Composition for tin or tin alloy electroplating comprising a leveling agent

Abstract

The present invention provides an aqueous composition comprising tin ions, optionally alloy metal ions selected from silver, copper, indium and bismuth ions, and at least one additive (L1) having the formula L1 wherein for each group RL1, RL1 is independently selected from C1 to C6 alkyl, C1 to C6 alkenyl, C1 to C6 alkoxy, halogen, CN and OH; rL2 is a C1 to C6 alkyl group, a C1 to C6 alkenyl group, a C5 to C12 aryl group, a C6 to C15 alkylaryl group, a C6 to C15 arylalkyl group, all of which may be substituted by CN, OH, a C1 to C6 alkoxy group or halogen; rL3 is selected from the group consisting of C1 to C6 alkyl; rL4 is H; n is the number of substituents RL1 selected from 0 to 5, where the amount of organic solvent in the composition is less than 0.1 g / l, and where the composition does not contain any electrodepositable metal ions other than tin ions and alloy metal ions. # imgabs0 #

Description

Background Art

[0001] The present invention relates to a tin or tin alloy electroplating composition comprising a leveling agent, use thereof and a method for tin or tin alloy electroplating.

[0002] Metals and metal alloys are commercially important, particularly in the electronics industry where they are commonly used as electrical contacts, final finishes, and solders.

[0003] Lead-free solders such as tin, tin-silver, tin-copper, tin-bismuth, tin-silver-copper, etc. are common metals used for solders. These solders are usually deposited on semiconductor substrates by metal electroplating baths.

[0004] Typical tin plating solutions contain dissolved tin ions, water, an acid electrolyte (such as methanesulfonic acid) in an amount sufficient to render the bath conductive, an antioxidant, and additives for improving plating uniformity and the quality of the metal deposit in terms of surface roughness and void formation. Such additives typically include surfactants and grain refiners, among others.

[0005] Certain applications of lead-free solder plating present challenges in the electronics industry. For example, when used as a capping layer on copper posts, a relatively small amount of lead-free solder (such as tin-silver solder) is deposited on top of the copper posts. When plating such a small amount of solder, it is often difficult to plate a uniform height of solder composition on top of each post (both within the chip and across the wafer). Use of known solder plating baths also often results in deposits with relatively rough surface morphology.

[0006] US 3 361 652 discloses an acidic tin electroplating composition comprising a primary brightener of the formula X-CH=CH-Y, wherein X is phenyl, furfuryl, or pyridyl, and Y can be hydrogen, formyl, carboxyl, alkyl, hydroxyalkyl, formylalkyl, or acyl of a carboxylic acid. One of the brighteners mentioned is 4-hydroxy-3-methoxy-benzylideneacetone.

[0007] In a preferred embodiment, US Pat. No. 4,582,576 discloses an acidic tin electroplating composition comprising a carbonyl compound having the formula

[0008]

[0009] Wherein X1 and X2 may be hydrogen, hydroxy, alkoxy, chlorine or bromine, and the alkyl group of the alkoxy may contain from about 1 to about 5 carbon atoms. Examples of such compounds include benzylideneacetone and 3'-chlorobenzylideneacetone.

[0010] US2014 / 183 050A1 discloses a tin or tin alloy electroplating solution suitable for through-hole filling, which selectively deposits tin or tin alloy in the through-hole, and discloses a method for using the liquid for through-hole filling, which can form a columnar deposit without actually having a void. The plating solution contains a specific α, β-unsaturated carbonyl compound added to the tin or tin alloy plating solution. Such carbonyl compounds can be specifically substituted by alkyl, alkenyl, alkoxy, amino, halogen atom, hydroxyl, carbonyl and cyano groups having 1 to 9 carbon atoms. Mention 3-chloroacetophenone, crotonyl chloride, crotonyl chloride and 4-chloro-2-butenal.

[0011] JP H10 102279A discloses an electroplated tin-zinc gradient alloy film having a zinc content of 0.1% or more and 15% or less on the underlayer side and a zinc content on the surface side of the plated film higher than that of the underlayer film. A standard tin-zinc electroplating bath can be used.

[0012] JP 2000 080493A discloses a composition for tin or tin alloy electroplating, which comprises (A) at least one or more tin salts or tin complexes, or at least one or more tin salts or tin complexes and at least one or more metal salts or complexes of metals other than tin, (B) at least one or more acids, bases and / or complexing agents, (C) at least one or more surfactants, (D) at least one or more 1C-6C saturated lower aliphatic water-soluble alcohols, ketones or ethers, and (E) at least one or more mono(or poly)hydroxybenzenes or mono(or poly)hydroxynaphthalenes obtained by further introducing carboxyl groups or sulfonic acid groups.

[0013] However, the prior art neither solves nor even addresses the problem of obtaining uniform height of deposited solder both within a chip and across a wafer. Thus, there remains a need in the electronics industry for a pure tin or tin alloy electroplating bath that results in solder deposits with improved height uniformity, also known as coplanarity (COP).

[0014] WO 2022 / 129238 discloses aqueous compositions comprising tin ions, optionally alloying metal ions selected from silver, indium and bismuth ions and fluorine-substituted α,β-unsaturated aliphatic carbonyl compounds. However, it is not desirable to use fluorinated or perfluorinated compounds in plating baths.

[0015] The object of the present invention is to provide a tin or tin alloy electroplating additive, in particular a leveling agent, having good leveling properties, which is capable of providing a substantially flat tin or tin alloy layer with a tin or tin alloy electroplating bath and filling micrometer-sized features without substantially forming defects (such as but not limited to voids). Another object of the present invention is to provide a tin or tin alloy electroplating bath that provides a uniform and flat tin or tin alloy deposit, in particular features having a width of 1 micrometer to 200 micrometers. Another object of the present invention is to provide a leveling agent with reduced environmental impact. Summary of the invention

[0016] The present invention provides an aqueous composition comprising tin ions, optionally alloying metal ions selected from silver, copper, indium and bismuth ions and at least one additive having formula L1

[0017]

[0018] in

[0019] For each group R L1 , R L1 independently selected from C1 to C6 alkyl, C1 to C6 alkenyl, C1 to C6 alkoxy, halogen, CN and OH;

[0020] R L2 is C1 to C6 alkyl, C1 to C6 alkenyl, C5 to C 12 Aryl, C6 to C 15 Alkyl aryl, C6 to C 15 Arylalkyl, all of which may be substituted by CN, OH, C1 to C6 alkoxy or halogen;

[0021] R L3 Selected from C1 to C6 alkyl;

[0022] R L4 It is H;

[0023] n is a substituent R selected from 0 to 5 L1 The number of

[0024] wherein the amount of organic solvent in the composition is less than 0.1 g / l, and

[0025] The composition does not contain any electrolytically depositable metal ions other than tin ions and alloying metal ions.

[0026] A further embodiment of the invention is the use of an additive as described herein in a bath for electrodeposition of a layer containing tin or a tin alloy, wherein the layer containing a tin alloy comprises an alloying metal selected from silver, copper, indium and bismuth in an amount of 0.01 to 10% by weight.

[0027] Yet another embodiment of the present invention is a method for depositing a tin or tin alloy layer on a substrate, the method being performed by:

[0028] a) contacting a tin alloy electroplating bath comprising a composition as described herein with a substrate, and

[0029] b) applying a current density to the substrate for a time sufficient to deposit a tin alloy layer onto the substrate.

[0030] The additive according to the invention can be advantageously used in bonding technology, such as in circuit board technology or in electronic circuit packaging processes to produce tin or tin alloy bumps typically 1 to 200 microns, preferably 3 to 100 microns, most preferably 5 to 50 microns high and wide for bumping processes. In a specific embodiment, the substrate comprises micron-sized features, and deposition is performed to fill these micron-sized features, wherein these micron-sized features have a size of 1 to 200 microns, preferably 3 to 100 microns.

[0031] The additives according to the invention lead to tin or tin alloy, in particular tin-silver deposits, which show better coplanarity (COP) than unsubstituted α,β-unsaturated carbonyl compounds or substituted α,β-unsaturated carbonyl compounds with α-substituents other than those described herein. The additives according to the invention also lead to tin or tin alloy deposits showing good or even better roughness. DETAILED DESCRIPTION

[0032] The leveling agent according to the present invention

[0033] Hereinafter, the terms "additive", "leveling agent" and "α-substituted carbonyl compound" are used synonymously herein.

[0034] In a first embodiment, the electroplating composition comprises, in addition to tin ions and optional alloying metal ions selected from the group consisting of silver, indium, copper and bismuth ions, at least one α-substituted carbonyl compound having the formula L1:

[0035]

[0036] For each group R L1 , R L1 can be independently selected from C1 to C6 alkyl, C1 to C6 alkenyl, C1 to C6 alkoxy, halogen, CN and OH. Preferably, for each group R L1 , R L1 Can be independently selected from C1 to C4 alkyl or C1 to C4 alkoxy. One or more most preferred groups R L1is methyl, ethyl, 1-propyl, 2-propyl, methoxy, ethoxy, 1-propoxy or 2-propoxy. n is a substituent R L1 The number of is selected from 0 to 5, preferably 0, 1 or 2, most preferably 1 or 2.

[0037] R L2 It can be C1 to C6 alkyl, C1 to C6 alkenyl, C5 to C 12 Aryl, C6 to C 15 Alkyl aryl, C6 to C 15 Arylalkyl, all of which may be substituted by CN, OH, C1 to C6 alkoxy or halogen. Preferably, R L2 is C1 to C4 alkyl, all of which may be substituted by CN, OH or C1 to C3 alkoxy. Most preferably, R L2 is methyl, ethyl or propyl, especially methyl.

[0038] R L3 It may be C1 to C6 alkyl, preferably C1 to C4 alkyl, most preferably methyl, ethyl, 1-propyl and 2-propyl. The inventors unexpectedly found that alkyl substitution at the alpha position to the carbonyl function leads to significantly higher coplanarity than the leveling agent not substituted at this position.

[0039] R L4 is H. The inventors unexpectedly found that any alkyl substituent would have a negative impact on the performance of the leveling agent.

[0040] As used herein, "alkyl" and "alkanediyl" refer to straight chain, branched or cyclic alkyl or alkanediyl, respectively. As used herein, "aromatic" or "aryl" refers to a monocyclic or bicyclic carbocyclic aromatic group, which may be unsubstituted or substituted by a substituent selected from the following R L1 Substituted: one or more Cl, C1 to C6 alkyl, particularly one or more C1 to C4 alkyl, more particularly one or more methyl, ethyl or propyl, most particularly one or two methyl or ethyl. As used herein, "alkenyl" and "alkenediyl" mean a linear, branched or cyclic alkenyl or alkenediyl, respectively. As used herein, "arylalkyl" means an alkyl substituted with one or more aryl, particularly one or more phenyl, most particularly one phenyl. As used herein, "alkylaryl" means an aryl substituted with one or more C1 to C6 alkyl, particularly one or more C1 to C4 alkyl, more particularly one or more methyl, ethyl or propyl, most particularly one or two methyl or ethyl.

[0041] In Formula 1, both configurations of the double bond are possible, E and Z. The E configuration (or the trans configuration of the phenyl and carbonyl substituents) is preferred.

[0042] A particularly preferred leveling agent may be a compound having formula L2

[0043]

[0044] Where R L2 and R L3 It may have the meanings described above. Preferably, R L2 is selected from methyl, ethyl and propyl, most preferably selected from methyl. L3 Selected from methyl, ethyl and propyl, most preferably selected from methyl.

[0045] The most preferred leveling agents having formula L2 are (E)-3-methyl-4-phenyl-but-3-en-2-one, (E)-3-ethyl-4-phenyl-but-3-en-2-one, (E)-4-methyl-5-phenyl-pent-4-en-3-one, and (E)-4-ethyl-5-phenyl-pent-4-en-3-one.

[0046] Another particularly preferred leveling agent may be a compound having formula L3

[0047]

[0048] Where R L1 , R L2 , and R L3 It may have the meanings described above. Preferably R L1 is selected from methyl, ethyl and propyl, methoxy, most preferably selected from methyl and methoxy. L2 is selected from methyl, ethyl and propyl, most preferably methyl. L3 Selected from methyl, ethyl and propyl, most preferably selected from methyl.

[0049] The most preferred leveling agent having formula L3 is selected from (E)-3-methyl-4-(4-methylphenyl)-but-3-ene-2-one, (E)-3-ethyl-4-(4-methylphenyl)-but-3-ene-2-one, (E)-4-methyl-5-(4-methylphenyl)-pent-4-ene-3-one, (E)-4-ethyl-5-(4-methylphenyl)-pent-4-ene-3-one, (E)-3-methyl-4- (4-methoxyphenyl)-but-3-en-2-one, (E)-3-ethyl-4-(4-methoxyphenyl)-but-3-en-2-one, (E)-4-methyl-5-(4-methoxyphenyl)-pent-4-en-3-one, and (E)-4-ethyl-5-(4-methoxyphenyl)-pent-4-en-3-one, all of which can be unsubstituted or further substituted with one or two methyl or methoxy phenyl groups.

[0050] The additive according to the invention can be prepared by any preparation method. A preferred preparation method is described below.

[0051] 3-Methyl-4-aryl-but-3-en-2-one can be synthesized according to the literature procedure (Org. Lett. [Org. Chemistry Communications] 2021, 23, 242-246) using the corresponding aldehyde, 2-butanone, sulfuric acid and acetic acid (Procedure 1).

[0052] 4-Methyl-5-aryl-pent-4-en-3-one can be synthesized according to the literature procedure (Org. Lett. [Org. Chemistry Communications] 2021, 23, 242-246) using the corresponding aldehyde, 3-pentanone, sodium hydroxide solution and ethanol (Procedure 2).

[0053] (E)-4-Phenylpent-3-en-2-one can be synthesized according to a literature procedure (J. Am. Chem. Soc. 2006, 128, 13368-13369) using acetylacetone, phenylmagnesium bromide and THF, followed by ammonium chloride and oxalic acid (Procedure 3).

[0054] 4-Aryl-but-3-en-2-ones can be synthesized according to literature procedures (J. Am. Chem. Soc. 2013, 135, 1891-1894) using the corresponding aldehyde, diethyl (2-oxopropyl)phosphonate, cesium carbonate, dioxane and water (Procedure 4).

[0055] During the preparation of the α-substituted carbonyl compounds, further compounds can be used, for example in order to introduce specific substituents into the leveling agent, to set specific properties or to enable further reactions on the resulting leveling agent at a later point in time.

[0056] Since most α-substituted carbonyl compounds have limited solubility in aqueous plating baths, it may be advantageous to dissolve them in a water-miscible solvent (such as, but not limited to, isopropanol, ethanol, ethylene glycol, etc.) before mixing them with the rest of the plating composition.

[0057] The composition as described herein may comprise further additives, in particular one or more surfactants and one or more grain refiners different from the above-mentioned α-substituted carbonyl compounds.

[0058] Typically, the total amount of leveling agent in the electroplating bath is 0.5 ppm to 10000 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 about 100 ppm to about 10000 ppm based on the total weight of the plating bath, although greater or lesser amounts may be used.

[0059] Other leveling agents

[0060] Those skilled in the art will appreciate that more than one leveling agent may be used. When two or more leveling agents are used, at least one of these leveling agents is an α-substituted carbonyl compound or a derivative thereof as described herein. It is preferred to use only one or more α-substituted carbonyl compounds as leveling agents in the plating bath composition.

[0061] Suitable additional leveling agents include, but are not limited to, polyaminoamides and derivatives thereof, polyalkanolamines and derivatives thereof, polyethyleneimine and derivatives thereof, quaternized polyethyleneimine, polyglycine, poly(allylamine), polyaniline, polyurea, polyacrylamide, poly(melamine-co-formaldehyde), reaction products of amines with epichlorohydrin, reaction products of amines, epichlorohydrin and polyalkoxides, reaction products of amines with polyepoxides, polyvinylpyridine, polyvinylimidazole, polyvinylpyrrolidone, or copolymers thereof, nigrosine, pentamethyl-para-purpurin hydrohalide, hexamethyl-para-purpurin hydrohalide, or compounds containing functional groups of formula NRS (wherein R is substituted alkyl, unsubstituted alkyl, substituted aryl or unsubstituted aryl). Typically, the alkyl group is a C1-C6 alkyl group and preferably a C1-C4 alkyl group. Typically, the aryl group includes a C6-C 20 Aryl, preferably C6-C 12 Aryl. Such aryl groups may further contain heteroatoms such as sulfur, nitrogen and oxygen. Preferably, the aryl group is phenyl or naphthyl. Compounds containing functional groups having the formula NRS are generally known, are generally commercially available and can be used without further purification.

[0062] In such compounds containing NRS functional groups, sulfur ("S") and / or nitrogen ("N") may be attached to such compounds via single bonds or double bonds. When sulfur is attached to such compounds via a single bond, sulfur will have another substituent such as, but not limited to, hydrogen, C1-C 12 Alkyl, C2-C 12 Alkenyl, C6-C 20 Aryl, C1-C 12 Alkylthio, C2-C 12 Thiol, C6-C 20 Likewise, nitrogen will have one or more substituents such as, but not limited to, hydrogen, C1-C 12 Alkyl, C2-C 12 Alkenyl, C7-C 10 Aryl, etc. The NRS functional group may be acyclic or cyclic. Compounds containing cyclic NRS functional groups include those having either nitrogen or sulfur or both nitrogen and sulfur in the ring system.

[0063] A further levelling agent is a triethanolamine condensate as described in the unpublished international patent application number PCT / EP 2009 / 066581.

[0064] Typically, the total amount of additional leveling agents in the electroplating bath is from 0.5 ppm to 10000 ppm, based on the total weight of the plating bath.

[0065] Typically a wide variety of additives can be used in the bath to provide the desired surface treatment for the plated tin or tin alloy bumps. Typically more than one additive is used, each additive forming the desired function. Advantageously, the electroplating bath may contain one or more of a surfactant, a grain refiner, a complexing agent (in the case of alloy deposition), an antioxidant, and a mixture thereof. Most preferably, in addition to the leveling agent according to the present invention, the electroplating bath also includes a surfactant and optionally a grain refiner. Other additives may also be suitably used in the electroplating bath of the present invention.

[0066] Surfactants

[0067] One or more nonionic surfactants can 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 composition at a concentration of 1 to 10,000 ppm, and preferably 5 to 10,000 ppm, based on the weight of the electrolyte composition. Preferred alkoxide compounds include polyalkylene glycols, such as, but not limited to, C2 to C6 having at least one hydroxyl group. 20 Alkoxide addition products of organic compounds, and products derived from the addition of different alkoxides to C2 to C 20 Polyfunctional, in particular tetrafunctional, pentafunctional or hexafunctional polyethers of polyamine compounds.

[0068] Preferred polyalkylene glycols are polyethylene glycol and polypropylene glycol. Such polyalkylene glycols are generally commercially available from various sources and can be used without further purification. Capped polyalkylene glycols in which one or more terminal hydrogens are replaced by hydrocarbon groups may also be suitably used. Examples of suitable polyalkylene glycols are those having the formula RO-(CXYCX'Y'O) n R', wherein R and R' are independently selected from H, C2-C 20 Alkyl and C6-C 20 Aryl; each of X, Y, X' and Y' is 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' is hydrogen.

[0069] Suitable EO / PO copolymers generally have a weight ratio of EO:PO of 10:90 to 90:10, and 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 various sources, such as those available from BASF under the trade names "PLURONIC" or TETRONIC.

[0070] Suitable alkoxide condensation products of organic compounds with at least one hydroxyl group and 20 or less carbon atoms include those of aliphatic hydrocarbons with one to seven carbon atoms, unsubstituted aromatic compounds, or alkylated aromatic compounds with six or less carbons in the alkyl moiety, such as those disclosed in US 5 174 887. Aliphatic alcohols can be saturated or unsaturated. Suitable aromatic compounds are those with up to two aromatic rings. Aromatic alcohols have up to 20 carbon atoms before derivatization with ethylene oxide. Such aliphatic alcohols and aromatic alcohols can be further substituted, such as substituted by sulfate or sulfonate groups.

[0071] Antioxidants

[0072] Antioxidants may optionally be added to the compositions of the present invention to help keep the tin in a soluble divalent state. It is preferred to use one or more antioxidants in the compositions of the present invention. Exemplary antioxidants include, but are not limited to, hydroquinone and hydroxylated and / or alkoxylated aromatic compounds (including sulfonic acid derivatives of such aromatic compounds), and are 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 871429. Other suitable antioxidants or reducing agents include, but are not limited to, vanadium compounds such as acetylacetonato vanadium, triacetylacetonato vanadium, vanadium halides, vanadium oxyhalides, vanadium alkoxides, and oxyvanadium alkoxides. The concentration of such reducing agents is well known to those skilled in the art, but is typically in the range of 0.1 to 10 g / l, and preferably 1 to 5 g / l. Such antioxidants are generally commercially available from various sources. It is particularly preferred to use the specified antioxidants in pure tin electroplating compositions.

[0073] Complexing agent

[0074] The tin or tin alloy electroplating bath may further contain a complexing agent for complexing tin and / or any other metal present in the composition. A typical complexing agent is 3,6-dithia-1,8-octanediol. Further useful complexing agents are described in WO 2019 / 185 468 and WO 2021 / 052817.

[0075] Typical complexing agents are polyoxymonocarboxylic acids, polycarboxylic acids, aminocarboxylic acids, lactone compounds and their salts.

[0076] Other complexing agents are organic sulfur compounds like thioureas, mercaptans 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.

[0077] Electrolytes

[0078] Generally, as used herein, "aqueous" means that the electroplating composition of the present invention contains water and less than 0.1 g / l, preferably less than 0.05 g / l, most preferably less than 0.01 g / l of optionally an organic solvent. Any type of water can be used, such as distilled water, deionized water or tap water. Preferably, the electroplating composition does not contain any organic solvent or even a lower amount of an organic solvent as described above, because due to the limited solubility of most α-substituted carbonyl compounds in aqueous plating baths, it may be necessary to dissolve them in a water-miscible solvent before mixing them with the rest of the plating composition.

[0079] The electroplating composition of the present invention is suitable for depositing a tin-containing layer, which may be a pure tin layer or a tin alloy layer.

[0080] tin

[0081] The tin ion source can be any compound capable of releasing metal ions in sufficient amounts to be deposited in the electroplating bath (i.e., at least partially soluble in the electroplating bath). It is preferred that the metal ion source is soluble in the plating bath. Suitable metal ion sources are metal salts and include, but are not limited to, metal sulfates, metal halides, metal acetates, metal nitrates, metal fluoroborates, metal alkyl sulfonates, metal aryl sulfonates, metal sulfamates, metal gluconates, and the like.

[0082] The metal ion source can be used in the present invention in any amount to provide enough metal ions for electroplating on the substrate. The tin salt is typically present in an amount within the range of about 1 to about 300 g / l of the plating solution. If there are no alloying metal ions, the composition does not contain any metal that can be electrolytically deposited from the aqueous solution except tin. For the avoidance of doubt, alkali metal ions or alkaline earth metal ions may be present because they do not interact with electroplating.

[0083] In a preferred embodiment, tin ions are present in the plating composition in an amount of 20 to 200 g / l, particularly 40 to 120 g / l, most particularly 60 to 90 g / l.

[0084] alloy metal

[0085] Optionally, the plating bath according to the present invention may contain one or more alloying metal ions. Suitable alloying metals include, but are not limited to, silver, gold, copper, bismuth, indium, zinc, antimony, manganese, and mixtures thereof. Preferred alloying metals are silver, copper, bismuth, indium, and mixtures thereof, and more preferably silver. Preferably, the composition of the present invention does not contain lead. Any bath-soluble salt of an alloying metal may be suitably used as a source of alloying metal ions. Examples of such alloying metal salts include, but are not limited to: metal oxides; metal halides; metal fluoroborates; metal sulfates; metal alkanesulfonates, such as metal methanesulfonates, metal ethanesulfonates, and metal propanesulfonates; metal arylsulfonates, such as metal phenylsulfonates, metal toluenesulfonates, and metal phenolsulfonates; metal carboxylates, such as metal gluconates and metal acetates; and the like. Preferred alloying metal salts are metal sulfates; metal alkanesulfonates; and metal arylsulfonates. When an alloying metal is added to the composition of the present invention, a binary alloy deposit is obtained. When 2, 3 or more different alloying metals are added to the present composition, a ternary, quaternary or higher alloy deposit is obtained. The amount of such alloying metals used in the present composition will depend on the desired specific tin alloy. The selection of the amount of such alloying metals is within the capabilities of those skilled in the art. Those skilled in the art will appreciate that when using certain alloying metals such as silver, additional complexing agents may be required. Such complexing agents (or complexing agents (complexer)) are well known in the art and can be used in any suitable amount.

[0086] If alloying metals are present, the composition does not contain any metals that can be electrolytically deposited from aqueous solution other than tin and one or more of the alloying metals mentioned above.For the avoidance of doubt, alkali metal ions or alkaline earth metal ions may be present as they do not interact with electroplating.

[0087] Most preferably, the composition does not contain any metals that can be electrolytically deposited from aqueous solution other than (a) tin and silver, (b) tin and copper, (c) tin and indium, or (d) tin and bismuth.

[0088] Exemplary tin alloy layers include, but are not limited to, tin-silver, tin-copper, tin-indium, tin-bismuth, tin-silver-copper, tin-silver-bismuth, tin-silver-indium, and tin-silver-indium-bismuth. Preferably, the electroplating composition of the present invention deposits pure tin, tin-silver, tin-silver-copper, tin-silver-bismuth, tin-silver-indium, and tin-silver-indium-bismuth, and more preferably pure tin, tin-silver or tin-copper.

[0089] The alloy deposited from the electroplating bath of the present invention contains tin in an amount ranging from 0.01 to 99.99 wt% and one or more 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), inductively coupled plasma (ICP), or differential scanning calorimetry (DSC). Preferably, the tin-silver alloy deposited using the present invention contains 90 to 99.99 wt% tin and 0.01 to 10 wt% silver and any other alloying metals. More preferably, the tin-silver alloy deposit contains 95 to 99.9 wt% tin and 0.1 to 5 wt% silver and any other alloying metals. Tin-silver alloy is the preferred tin alloy deposit, and preferably contains 90 to 99.9 wt% tin and 10 to 0.1 wt% silver. More preferably, the tin-silver alloy deposit contains 95 to 99.9 wt% tin and 5 to 0.1 wt% silver. For many applications the eutectic composition of the alloy may be used.The alloys deposited according to the invention are substantially lead free, ie they contain 1 wt%, more preferably less than 0.5 wt% and even more preferably less than 0.2 wt% lead and still more preferably are lead free.

[0090] The alloying metal ion is present in the plating composition in an amount of 0.1 to 5% by weight, specifically 0.2 to 3% by weight, most specifically 0.3 to 2.0% by weight.

[0091] bath

[0092] Typically, in addition to a metal ion source and at least one leveling agent according to the present invention, the metal electroplating composition of the present invention preferably also comprises an electrolyte (i.e., an acidic or alkaline electrolyte), one or more metal ion sources, optionally halide ions, and optionally other additives (like surfactants and grain refiners). Such baths are typically aqueous. The water may be present in a wide range of amounts. Any type of water may be used, such as distilled water, deionized water, or tap water.

[0093] Preferably, the plating compositions of the present invention are acidic, ie, they have a pH below 7. Typically, the pH of tin or tin alloy electroplating compositions is below 4, preferably below 3, most preferably below 2.

[0094] The electroplating baths of the present invention can be prepared by combining the components in any order. Preferably, inorganic components such as metal salts, water, electrolytes and optional halide ion sources are added to the bath vessel first, followed by organic components such as surfactants, grain refiners, leveling agents, etc.

[0095] Typically, the plating baths of the present invention may be used at any temperature from 10°C to 65°C or higher. Preferably, the temperature of the plating bath is from 10°C to 35°C, and more preferably from 15°C to 30°C.

[0096] Suitable electrolytes include, for example, but 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), aminosulfonic 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.

[0097] Such electrolytes may optionally contain a halide source, such as chloride ions in tin chloride or hydrochloric acid. A wide range of halide concentrations may be used in the present invention, such as from about 0 to about 500 ppm. Typically, halide concentrations are in the range of from about 10 to about 100 ppm based on the plating bath. Preferably, the electrolyte is sulfuric acid or methanesulfonic acid, and preferably a mixture of sulfuric acid or methanesulfonic acid and a chloride source. Acids and halide sources that can be used in the present invention are typically commercially available and can be used without further purification.

[0098] Preferred compositions consist essentially of or consist of:

[0099] (a) 20 to 200 g / l of tin ions, especially tin methanesulfonate;

[0100] (b) additives of formula L1, in particular of formula L2 or L3, including all preferred embodiments described above;

[0101] (c) 1 to about 300 g / l of acid, in particular an acid selected from the group consisting of 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), aminosulfonic acid, hydrochloric acid and phosphoric acid, most particularly sulfuric acid and methanesulfonic acid;

[0102] (d) optionally further leveling agents, in particular leveling agents selected from the group consisting of polyaminoamides and derivatives thereof, polyalkanolamines and derivatives thereof, polyethyleneimines and derivatives thereof, quaternized polyethyleneimines, polyglycine, poly(allylamine), polyaniline, polyureas, polyacrylamide, poly(melamine-co-formaldehyde), reaction products of amines with epichlorohydrin, reaction products of amines, epichlorohydrin and polyalkoxides, reaction products of amines with polyepoxides, polyvinylpyridine, polyvinylimidazole, polyvinylpyrrolidone, or copolymers thereof, nigrosine, pentamethyl-para-magenta hydrohalide, hexamethyl-para-magenta hydrohalide, and compounds containing functional groups of the formula NRS (wherein R is substituted alkyl, unsubstituted alkyl, substituted aryl or unsubstituted aryl);

[0103] (e) optionally a surfactant, especially a polyalkylene glycol, most especially a C2 to C4 glycol having at least one hydroxyl group and 20 or fewer carbon atoms. 20 Alkoxide addition products of organic compounds, and products derived from the addition of different alkoxides to C2 to C 20 Tetrafunctional, pentafunctional, hexafunctional or higher functional polyethers of polyamine compounds;

[0104] (f) optionally antioxidants, in particular 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;

[0105] (g) optionally a complexing agent, in particular a sulfur-containing complexing agent.

[0106] (h) optionally an organic solvent in an amount below 0.1 g / l.

[0107] Particularly preferred compositions consist essentially of or consist of:

[0108] (a) 20 to 200 g / l of tin ions, especially tin methanesulfonate;

[0109] (b) additives of formula L1, in particular of formula L2 or L3, including all preferred embodiments described above;

[0110] (c) 1 to about 300 g / l of acid, in particular an acid selected from the group consisting of 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), aminosulfonic acid, hydrochloric acid and phosphoric acid, most particularly sulfuric acid and methanesulfonic acid;

[0111] (d) optionally antioxidants, in particular 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;

[0112] (e) optionally a complexing agent, in particular a sulfur-containing complexing agent.

[0113] (f) optionally an organic solvent in an amount less than 0.1 g / l.

[0114] Another preferred composition consists essentially of or consists of:

[0115] (a) 20 to 200 g / l of tin ions, especially tin methanesulfonate;

[0116] (b) 0.2 to 3% by weight, in particular 0.3 to 2.0% by weight, of alloying metal ions, most in particular silver or indium.

[0117] (c) additives of formula L1, in particular of formula L2 or L3, including all preferred embodiments described above;

[0118] (d) 1 to about 300 g / l of acid, in particular an acid selected from the group consisting of 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), aminosulfonic acid, hydrochloric acid and phosphoric acid, most particularly sulfuric acid and methanesulfonic acid;

[0119] (e) optionally additional leveling agents, in particular leveling agents selected from the group consisting of polyaminoamides and derivatives thereof, polyalkanolamines and derivatives thereof, polyethyleneimines and derivatives thereof, quaternized polyethyleneimines, polyglycine, poly(allylamine), polyanilines, polyureas, polyacrylamides, poly(melamine-co-formaldehyde), reaction products of amines with epichlorohydrin, reaction products of amines, epichlorohydrin and polyalkoxides, reaction products of amines with polyepoxides, polyvinylpyridine, polyvinylimidazole, polyvinylpyrrolidone, or copolymers thereof, nigrosine, pentamethyl-para-magenta hydrohalide, hexamethyl-para-magenta hydrohalide, and compounds containing functional groups of the formula NRS (wherein R is substituted alkyl, unsubstituted alkyl, substituted aryl or unsubstituted aryl);

[0120] (f) optionally a surfactant, especially a polyalkylene glycol, most especially a C2 to C4 glycol having at least one hydroxyl group and 20 or fewer carbon atoms. 20 Alkoxide addition products of organic compounds, and products derived from the addition of different alkoxides to C2 to C 20 Tetrafunctional, pentafunctional, hexafunctional or higher functional polyethers of polyamine compounds;

[0121] (g) optionally antioxidants, in particular 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;

[0122] (h) optionally a complexing agent, in particular a sulfur-containing complexing agent.

[0123] (i) optionally an organic solvent, in an amount below 0.1 g / l, in particular an organic solvent selected from isopropanol, ethanol, and glycols.

[0124] Particularly preferred compositions consist essentially of or consist of:

[0125] (a) 20 to 200 g / l of tin ions, especially tin methanesulfonate;

[0126] (b) 0.2 to 3% by weight, in particular 0.3 to 2.0% by weight, of alloying metal ions, most in particular silver or indium.

[0127] (c) additives of formula L1, in particular of formula L2 or L3, including all preferred embodiments described above;

[0128] (d) 1 to about 300 g / l of acid, in particular an acid selected from the group consisting of 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), aminosulfonic acid, hydrochloric acid and phosphoric acid, most particularly sulfuric acid and methanesulfonic acid;

[0129] (e) optionally antioxidants, in particular 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;

[0130] (f) optionally a complexing agent, in particular a sulfur-containing complexing agent.

[0131] (g) optionally an organic solvent, in an amount below 0.1 g / l, in particular an organic solvent selected from isopropanol, ethanol, and glycols.

[0132] application

[0133] The plating composition of the present invention can be used for various plating methods in which a tin-containing layer is desired, and is particularly used for depositing a tin-containing solder layer on a semiconductor wafer including a plurality of conductive bonding features. Plating methods include, but are not limited to, horizontal or vertical wafer plating, roll plating, rack plating, high-speed plating (such as roll-to-roll and spray plating) and rackless plating, and preferably horizontal or vertical wafer plating. Various substrates can be plated with tin-containing deposits according to the present invention. The substrate to be plated is conductive and can include copper, copper alloys, nickel, nickel alloys, and materials containing nickel-iron. Such substrates can 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, the method comprising: providing a semiconductor wafer including a plurality of conductive bonding features; contacting the semiconductor wafer with the above-mentioned composition; and applying enough current density to deposit a tin-containing layer on the conductive bonding feature. Preferably, the bonding feature comprises copper, which can be in the form of a pure copper layer, a copper alloy layer or any interconnect structure comprising copper. A copper post is a preferred conductive bonding feature. Alternatively, the copper post can include a top metal layer, such as a nickel layer. When the conductive bonding feature has a top metal layer, a tin or tin alloy solder layer is deposited on the top metal layer of the bonding feature. Conductive bonding features such as bonding pads, copper posts, etc. are well known in the art, as described in US 7,781,325, US2008 / 0054459 A, US 2008 / 0296761A and US2006 / 0094226 A.

[0134] method

[0135] One embodiment of the present invention is the use of an additive having formula L1 and any other leveling agent described herein in a bath for depositing a layer containing tin or a tin alloy, wherein the layer containing the tin alloy comprises an alloying metal selected from silver, copper, indium and bismuth in an amount of 0.01% to 10% by weight. Preferably, the deposited tin alloy layer has an alloying metal content of 0.1% to 5% by weight.

[0136] Another embodiment of the present invention is a method for depositing a tin or tin alloy layer on a substrate, the method being performed by:

[0137] A method for depositing a tin or tin alloy layer on a substrate, the method being carried out by

[0138] a) contacting a tin alloy electroplating bath comprising a composition as described herein with a substrate, and

[0139] b) applying a current density to the substrate for a time sufficient to deposit the tin or tin alloy layer onto the substrate.

[0140] As used herein, "recessed feature" means a via, trench, or any other opening in a substrate, particularly an opening for depositing a solder bump. As used herein, "aperture size" means the shortest distance in the opening of a recessed feature.

[0141] Preferably, the substrate comprises recessed features having a pore size of 1 to 1000 microns, and the deposition is performed to at least partially fill these micron-sized recessed features. Most preferably, the recessed features have a pore size of 1 to 200 microns, preferably 3 to 100 microns.

[0142] Typically, when the present invention is used to deposit tin or tin alloy on substrate, the plating bath is stirred during use. Preferably, tin alloy is deposited, and the alloy metal content of the deposited tin alloy is 0.01% to 10% by weight. Any suitable agitation method can be used for 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 bubbling, workpiece agitation, impact (impingement) etc. Such methods are well known to those skilled in the art. When the present invention is used to plate integrated circuit substrates such as wafers, the wafer can be rotated as 1 to 150RPM, and the plating solution contacts the rotating wafer, such as by pumping or spraying. In an alternative scheme, when the flow rate of the plating bath is enough to provide the desired metal deposit, the wafer does not need to rotate.

[0143] According to the present invention, tin or tin alloy is deposited in the recesses without substantially forming voids within the metal deposit. The term "substantially without forming voids" means that there are no voids larger than 1000 nm, preferably 500 nm, most preferably 100 nm in the metal deposit.

[0144] The plating equipment for plating semiconductor substrates is well known. The plating equipment comprises a plating tank which accommodates tin or tin alloy electrolytes and is made of suitable materials such as plastics or other materials inert to the electrolytic plating solution. The tank can be cylindrical, especially for wafer plating. The cathode is horizontally arranged at the top of the tank and can be any type of substrate, such as a silicon wafer with an opening.

[0145] These additives can be used with soluble and insoluble anodes with or without the presence of one or more membranes separating the cathode electrolyte from the anode electrolyte.

[0146] The cathode substrate and the anode are electrically connected by wiring and are electrically connected to a power supply respectively. The cathode substrate for direct current or pulse current has a net negative charge, so that the metal ions in the solution are reduced at the cathode substrate, thereby forming a plated metal on the cathode surface. The oxidation reaction occurs at the anode. The cathode and the anode can be arranged in the tank horizontally or vertically.

[0147] Typically, when preparing tin or tin alloy bumps, a photoresist layer is applied to a semiconductor wafer, followed by standard photolithography exposure and development techniques to form a patterned photoresist layer (or plating mask) with openings or vias therein. The dimensions of the plating mask (the thickness of the plating mask and the 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.

[0148] Unless otherwise indicated, all percentages, ppm or similar values ​​refer to weight relative to the total weight of the corresponding composition.All cited documents are incorporated herein by reference.

[0149] The following examples shall further illustrate the present invention without limiting the scope of the present invention.

[0150] Methods used in this article

[0151] The molecular weight of the polymeric ionic compounds was determined by size exclusion chromatography (SEC).

[0152] Coplanarity and morphology (roughness) were determined by measuring the height of the substrate using a laser scanning microscope.

[0153] The patterned photoresist contains vias of 8 μm diameter and 15 μm depth and preformed copper μ-bumps of 5 μm height. The isolated (iso) region consists of a 3×6 column array with a center-to-center distance (pitch) of 32 μm. The dense region consists of an 8×16 column array with a center-to-center distance (pitch) of 16 μm. To calculate the intra-chip coplanarity, 3 bumps from the isolated region and 3 bumps from the center of the dense region are taken.

[0154] Determine the within-die (WID) coplanarity (COP) by using the following formula

[0155] COP=(H 隔离 -H 密集 ) / H Av

[0156] Here, H 隔离 and H 密集 is the average height of bumps in isolated / dense areas, and H Av is the total average height of all bumps in the isolated and dense regions as described above.

[0157] For the leveling agent screening experiments, a double-walled tempered beaker equipped with a rotating disk electrode (platinum surface), a platinum counter electrode and an Ag / AgCl reference electrode and a potentiostat was used. Before each measurement, the platinum disk electrode was chemically and electrochemically cleaned. The measurements were performed in constant current mode. The plating solution was temperature adjusted to 25 °C. 4 A / dm 2 The current density was measured and the potential was measured over time. The rotation speed of the rotating disk electrode was changed over time in the following manner throughout a measurement: 800 rpm from 0 to 60 s, 50 rpm from 61 to 120 s, and 400 rpm from 121 to 180 s. The step height between 800 and 50 rpm was calculated by replacing the potential at 60 s with the potential at 120 s. Each experiment was repeated at least once to verify the results. The average value of the step heights of the two experiments was used to compare different leveling agents.

[0158] The inventors have found that the coplanarity of the deposited copper layer is related to the step height determined as described above. In general, as the step height increases, the leveling performance increases.

[0159] Examples

[0160] The following leveling agents are used in the following examples:

[0161] Leveling agent 1 (comparative): (E)-4-phenyl-but-3-en-2-one, benzylideneacetone;

[0162] Leveling agent 2: (E)-3-methyl-4-phenyl-but-3-ene-2-one;

[0163] Leveling agent 3 (comparative): (E)-4-methyl-4-phenyl-but-3-ene-2-one;

[0164] Leveling agent 4 (comparative): (E)-4-(4-methoxyphenyl)-but-3-en-2-one;

[0165] Leveling agent 5: (E)-3-methyl-4-(4-methoxyphenyl)-but-3-ene-2-one;

[0166] Leveling agent 6: (E)-1-(4-methoxyphenyl)-2-methylpent-1-en-3-one.

[0167] Source / Preparation of Leveling Agent

[0168] Leveling agent 1: available from Sigma-Aldrich;

[0169] Leveling agent 2: According to procedure 1, use benzaldehyde;

[0170] Leveling agent 3: According to procedure 3;

[0171] Leveling agent 4: According to procedure 4, use 4-methoxybenzaldehyde;

[0172] Leveling agent 5: According to procedure 1, use 4-methoxybenzaldehyde;

[0173] Leveling agent 6: According to procedure 2, 4-methoxybenzaldehyde was used.

[0174] Procedure 1: Synthesis of 3-methyl-4-aryl-but-3-en-2-one:

[0175]

[0176] Under nitrogen, benzaldehyde (2.65g, 25mmol, 1.0 equivalent) and 2-butanone (3.61g, 50mmol, 2.0 equivalent) were added to 20ml acetic acid. Concentrated sulfuric acid (2.40g, 25mmol, 1.0 equivalent) was added to the colorless solution over a period of 5 minutes at room temperature, causing the color to change from yellow to brown. After stirring at room temperature for 20h, 100mL of water was added, and the pH was subsequently adjusted to pH=5 with a 25% NaOH aqueous solution. The mixture was extracted twice with ethyl acetate (50ml, 30ml). The combined organic layers were washed with saturated NaHCO3 solution and subsequently with saturated NaCl solution. After drying the organic layer (Na2SO4), the solvent was subsequently filtered and removed in vacuo. The crude product was purified using column chromatography (silicon dioxide, cyclohexane / ethyl acetate gradient) to isolate the desired product (2.20g, GC-FID 96.7 area-%, 13.3mmol, 53% yield) as a yellow oil.

[0177] Procedure 2: Synthesis of 4-methyl-5-aryl-pent-4-en-3-one:

[0178]

[0179] Under nitrogen, 4-methoxybenzaldehyde (2.72g, 20mmol, 1.0 equivalent) was dissolved in 20ml ethanol. Diethyl ketone (6.89g, 80mmol, 4.0 equivalent) was added, followed by aqueous sodium hydroxide solution (10%, 2.5ml, 6.93mmol, 0.35 equivalent) over 3 minutes. The reaction mixture was stirred at room temperature overnight. After the pH was adjusted to a pH of about 2 with aqueous HCl solution (37%), 70mL of water was added. The aqueous mixture was extracted with DCM (2×30ml). The combined organic layers were dried (MgSO4), then filtered and the solvent was removed in vacuo. The crude product was purified using column chromatography (silicon dioxide, cyclohexane / ethyl acetate gradient) to give the desired product (2.50g, GC-FID 98.2 area-%, 12.0mmol, 60% yield) as white crystals.

[0180] Procedure 3: Synthesis of 4-aryl-pent-3-en-2-one (comparative):

[0181]

[0182] Under nitrogen, add acetylacetone (4.85g, 48.4mmol, 1.0 equivalent) in 50ml THF solution to phenylmagnesium bromide (3M in Et2O, 25.7ml, 77.1mmol, 1.6 equivalent) at room temperature over a period of 30 minutes. After stirring at room temperature for 20h, add 200ml saturated NH4Cl solution at room temperature. Separate the layers, and extract the water layer three times with MTBE (3×100ml). Dry the combined organic layer (MgSO4), filter and remove the solvent in a vacuum subsequently. Add the residue to 100ml water, then add oxalic acid dihydrate (8.41g, 66.7mmol, 1.4 equivalent), and heat the mixture to reflux for 30min. After cooling to room temperature, add 100mL DCM. Separate the layers, and extract the water layer twice with DCM (2×100ml). Dry the combined organic layer (MgSO4), filter and remove the solvent in a vacuum subsequently. The crude product was purified using column chromatography (silica, cyclohexane / ethyl acetate gradient) to give the desired product (1.10 g, GC-FID 92.1 area-%, 5.84 mmol, 12% yield) as a yellow oil. The product contained acetophenone as an impurity.

[0183] Program 4: Horner-Wadsworth-Emmons Route:

[0184]

[0185] Under nitrogen atmosphere, 20 ml of dioxane and 3.6 mL of water were mixed, followed by the addition of diethyl (2-oxopropyl)phosphonate (5.01 g, 25.8 mmol, 1.25 eq.), 2-methylbenzaldehyde (2.48 g, 20.6 mmol, 1.0 eq.) and CsCO (6.73 g, 20.6 mmol, 1.0 eq.). The reaction mixture was stirred at room temperature overnight. The solvent was removed in vacuo, and the crude product was purified using column chromatography (silicon dioxide, hexane / DCM gradient). The desired unsaturated ketone (2.5 g, 15.6 mmol, 76%) was isolated as a pale yellow liquid.

[0186] Step height measurement

[0187] Compositions were prepared containing 75 g / l tin (as tin methanesulfonate), 180 g / l methanesulfonic acid, 0.3 g / l commercial antioxidant, and 0.04 g / l of the corresponding leveling agents 1 to 6 in isopropanol.

[0188] The step height was measured as described above. The results are shown in Table 1.

[0189] Table 1

[0190]

[0191] Table 1 shows that leveling agents Nos. 2, 5 and 6 substituted in the α position of the carbonyl function have significantly higher step heights, indicating better coplanarity, compared to leveling agents Nos. 1 and 4, which are not substituted in this position. Surprisingly, Example C3 shows that substitution in the β position of the carbonyl function even leads to a reduction in the step height compared to prior art leveling agent No. 1, indicating a reduction in the leveling function.

Claims

1. An aqueous composition comprising tin ions, optionally alloying metal ions selected from silver, copper, indium and bismuth ions and at least one additive having formula L1 in For each group R L1 , R L1 independently selected from C1 to C6 alkyl, C1 to C6 alkenyl, C1 to C6 alkoxy, halogen, CN and OH; R L2 is C1 to C6 alkyl, C1 to C6 alkenyl, C5 to C 12 Aryl, C6 to C 15 Alkyl aryl, C6 to C 15 Arylalkyl, all of which may be substituted by CN, OH, C1 to C6 alkoxy or halogen; R L3 Selected from C1 to C6 alkyl; R L4 It is H; n is a substituent R selected from 0 to 5 L1 Number of wherein the amount of organic solvent in the composition is less than 0.1 g / l, and The composition does not contain any electrolytically depositable metal ions other than tin ions and alloying metal ions.

2. The composition according to claim 1, wherein R L3 Selected from C1 to C4 alkyl.

3. The composition according to claim 2, wherein R L3 It's methyl.

4. The composition according to any one of claims 1 to 3, wherein n is 0.

5. The composition according to any one of claims 1 to 3, wherein n is 1 or 2, and for each group R L1 , R L1 n Independently selected from C1 to C4 alkyl and C1 to C4 alkoxy.

6. A composition according to any one of the preceding claims, wherein R L2 Selected from methyl, ethyl, 1-propyl and 2-propyl, preferably selected from methyl and ethyl.

7. A composition according to any one of the preceding claims, wherein These tin ions are present in an amount of 40 to 120 g / l, in particular 60 to 90 g / l.

8. A composition according to any one of the preceding claims, wherein These alloying metal ions are present in an amount of 0.2 to 3% by weight, in particular 0.3 to 2.0% by weight.

9. The composition according to claim 8, wherein These alloying metal ions comprise, and preferably consist of, silver ions.

10. A composition according to any one of the preceding claims, wherein The pH of the composition is below 4, preferably below 3, most preferably below 2.

11. Use of an additive of formula L1 in a composition for electrodeposition of a layer containing tin or a tin alloy, wherein the tin-alloy-containing layers contain an alloying metal selected from the group consisting of silver, copper, indium and bismuth in an amount of 0.01 to 10% by weight, in For each group R L1 , R L1 independently selected from C1 to C6 alkyl, C1 to C6 alkenyl, C1 to C6 alkoxy, halogen, CN and OH; R L2 is C1 to C6 alkyl, C1 to C6 alkenyl, C5 to C 12 Aryl, C6 to C 15 Alkyl aryl, C6 to C 15 Arylalkyl, all of which may be substituted by CN, OH, C1 to C6 alkoxy or halogen; R L3 Selected from C1 to C6 alkyl; R L4 It is H; n is a substituent R selected from 0 to 5 L1 Number of wherein the amount of organic solvent in the composition is less than 0.1 g / l, and The composition does not contain any electrolytically depositable metal ions other than tin ions and alloying metal ions.

12. The use according to claim 11, wherein The deposited tin alloy layer has an alloy metal content of 0.1 to 5% by weight.

13. A method for depositing a tin or tin alloy layer onto a substrate, the method being carried out by: a) contacting a tin alloy electroplating bath comprising a composition according to any one of claims 1 to 10 with the substrate, and b) applying a current density to the substrate for a time sufficient to deposit the tin or tin alloy layer onto the substrate.

14. The method according to claim 13, wherein: The substrate comprises recessed features having pore sizes of 1 to 1000 microns, preferably 1 to 200 microns, most preferably 3 to 100 microns, and the deposition is performed to at least partially fill the micron-sized recessed features.

15. A compound selected from (E)-4-ethyl-5-(4-methylphenyl)-pent-4-en-3-one and (E)-4-ethyl-5-(4-methoxyphenyl)-pent-4-en-3-one.

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