Composition for electroplating tin-silver alloys containing a complexing agent

Abstract

(a) metal ions including or consisting of tin ions and silver ions; and (b) a compound of formula C11 R C12 -X C11 -R C11 (C11) [In the formula, X C11 teeth, (a) (i) one N atom, or (ii) a first N atom and a second heteroatom selected from N and S, the first N atom and the second heteroatom being separated by at least one C atom; or (iii) triazole or thiadiazole a divalent 5- or 6-membered aromatic N-heterocyclic group containing (b) a divalent six-membered aromatic carbocyclic group, (c) a divalent 5- or 6-membered aliphatic N-heterocyclic group containing one N atom and optionally a second heteroatom selected from N and O; all of which may be unsubstituted or contain one or more OH or one or more R C14 may be substituted with R C11 teeth, (a)-X C12 -S[-X C13 -D C11 ] n -R C13 , [Formula 1] Selected from TIFF2022549593000044.tif5971, R C12 is R C11 , X C11 -R C11 , H, OH, NR C14 2. C1~C 10 Alkyl, and C1-C 10 alkoxy; X C12 is a chemical bond or a linear, branched or cyclic C1-C6 alkanediyl which may be unsubstituted or substituted with OH, provided that (a) X C11is a divalent 5- or 6-membered aromatic N-heterocyclic group, and (b) R C13 is substituted with one OH, and (c) R C12 R C11 Otherwise, X C12 is a chemical bond, X C13 is a linear, branched or cyclic C1-C6 alkanediyl which may be unsubstituted or substituted with OH, X C14 is a chemical bond or a linear or branched C1-C4 alkanediyl, D C11 is selected from S and O; R C13 is (a) a linear, branched or cyclic C1-C6 alkyl which may be unsubstituted or substituted with one or more OH; (b) X C11 is not an aromatic carbocyclic group, Ph, X C14 -Ph (Ph=phenyl), and (c) a C2-C4 polyoxyalkylene group, provided that X C11 is a divalent 5- or 6-membered aromatic N-heterocyclic group, R C13 is unsubstituted or substituted with one OH, with the exception of X C11 is a divalent 5- or 6-membered aromatic N-heterocyclic group containing a first N atom and a second heteroatom selected from N, then R C13 is non-substituted, R C14 is selected from H and linear, branched or cyclic C1-C6 alkyl; n is 0 or an integer from 1 to 5. and salts thereof.

Description

[Technical Field]

[0001] The present invention relates to a tin-silver alloy electroplating composition containing a complexing agent, a method for using the same, and a method for electroplating tin-silver alloys. [Background technology]

[0002] Metals and metal alloys are commercially important, particularly in the electronics industry, where they are often used as electrical contacts, final finishes, and solders. Lead-free solders such as tin, tin-silver, tin-copper, tin-bismuth, tin-silver-copper, and others are common metals used in solders. These solders are often deposited on semiconductor substrates by means of metal electroplating baths.

[0003] Certain applications of lead-free solder plating present challenges in the electronics industry: for example, when used as a capping layer on copper pillars, a relatively small amount of lead-free solder, such as tin or tin-silver solder, is deposited on top of the copper pillar.

[0004] A typical tin-silver plating solution contains dissolved tin and silver ions, water, an acid electrolyte (such as sulfuric acid or methanesulfonic acid in an amount sufficient to render the bath conductive), an antioxidant, and proprietary additives to improve plating uniformity and deposited metal quality in terms of surface roughness, coplanarity, and void formation. Such additives usually contain complexing agents that (a) combine with tin to stably dissolve silver, and (b) can form complexes with silver to deposit it alongside the less noble tin.

[0005] JP2007218952A, EP166347A, and EP144990A disclose photographic films containing a silver compound and a sulfur-containing compound containing a nitrogen-containing ring system substituent such as 1,8-bis(2-pyridyl)-3,6-dithiaoctane or 1,11-bis(2-pyridyl)-3,6,9-trithiaundecane.

[0006] JP2006206946A discloses, inter alia, the formula R a -S-(CH2-CH2-S) n -R b The present invention discloses a silver plating bath containing the compound of formula (I) which can be used to deposit silver on printed circuit boards, semiconductor integrated circuits, resistors, variable resistors, capacitors, filters, inductors, thermistors, crystal oscillators, switches, wires, and other electronic components.

[0007] US6607653B1 discloses compositions for depositing tin-copper, tin-copper-bismuth, or tin-copper-silver alloys that contain certain sulfur-containing compounds, one of which may be 1,10-di(2-pyridyl)-1,4,7,10-tetrathiadecane.

[0008] US 2012 / 138471 A1 and EP 2626449 A2 disclose tin-silver alloy electroplating compositions containing N-heterocyclic thiol complexing agents such as mercaptopyridine.

[0009] WO2019 / 185468 discloses a tin-silver alloy electroplating composition containing a complexing agent, a method for using the same, and a method for electroplating a tin-silver alloy. The complexing agent contains at least a spacer group X 21 and again separated by a spacer group X 1 and X 3 It contains at least two sulfur atoms terminated by a 5- or 6-membered aromatic N-heterocyclic group containing one or two N atoms separated by [Prior art documents] [Patent documents]

[0010] [Patent Document 1] JP2007218952A [Patent Document 2] EP166347A [Patent Document 3] EP144990A [Patent Document 4] JP2006206946A [Patent Document 5] US6607653B1 [Patent Document 6] US2012 / 138471A1 [Patent Document 7] EP2626449A2 [Patent Document 8] WO2019 / 185468 Summary of the Invention [Problem to be solved by the invention]

[0011] It is an object of the present invention to provide a tin-silver electroplating composition that is stable for extended periods of time without exhibiting significant degradation or aging, e.g., by the development of strong coloration or deposits, and that is capable of electrodepositing tin-silver alloys onto semiconductor substrates. [Means for solving the problem]

[0012] The present invention relates to a compound comprising (a) metal ions, including tin ions and silver ions, and (b) a compound of formula C11 R C12 -X C11 -R C11 (C11) [In the formula, X C11 teeth, (a) (i) one N atom, or (ii) a first N atom and a second heteroatom selected from N and S, the first N atom and the second heteroatom being separated by at least one C atom; or (iii) triazole or thiadiazole a divalent 5- or 6-membered aromatic N-heterocyclic group containing (b) a divalent six-membered aromatic carbocyclic group, (c) a divalent 5- or 6-membered aliphatic N-heterocyclic group containing one N atom and optionally a second heteroatom selected from N and O; all of which may be unsubstituted or contain one or more OH or one or more R C14 may be substituted with R C11 is (a)-X C12 -S[-X C13 -D C11 ] n -R C13 ,

[0013] [ka] is selected from R C12 is R C11 , X C11 -R C11 , H, OH, NR C14 2. C1~C 10 Alkyl, and C1-C 10 alkoxy; X C12 is a chemical bond or a linear, branched or cyclic C1-C6 alkanediyl which may be unsubstituted or substituted with OH, provided that X C11 is (a) a divalent 5- or 6-membered aromatic N-heterocyclic group, and (b) R C13 is substituted with one OH, and (c) R C12 R C11 Otherwise, X C12 is a chemical bond, X C13 is a linear, branched or cyclic C1-C6 alkanediyl which may be unsubstituted or substituted with OH, X C14 is a chemical bond or a linear or branched C1-C4 alkanediyl, D C11 is selected from S and O; R C13 is (a) a linear, branched or cyclic C1-C6 alkyl which may be unsubstituted or substituted with one or more OH; (b) X C11 is not an aromatic carbocyclic group, Ph, X C14-Ph (Ph=phenyl), and (c) a C2-C4 polyoxyalkylene group, provided that X C11 is a divalent 5- or 6-membered aromatic N-heterocyclic group, R C13 is unsubstituted or substituted with one OH, with the exception of X C11 is a divalent 5- or 6-membered aromatic N-heterocyclic group containing a first N atom and a second heteroatom selected from N, then R C13 is non-substituted, R C14 is selected from H and linear, branched or cyclic C1-C6 alkyl; n is 0 or an integer from 1 to 5. and salts thereof.

[0014] With the aid of the complexing agent, the plating bath is stable for extended periods of time without exhibiting coloration or deposition, and is capable of electrodepositing tin-silver alloys onto semiconductor substrates, particularly tin-silver alloy solder bumps.

[0015] The present invention further relates to a method of using a tin-silver alloy plating bath comprising the composition defined herein for depositing a tin-silver alloy on a substrate, the tin-silver alloy comprising features having an opening size of from 500 nm to 500 μm.

[0016] The present invention further comprises: a) contacting a composition as defined herein with a substrate; b) depositing a tin-silver alloy layer on the substrate by applying an electric current to the substrate for a time sufficient to deposit a tin or tin alloy layer on the substrate; The method relates to a method in which the substrate includes features with opening sizes of 500 nm to 500 μm, and the deposition is carried out to fill the features.

[0017] The present invention further provides 3-[2-(2,3-dihydroxypropyl-sulfanyl)phenyl]sulfanylpropane-1,2-diol, 3-[2-(2,3-dihydroxypropylsulfanyl)-4-methyl-phenyl]sulfanylpropane-1,2-diol, 3-[[2-(2,3-dihydroxypropylsulfanylmethyl)phenyl]methylsulfanyl]propane-1,2-diol, 2,6-bis(2-ethylsulfanylethylsulfanylmethyl)pyridine, morpholine-4-carbo-dithioate tetramethylammonium salt, piperazine-1,4-dicarbodithioate ditetramethylammonium salt, 3-[[3-(2,3-dihydroxypropylsulfanylmethyl)phenyl]methylsulfanyl]propane-1,2-diol, 2-[2-(2-propylsulfanylethylsulfanyl)ethyl]pyridine, 2-[2-(2- the complexing agent is selected from the group consisting of 2-(2-ethylsulfanylethylsulfanylmethyl)-6-[6-(2-ethylsulfanylethylsulfanylmethyl)-2-pyridyl]pyridine, 2,6-bis(2-methylsulfanylethylsulfanylmethyl)pyridine, 4-[2-(2-ethylsulfanylethylsulfanyl)ethyl]morpholine, 2-[2-(2-isopropylsulfanylethylsulfanyl)ethyl]pyridine, 2-(2-propylsulfanylethyl-sulfanylmethyl)pyridine, 2-[2-(2-ethylsulfanylethylsulfanyl)-1-methyl-ethyl]thiazole, 2-[2-(2-benzylsulfanylethylsulfanyl)ethyl]pyridine and 2-[2-(2-phenylsulfanylethylsulfanyl)ethyl]pyridine, and salts thereof. [Brief explanation of the drawings]

[0018] [Figure 1] 1 is an SEM image of tin bumps electroplated according to Comparative Example 3.1. [Figure 2] 1 is an SEM image of tin bumps electroplated according to Example 3.2. [Figure 3]1 is an SEM image of tin bumps electroplated according to Example 3.3. DETAILED DESCRIPTION OF THE INVENTION

[0019] Complexing agents according to the present invention It has been discovered that a composition for electroplating tin-silver alloys according to the present invention, which contains at least one complexing agent described below, is stable for long periods of time without producing coloration or deposition, and is capable of electrodepositing tin-silver alloys onto semiconductor substrates, particularly tin-silver alloy solder bumps, where long-term stability means a bath that is stable for a period of at least six months.

[0020] In addition to stannous and silver ions, the aqueous composition (preferably an aqueous solution) according to the present invention may also contain tin ions and silver ions of formula C11 R C12 -X C11 -R C11 (C11) and salts thereof.

[0021] In formula C11, X C11 teeth, (a) (i) one N atom, or (ii) a first atom and a second heteroatom selected from N and S, wherein the first N atom and the second heteroatom are separated by at least one C atom; or (iii) triazole or thiadiazole a divalent 5- or 6-membered aromatic N-heterocyclic group containing (b) a divalent six-membered aromatic carbocyclic group, (c) a divalent 5- or 6-membered aliphatic N-heterocyclic group containing a first N atom and optionally a second heteroatom selected from N and O. (All of these may be unsubstituted or may contain one or more OH or one or more R C14 (which may be substituted with is selected from R C11 is (a)-XC12 -S[-X C13 -D C11 ] n -R C13 ,

[0022] [ka] is selected from R C12 is R C11 , X C11 -R C11 , H, OH, NR C14 2. C1~C 10 Alkyl, and C1-C 10 alkoxy; X C12 is a chemical bond or a linear, branched or cyclic C1-C6 alkanediyl which may be unsubstituted or substituted by OH, provided that X C11 is (a) a divalent 5- or 6-membered aromatic N-heterocyclic group, and (b) R C13 is substituted with one OH, and (c) R C12 R C11 Otherwise, X C12 is a chemical bond, X C13 is a linear, branched or cyclic C1-C6 alkanediyl, preferably a linear or branched C1-C4 alkanediyl, which may be unsubstituted or substituted with OH, preferably unsubstituted; X C14 is a chemical bond or a linear or branched C1-C4 alkanediyl, preferably a chemical bond, methanediyl, ethanediyl, 1,2- or 1,3-propanediyl, D C11 is selected from S and O, preferably S; R C13 is (a) a linear, branched or cyclic C1-C6 alkyl which may be unsubstituted or substituted with one or more OH; (b) X C11 is not an aromatic carbocyclic group, Ph, X C14-Ph (Ph=phenyl), and (c) a C2-C4 polyoxyalkylene group, provided that X C11 is a divalent 5- or 6-membered aromatic N-heterocyclic group, R C13 is unsubstituted or substituted with one OH, with the exception of X C11 is a divalent 5- or 6-membered aromatic N-heterocyclic group containing a first N atom and a second heteroatom selected from N, then R C13 is non-substituted, R C14 is selected from H and linear, branched or cyclic C1-C6 alkyl, preferably H and linear or branched C1-C4 alkyl, most preferably H, methyl, ethyl, 1-propyl or 2-propyl; n is 0 or an integer of 1 to 5, preferably 0, 1 or 2, and most preferably 0 or 1.

[0023] Essentially, such complexing agents contain one or two sulfur-containing groups R C11 A carbocyclic or heterocyclic moiety X to which is attached C11 Includes:

[0024] As used herein, a "chemical bond" refers to the absence of each moiety, but the adjacent moieties being bridged such that a direct chemical bond is formed between them. For example, in XYZ, if the Y moiety is a chemical bond, then the adjacent moieties X and Z together form the group XZ.

[0025] carbocyclic or heterocyclic group X C11 In a first embodiment, the divalent cyclic moiety X C11 may be unsubstituted or may contain one or more OH or one or more R C14 , in particular a 5- or 6-membered aromatic N-heterocyclic group optionally substituted by methyl, ethyl or propyl.

[0026] As used herein, "5- or 6-membered" means that the ring itself contains 5 or 6 carbon atoms or heteroatoms, while not including any substituents.

[0027] In a first alternative of the first embodiment, the heteroaromatic moiety X C11 may have one N atom. Examples of 5-membered N-heterocyclic groups include, but are not limited to, pyrrole. Examples of 6-membered N-heterocyclic groups include, but are not limited to, pyridine. All of these may be unsubstituted or may contain one or more OH or one or more R C14 , in particular methyl, ethyl or propyl.

[0028] In a second alternative of the first embodiment, the cyclic moiety X C11 may have a first N atom and a second heteroatom selected from N and S, and the first N atom and the second heteroatom are separated by at least one C atom. Examples of 5-membered N-heterocyclic groups include, but are not limited to, imidazole, thiazole, or isothiazole. Examples of 6-membered N-heterocyclic groups include, but are not limited to, pyrimidine or pyrazine. All of these may be unsubstituted or may contain one or more OH or one or more R C14 , in particular methyl, ethyl or propyl.

[0029] In a third alternative of the first embodiment, the heteroaromatic moiety X C11 may be a triazole or a thiadiazole, all of which may be unsubstituted or may contain one or more OH or one or more R C14 , in particular methyl, ethyl or propyl.

[0030] In a second embodiment, the cyclic moiety X C11 may be unsubstituted or may contain one or more OH or one or more R C14The aromatic carbocyclic group may be a divalent six-membered aromatic carbocyclic group, optionally substituted with, in particular, methyl, ethyl, or propyl. Such aromatic carbocyclic groups may be, but are not limited to, benzene, toluene, xylene, and hydroxybenzene.

[0031] In a third embodiment, the cyclic moiety X C11 may be a divalent 5- or 6-membered aliphatic N-heterocyclic group containing a first N atom and optionally a second heteroatom selected from N and O, which may be unsubstituted or may contain one or more OH or one or more R C14 , in particular methyl, ethyl or propyl.

[0032] In a first alternative, such divalent 5- or 6-membered aliphatic N-heterocyclic groups may have only one N atom incorporated into a ring system such as, but not limited to, pyrrolidine or piperidine, which preferably has an R C11 is replaced by

[0033] In a second alternative, such divalent 5- or 6-membered aliphatic N-heterocyclic groups may have two N atoms incorporated into a ring system, such as, but not limited to, imidazolidine and piperazine, which may be unsubstituted or may contain one or more OH or one or more R C14 , in particular methyl, ethyl or propyl.

[0034] In a third alternative, such a divalent 5- or 6-membered aliphatic N-heterocyclic group may have one N atom incorporated into the ring system and one O atom incorporated into or attached to the ring system. When the O atom is incorporated into the ring system, it forms an ether group, and when attached thereto, it may be a C=O group. Examples of 5-membered heterocyclic groups include, but are not limited to, N-pyrrolidone, N-oxazolidine, succinimide, and N-hydroxysuccinimide. N-pyrrolidone is preferred. Examples of 6-membered heterocyclic groups include, but are not limited to, N-morpholine. All of these may be unsubstituted or may contain one or more OH or one or more R groups. C14 , in particular methyl, ethyl or propyl.

[0035] Sulfur-containing group R C11 In a first embodiment, the monovalent sulfur-containing group R C11 is the formula -X C12 -S-[X C13 -D C11 ] n -R C13 is selected from.

[0036] As used herein, the first divalent spacer group X C12 may be a chemical bond or a linear, branched or cyclic C1-C6 alkanediyl, preferably a chemical bond or a linear or branched C1-C4 alkanediyl, most preferably a chemical bond, methanediyl, ethanediyl or propanediyl. Such alkyl may be unsubstituted or substituted with OH. The inventors have determined that only the complexing agent, X C11 is a divalent 5- or 6-membered aromatic N-heterocyclic group, and R C13 is replaced by one OH, and R C12 is R C11 If not, X C12 It was discovered that this often occurs under conditions where chemical bonding is required.

[0037] If n>0, a further divalent spacer group X C13may be present. It may be a linear or branched C1-C6 alkanediyl, preferably a C1-C4 alkyl, most preferably methanediyl, ethanediyl or propanediyl. Such alkyl may be unsubstituted or substituted with OH.

[0038] If n>0, then a further heteroatom D C11 Such heteroatoms D 1 may be one or more additional sulfur atoms or one or more oxygen atoms.

[0039] In the first alternative, R C13 may be a linear, branched or cyclic C1-C6 alkyl which may be unsubstituted or substituted with one or more OH. Preferably, R C13 may be a straight or branched C1-C4 alkyl which may be unsubstituted or substituted with one or more OH. Most preferably, R C13 may be selected from methyl, ethyl, 1-propyl, 2-propyl, 2-hydroxyethyl, and 2,3-dihydroxypropyl.

[0040] However, X C11 is a divalent 5- or 6-membered aromatic N-heterocyclic group, R C13 The complexing agent only works properly if X is unsubstituted or substituted with only one OH, with the exception that C11 is a divalent 5- or 6-membered aromatic N-heterocyclic group containing a first N atom and a second heteroatom selected from N (i.e., the N-heterocyclic group contains two N atoms), then R C13 is non-substituted.

[0041] In yet another alternative, X C11 is not an aromatic carbocyclic group, R C13 is Ph or X C14-Ph. As used herein, Ph is phenyl. If this condition is not met, the complexing agent will not meet the required performance. In this embodiment, the preferred group R C13 is Ph, hydroxyphenyl, benzyl, 2-phenylethyl, 2- or 3-phenylpropyl, and their derivatives which can be subjected to methylation or ethylation.

[0042] In yet another alternative, R C13 may be a C2-C4 polyoxyalkylene group. Preferably, R C11 is a compound of the formula -(O-CH2-CHR C15 ) m R is a monovalent group of —OH, where m is an integer from 2 to 20, preferably from 2 to 10, and most preferably from 2 to 6. C13 R can be prepared by the polyalkoxylation of one or more alkylene oxides in this alternative and is therefore also referred to herein as a "polyalkylene oxide" or "polyoxyalkylene" group. C15 may be H, methyl or ethyl, preferably H or methyl, more preferably H or H and methyl. The most preferred polyoxyalkylene groups are polyoxyethylene or poly(oxyethylene-co-oxypropylene) groups. Polyoxyethylene groups are especially preferred.

[0043] When n is 0, the sulfur-containing group R C11 contains only one sulfur atom. If n is 1 or more, then n further heteroatoms D 1 Preferably, n is 0 or an integer of 1 to 4, more preferably 0 or an integer of 1 to 3, even more preferably 0, 1 or 2, and most preferably 0 or 1.

[0044] In another alternative, R C13 may be selected from H.

[0045] In a second embodiment, the sulfur-containing group R C11 teeth,

[0046] [ka] is selected from.

[0047] As used herein, R C14 may be selected from H and linear or branched C1-C6 alkyl, preferably H and linear or branched C1-C4 alkyl, more preferably H, methyl, ethyl or propyl, and most preferably H.

[0048] X C14 may be a chemical bond or a linear or branched C1-C4 alkanediyl, preferably a chemical bond, or methanediyl, ethanediyl, 1,2- or 1,3-propanediyl, most preferably a chemical bond.

[0049] In a third embodiment, the sulfur-containing group R C11 teeth,

[0050] [ka] is selected from.

[0051] In this specification, X C14 may be a chemical bond or a linear or branched C1-C4 alkanediyl, preferably a chemical bond, or methanediyl, ethanediyl or propanediyl, most preferably a chemical bond.

[0052] The second group R C12 Sulfur-containing group R C11 In addition to the group R C12 is present in the complexing agent.

[0053] In the first alternative, R C12 is R C11 i.e., the group R C11There is a second sulfur-containing group, which can be independently selected from the group consisting of: The first sulfur-containing group and the second sulfur-containing group can be the same or different, and are preferably the same. In this alternative, the first sulfur-containing group and the second sulfur-containing group are independently selected from the group consisting of: C11 is directly bonded to

[0054] In the second alternative, R C12 is X C11 -R C11 i.e., as in alternative 1, the group R C11 and wherein the second divalent heterocyclic group is a second sulfur-containing group that may be independently selected from the first divalent heterocyclic group X C11 and the second sulfur-containing group. The second divalent heterocyclic group and the first sulfur-containing group may be the same or different, and are preferably the same. The first divalent heterocyclic group X C11 and a second sulfur-containing group, typical non-limiting examples of such compounds include bipyridyl or biphenyl compounds.

[0055] In a third alternative, R C12 is an atom / group containing no sulfur: H, OH, NR C14 2. Linear, branched or cyclic C1-C 10 Alkyl, and linear, branched or cyclic C1-C 10 The preferred group R is selected from alkoxy groups. These groups can be used to adjust specific properties, such as solubility in aqueous solution and surface interaction, to desired levels. In this embodiment, the preferred group R C12 is H, OH, NH2, NH(CH3), N(NH3)2, NH(C2H5), N(C2H5), linear, branched or cyclic C1-C6 alkyl, and linear, branched or cyclic C1-C6 alkoxy. More preferred groups R C12 is H, OH, NH2, linear or branched C1-C4 alkyl, and linear or branched C1-C4 alkoxy. Most preferred are H, OH, NH2, methyl, ethyl, 1-propyl, 2-propyl, methoxy, ethoxy, and 1- or 2-propoxy.

[0056] Particularly preferred groups R C12 is R C11 , X C11 -R C11 , H, OH, and NH2.

[0057] R C11 Ga-X C12 -S-[X C13 -D C11 ] n -R C13 Particularly preferred embodiments of the complexing agent selected from are shown in Tables 1-3.

[0058] [Table 1]

[0059] [Table 2]

[0060] [Table 3]

[0061] * The number is X C11 Substituent R in C11 and R C12 Indicates the position of (excluding H substitution)

[0062] Abbreviations in Tables 1, 2 and 3: Me = methyl / methanediyl, Et = ethyl / 1,2-ethanediyl, Pr = 1-propyl / 1,3-propanediyl, Et-OH = 2-hydroxyethyl, Pr(OH)2 = 2,3-dihydroxypropyl, i-Pr = 2-propyl / 1,2-propanediyl, Ph = phenyl / phenylene, OEt = oxyethylene.

[0063] The most preferred complexing agents are 3-[2-(2,3-dihydroxypropylsulfanyl)phenyl]-sulfanylpropane-1,2-diol, 3-[2-(2,3-dihydroxypropylsulfanyl)-4-methyl-phenyl]sulfanylpropane-1,2-diol, 3-[[2-(2,3-dihydroxypropylsulfanylmethyl)phenyl]methylsulfanyl]propane-1,2-diol, 2,6-bis(2-ethylsulfanylethylsulfanylmethyl)pyridine, morpholine-4-carbodithioate ditetramethylammonium salt, piperazine-1,4-dicarbodithioate ditetramethylammonium salt, 3-[[3-(2,3-dihydroxypropylsulfanylmethyl)phenyl]methylsulfanyl]propane-1,2-diol, 2-[2-(2-propylsulfanyl-ethylsulfanyl)ethyl]pyridine, 2-[2 2-(2-methylsulfanylethylsulfanyl)ethyl]pyridine, 2-(2-ethylsulfanyl-ethylsulfanylmethyl)-6-[6-(2-ethylsulfanylethylsulfanylmethyl)-2-pyridyl]pyridine, 2,6-bis(2-methylsulfanylethylsulfanylmethyl)pyridine, 4-[2-(2-ethylsulfanylethylsulfanyl)ethyl]morpholine, 2-[2-(2-isopropylsulfanylethylsulfanyl)ethyl]pyridine, 2-(2-propylsulfanylethylsulfanylmethyl)-pyridine, 2-[2-(2-ethylsulfanylethylsulfanyl)-1-methyl-ethyl]thiazole, 2-[2-(2-benzylsulfanylethyl-sulfanyl)ethyl]pyridine, and 2-[2-(2-phenylsulfanylethylsulfanyl)ethyl]pyridine, and salts thereof.

[0064] Other complexing agents The tin-silver alloy electroplating baths may further contain an additional complexing agent to complex tin and / or any other metals present in the composition. An exemplary additional complexing agent is 3,6-dithia-1,8-octanediol.

[0065] Other typical complexing agents are polyoxymonocarboxylic acids, polycarboxylic acids, aminocarboxylic acids, lactone compounds, and salts thereof.

[0066] Other complexing agents are organic thio compounds such as thioureas, thiols or thioethers as disclosed in US Pat. No. 7,628,903, JP 4,296,358 B2, EP 0,854,206 A and US Pat. No. 8,980,077 B2.

[0067] The tin alloy bath preferably contains no other complexing agents other than those according to the invention.

[0068] Typically, various other additives can be used in the bath to provide the desired surface finish for the plated tin alloy bumps. Usually, multiple additives are used, with each additive performing a desired function. Advantageously, the electroplating bath may further contain one or more of suppressors (often called surfactants), grain refiners, antioxidants, and mixtures thereof. Other additives can also be suitably used in the present electroplating baths.

[0069] Inhibitors or surfactants One or more suppressors (also called surfactants) may be present in the tin-silver alloy plating baths.

[0070] Any nonionic surfactant may be used in the present composition. Typically, the nonionic surfactant has an average molecular weight of 200 to 100,000, preferably 500 to 50,000, more preferably 500 to 25,000, and even more preferably 750 to 15,000. Such nonionic surfactants are typically present in the electrolyte composition at a concentration of 1 to 10,000 ppm, preferably 5 to 10,000 ppm, based on the weight of the composition. Preferred alkylene oxide compounds include, but are not limited to, alkylene oxide addition products of organic compounds having at least one hydroxy group and 20 or fewer carbon atoms, and polyalkylene glycols such as tetrafunctional polyethers formed by the addition of different alkylene oxides to low molecular weight polyamine compounds.

[0071] Preferred polyalkylene glycols are polyethylene glycol and polypropylene glycol. Such polyalkylene glycols are generally commercially available from a variety of sources and can be used without further purification. Capped polyalkylene glycols, in which one or more terminal hydrogen atoms are replaced with hydrocarbyl groups, can also be suitably used. Examples of suitable polyalkylene glycols include those of the formula RO-(CXYCX'Y'O) n R', wherein R and R' are independently H, C2-C 20 Alkyl groups and C6-C 20 aryl groups, where X, Y, X', and Y' are each independently selected from hydrogen, alkyl such as methyl, ethyl, or propyl, aryl such as phenyl, or aralkyl such as benzyl, and n is an integer from 5 to 100,000. Typically, one or more of X, Y, X', and Y' are hydrogen.

[0072] Suitable EO / PO copolymers generally have an EO:PO weight ratio of 10:90 to 90:10, preferably 10:90 to 80:20. Such EO / PO copolymers preferably have an average molecular weight of 750 to 15,000. Such EO / PO copolymers are available from a variety of sources, such as those commercially available from BASF under the trade name "PLURONIC®."

[0073] Suitable alkylene oxide condensation products of organic compounds having at least one hydroxy group and 20 or fewer carbon atoms include those with aliphatic hydrocarbons of 1 to 7 carbon atoms, unsubstituted aromatic compounds or alkylated aromatic compounds having 6 or fewer carbon atoms in the alkyl portion, such as those disclosed in U.S. Pat. No. 5,174,887. The aliphatic alcohols may be saturated or unsaturated. Suitable aromatic compounds are those having up to two aromatic rings. The aromatic alcohols have up to 20 carbon atoms before being derivatized with ethylene oxide. Such aliphatic and aromatic alcohols may be further substituted, for example, with sulfate or sulfonate groups.

[0074] Preferred surfactants have the formula S1: [ka] It is of the type.

[0075] Compounds of formula S1 can be prepared by reacting a polyamine starting material with one or more C2-C6 alkylene oxides to form the respective amine inhibitor.

[0076] In general, s may be an integer from 1 to 6. Preferably, s is an integer from 1 to 4, and most preferably, s is 1 or 2.

[0077] X S1 and X S2 are divalent spacer groups in the polyamine starting material. These are independently linear or branched C1-C 12Such alkanediyl spacers may be unsubstituted but may be optionally interrupted by O or S. X S1 and X S2 may be the same or different, and are preferably the same. S1 and X S2 is C1-C6 alkanediyl, more preferably C1-C4 alkanediyl, most preferably methanediyl, ethanediyl or propanediyl. In a second preferred embodiment, a heteroatom is present and X S1 and X S2 Ha-(CHR 41 ) q -[Q-(CHR 41 ) r ] v -, where Q is selected from O or S, and where q+r·v is the number of C atoms in the spacer. Particularly preferred are spacers where Q=O and q=r=1 or 2.

[0078] R S11 is a compound of the formula -(O-CH2-CHR S41 ) m -OR S42 [wherein m is an integer of 2 to 250, preferably 3 to 120, and most preferably 10 to 65]. S11 R can be prepared by the polyalkoxylation of one or more alkylene oxides, also referred to herein as "polyalkylene oxides" or "polyoxyalkylenes." S41 is selected from H and linear or branched C1-C5 alkyl, preferably H and linear or branched C1-C3 alkyl, more preferably H, methyl, ethyl and n-propyl, most preferably H or methyl. S42 is a linear or branched C1-C alkyl group optionally substituted with H and hydroxy, alkoxy or alkoxycarbonyl; 20 Alkyl, preferably H and linear or branched C1-C 10It is selected from alkyl, more preferably H and methyl, ethyl, propyl or butyl, most preferably H.

[0079] In general, R S12 , R S13 , R S14 are independently H, R S11 and R S40 From, preferably R S11 and R S40 From, most preferably R S11 is selected from.

[0080] R S40 is linear or branched C1-C 20 Preferably, R S40 is C1~C 10 Alkyl, even more preferably C1-C6 alkyl, most preferably methyl, ethyl or propyl.

[0081] R S42 is a linear or branched C1-C alkyl group optionally substituted with hydroxy, alkoxy or alkoxycarbonyl. 20 Preferably, R S42 is an unsubstituted linear or branched C1-C 20 It is alkyl.

[0082] In general, R S15 H, R S11 , R S40 , and -X S4 -N(R S21 )2, wherein R S21 is R S11 and R S40 From, preferably R S11 is selected from.

[0083] In a preferred embodiment, R S15 is R S11 and -X S4 -N(R S11 In another preferred embodiment, R S15 is RS40 and -X S4 -N(R S40 )2 is selected.

[0084] In one embodiment, X S4 is linear or branched C1-C 12 Preferably, X is an alkanediyl. S4 is C1-C6 alkanediyl, more preferably methanediyl, ethanediyl, propanediyl or butanediyl, most preferably methanediyl or ethanediyl.

[0085] In another embodiment, X S4 is a compound of the formula -(O-CH2-CHR S41 ) o - is a divalent group selected from C2-C6 polyoxyalkylene groups (hereinafter also referred to as polyalkylene oxide groups). In this specification, o may be an integer of 1 to 250, preferably 2 to 120, and most preferably 5 to 65. The C2-C6 polyoxyalkylene group can be prepared from one or more corresponding alkylene oxides. Preferably, at least one C2-C6 polyoxyalkylene group is selected from polyoxyethylene (prepared from ethylene oxide), polyoxypropylene (prepared from propylene oxide), and polyoxybutylene (prepared from butylene oxide). More preferably, the polyoxyalkylene group X S4 is a copolymer of ethylene oxide and at least one C3-C6 alkylene oxide. The further alkylene oxide is preferably selected from propylene oxide and 1,2-butylene oxide or any isomer thereof. In another preferred embodiment, the C3-C4 alkylene oxide is selected from propylene oxide (PO). In this case, EO / PO copolymer side chains are formed from the starter molecule. Such copolymers of ethylene oxide and at least one further alkylene oxide may have a random, block, alternating or any other arrangement.

[0086] As used herein, "random" means that the comonomers are polymerized from a mixture and are therefore arranged statistically according to their copolymerization parameters.

[0087] As used herein, "block" means that comonomers are polymerized sequentially with one another to form blocks of corresponding comonomers in a predetermined sequence. By way of example, but not limitation, such blocks for EO and propylene oxide (PO) comonomers include -EO x -PO y , -PO x -EO y , -EO x -PO y -EO z , -PO x -EO y -PO z A preferred block alkylene oxide is -PO x -EO y , and -EO x -PO y -EO z [wherein x is in the range of 2 to 300, y is in the range of 2 to 300, and z is in the range of 2 to 300].

[0088] In a preferred embodiment, the block -PO x -EO y or -EO x -PO y -EO z Copolymers are used in which the PO units can be replaced with different C4-C6 alkylene oxides.

[0089] When a copolymer of ethylene oxide (EO) with a further C3-C4 alkylene oxide is used, the EO content may generally be 3-95% by weight. Preferably, the EO content is 5-80% by weight, more preferably 5-60% by weight, even more preferably less than 50% by weight, even more preferably less than 40% by weight, even more preferably 5-40% by weight, even more preferably 5-30% by weight, even more preferably 6-25% by weight, and most preferably 8-20% by weight.

[0090] Generally, the molecular weight of the inhibitor, M w In one embodiment, the molecular weight M of the inhibitor may be about 500 to about 30,000 g / mol, preferably 2,000 to 15,000 g / mol. w In another embodiment, the molecular weight M of the inhibitor is about 500 to about 8000 g / mol, most preferably about 1500 to about 3500 g / mol. w is about 5000 to about 20000 g / mol, particularly about 6000 to about 15000 g / mol.

[0091] In a first preferred embodiment, s is 1, 2 or 3, most preferably 1 or 2, and R S12 , R S13 , R S14 and R S15 are independently a C2-C6 polyoxyalkylene group R S11 A compound of formula I is used, selected from the group consisting of: Such compounds may be prepared starting from symmetric dialkylenetriamines, trialkylenetetramines, tetraalkylenepentamines, such as, but not limited to, diethylenetriamine, triethylenetetramine, dipropylenetriamine, tripropylenetetramine, methyldiethylenetriamine, dimethyltriethylenetetramine, and the like.

[0092] In a second preferred embodiment, s is 1, 2 or 3, most preferably 1 or 2, and R S12 , R S13 , R S14 are independently a C2-C6 polyoxyalkylene group RS11 Selected from R S15 is X S4 -N(R S11 )2 is used. In this way, more branched polyoxyalkylene inhibitors are obtained. Such compounds may be prepared starting from a branched amine starting material, such as, but not limited to, trisaminoethylamine.

[0093] In a third preferred embodiment, n is 1, 2 or 3, most preferably 1 or 2, and R S12 , R S13 and R S14 is a C2-C6 polyoxyalkylene group R S11 Selected from R S15 is R S40 and -X S4 -N(R S40 )2. In this way, linear or branched inhibitors are obtained which, in addition to the polyoxyalkylene side chain, also contain one or more alkyl substituents. Such compounds can be prepared starting from the linear amines described above in which the secondary amino group is alkyl-substituted, or from branched amines in which one or more amine groups are alkyl-substituted, such as, but not limited to, trisalkylaminoethylamine.

[0094] In a fourth preferred embodiment, s is 1, 2 or 3, preferably 1 or 2, most preferably 1, and R S12 is R S11 Selected from R S13 and R S14 is R S40 Selected from R S15 is R S21 Such compounds may be prepared starting from a symmetric alkyl substituted di- or trialkylene tetramine, such as, but not limited to, N,N-dimethyldiethylenetriamine, N,N,N-trimethyldiethylenetriamine, and the like.

[0095] In a fifth preferred embodiment, n is 1, 2 or 3, preferably 1 or 2, most preferably 1, and R S13 is R S11 Selected from R S12 and R S14 At least one of S40 Selected from R S15 is R S21 Such compounds may be prepared starting from an unsymmetrical dialkylenetriamine or trialkylenetetramine, such as, but not limited to, 1-N-methyldiethylenetriamine, 1,3-N-dimethyldiethylenetriamine, and the like.

[0096] In a particularly preferred embodiment, the inhibitor of formula I is: (a)X S1 and X S2 is ethanediyl or propanediyl, and R S11 , R S12 , R S13 , R S14 and R S15 is a polyoxyalkylene, in particular an oxyethylene-co-oxypropylene polymer, (b)X S1 and X S2 is ethanediyl or propanediyl, and R S11 , R S12 , R S13 and R S14 is a polyoxyalkylene, especially an oxyethylene-co-oxypropylene polymer, and R S15 is C1-C6 alkyl or polyoxyalkylene-substituted C1-C6 alkyl, (c)X S1 and X S2 is ethanediyl or propanediyl, and R S11 , R S12 , R S13 and R S14 is a polyoxyalkylene, especially an oxyethylene-co-oxypropylene polymer, and R S15is a C1-C6 amine further substituted by polyoxyalkylene, particularly an oxyethylene-co-oxypropylene polymer.

[0097] Leveler One or more levelers may be present in the tin or tin alloy plating bath.

[0098] A class of levelers includes linear or branched polyimidazoliums containing structural units of formula L1.

[0099] [ka]

[0100] In general, R L1 and R L2 may be an H atom or an organic radical having 1 to 20 carbon atoms. The radical may be branched or unbranched, or may contain functional groups that can contribute, for example, to further crosslinking of the polymeric imidazolium compound. Preferably, R L1 and R L2 are each, independently of one another, a hydrogen atom or a hydrocarbon radical having 1 to 6 carbon atoms. L1 and R L2 is a H atom.

[0101] In general, R L3 may be an H atom or an organic radical having 1 to 20 carbon atoms. L3 is an H atom or methyl, ethyl or propyl. Most preferably, R L3 is a H atom.

[0102] In general, X L1 may contain one or more consecutive imidazolium compounds by branching, C4-C 20 It may be a linear, branched or cyclic aliphatic diradical selected from alkanediyl.

[0103] As used herein, "a series of polyimidazolium compounds by branching" refers to a series of polyimidazolium compounds with corresponding spacer groups X L1 means that it contains one or more, preferably one or two groups from which polyimidazole branches start. L1 does not contain any continuation of the polyimidazolium compound due to branching, that is, the polyimidazolium compound is a linear polymer.

[0104] In the first embodiment, X L1 is C4~C 14 Alkanediyl, most preferably C4-C 12 Alkanediyl, which may be unsubstituted or L4 , N.R. L4 2 and S L R 4 where R L4 is a C1-C4 alkyl group. L1 is a pure hydrocarbon radical that does not contain any functional groups.

[0105] Particularly preferred groups X L1 is selected from linear or branched butanediyl, pentanediyl, hexanediyl, heptanediyl, octanediyl, nonanediyl, decanediyl, undecanediyl and dodecanediyl, which may be unsubstituted or L4 , N.R. L4 Particularly preferred groups X L1 is selected from linear butanediyl, hexanediyl and octanediyl.

[0106] In a second embodiment, the group X L1 may be a cyclic alkanediyl of the formula:

[0107] [ka] [In the formula, X L2 are independently O and NR L4C1-C4 alkanediyl, which may be interrupted by one or two selected from X L3 are independently (a) a chemical bond or (b) O or NR L4 C1-C4 alkanediyl, which may be interrupted by R L4 is a C1-C4 alkyl group.

[0108] X L2 or X L3 Either or X L2 and X L3 may contain one or more successive imidazolium compounds by branching, and preferably X 2 Only the imidazolium compounds may be branched in this way.

[0109] In this second embodiment, most preferably, one of X L2 is selected from methanediyl, and the other X L2 propanediyl, or both X's are selected from L2 Particularly preferred are groups X selected from isophoronediamine, biscyclohexyldiaminomethane, and methylcyclohexyldiamine (MDACH). L1 is.

[0110] In the third embodiment, X L1 is Y L2 -Y L1 -Y L2 In this specification, Y may be a (hetero)arylalkyl diradical selected from L1 is C5~C 20 may be an aryl group, and Y L2 may be independently selected from linear or branched C1-C6 alkanediyl. L1 and Y L2 Both of the above may contain one or more successive imidazolium compounds by branching.

[0111] Preferred groups Y L1is selected from phenyl, naphthyl, pyridyl, pyrimidyl, and furanyl, most preferably phenyl. L2 is selected from linear or branched C1-C4 alkanediyls, preferably from methanediyl, ethanediyl, 1,3-propanediyl and 1,4-butanediyl.

[0112] Organic Radical X L1 may contain not only carbon and hydrogen but also heteroatoms such as oxygen, nitrogen, sulfur or halogens, for example in the form of functional groups such as hydroxyl groups, ether groups, amide groups, aromatic heterocycles, primary, secondary or tertiary amino groups or imino groups.

[0113] In particular, the organic radical X L1 may be a hydrocarbon diradical, optionally substituted or interrupted by a functional group containing a heteroatom, in particular an ether group. L1 Preferably, does not contain any hydroxyl groups.

[0114] I may generally be an integer of 2 to about 5000, preferably about 5 to about 3000, even more preferably about 8 to about 1000, even more preferably about 10 to about 300, even more preferably about 15 to about 250, and most preferably about 25 to about 150.

[0115] Mass average molecular weight M of additive w Generally, it may be 500 g / mol to 1,000,000 g / mol, preferably 1000 g / mol to 500,000 g / mol, more preferably 1500 g / mol to 100,000 g / mol, even more preferably 2,000 g / mol to 50,000 g / mol, even more preferably 3,000 g / mol to 40,000 g / mol, and most preferably 5,000 g / mol to 25,000 g / mol.

[0116] Preferably, at least one additive has a counterion Y o-where o is a positive integer selected so that the entire additive is electrically neutral. Preferably, o is 1, 2, or 3. Most preferably, the counterion Y o- is selected from chloride, sulfate, methanesulfonate or acetate.

[0117] Preferably, the number average molecular weight M of the polymeric imidazolium compound is determined by gel permeation chromatography. n is greater than 500 g / mol.

[0118] Preferably, the polymeric imidazolium compound may comprise more than 80% by weight of structural units of formula L1.

[0119] Further details and alternatives are described in unpublished European Patent Application No. 17173987.3, Patent Publication WO2016 / 020216 and International Published Patent Application No. PCT / EP2017 / 050054, each of which is incorporated herein by reference.

[0120] Other suitable leveling agents include, but are not limited to, polyaminoamides and their derivatives, polyalkanolamines and their derivatives, polyethyleneimine and its derivatives, quaternized polyethyleneimine, polyglycine, poly(allylamine), polyaniline, polyurea, polyacrylamide, poly(melamine-co-formaldehyde), reaction products of amines with epichlorohydrin, reaction products of amines with epichlorohydrin and polyalkylene oxides, reaction products of amines with polyepoxides, polyvinylpyridines, polyvinylimidazoles, polyvinylpyrrolidone or copolymers thereof, nigrosine, pentamethyl-para-rosaniline hydrogen halide, hexamethyl-pararosaniline hydrogen halide, or compounds containing a functional group of the formula NRS (where R is a substituted alkyl, unsubstituted alkyl, substituted aryl, or unsubstituted aryl). Typically, the alkyl group is a C1-C6 alkyl, preferably a C1-C4 alkyl. Generally, the aryl group is a C6-C6 alkyl. 20Aryl, preferably C6-C 12 The aryl group may further contain heteroatoms such as sulfur, nitrogen, and oxygen. The aryl group is preferably phenyl or naphthyl. Compounds containing the functional group of formula NRS are generally known, generally commercially available, and can be used without further purification.

[0121] In compounds containing such NRS functional groups, sulfur ("S") and / or nitrogen ("N") may be bonded to such compounds by single or double bonds. When sulfur is bonded to such compounds by a single bond, the sulfur may be bonded to any of a number of groups, including, but not limited to, hydrogen, C1-C6, 12 Alkyl, C2-C 12 Alkenyl, C6-C 20 Aryl, C1-C 12 Alkylthio, C2-C 12 Alkenylthio, C6-C 20 Similarly, nitrogen may have other substituents such as, but not limited to, hydrogen, C1-C6 12 Alkyl, C2-C 12 Alkenyl, C7-C 10 The NRS functional group may have one or more substituents, such as aryl. The NRS functional group may be acyclic or cyclic. Compounds containing cyclic NRS functional groups include those having either nitrogen, sulfur, or both nitrogen and sulfur in the ring system.

[0122] Further levelling agents are the triethanolamine condensates described in unpublished international patent application no. PCT / EP2009 / 066581.

[0123] Generally, the total amount of leveling agents in an electroplating bath is from 0.5 ppm to 10,000 ppm, based on the total weight of the plating bath. Leveling agents according to the present invention are typically used in a total amount of from about 100 ppm to about 10,000 ppm, based on the total weight of the plating bath, although greater or lesser amounts may be used.

[0124] Crystal Refining Agent The tin or tin alloy electroplating bath may further contain a grain refiner. The grain refiner may be selected from compounds of formula G1 or G2.

[0125] [ka] [In the formula, each R 1 are independently C1-C6 alkyl, C1-C6 alkoxy, hydroxy, or halogen, and R 2 and R 3 is independently selected from H and C1-C6 alkyl; R 4 is H, OH, C1-C6 alkyl or C1-C6 alkoxy, m is an integer of 0 to 2, and each R 5 are independently C1-C6 alkyl, and each R 6 are independently selected from H, OH, C1-C6 alkyl or C1-C6 alkoxy, n is 1 or 2, and p is 0, 1, or 2.

[0126] Preferably, each R 1 are independently C1-C6 alkyl, C1-C6 alkoxy, or hydroxy, more preferably C1-C4 alkyl, C1-C2 alkoxy, or hydroxy. 2 and R 3 are independently selected from H and C1-C3 alkyl, more preferably H and methyl. Preferably, R 4 are H, OH, and C 1 ~C 4 alkyl or C1-C4 alkoxy, more preferably H, OH or C1-C4 alkyl. 6 is preferably a C1 to C4 alkyl, more preferably a C1 to C3 alkyl. 6is preferably selected from H, OH, or C1-C6 alkyl, more preferably H, OH or C1-C3 alkyl, even more preferably H or OH. Preferably, m is 0 or 1, more preferably m is 0. Preferably, n is 1. Preferably, p is 0 or 1, more preferably p is 0. Mixtures of first crystal refiners may be used, such as two different crystal refiners of Formula 1, two different crystal refiners of Formula 2, or a mixture of a plasma growth inhibitor of Formula 1 and a crystal refiner of Formula 2.

[0127] Exemplary compounds useful as such crystal refiners include, but are not limited to, cinnamic acid, cinnamaldehyde, benzalacetone, picolinic acid, pyridinedicarboxylic acid, pyridinecarboxaldehyde, pyridinedicarboxaldehyde, or mixtures thereof. Preferred crystal refiners include benzalacetone, 4-methoxybenzaldehyde, benzylpyridine-3-carboxylate, and 1,10-phenanthroline.

[0128] Further crystal refiners can be selected from α,β-unsaturated aliphatic carbonyl compounds. Suitable α,β-unsaturated aliphatic carbonyl compounds include, but are not limited to, α,β-unsaturated carboxylic acids, α,β-unsaturated carboxylic acid esters, α,β-unsaturated amides, and α,β-unsaturated aldehydes. Preferably, such crystal refiners are selected from α,β-unsaturated carboxylic acids, α,β-unsaturated carboxylic acid esters, and α,β-unsaturated aldehydes, more preferably α,β-unsaturated carboxylic acids and α,β-unsaturated aldehydes. Exemplary α,β-unsaturated aliphatic carbonyl compounds include (meth)acrylic acid, crotonic acid, C-C alkyl methacrylate, (meth)acrylamide, C-C alkyl crotonate, crotonamide, crotonaldehyde, (meth)acrolein, or mixtures thereof. Preferred α,β-unsaturated aliphatic carbonyl compounds are (meth)acrylic acid, crotonic acid, crotonaldehyde, (meth)acrylaldehyde, or mixtures thereof.

[0129] In one embodiment, the crystal refiner may be present in the plating bath in an amount of 0.0001 to 0.045 g / L. Preferably, the crystal refiner is present in an amount of 0.0001 to 0.04 g / L, more preferably 0.0001 to 0.035 g / L, and even more preferably 0.0001 to 0.03 g / L. Compounds useful as first crystal refiners are generally commercially available from a variety of sources and may be used as is or may be further purified.

[0130] In another more preferred embodiment, the composition for electroplating tin or tin alloys comprises one grain refiner, more preferably one that is not an α,β-unsaturated aliphatic carbonyl compound, and most preferably essentially no or no grain refiner. Surprisingly, it has been discovered that, to fill recesses and features, particularly those having opening sizes less than 50 μm, it is not necessary to use any grain refiner, but that the suppressor provides good coplanarity without the use of any grain refiner.

[0131] The composition may optionally include further additives such as antioxidants, organic solvents, complexing agents, and mixtures thereof.

[0132] antioxidants An antioxidant can be optionally added to the composition to help maintain tin in a soluble divalent state. Preferably, one or more antioxidants are used in the composition. Exemplary antioxidants include, but are not limited to, hydroquinone, hydroxylated and / or alkoxylated aromatic compounds (including sulfonic acid derivatives of such aromatic compounds), preferably hydroquinone, methylhydroquinone, resorcinol, catechol, 1,2,3-trihydroxybenzene, 1,2-dihydroxybenzene-4-sulfonic acid, 1,2-dihydroxybenzene-3,5-disulfonic acid, 1,4-dihydroxybenzene-2-sulfonic acid, 1,4-dihydroxybenzene-2,5-disulfonic acid, 2,4-dihydroxybenzenesulfonic acid, and p-methoxyphenol. Such antioxidants are disclosed in US 4,871,429. Other suitable antioxidants or reducing agents include, but are not limited to, vanadium compounds such as vanadyl acetylacetonate, vanadium triacetylacetonate, vanadium halides, vanadium oxyhalides, vanadium alkoxides, and vanadyl alkoxides. The concentrations of such reducing agents are well known to those skilled in the art but typically range from 0.1 to 10 g / L, preferably 1 to 5 g / L. Such antioxidants are generally commercially available from a variety of sources.

[0133] electrolyte Generally, as used herein, "aqueous" means that the electroplating compositions of the present invention comprise a solvent that includes at least 50% water. Preferably, "aqueous" means that the composition is predominantly water, more preferably 90% of the solvent is water, and most preferably the solvent consists essentially of water. Any type of water may be used, such as distilled water, deionized water, or tap water.

[0134] The bath contains tin and silver ions. Preferably, the bath contains metal ions consisting essentially of tin and silver ions, i.e., essentially no metal ions are present other than tin and silver ions. Essentially free of any other metal ions means that the concentration of metal ions in the bath is less than 1% by weight, preferably less than 0.1% by weight, and most preferably less than 0.01% by weight.

[0135] Tin The tin ion source may be any compound capable of releasing metal ions and depositing them in sufficient quantities in the electroplating bath, i.e., at least partially soluble in the electroplating bath. Preferably, the metal ion source is soluble in the plating bath. Suitable metal ion sources are metal salts, including, but not limited to, metal sulfates, metal halides, metal acetates, metal nitrates, metal fluoroborates, metal alkylsulfonates, metal arylsulfonates, metal sulfamates, metal gluconates, and the like.

[0136] The metal ion source can be used in the present invention in any amount that provides sufficient metal ions for electroplating onto a substrate. When the metal is tin alone, the tin salt is typically present in an amount ranging from about 1 to about 300 g / L of the plating solution. In a preferred embodiment, the plating solution is lead-free, i.e., contains less than 1 wt.% lead, more preferably less than 0.5 wt.%, even more preferably less than 0.2 wt.%, and even more preferably no lead. In another preferred embodiment, the plating solution is essentially copper-free, i.e., contains less than 1 wt.% copper, more preferably less than 0.1 wt.%, even more preferably less than 0.01 wt.%, and even more preferably no copper.

[0137] silver In addition to tin, the plating baths according to the present invention contain silver ions and optionally one or more other alloying metal ions. Suitable alloying metals include, but are not limited to, gold, copper, bismuth, indium, zinc, antimony, manganese, and mixtures thereof. Preferred alloying metals are copper, bismuth, indium, and mixtures thereof. Any salt of silver and other alloying metals (collectively referred to as alloying metals) that is soluble in the bath may be suitably used as a source of alloying silver and other alloying metal ions. Examples of such alloying metal salts include, but are not limited to, metal oxides, metal halides, metal fluoroborates, metal sulfates, metal alkane sulfonates such as metal methanesulfonates, metal ethanesulfonates, and metal propanesulfonates, metal arylsulfonates such as metal phenylsulfonates, metal toluenesulfonates, and metal phenolsulfonates, metal carbonates such as metal gluconates and metal acetates, and the like. Preferred alloying metal salts are metal sulfates, metal alkane sulfonates, and metal arylsulfonates. When silver is added to the composition, the deposition of a binary alloy is achieved. When two or more different alloying metals are added to the composition, the deposition of tertiary, quaternary, or even higher order alloys is achieved. The amount of such alloying metals used in the composition will depend on the particular tin alloy desired. The selection of such amounts of alloying metals is within the ability of one skilled in the art. One skilled in the art will understand that when a particular alloying metal other than silver is used, additional complexing agents other than those of the present invention may be required.

[0138] The electroplating compositions of the present invention are suitable for depositing tin-silver-containing layers. Exemplary tin alloy layers include, but are not limited to, tin-silver-copper, tin-silver-indium, tin-silver-bismuth, tin-silver-copper-antimony, tin-silver-copper-manganese, tin-silver-zinc-copper, and tin-silver-indium-bismuth. Preferably, the electroplating compositions of the present invention deposit pure tin-silver, tin-silver-copper, tin-indium, tin-silver-bismuth, tin-silver-indium, and tin-silver-indium-bismuth, more preferably pure tin-silver.

[0139] The silver alloys deposited from the electroplating baths of the present invention contain tin in an amount ranging from 0.01 to 99.99 wt. % and silver and optional other alloying metals in an amount ranging from 99.99 to 0.01 wt. % based on the weight of the alloy, as measured by atomic adsorption spectroscopy (AAS), X-ray fluorescence (XRF), or inductively coupled plasma mass spectrometry (ICP-MS). Preferably, the tin-silver alloys deposited using the present invention contain 90 to 99.99 wt. % tin and 0.01 to 10 wt. % silver and optional other alloying metals.

[0140] More preferably, the tin-silver alloy deposit contains 95-99.9 wt% tin and 0.1-5 wt% silver and any other alloying metals. Tin-silver alloys are the preferred tin alloy deposits, preferably containing 90-99.9 wt% tin and 10-0.1 wt% silver. More preferably, the tin-silver alloy deposit contains 95-99.9 wt% tin and 5-0.1 wt% silver. In many applications, the eutectic composition of the alloy can be used. The alloys deposited according to the present invention are substantially lead-free, i.e., contain less than 1 wt% lead, more preferably less than 0.5 wt%, even more preferably less than 0.2 wt%, and even more preferably no lead.

[0141] bath Generally, in addition to a metal ion source and at least one complexing agent, the metal electroplating compositions of the present invention (also referred to as "electroplating baths") preferably contain an electrolyte, i.e., an acidic or alkaline electrolyte, one or more metal ion sources, optional halide ions, and optional other additives (such as surfactants and plasma growth inhibitors). Such baths are typically aqueous, i.e., do not contain any additional solvents other than water. Water can be present in a wide range of amounts. Any type of water can be used, such as distilled water, deionized water, or tap water. Preferably, the tin-silver electroplating bath is a homogeneous solution, i.e., essentially free of any particles. As used herein, essentially free of particles means that such particles do not interfere with the metal electroplating process.

[0142] Preferably, the plating baths of the present invention are acidic, i.e., have a pH of less than 7. Typically, the pH of tin or tin alloy electroplating compositions is less than 4, preferably less than 3, and most preferably less than 2.

[0143] The electroplating baths of the present invention can be prepared by combining the components in any order, preferably by first adding inorganic components such as metal salts, water, and electrolyte to the bath, followed by the addition of organic components such as surfactants, crystal refiners, and levelers.

[0144] Typically, the plating bath of the present invention can be used at any temperature of 10 to 65°C or higher. The temperature of the plating bath is preferably 10 to 35°C, more preferably 15 to 30°C.

[0145] Suitable electrolytes include, for example, but are not limited to, sulfuric acid, acetic acid, fluoroboric acid, alkylsulfonic acids such as methanesulfonic acid, ethanesulfonic acid, propanesulfonic acid, and trifluoromethanesulfonic acid, arylsulfonic acids such as phenylsulfonic acid and toluenesulfonic acid, sulfamic acid, hydrochloric acid, phosphoric acid, tetraalkylammonium hydroxide, preferably tetramethylammonium hydroxide, sodium hydroxide, potassium hydroxide, etc. The acid is typically present in an amount ranging from about 1 to about 300 g / L.

[0146] In one embodiment, the at least one additive has a counterion Y selected from methanesulfonate, sulfate, or acetate. o- where o is a positive integer.

[0147] Purpose The plating compositions of the present invention are useful in various plating processes for depositing tin-containing layers, particularly tin-containing solder layers, on semiconductor wafers containing multiple conductive joints. Plating processes include, but are not limited to, horizontal or vertical wafer plating, high-speed plating such as barrel plating, rack plating, reel-to-reel and jet plating, and rackless plating, preferably horizontal or vertical wafer plating. A wide variety of substrates can be plated with the tin-containing deposits of the present invention. The substrates to be plated are conductive and may include copper, copper alloys, nickel, nickel alloys, and nickel-iron-containing materials. Such substrates may be in the form of electronic components, such as (a) lead frames, connectors, chip capacitors, chip resistors, and semiconductor packages; (b) plastics such as circuit boards; and (c) semiconductor wafers. Preferably, the substrate is a semiconductor wafer. Therefore, the present invention also provides a method for depositing a tin-containing layer on a semiconductor wafer, comprising manufacturing a semiconductor wafer including a plurality of conductive interfaces, contacting the semiconductor wafer with the composition described above, and applying a sufficient current density to deposit a tin-containing layer at the conductive interfaces. Preferably, the interfaces comprise copper, which may be in the form of a pure copper layer, a copper alloy layer, or any interconnect structure containing copper. Copper pillars are one preferred conductive interface. Optionally, the copper pillars may include an upper metal layer, such as a nickel layer. If the conductive interface has an upper metal layer, a pure tin solder layer is deposited on the upper metal layer of the interface. Conductive interfaces, such as bond pads and copper pillars, are well known in the art and are described, for example, in US Pat. No. 7,781,325, US 2008 / 0054459 A, US 2008 / 0296761 A, and US 2006 / 0094226 A.

[0148] method Generally, when using the present invention to deposit a tin-silver alloy on a substrate, the plating bath is agitated during use. Any suitable agitation method may be used with the present invention, and such methods are well known in the art. Suitable agitation methods include, but are not limited to, inert gas or air sparging, workpiece agitation, impingement, and the like. Such methods are known to those skilled in the art. When using the present invention to plate an integrated circuit substrate, such as a wafer, the wafer may be rotated, for example, at 1 to 150 RPM, and the plating solution contacts the rotating wafer, for example, by a pump or spray. In an alternative embodiment, if the flow of the plating bath is sufficient to provide the desired metal deposit, the wafer need not be rotated.

[0149] The tin-alloy is deposited in the recesses according to the present invention without forming substantially voids in the metal deposit, the term "substantially without forming voids" meaning that the metal deposit is free of voids larger than 1000 nm, preferably 500 nm, and most preferably 100 nm.

[0150] Plating equipment for plating semiconductor substrates is well known. The plating equipment includes an electroplating tank that holds a tin or tin alloy electrolyte and is made of a suitable material, such as plastic or other material that is inert to the electroplating solution. The tank may be cylindrical, particularly for wafer plating. A cathode is positioned horizontally at the top of the tank and may be any type of substrate, such as a silicon wafer, with an opening.

[0151] These additives can be used with soluble and insoluble anodes, with or without a membrane(s) separating the catholyte from the anolyte.

[0152] The cathode substrate and the anode are each electrically connected to a power supply by wires. For direct or pulsed current, the cathode substrate has a net negative charge, so metal ions in the solution are reduced at the cathode substrate, and plating metal is formed on the cathode surface. An oxidation reaction occurs at the anode. The cathode and anode may be positioned horizontally or vertically within the cell.

[0153] Typically, when fabricating tin-alloy bumps, a photoresist layer is applied to a semiconductor wafer, followed by standard photolithographic exposure and development techniques to form a patterned photoresist layer (or plating mask) with openings or vias therein. The dimensions of the plating mask (thickness of the plating mask and size of the openings in the pattern) define the size and location of the tin or tin-alloy layer deposited on the I / O pads and UBM. The diameter of such deposits is typically in the range of 1 to 300 μm, preferably 2 to 100 μm.

[0154] All percentages, ppm or equivalent values ​​refer to weight relative to the total weight of each composition unless otherwise specified. All citations are incorporated herein by reference.

[0155] The following examples further illustrate the invention without limiting its scope. [Example]

[0156] [Example 1] Preparation of complexing agent Thiol production

[0157] 2-(Ethylsulfanyl)ethane-1-thiol [ka]

[0158] Under an inert atmosphere, 36.4 g of thiourea was added to a solution of 51.8 g of 2-ethylthioethanol in 142.2 g of 32% hydrochloric acid. The mixture was stirred at 100°C for 7.5 hours and then at room temperature overnight. After adding 634 ml of 2 M aqueous potassium hydroxide, the mixture was refluxed for 3.5 hours, cooled to room temperature, and acidified to pH 1 with hydrochloric acid. The mixture was extracted five times with 100 ml of dichloromethane, and the combined organic layers were dried over sodium sulfate. The solvent was removed under vacuum to give 52.5 g of 2-(ethylsulfanyl)ethane-1-thiol as a colorless liquid.

[0159] 2-Isopropylsulfanylethanethiol [ka]

[0160] Under an inert atmosphere, 15.6 g of thiourea was added to a solution of 24.6 g of 2-isopropylthioethanol in 60.9 g of 32% hydrochloric acid. The mixture was refluxed for 7.5 hours and then stirred at room temperature overnight. After adding 272 ml of 2 M aqueous potassium hydroxide, the mixture was refluxed for 3.5 hours, cooled to room temperature, and acidified to pH 1 with hydrochloric acid. The mixture was extracted three times with 100 ml of dichloromethane, and the combined organic layers were dried over sodium sulfate. The solvent was removed under vacuum to give 24.7 g of 2-isopropylsulfanylethanethiol as a colorless liquid.

[0161] 2-Benzylsulfanylethanethiol [ka]

[0162] 11.4 g of 2-hydroxyethyl benzyl sulfide was dissolved in 20 ml of chloroform. A solution of 10.0 g of thionyl chloride in 30 ml of chloroform was added dropwise over 35 minutes while maintaining the temperature between 21 and 29°C. The mixture was stirred at room temperature for 1 hour. The solvent was removed under vacuum, yielding 12.7 g of 2-chloroethylsulfanylmethylbenzene as a yellow liquid.

[0163] 12.7 g of 2-chloroethylsulfanylmethylbenzene was dissolved in 30 ml of ethanol. A solution of 5.16 g of thiourea in 50 ml of ethanol was added. The mixture was refluxed for 5 hours and then stirred at room temperature overnight. The solvent was removed under vacuum, and the residue was mixed with 200 ml of dichloromethane. The precipitate was filtered off and washed with dichloromethane. After drying in air, 15.7 g of (2-benzylsulfanylethylsulfanylcarbonimidoyl)ammonium chloride was obtained as a white powder.

[0164] 6.0 g of (2-benzylsulfanylethylsulfanylcarbonimidoyl)ammonium chloride was suspended in 150 ml of water. After adding 1.5 g of sodium hydroxide, the mixture was stirred at 100 °C for 45 minutes. The mixture was cooled to room temperature and acidified to pH 1-2 using hydrochloric acid. The mixture was extracted three times with 30 ml of dichloromethane each. The combined organic layers were dried over sodium sulfate. The solvent was removed under vacuum to give 3.8 g of 2-benzylsulfanylethanethiol as a yellow liquid.

[0165] [Example 1.1] 3-[2-(2,3-dihydroxypropylsulfanyl)phenyl]sulfanylpropane-1,2-diol [ka]

[0166] To a solution of 1.81 g of 1,2-benzenedithiol in 40 ml of dichloromethane was added 0.17 g of potassium carbonate, followed by dropwise addition of 1.88 g of glycidol at room temperature. The reaction mixture was stirred overnight at room temperature. After concentration in vacuo, the residue was purified by chromatography on silica gel using dichloromethane / methanol as the eluent (gradient elution) to give 2.4 g of 3-[2-(2,3-dihydroxypropylsulfanyl)phenyl]-sulfanylpropane-1,2-diol as a colorless oil (C-NMR analysis >95%).

[0167] [Example 1.2] 3-[2-(2,3-dihydroxypropylsulfanyl)-4-methyl-phenyl]sulfanylpropane-1,2-diol [ka]

[0168] To a solution of 1.98 g of toluene-3,4-dithiol in 40 ml of dichloromethane, 0.17 g of potassium carbonate was added, followed by dropwise addition of 1.88 g of glycidol at room temperature. The reaction mixture was stirred overnight at room temperature. After concentration in vacuo, the residue was purified by chromatography on silica gel using dichloromethane / methanol as the eluent (gradient elution) to give 2.6 g of 3-[2-(2,3-dihydroxypropylsulfanyl)-4-methyl-phenyl]sulfanylpropane-1,2-diol as a colorless oil (C-NMR analysis 95%).

[0169] [Example 1.3] 3-[[4-(2,3-dihydroxypropylsulfanylmethyl)phenyl]methylsulfanyl]propane-1,2-diol [ka]

[0170] Under an inert atmosphere, 5.9 g of a 30% solution of sodium methylate in methanol was mixed with 30 ml of methanol. 3.25 g of 3-mercapto-1,2-propanediol was added, and the mixture was stirred at room temperature for 30 minutes. 2.6 g of α,α'-dichloro-p-xylene was added, and the mixture was stirred at 50°C for 5.5 hours and then at room temperature overnight. After concentration in vacuo, the residue was purified by chromatography on silica gel using dichloromethane / methanol as the eluent (gradient elution) to give 2.0 g of 3-[[4-(2,3-dihydroxypropylsulfanylmethyl)phenyl]methylsulfanyl]propane-1,2-diol as a colorless oil (C-NMR analysis >95%).

[0171] [Example 1.4] 3-[[3-(2,3-dihydroxypropylsulfanylmethyl)phenyl]methylsulfanyl]propane-1,2-diol [ka]

[0172] To a solution of 2.20 g of 1,3-benzenedimethanedithiol in 40 ml of dichloromethane was added 0.17 g of potassium carbonate, followed by dropwise addition of 1.96 g of glycidol at room temperature. The reaction mixture was stirred overnight at room temperature. After concentration in vacuo, the residue was purified by chromatography on silica gel using dichloromethane / methanol as the eluent (gradient elution) to give 1.8 g of 3-[[3-(2,3-dihydroxypropylsulfanylmethyl)phenyl]methylsulfanyl]propane-1,2-diol as a white oil (95% analysis by C-NMR).

[0173] [Example 1.5] 2-[2-(2-hydroxyethylsulfanyl)phenyl]sulfanylethanol [ka]

[0174] To a solution of 2.10 g of 1,2-dithiobenzene in 40 ml of methanol was added 5.60 g of a 30% solution of sodium methylate at room temperature. 2.30 g of chloroethanol was added, and the mixture was stirred at room temperature overnight. 100 ml of water was added, and the mixture was extracted three times with 100 ml of methyl tert-butyl ether each time. The combined organic layers were washed with 100 ml of water and dried over sodium sulfate. After concentration under vacuum, the residue was purified by chromatography on silica gel using cyclohexane / ethyl acetate as eluent (gradient elution) to give 0.7 g of 2-[2-(2-hydroxyethylsulfanyl)phenyl]sulfanylethanol (C-NMR analysis >95%).

[0175] [Example 1.6] 2-Phenylsulfanylethanol [ka]

[0176] Commercially available: Aldrich, TCI

[0177] [Example 1.7] 1-(3-hydroxyphenyl)-3-methyl-thiourea [ka]

[0178] Available from: FCH-Group, ZereneX Company

[0179] [Example 1.8] 2-[2-(2-ethylsulfanylethylsulfanyl)ethyl]pyridine [ka]

[0180] Under an inert atmosphere, 3.22 g of 2-vinylpyridine was dissolved in 30 ml of isopropanol. 3.67 g of 2-(ethylsulfanyl)ethane-1-thiol was added, and the mixture was refluxed for 7.5 hours and then stirred at room temperature overnight. After concentration in vacuo, the residue was purified by chromatography on silica gel using cyclohexane / ethyl acetate as the eluent (gradient elution) to give 5.6 g of 2-[2-(2-ethylsulfanylethylsulfanyl)ethyl]pyridine as a colorless liquid (C-NMR analysis >95%).

[0181] [Example 1.9] 2,6-bis(2-ethylsulfanylethylsulfanylmethyl)pyridine [ka]

[0182] Under an inert atmosphere, 3.67 g of 2-(ethylsulfanyl)ethane-1-thiol was added to a mixture of 5.94 g of a 30% solution of sodium methylate in methanol and 30 ml of methanol. After adding 3.97 g of 2,6-bis(bromomethyl)pyridine, the mixture was stirred at 50° C. for 5.5 hours and then at room temperature overnight. After concentration in vacuo, the residue was purified by chromatography on silica gel using cyclohexane / ethyl acetate as the eluent (gradient elution) to give 4.1 g of 2,6-bis(2-ethylsulfanylethylsulfanylmethyl)pyridine as a pale yellow oil (C-NMR analysis 95%).

[0183] [Example 1.10] 2-(2-ethylsulfanylethylsulfanylmethyl)pyridine [ka]

[0184] Under an inert atmosphere, 1.22 g of 2-(ethylsulfanyl)ethane-1-thiol was added to a mixture of 7.13 g of a 21% solution of sodium ethylate in ethanol and 15 ml of ethanol. A solution of 1.64 g of 2-chloromethylpyridine hydrochloride in 15 ml of ethanol was slowly added at 0 °C. The mixture was stirred overnight at room temperature. After concentration in vacuo, the residue was purified by chromatography on silica gel using cyclohexane / ethyl acetate as the eluent (gradient elution) to give 1.5 g of 2-(2-ethylsulfanylethylsulfanylmethyl)pyridine as a pale yellow liquid (C-NMR analysis 95%).

[0185] [Example 1.11] 2-(2-pyridylsulfanyl)ethanol [ka]

[0186] For example, commercially available from Aldrich

[0187] [Example 1.12] 2-pyrimidin-2-ylsulfanylethanol [ka]

[0188] For example, commercially available from Enamine

[0189] [Example 1.13] 2-[2-(2-isopropylsulfanylethylsulfanyl)ethyl]pyridine [ka]

[0190] Under an inert atmosphere, 1.05 g of 2-vinylpyridine was added to a solution of 1.36 g of 2-isopropylsulfanylethanethiol in 20 ml of isopropanol. The mixture was refluxed for 7.5 hours and then stirred at room temperature overnight. After concentration in vacuo, the residue was purified by chromatography on silica gel using cyclohexane / ethyl acetate as the eluent (gradient elution) to give 1.8 g of 2-[2-(2-isopropylsulfanylethylsulfanyl)ethyl]pyridine as a pale yellow liquid (C-NMR analysis 95%).

[0191] [Example 1.14] 2-(2-ethylsulfanylethylsulfanylmethyl)-6-[6-(2-ethylsulfanylethylsulfanylmethyl)-2-pyridyl]pyridine [ka]

[0192] Under an inert atmosphere, 0.97 g of 2-(ethylsulfanyl)ethane-1-thiol was added to a mixture of 1.57 g of a 30% solution of sodium methylate in methanol and 20 ml of methanol. After adding 1.0 g of 6,6'-bis(chloromethyl)-2,2'-bipyridine, the mixture was stirred at 50°C for 5.5 hours and then at room temperature overnight. After concentration in vacuo, the residue was purified by silica gel chromatography using cyclohexane / ethyl acetate as the eluent (gradient elution) to give 1.3 g of 2-(2-ethylsulfanylethylsulfanylmethyl)-6-[6-(2-ethylsulfanylethylsulfanylmethyl)-2-pyridyl]pyridine as a yellow liquid (C-NMR analysis 95%).

[0193] [Example 1.15] 2-[2-(2-benzylsulfanylethylsulfanyl)ethyl]pyridine [ka]

[0194] Under an inert atmosphere, 1.05 g of 2-vinylpyridine was added to a solution of 1.84 g of 2-benzylsulfanylethanethiol in 20 ml of isopropanol. The mixture was refluxed for 4.5 hours and then stirred at room temperature overnight. After concentration in vacuo, the residue was purified by chromatography on silica gel using cyclohexane / ethyl acetate as the eluent (gradient elution) to give 2.0 g of 2-[2-(2-benzylsulfanylethylsulfanyl)ethyl]pyridine as a colorless liquid (90% analysis by C-NMR).

[0195] [Example 1.16] 2-[2-(2-ethylsulfanylethylsulfanyl)-ethyl]pyrazine [ka]

[0196] Under an inert atmosphere, 1.31 g of 2-(ethylsulfanyl)ethane-1-thiol was added to a solution of 1.14 g of 2-vinylpyrazine in 20 ml of isopropanol. The mixture was refluxed for 6 hours, after which 25 mg of azobisisobutyronitrile was added. The mixture was refluxed for 7 hours, after which an additional 25 mg of azobisisobutyronitrile was added. The mixture was refluxed for 6 hours. After concentration in vacuo, the residue was purified by chromatography on silica gel using cyclohexane / ethyl acetate as eluent (gradient elution) to give 0.11 g of 2-[2-(2-ethylsulfanylethylsulfanyl)-ethyl]pyrazine as an orange liquid (95% analysis by C-NMR).

[0197] [Example 1.17] 3-[[6-[6-(2,3-dihydroxypropylsulfanylmethyl)-2-pyridyl]-2-pyridyl]methylsulfanyl]-propane-1,2-diol [ka]

[0198] Under an inert atmosphere, 1.20 g of potassium carbonate and 0.85 g of 3-mercapto-1,2-propanediol were added to a solution of 1.0 g of 6,6'-bis(chloromethyl)-2,2'-bipyridine in 20 ml of N,N-dimethylformamide. The mixture was stirred at 80 °C for 7 hours and then at room temperature overnight. An additional 0.86 g of 3-mercapto-1,2-propanediol was added, and the mixture was stirred at 80 °C for 6 hours and then at room temperature for 2 days. The solvent was removed under vacuum, 10 ml of water was added, and the pH was adjusted to 6-7 using hydrochloric acid. 50 ml of ethyl acetate was added, and the mixture was extracted three times with 50 ml of ethyl acetate each time. The combined organic layers were dried over sodium sulfate. After concentration in vacuo, the residue was purified by chromatography on silica gel with dichloromethane / methanol as eluent (gradient elution) to give 1.0 g of 3-[[6-[6-(2,3-dihydroxypropylsulfanylmethyl)-2-pyridyl]-2-pyridyl]methylsulfanyl]-propane-1,2-diol as a pale yellow powder (assay by C-NMR 95%).

[0199] [Example 1.18] 2-[2-(2-phenylsulfanylethylsulfanyl)ethyl]pyridine [ka]

[0200] Under an inert atmosphere, 1.05 g of 2-vinylpyridine was added to a solution of 1.70 g of 2-(phenylsulfanyl)ethane-1-thiol in 20 ml of isopropanol. The mixture was refluxed for 4.5 hours and then stirred at room temperature overnight. After concentration in vacuo, the residue was purified by chromatography on silica gel using cyclohexane / ethyl acetate as the eluent (gradient elution) to give 2.5 g of 2-[2-(2-phenylsulfanylethylsulfanyl)ethyl]pyridine as a colorless liquid (C-NMR analysis 95%).

[0201] [Example 1.19] 1-[2-(2-ethylsulfanylethylsulfanyl)ethyl]imidazole [ka]

[0202] Under an inert atmosphere, 0.94 g of 1-vinylimidazole was dissolved in 20 ml of isopropanol. 1.22 g of 2-(ethylsulfanyl)ethane-1-thiol and 25 mg of azobisisobutyronitrile were added, and the mixture was refluxed for 6.5 hours and then stirred at room temperature for 2 days. After concentration in vacuo, the residue was purified by silica gel chromatography using cyclohexane / ethyl acetate as the eluent (gradient elution) to give 1.4 g of 1-[2-(2-ethylsulfanylethylsulfanyl)ethyl]imidazole as a pale yellow liquid (C-NMR analysis 90%).

[0203] [Example 1.20] 2-[2-(2-ethylsulfanylethylsulfanyl)-1-methyl-ethyl]thiazole [ka]

[0204] Under an inert atmosphere, 1.25 g of 2-isopropenylthiazole was dissolved in 20 ml of isopropanol. 1.22 g of 2-(ethylsulfanyl)ethane-1-thiol was added, and the mixture was refluxed for 6.0 hours, after which 25 mg of azobisisobutyronitrile was added. The mixture was refluxed for 7.0 hours, after which an additional 25 mg of azobisisobutyronitrile was added. The mixture was refluxed for 6.0 hours. After concentration in vacuo, the residue was purified by chromatography on silica gel using cyclohexane / ethyl acetate as eluent (gradient elution) to give 0.58 g of 2-[2-(2-ethylsulfanylethylsulfanyl)-1-methyl-ethyl]thiazole as a pale yellow liquid (95% analysis by C-NMR).

[0205] Example 1.21 Morpholine-4-carbodithioate, tetramethylammonium salt [ka]

[0206] 16.4 g of morpholine and 38 g of tetramethylammonium hydroxide were dissolved in 50 g of THF at 25° C. under an inert atmosphere. The reaction mixture was then cooled to 5° C., and 15.2 g of CS2 dissolved in 100 ml of THF was added over a period of 2 hours. The crude product was filtered, washed three times with acetone, and dried under vacuum. 22.5 g of the final product was obtained as orange crystals (48%).

[0207] Example 1.22: Piperazine-1,4-dicarbodithioate, ditetramethylammonium salt [ka]

[0208] 8.6 g of piperazine and 38.1 g of tetramethylammonium hydroxide were dissolved in 60 g of methanol at 25° C. under an inert atmosphere. The reaction mixture was then cooled to 5° C., and 15.2 g of CS2 dissolved in 100 ml of THF was added over a period of 2 hours. The reaction mixture was post-reacted for 2 hours at an elevated temperature up to 25° C. The crude product was filtered, washed three times with acetone, and dried under vacuum. 22.6 g of the final product was obtained as yellow crystals (59%).

[0209] [Example 1.23] 4-[2-(2-ethylsulfanylethylsulfanyl)ethyl]morpholine [ka]

[0210] Under an inert atmosphere, 1.22 g of 2-(ethylsulfanyl)ethane-1-thiol was added to a mixture of 7.13 g of a 21% solution of sodium ethylate in ethanol and 10 ml of ethanol. The mixture was stirred at room temperature for 15 minutes. A solution of 1.86 g of 4-(2-chloroethyl)morpholine hydrochloride in 15 ml of ethanol was slowly added. The mixture was stirred at room temperature for 96 hours. After concentration in vacuo, the residue was purified by chromatography on silica gel using cyclohexane / ethyl acetate as the eluent (gradient elution) to give 1.3 g of 4-[2-(2-ethylsulfanylethylsulfanyl)ethyl]morpholine as a pale yellow liquid (C-NMR analysis 95%).

[0211] [Example 1.24] 1-[2-(2-ethylsulfanylethylsulfanyl)ethyl]pyrrolidin-2-one [ka]

[0212] 1.11 g of 1-vinyl-2-pyrrolidone was dissolved in 30 ml of isopropanol. 1.22 g of 2-(ethylsulfanyl)ethane-1-thiol was added, and the mixture was refluxed for 7.5 hours and then stirred at room temperature overnight. 25 mg of azobisisobutyronitrile was added, and the mixture was refluxed for 7.0 hours. After concentration in vacuo, the residue was purified by chromatography on silica gel using cyclohexane / ethyl acetate as the eluent (gradient elution) to give 1.6 g of 41-[2-(2-ethylsulfanylethylsulfanyl)ethyl]pyrrolidin-2-one as a colorless liquid (C-NMR analysis 95%).

[0213] [Example 2] Stability test A silver methanesulfonate solution was added to the complexing agent (complexing agent:Ag ratio = 10:1). If the complexing agent was insoluble, 2-3 drops of methanesulfonic acid were added. Next, a tin methanesulfonate solution containing 4-methoxyphenol (MeHQ) as an antioxidant was added. The mixture was then stored at 50°C for 7 days. If a precipitate formed, the complexing agent failed the test. If the mixture remained clear over a 3-day period, this indicated good complexation ("o"); if the mixture remained clear over a 7-day period, this indicated very good complexation ("+").

[0214] The reaction rate at temperatures below 100°C triples with each 10°C increase in temperature, so 7 days at 50°C represents 6 months of stability at 20°C.

[0215] The complexing agent of Example 1 was subjected to the above test procedures, and the results are listed in Table 1.

[0216] [Table 4]

[0217] [Example 3] Electroplating experiment The patterned photoresist contained vias with a diameter of 8 μm and a depth of 15 μm, as well as pre-formed copper μ-bumps with a height of 5 μm. The isolated (iso) region consisted of a 3 × 6 pillar array with a center-to-center distance (pitch) of 32 μm. The high-density region consisted of an 8 × 16 pillar array with a center-to-center distance (pitch) of 16 μm. To calculate die coplanarity, three bumps from the iso region and three bumps from the center of the high-density region were used.

[0218] The morphology (roughness) was determined qualitatively by scanning electron microscopy (SEM).

[0219] Example 3.1 A tin-silver plating bath with the following composition was prepared: 75 g / L tin as tin methanesulfonate, 165 g / L methanesulfonic acid, 0.5 g / L silver as silver methanesulfonate, 5.1 g / L mercaptopyridine as an Ag complexing agent, 2 g / L of a commercially available antioxidant, and 2 g / L of a surfactant. 7.37 μm of tin-silver alloy (SnAg) (silver content 1.5 wt.%) was electroplated onto copper bumps. The copper bumps had a diameter of 50 μm and a height of 5 μm. Large wafer coupons measuring 2 cm × 2 cm with a 70 μm-thick patterned photoresist layer were immersed in the plating bath and electroplated at 6 ASD (=60 mA / cm). 2 ) was applied at 25°C for 814 seconds.

[0220] The plated tin-silver bumps were examined by scanning electron microscopy (SEM). SEM images are shown in Figure 1. Qualitative morphology assessments are summarized in Table 2.

[0221] Example 3.2 A tin-silver plating bath with the following composition was prepared: 75 g / L tin as tin methanesulfonate, 165 g / L methanesulfonic acid, 0.5 g / L silver as silver methanesulfonate, 5.1 g / L 3-[2-(2,3-dihydroxypropylsulfanyl)phenyl]sulfanylpropane-1,2-diol from Example 1.1 as an Ag complexing agent, 2 g / L of a commercially available antioxidant, and 2 g / L of a surfactant. 7.37 μm of tin-silver alloy (SnAg) (1.5 wt. % Ag content) was electroplated onto copper bumps. The copper bumps had a diameter of 50 μm and a height of 5 μm. A 2 cm × 2 cm large wafer coupon with a 70 μm-thick patterned photoresist layer was immersed in the plating bath, and a direct current of 6 ASD was applied at 25°C for 814 seconds.

[0222] The plated tin-silver bumps were examined by scanning electron microscopy (SEM). Qualitative morphology assessment is summarized in Table 2.

[0223] Example 3.3 A tin-silver plating bath with the following composition was prepared: 75 g / L tin as tin methanesulfonate, 165 g / L methanesulfonic acid, 0.5 g / L silver as silver methanesulfonate, 5.1 g / L 3-[2-(2,3-dihydroxypropylsulfanyl)phenyl]sulfanylpropane-1,2-diol from Example 1.6 as an Ag complexing agent, 2 g / L of a commercially available antioxidant, and 2 g / L of a surfactant. 7.37 μm of tin-silver alloy (SnAg) (1.5 wt. % Ag content) was electroplated onto copper bumps. The copper bumps had a diameter of 50 μm and a height of 5 μm. A 2 cm × 2 cm large wafer coupon with a 70 μm-thick patterned photoresist layer was immersed in the plating bath, and a direct current of 6 ASD was applied at 25°C for 814 seconds.

[0224] The plated tin-silver bumps were examined by scanning electron microscopy (SEM). Qualitative morphology assessment is summarized in Table 2.

[0225] [Table 5]

[0226] Table 2 shows that the thioether compound of Example 3.2 (compound 1.1) and Example 3.3 (compound 1.6) according to the invention exhibit much better morphology compared to the thiol compound of Comparative Example C3.1.

Claims

1. (a) metal ions including or consisting of tin ions and silver ions; and (b) a compound of formula C11 2 Ｃ１２ -️ Ｃ１１ -2 Ｃ１１ (311) [In the formula, X Ｃ１１ teeth, (a) (i) one N atom, or (ii) a first N atom and a second heteroatom selected from N and S, the first N atom and the second heteroatom being separated by at least one C atom; or (iii) triazole or thiadiazole a divalent 5- or 6-membered aromatic N-heterocyclic group comprising (b) a divalent 6-membered aromatic carbocyclic group, (c) a divalent 5- or 6-membered aliphatic N-heterocyclic group containing one N atom and optionally a second heteroatom selected from N and O. all of which may be unsubstituted or contain one or more OH or one or more R Ｃ１４ may be substituted with R Ｃ１１ is (a)-X Ｃ１２ -S[-X Ｃ１３ -D Ｃ１１ ] ｎ -R Ｃ１３ , 【Chemical 1】 is selected from R Ｃ１２ is R Ｃ１１ , H, OH, C １ ~C １０ Alkyl, and C １ ~C １０ alkoxy; X Ｃ１２ represents a chemical bond or a linear or branched C １ ~C ６ alkanediyl, wherein (a) X Ｃ１１ is a divalent 5- or 6-membered aromatic N-heterocyclic group, and (b) R Ｃ１３ is substituted with one OH, and (c) R Ｃ１２ is R Ｃ１１ Otherwise, X Ｃ１２ is a chemical bond, X Ｃ１３ is a linear or branched C which may be unsubstituted or substituted with OH １ ~C ６ is an alkanediyl, X Ｃ１４ is a chemical bond or a linear C １ ~C ４ is an alkanediyl, D Ｃ１１ is S, R Ｃ１３ is (a) a linear or branched C alkyl group which may be unsubstituted or substituted with one or more OH groups; １ ~C ６ alkyl, and (c) C ２ ~C ４ polyoxyalkylene groups, provided that X Ｃ１１ is a divalent 5- or 6-membered aromatic N-heterocyclic group, R Ｃ１３ is unsubstituted or substituted with one OH, with the exception of X Ｃ１１ is a divalent 5- or 6-membered aromatic N-heterocyclic group containing a first N atom and a second heteroatom selected from N, then R Ｃ１３ is non-substituted, R Ｃ１４ is H and linear or branched C １ ~C ６ alkyl, n is 0 or an integer from 1 to 5. and at least one complexing agent of the formula (I) and salts thereof.

2. R Ｃ１１ But, -X Ｃ１２ -S-[X Ｃ１３ -D Ｃ１１ ] ｎ -R Ｃ１３ 2. The aqueous composition of claim 1, wherein:

3. X Ｃ１２ is a linear or branched C which may be unsubstituted or substituted with OH; １ ~C ４ alkanediyl, provided that (a) X Ｃ１１ is a divalent 5- or 6-membered aromatic N-heterocyclic group, and (b) R Ｃ１３ is substituted with one OH, and (c) R Ｃ１２ is R Ｃ１１ Otherwise, X Ｃ１２ The aqueous composition of claim 2 , wherein is a chemical bond.

4. n is 1 or 2, and D Ｃ１１ is S and X Ｃ１３ is a linear or branched C which may be unsubstituted or substituted with one or more OH groups; １ ~C ４ 4. The aqueous composition of claim 2 or 3, wherein the alkyl group is an alkanediyl.

5. R Ｃ１３ (a) a linear or branched C which may be unsubstituted or substituted with one or more OH groups; １ ~C ４ alkyl, (b) X Ｃ１１ is not an aromatic carbocyclic group, it is selected from (c) phenyl or benzyl optionally substituted with OH, methyl or ethyl, and (d) polyoxyethylene or poly(oxyethylene-co-oxypropylene), with the proviso that X Ｃ１１ is a divalent 5- or 6-membered aromatic N-heterocyclic group, R Ｃ１３ is unsubstituted or substituted with one OH, with the exception of X Ｃ１１ is a divalent 5- or 6-membered aromatic N-heterocyclic group containing a first N atom and a second heteroatom selected from N, then R Ｃ１３ 5. The aqueous composition of claim 2, wherein is unsubstituted.

6. 6. The aqueous composition of claim 2, wherein n is 0 or 1.

7. R Ｃ１１ but, 【Chemistry 2】 [In the formula, X Ｃ１４ is a chemical bond, methanediyl, ethanediyl, or propanediyl; R Ｃ１４ is H, methyl, ethyl or propyl.

2. The aqueous composition of claim 1, wherein:

8. X Ｃ１１ 8. The aqueous composition of claim 1, wherein R is selected from pyrrole, pyridine, imidazole, thiazole, pyrimidine, or thiazole, which may be unsubstituted or substituted with one or more methyl, ethyl, or propyl.

9. X Ｃ１１ 8. The aqueous composition of claim 1, wherein is selected from phenyl, which may be unsubstituted or substituted with one or more methyl, ethyl or propyl.

10. X Ｃ１１ 8. The aqueous composition of claim 1, wherein R is selected from piperidine, piperazine, pyrrolidinone and morpholine, which may be unsubstituted or substituted with one or more methyl, ethyl or propyl.

11. R Ｃ１２ But, R Ｃ１１ , X Ｃ１１ -R Ｃ１１ , H, OH, NR Ｃ１４ ２ , C １ ~C １４ Alkyl, and C １ ~C １４ 11. The aqueous composition of claim 1, wherein the alkyl group is selected from alkoxy groups.

12. 12. A method of using an aqueous composition according to any one of claims 1 to 11 for depositing a tin-silver alloy onto a substrate containing features with an opening size of 500 nm to 500 μm.

13. a) contacting a substrate with the composition of any one of claims 1 to 11; b) applying an electric current to the substrate for a time sufficient to deposit a tin or tin-alloy layer on the substrate; A method for electrodepositing tin or a tin-silver alloy onto said substrate, comprising: The method wherein the substrate contains features with opening sizes between 500 nm and 500 μm, and the deposition is carried out to fill these features.

14. The method of claim 13, wherein the opening size is between 1 μm and 200 μm.

15. 3-[2-(2,3-dihydroxypropylsulfanyl)phenyl]sulfanylpropane-1,2-diol, 3-[2-(2,3-dihydroxypropylsulfanyl)-4-methyl-phenyl]sulfanylpropane-1,2-diol, 3-[[2-(2,3-dihydroxypropylsulfanylmethyl)phenyl]methylsulfanyl]propane-1,2-diol, 2,6-bis(2-ethyl-sulfanylethylsulfanylmethyl ) pyridine, morpholine-4-carbodithioate tetramethylammonium salt, piperazine-1,4-dicarbodithioate ditetramethylammonium salt, 3-[[3-(2,3-dihydroxy-propylsulfanylmethyl)phenyl]methylsulfanyl]propane-1,2-diol, 2-[2-(2-propylsulfanylethyl-sulfanyl)ethyl]pyridine, 2-[2-(2-methylsulfanylethylsulfanyl)ethyl]pyridine A compound used as a complexing agent for metal ions containing or consisting of tin ions and silver ions, selected from lysine, 2-(2-ethylsulfanyl-ethylsulfanylmethyl)-6-[6-(2-ethylsulfanylethylsulfanylmethyl)-2-pyridyl]pyridine, 2,6-bis(2-methylsulfanylethylsulfanylmethyl)pyridine, 4-[2-(2-ethylsulfanylethylsulfanyl)ethyl]-morpholine, 2-[2-(2-isopropylsulfanylethylsulfanyl)ethyl]pyridine, 2-(2-propylsulfanylethyl-sulfanylmethyl)pyridine, 2-[2-(2-ethylsulfanylethylsulfanyl)-1-methyl-ethyl]thiazole, 2-[2-(2-benzylsulfanylethylsulfanyl)ethyl]pyridine, 2-[2-(2-phenylsulfanylethylsulfanyl)ethyl]pyridine, and salts thereof.

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