can be formed by O or NR 7 Exchange C 5 or C 6 A divalent group, wherein R 7 is selected from hydrogen, methyl or ethyl.

[0204] Examples of such compounds are:

[0205]

[0206] These can be received by reaction of propargyl alcohol with formaldehyde and piperidine or morpholine, respectively.

[0207] By partial reaction with the alkylating agent, a mixture of additives can be formed. In one embodiment, such mixtures can be obtained by reacting 1 mol of diethylaminopropyne with 0.5 mol of epichlorohydrin, 1 mol of diethylaminopropyne with 0.5 mol of benzyl chloride, 1 mol of diethylaminopropyne with 0.9 mol of dimethyl sulfate, 1 mol of dimethylpropargylamine with 0.33 mol of dimethyl sulfate or 1 mol of dimethylpropargylamine with 0.66 mol of dimethyl sulfate. In another embodiment, such mixtures can be obtained by reacting 1 mol of dimethylpropargylamine with 1.5, 1.9 or 2.85 mol of dimethyl sulfate, 1 mol of dimethylpropargylamine with 0.5 mol of epichlorohydrin, 1 mol of dimethylpropargylamine with 2.85 diethyl sulfate or 1 mol of dimethylpropargylamine with 1.9 mol of dipropyl sulfate.

[0208] In another embodiment, the inhibitor may be SO 3 H (sulfonic acid) group or COOH (carboxyl) substitution. 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.

[0209] In general, the total amount of inhibitor in the electroplating bath is 0.5-10,000 ppm based on the total weight of the plating bath. Although larger or smaller amounts can be used, the inhibitor is used in a total amount of about 0.1-about 1,000 ppm, more typically 1-100 ppm, based on the total weight of the plating bath. Preferred concentration ranges are, for example, about 10-60 ppm or about 15-60 ppm or about 30-60 ppm. In this context, one part per million (ppm) is the mass fraction of inhibitor molecules in the electrolyte. In some cases, the concentration of the inhibitor may be at least about 10 ppm or at least about 15 ppm or at least about 20 ppm or at least about 30 ppm or at least about 50 ppm. In these or other cases, the concentration of the inhibitor may be about 1,000 ppm or less, such as about 500 ppm or less, about 100 ppm or less, about 75 ppm or less, about 60 ppm or less, or about 50 ppm or less.

[0210] Other additives

[0211] A wide variety of other additives may typically be used in the bath to provide the desired surface finish for the plated Co metal. Often more than one additive is used, with 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 trapped air or hydrogen bubbles etc. Other components to be added are grain refiners, stress reducers, leveling agents and mixtures thereof.

[0212] The bath may also contain a complexing agent for the cobalt ions, such as, but not limited to, sodium acetate, sodium citrate, EDTA, sodium tartrate, or ethylenediamine.

[0213] Other 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.

[0214] In another 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.

[0215] In a preferred embodiment, nonionic surfactants are used. Typical nonionic surfactants are fluorinated surfactants, polyglycols, or molecules containing polyoxyethylene and / or oxypropylene.

[0216] Electrolytes

[0217] In one embodiment, the aqueous plating baths typically used for void-free filling with cobalt may contain a source of cobalt ions, such as, but not limited to, cobalt sulfate, cobalt chloride, or cobalt sulfamate. The metal ions are preferably substantially composed of cobalt ions. As used herein, "substantially composed of cobalt ions" means that the content of other metal ions is less than 1% by weight, preferably less than 0.1% by weight, and more preferably less than 0.01% by weight. Most preferably, the electrodeposition composition does not contain any metal ions other than cobalt ions.

[0218] The cobalt ion concentration in the electroplating solution may be 0.01-1 mol / l. In one specific example, the ion concentration may be 0.1-0.6 mol / l. In another specific example, the range may be 0.3-0.5 mol / l. In yet another specific example, the range may be 0.03-0.1 mol / l.

[0219] In a preferred embodiment, the composition is substantially free of chloride ions. "Substantially free of chloride ions" means that the chloride ion content is below 1 ppm, in particular below 0.1 ppm.

[0220] During deposition, the pH of the plating bath can be adjusted to have a high Faradaic efficiency while avoiding co-deposition of cobalt hydroxide. To this end, a pH range of 1-5 can be used. In a specific example, a pH range of 2-4.5 can be used. In another specific example, a pH range of 3-4 can be used. The pH is preferably below 5, and most preferably below 4.

[0221] In a preferred embodiment, boric acid may be used as a supporting electrolyte in the cobalt electroplating bath. Boric acid may be introduced into the composition at a concentration of about 15 to about 40 g / l, such as about 5 to about 50 g / l.

[0222] In another preferred embodiment, the cobalt electrodeposition composition comprises an ammonium compound. The ammonium compound is added to the electrolyte in the form of different types of ammonium compounds such as ammonium sulfate, ammonium chloride, ammonium methanesulfonate as described in unpublished European Patent Application No. 18168249.3.

[0223] Generally speaking, ammonium compounds are represented by the formula (NR B1 R B2 R B3 H + ) n X n- describe.

[0224] Here, R B1 , R B2 and R B3 independently selected from H, straight chain or branched C 1 -C6 Alkyl. 1 , R 2 and R 3 Preferably independently selected from H and straight or branched C 1 -C 4 Alkyl, especially methyl and ethyl. More preferably R B1 , R B2 and R B3 At least one of them is H, and even more preferably R B1 , R B2 and R B3 At least two of are H. Most preferably, R B1 , R B2 and R B3 For H.

[0225] X is an n-valent inorganic or organic counter ion. Typical inorganic counter ions include, but are not limited to, chloride, sulfate (including hydrogen sulfate), phosphate (hydrogen phosphate and dihydrogen phosphate) and nitrate. Typical organic counter ions include, but are not limited to, C 1 -C 6 Alkyl sulfonate, preferably methane sulfonate, C 1 -C 6 Carboxylate, preferably acetate or citrate, phosphonate, sulfamate, etc. is preferred as an inorganic counterion. Chloride is the most preferred counterion X because the heterogeneity of the cobalt deposition across the wafer can be further improved by using chloride in combination with ammonium cations.

[0226] Depending on the valence of the counterion, n is an integer selected from 1, 2 or 3. For example, for chloride and hydrogen sulfate, n is 1; for sulfate or hydrogen phosphate, n is 2; for phosphate, n is 3.

[0227] Depending on the pH of the composition, the amine compound may be fully or partially protonated or deprotonated.

[0228] Preferably the cobalt or electroplating composition is substantially free of boric acid. "Substantially free of boric acid" as used herein 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.

[0229] Preferably, the electrodeposition composition does not contain zinc ions, nickel ions, and iron ions. If nickel ions or iron ions are present, the molar ratio of nickel ions and iron ions to cobalt ions and the molar ratio of the sum of zinc ions, nickel ions, and iron ions to cobalt ions are preferably no greater than about 0.01 or are from about 0.00001 to about 0.01.

[0230] The electrodeposition composition is also preferably substantially free of copper ions. Although it may be difficult to avoid very small amounts of copper contamination, it is particularly preferred that the electroplating bath contain no more than 20 ppb copper ions, such as 0.1 to 20 ppb.

[0231] The electrodeposition composition preferably does not contain cobaltous ions (Co 2+ ) is reduced to metallic cobalt (Co 0 ). "Functional concentration" means any concentration of a reducing agent that can effectively reduce cobaltous ions in the absence of an electrolytic current or that is activated by an electrolytic current or electrolytic field to react with cobaltous ions.

[0232] The electrodeposition composition is substantially free of dispersed particles, preferably free of particles. "Substantially free of dispersed particles" means that there are no macroscopic particulate solids in the solution that are dispersed and thus negatively interfere with the metal electroplating process. Any particles that are deposited and not dispersed during bath storage or during the electroplating process generally do not interfere with metal electroplating.

[0233] The electrodeposition composition is preferably a homogeneous composition. "Homogeneous" as used herein means that the composition is a solution of the components in a liquid that is substantially free of any particles, particularly free of any dispersed particles.

[0234] method

[0235] An electrolytic bath comprising cobalt ions and at least one additive of the present invention is prepared. A dielectric substrate having a seed layer is placed in the electrolytic bath, wherein the electrolytic bath contacts at least one exterior surface and, in the case of a dielectric substrate, a three-dimensional pattern having 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.

[0236] The present invention can be used to deposit a layer comprising cobalt on various substrates, particularly substrates having nanometer-sized and various-sized holes. 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 holes. In one embodiment, semiconductor devices are plated according to the present invention. The semiconductor devices include, but are not limited to, wafers used to manufacture integrated circuits.

[0237] In order to allow deposition on a substrate comprising a dielectric surface, a seed layer needs to be applied to the surface. The seed layer may be composed of cobalt, iridium, osmium, palladium, platinum, rhodium and ruthenium or an alloy comprising the metal. Preferably, it is deposited on a cobalt seed. The seed layer is described in detail, for example, in US20140183738A.

[0238] The seed layer can be deposited or grown by chemical vapor deposition (CVD), atomic layer deposition (ALD), physical vapor deposition (PVD). Electroplating, electroless plating or other suitable methods for depositing conformal 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 opening and the upper surface. In one embodiment, a high-quality seed layer can be formed. The conformal seed layer is uniformly and continuously deposited by depositing the cobalt seed material at a slow deposition rate. By forming the seed layer in a conformal manner, the compatibility of the subsequently formed fill material with the underlying structure can be improved. In particular, the seed layer can assist the deposition process by providing appropriate surface energetics for deposition thereon.

[0239] The substrate preferably comprises submicron-sized features and cobalt deposition is performed to fill the submicron-sized features. Most preferably, the submicron-sized features have an (effective) pore size of 10 nm or less and / or have an aspect ratio of 4 or more. More preferably, the features have a pore size of 7 nanometers or less, most preferably 5 nanometers or less.

[0240] The electrodeposition current density should be selected to promote void-free, especially bottom-up filling behavior. For this purpose, 0.1-40 mA / cm 2 In a specific example, the current density may be 1-10 mA / cm 2 In another specific embodiment, the current density may be 5-15 mA / cm 2 .

[0241] General requirements for a cobalt electrodeposition process on a semiconductor integrated circuit substrate are described in US 2011 / 0163449 A1.

[0242] Typically, the substrate is electroplated by contacting the substrate with the plating bath of the present invention. The substrate typically acts as a cathode. The plating bath contains an anode, which may be soluble or insoluble. Optionally, the cathode and anode may be separated by a membrane. Typically, a potential is applied to the cathode. Sufficient current density is applied and plating is carried out 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, 1-250 mA / cm 2 Typically, when used to deposit cobalt in integrated circuit manufacturing, the current density is 1-60 mA / cm 2 The specific current density depends on the substrate to be plated, the selected leveling agent, etc. The current density selection is within the capabilities of those skilled in the art. The applied current may be direct current (DC), pulsed current (PC), pulsed reverse current (PRC), or other suitable current.

[0243] Typically, 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 stirred during use. Any suitable agitation method can be used with the present invention and these methods are well known in the art. Suitable agitation methods include, but are not limited to, inert gas or air injection, workpiece agitation, jetting, etc. These methods are known to those skilled in the art. When the present invention is used to plate an integrated circuit substrate such as a wafer, the wafer can be rotated at, for example, 1-300 RPM and the plating solution can be contacted with the rotating wafer, for example, by pumping or spraying. In an alternative, when the plating bath flows enough to provide the desired metal deposition, there is no need to rotate the wafer.

[0244] Cobalt is deposited in the pores according to the present invention without substantially forming voids within the metal deposit.

[0245] “Void-free filling” as used herein can be ensured by very pronounced bottom-up cobalt growth while perfectly suppressing sidewall cobalt growth, both of which lead to a flat growth front and thus provide essentially defect-free trench / via filling (so-called bottom-up filling); or by so-called V-shaped filling.

[0246] 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 voids. Preferably, at least 98% of the plated holes are free of seams, and most preferably, all plated holes are free of seams.

[0247] The plating equipment for plating semiconductor substrates is well-known. The plating equipment includes a plating tank that holds the Cu electrolyte and is made of suitable materials such as plastics or other materials that are inert to the electrolytic plating solution. The plating tank can be cylindrical, especially for wafer plating. The cathode is horizontally placed on the top of the groove and can be any type of substrate, for example, a silicon wafer with an opening such as a trench and a through hole. Usually, the wafer substrate is coated with a seed layer of Co or other metals or a layer containing metal to cause plating thereon. For wafer plating, the anode is also preferably circular, and is horizontally placed on the bottom of the groove, thereby forming a space between the anode and the cathode. The anode is generally a soluble anode.

[0248] These bath additives can be used in combination with membrane technology developed by various tool manufacturers. In this system, the anode can be isolated from the organic bath additives by a membrane. The purpose of isolating the anode from the organic bath additives is to minimize oxidation of the organic bath additives.

[0249] The cathode substrate and the anode are electrically connected to a rectifier (power supply) by wiring, respectively. The cathode substrate for direct current or pulse current has a net negative charge to reduce the Co ions in the solution at the cathode substrate, thereby forming a plated Co metal on the cathode surface. An oxidation reaction occurs at the anode. The cathode and anode can be placed in the tank horizontally or vertically.

[0250] Although the method of the present invention has been generally described with reference to semiconductor manufacturing, it will be appreciated that the present invention is applicable to any electrolytic process requiring substantially void-free cobalt deposition. Such processes include printed wiring board manufacturing. For example, the plating bath of the present invention can be used to plate through-holes, pads or traces on a printed wiring board, and can be used for bump plating on a wafer. Other suitable processes include package and interconnect manufacturing. Thus, suitable substrates include lead frames, interconnects, printed wiring boards, and the like.

[0251] Unless otherwise stated, all percentages, ppm or comparable values ​​refer to weight relative to the total weight of the corresponding composition.All cited documents are incorporated herein by reference.

[0252] The following examples will further illustrate the present invention but are not intended to limit the scope of the present invention. Example

[0253] A. Example leveling agent

[0254] Leveling agent 1: (mass average) molecular weight M w A copolymer of 3,000 g / mol and a MA content of 50% by weight of acrylic acid and maleic acid.

[0255] Leveling agent 2: molecular weight M w A copolymer of acrylic acid and methacrylic acid having a weight of 20,000 g / mol and a MA content of 70% by weight.

[0256] Leveling agent 3: molecular weight M w 2,500 g / mol polyacrylic acid

[0257] Leveling agent 4: molecular weight M w 250,000 g / mol polyacrylic acid

[0258] Leveling agent 5: sodium p-toluenesulfonate

[0259]

[0260] Leveling agent 6: vinylphosphonic acid

[0261] Leveling agent 7: molecular weight M w 2,310 g / mol of polyvinylphosphonic acid

[0262] Leveling agent 8: molecular weight Mw 250,000 g / mol of polyvinyl sulfonic acid,

[0263] These compounds are available commercially.

[0264] B. Plating Experiment

[0265] Example 1 (Comparative)

[0266] Using a constant potential device, the wafer coupon was immersed in an electrolyte bath opposite to a blank Co anode for plating. The electrolyte was an aqueous sulfuric acid Co-based solution consisting of 3 g / l cobalt, 33 g / l boric acid and water. 1M H 2 SO 4 The electrolyte was adjusted to pH 2.75. An acetylene alcohol inhibitor was used at a concentration of 72 ppm. The electrolyte was maintained at 25°C and pH 2.75. Before constant current control could be performed, the patterned wafer test pieces were immersed in the electrolyte solution at a constant potential inlet of -1V for 0.5 seconds, wherein each test piece included channel components of various sizes of 40nm, 50nm, 85nm and 120nm (spacing: 1:1). Constant current plating was then performed in a two-step process: Step 1, 2 mA / cm was applied 2 The current density was 200 seconds, wherein the wafer test piece cathode was rotated at 100 rpm; Step 2, 10 mA / cm 2 The current density was 110 seconds with the wafer coupons spinning at 25 rpm. Plating conditions were selected so that optimal filling was achieved with a bath containing only inhibitor, and plating was performed with a bath containing only inhibitor and a bath containing a combination of inhibitor and leveling agent.

[0267] The measurement of the bump height was done by profilometry and was measured relative to a reference point in the unpatterned wafer area. The results are summarized in Table 1. The cobalt deposition that failed in the desired leveling can be clearly seen from the formation of bumps exceeding 200 nm in densely packed features.

[0268] Embodiment 2-9

[0269] Example 1 was repeated, but the corresponding leveling agent was added to the plating bath in the concentrations described in Table 1.

[0270] The results are summarized in Table 1. Table 1 shows that the cobalt deposition provides the desired leveling behavior. This can be seen in particular from the reduced ridge formation, especially in densely packed features of 40 nm and 50 nm width, when a corresponding leveling agent is added.

[0271] Table 1

[0272]

Claims

1. A composition for electroplating cobalt, comprising the following components: (a) metal ions consisting essentially of cobalt ions, and (b) a leveling agent comprising a compound of formula L1: [B] n [A] p (L1) and their salts, in: A is a comonomer selected from vinyl alcohol and acrylamide, which may be optionally ethoxylated or polyethoxylated, B is selected from the formula L1a: R 1 Choice X 1 -CO-OR 11 , X 1 -SO 2 -OR 11 Japanese X 1 -PO(OR 11 ) 2 ; R 2 , R 3 , R 4 Independently selected from R 1 and (i) H, (ii) aryl, (iii) C 1 -C 10 alkyl, (iv) aralkyl, (v) alkaryl and (vi) -(OC 2 H 3 R 12 ) m -OH, provided that if R 2 , R 3 or R 4 One of the selected R 1 , then other groups R 2 , R 3 or R 4 Different from R 1 , X 1 is a divalent group selected from the following: (i) a chemical bond, (ii) an aromatic group, (iii) a C group which may be interrupted by an O atom 1 -C 12 Alkanediyl, (iv) aralkyl-X 11 -X 12 -, (v) alkylaryl-X 12 -X 11 - and (vi)-(OC 2 H 3 R 12 ) m O-, R 11 Selected from H and C 1 -C 4 alkyl, R 12 Selected from H and C 1 -C 4 alkyl, X 12 is a divalent aromatic group, X 11 For divalent C 1 -C 15 Alkanediyl, n is an integer from 2 to 10,000, m is an integer from 2 to 50, and p is 0 or an integer from 1 to 10,000, And wherein the composition does not contain any dispersed particles.

2. The composition of claim 1, wherein R 2 , R 3 and R 4 Selected from H, methyl, ethyl or propyl.

3. The composition of claim 1, wherein R 2 and R 3 or R 4 is selected from H, methyl, ethyl or propyl, and the other groups R 3 or R 4 Selected from R 1 .

4. The composition of claim 1, wherein R 3 and R 4 is selected from H, methyl, ethyl or propyl, and R 2 Selected from R 1 .

5. The composition of any one of claims 1 to 4, wherein R 11 For H.

6. The composition of any one of claims 1 to 4, wherein n+p is an integer from 10 to 5000 and m is an integer from 2 to 30.

7. The composition of claim 5, wherein n+p is an integer from 10 to 5000 and m is an integer from 2 to 30.

8. The composition of any one of claims 1 to 4, wherein the leveling agent is selected from the group consisting of polyacrylic acid, polyitaconic acid, maleic acid acrylic acid copolymer, itaconic acid acrylic acid copolymer, polyphosphonic acid and polysulfonic acid.

9. The composition of claim 7, wherein the leveling agent is selected from the group consisting of polyacrylic acid, polyitaconic acid, maleic acid acrylic acid copolymer, itaconic acid acrylic acid copolymer, polyphosphonic acid and polysulfonic acid.

10. The composition of any one of claims 1 to 4, wherein R 1 It is a sulfonate group.

11. The composition of claim 5, wherein R 1 It is a sulfonate group.

12. The composition of any one of claims 1-4, wherein the composition further comprises an inhibitor selected from hydroxyalkynes or aminoalkynes.

13. The composition of claim 11, wherein the composition further comprises an inhibitor selected from hydroxyalkynes or aminoalkynes.

14. Use of a compound for depositing a metal consisting essentially of cobalt on a semiconductor substrate, wherein the semiconductor substrate comprises recessed features with a pore size below 100 nm, the compound comprising the structural element of formula L1: [B] n [A] p (L1) and their salts, in: A is a comonomer selected from vinyl alcohol and acrylamide which may be optionally ethoxylated or polyethoxylated, and B is selected from the formula L1a: R 1 Choice X 1 -CO-OR 11 , X 1 -SO 2 -OR 11 Japanese X 1 -PO(OR 11 ) 2 ; R 2 , R 3 , R 4 Independently selected from R 1 and (i) H, (ii) aryl, (iii) C 1 -C 10 Alkyl, (iv) aralkyl, (v) alkylaryl and (vi) -(OC 2 H 3 R 12 ) m -OH, provided that if R 2 , R 3 or R 4 One of the selected R 1 , then other groups R 2 , R 3 or R 4 Different from R 1 , X 1 is a divalent group selected from the following: (i) a chemical bond, (ii) an aromatic group, (iii) a C group which may be interrupted by an O atom 1 -C 12 Alkanediyl, (iv) aralkyl-X 11 -X 12 -, (v) alkylaryl-X 12 -X 11 - and (vi)-(OC 2 H 3 R 12 ) m O-, R 11 Selected from H and C 1 -C 4 alkyl, R 12 Selected from H and C 1 -C 4 alkyl, X 12 is a divalent aromatic group, X 11 For divalent C 1 -C 15 Alkanediyl, n is an integer from 2 to 10,000, m is an integer from 2 to 50, and p is 0 or an integer from 1 to 10,000.

15. Use according to claim 14, wherein the semiconductor substrate comprises recessed features with a pore size below 50 nm.

16. A method of depositing cobalt onto a semiconductor substrate comprising a recessed feature having a pore size below 100 nm, the method comprising: include: (a) contacting the composition according to any one of claims 1 to 13 with the semiconductor substrate, (b) Applying an electrical potential for a time sufficient to fill the recessed features with cobalt.

17. The method of claim 16, comprising a step (a1) comprising depositing cobalt seeds onto the dielectric surface of the recessed feature prior to step (a).

18. The method of claim 16 or 17, wherein the pore size of the concave member is 30 nm or less.

19. The method of claim 18, wherein the pore size of the concave member is 15 nm or less.

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