Electroplating with polycarboxylate ether inhibitors

Abstract

The electroplating should have good leveling properties, in particular provide a substantially planar metal layer and provide filled features on a nanometer and micrometer scale without substantially forming defects.SOLUTION: The present invention relates to a method of depositing a metal layer on a substrate by contacting the substrate with a metal plating bath comprising a source of metal ions and a suppressor and applying a current density to the substrate, wherein the suppressor is a polycarboxylate ether as described below. The present invention further relates to a metal plating bath comprising a source of metal ions and a suppressor being a polycarboxylate ether and to the use of a polycarboxylate ether in a metal plating bath for depositing a metal layer on a substrate.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a method for depositing a metal layer on a substrate by contacting the substrate with a metal plating bath comprising a source of metal ions and a suppressor and applying a current density to the substrate, wherein the suppressor is a polycarboxylate ether as described below. The present invention further relates to a metal plating bath comprising a source of metal ions and a suppressor that is a polycarboxylate ether, and to the use of the polycarboxylate ether in the metal plating bath to deposit a metal layer on a substrate. [Background technology]

[0002] Electroplating presents several problems that need to be overcome. Plating baths should have high electrochemical stability, as additives tend to decompose over time. This is important for a cost-effective electroplating process. The metal layer deposited on the substrate should have a smooth and uniform layer thickness and should have a high gloss. Electroplating should have good leveling properties, particularly to provide a substantially flat metal layer and to provide fill features on the nanometer and micrometer scale without forming substantial defects. Summary of the Invention [Means for solving the problem]

[0003] The purpose is a) contacting the substrate with a metal plating bath containing a source of metal ions and a suppressor; and b) applying a current density to the substrate; 1. A method for depositing a metal layer on a substrate by: The inhibitor is (I) at least one ethylenically unsaturated monomer (I) containing at least one group from the series of carboxylic acids, carboxylic acid salts, carboxylic acid esters, carboxylic acid amides, carboxylic acid anhydrides, and carboxylic acid imides; and (II) at least one ethylenically unsaturated monomer having a polyalkylene oxide group (II) is a polycarboxylate ether obtained by polymerizing a mixture of monomers comprising was solved by the method.

[0004] The object has also been solved by a metal plating bath comprising a source of metal ions and a suppressor which is a polycarboxylate ether.

[0005] The object has also been solved by the use of a suppressor which is a polycarboxylate ether in a metal plating bath for depositing a metal layer on a substrate. DETAILED DESCRIPTION OF THE INVENTION

[0006] The method for depositing a metal layer on a substrate is usually electroplating. Typically, a substrate is electroplated by immersing the substrate in a metal plating bath and contacting the substrate as the cathode with an electric frequency. The metal plating bath contains an anode as a counter electrode, which may be soluble or insoluble. Optionally, the cathode and anode may be separated by a membrane.

[0007] A sufficient current density is applied and plating is carried out for a sufficient time to deposit a metal layer, e.g., a copper layer, having the desired thickness on the substrate. Suitable current densities include 0.1 to 25 A / dm 2 This includes, but is not limited to, the range of

[0008] The particular current density will depend on the substrate being plated, the leveling agent selected, etc. Selection of such a current density is within the skill of one of ordinary skill in the art. The applied current may be direct current (DC), pulsed current (PC), pulsed reverse current (PRC), or other suitable current.

[0009] Generally, when electroplating is used to deposit metals on substrates, the metal plating bath is agitated during use. Any suitable agitation method may be used in 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, work piece agitation, impingement, etc.

[0010] Plating equipment is well known. It typically includes an electroplating tank that holds the Cu electrolyte and is made of a suitable material, such as plastic or other material that is inert to the electroplating solution. The anode is typically a soluble anode.

[0011] The cathode substrate and anode are each electrically connected to a rectifier (power supply) by wiring. The cathode substrate for direct current or pulsed current has a net negative charge, so Cu ions in the solution are reduced at the cathode substrate, forming Cu metal plating on the cathode surface. The oxidation reaction occurs at the anode. The cathode and anode can be arranged horizontally or vertically in the tank.

[0012] Suitable substrates are any used in the manufacture of decorative or electronic devices, thus allowing the metal plating baths to have a wide range of applications from decorative to functional purposes.

[0013] Suitable electronic devices typically contain numerous features, particularly openings, of various sizes. Particularly suitable substrates are those having openings on the nanometer and micrometer scale. For example, the present method is particularly suitable for depositing copper on integrated circuit substrates, such as semiconductor devices, having small diameter vias, trenches, or other openings. In one embodiment, semiconductor devices (e.g., wafers used in the manufacture of integrated circuits) are plated by the present method. As used herein, "feature" refers to the geometric shape of the substrate, such as, but not limited to, trenches and vias. "Opening" refers to recessed features, such as vias and trenches.

[0014] Although the present method can be used with any electrolytic process, essentially horizontal or planar metal (e.g., copper) deposits are desired (preferably with high reflectivity). Accordingly, suitable substrates include lead frames, interconnects, printed wiring boards, and the like.

[0015] Suitable decorative substrates are steel, brass or plastic.

[0016] The metal ion source can be any compound capable of releasing sufficient amounts of metal ions to be deposited into the electroplating bath and is generally 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 metal sulfates, metal halides, metal acetates, metal nitrates, metal fluoroborates, metal alkylsulfonates, metal arylsulfonates, metal sulfamates, metal gluconates, and the like.

[0017] The metal ion source preferably comprises a copper salt. Sources of metal ions include copper sulfate, copper chloride, copper acetate, copper citrate, copper nitrate, copper fluoroborate, copper methanesulfonate, copper phenylsulfonate, and copper p-toluenesulfonate. Copper sulfate pentahydrate and copper methanesulfonate are particularly preferred. Such metal salts are generally commercially available and can be used without further purification.

[0018] In addition to metal electroplating, the compositions may also be used for electroless plating of metal-containing layers. The compositions may be particularly useful for depositing barrier layers containing Ni, Co, Mo, W, and / or Re. In this case, in addition to the metal ions, further elements of groups III and V, particularly B and P, may be present in the compositions for electroless plating and thus may be co-deposited with the metal.

[0019] The metal ion source can be used in any amount that provides sufficient metal ions for electroplating onto the substrate. Suitable metal ion sources include, but are not limited to, tin salts, copper salts, and the like. When the metal is copper, the copper salt is typically present in an amount ranging from about 1 to about 300 g / L of the plating solution. Mixtures of metal salts are also suitable. Thus, alloys, such as copper-tin alloys having up to about 2 weight percent tin, can be advantageously plated. The amount of each metal salt in such a mixture depends on the particular alloy being plated and is well known to those skilled in the art.

[0020] Metal plating baths may further comprise an electrolyte, i.e., an acidic or alkaline electrolyte, a source of one or more metal ions, optionally halide ions, and optionally other additives, such as accelerators and / or inhibitors. Such baths are typically aqueous. Water can be present in a wide range of amounts. Any type of water can be used, for example, distilled water, deionized water, or tap water.

[0021] Metal plating baths can be prepared by combining the components in any order, although it is preferred that the inorganic components, such as metal salts, water, electrolyte, and optionally a halide ion source, be added to the bath container first, followed by the organic components, such as leveling agents, accelerators, suppressors, surfactants, etc.

[0022] Typically, the metal plating bath may be used at any temperature from 10 to 65°C or higher. The temperature of the metal plating bath is preferably from 10 to 35°C, more preferably from 15 to 30°C.

[0023] Suitable electrolytes include 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 hydroxides, 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, and the alkaline electrolyte is typically present in an amount from about 0.1 to about 20 g / L, or in an amount to produce a pH of 8 to 13, more typically a pH of 9 to 12, respectively.

[0024] The metal plating bath may optionally further comprise a source of halide ions, e.g., chloride ions as in the case of copper chloride or hydrochloric acid. A wide range of halide ion concentrations can be used in the present invention, e.g., from about 0 to about 500 mg / L. Typically, the halide ion concentration ranges from about 10 to about 100 mg / L based on the plating bath. The electrolyte is preferably sulfuric acid or methanesulfonic acid, preferably a mixture of sulfuric acid or methanesulfonic acid and a source of chloride ions.

[0025] Polycarboxylate ethers (also called PCEs) are commercially available.

[0026] The inhibitor is (I) at least one ethylenically unsaturated monomer (I) containing at least one group from the series of carboxylic acids, carboxylic acid salts, carboxylic acid esters, carboxylic acid amides, carboxylic acid anhydrides, and carboxylic acid imides; and (II) at least one ethylenically unsaturated monomer having a polyalkylene oxide group (II) It is a polycarboxylate ether obtained by polymerizing a mixture of monomers including

[0027] The PCE comprises at least two types of monomer units. The use of copolymers having three or more types of monomer units may also be advantageous.

[0028] In one preferred embodiment, the ethylenically unsaturated monomer (I) has the general formula of the following group (Ia), (Ib) and (Ic):

[0029] [ka] is represented by at least one of:

[0030] In the monocarboxylic or dicarboxylic acid derivatives (Ia) and in the cyclic form of the monomers (Ib), Z is O (anhydride) or NR 2 (acid imide), and R 1 and R 2 are each independently hydrogen or an aliphatic hydrocarbon group having 1 to 20 carbon atoms, preferably a methyl group. Y is H, -COOM a , -CO-O(C q H 2q O) r -R 3 or -CO-NH-(C q H 2q O) r -R 3 is.

[0031] M is hydrogen, a monovalent or divalent metal cation, preferably sodium, potassium, calcium or magnesium ion, and optionally ammonium or an organic amine group, where a=1 / 2 or 1 depending on whether M is a monovalent or divalent cation. The organic amine group used is preferably a primary, secondary or tertiary C 1~20 Alkylamines, C 1~20 Alkanolamines, C 5~8 Cycloalkylamines and C 6~14 Substituted ammonium groups derived from arylamines. Examples of such amines are the protonated (ammonium) forms of methylamine, dimethylamine, trimethylamine, ethanolamine, diethanolamine, triethanolamine, methyldiethanolamine, cyclohexylamine, dicyclohexylamine, phenylamine, and diphenylamine.

[0032] R 3 is hydrogen, an aliphatic hydrocarbon group having 1 to 20 carbon atoms, an alicyclic hydrocarbon group having 5 to 8 carbon atoms, or an aryl group having 6 to 14 carbon atoms (which may be optionally substituted); q=2, 3, or 4; and r=0 to 200, preferably 1 to 150. The aliphatic hydrocarbon here may be linear or branched, and may be saturated or unsaturated. Preferred cycloalkyl groups are cyclopentyl or cyclohexyl groups, and preferred aryl groups are phenyl or naphthyl groups, which may in particular be substituted with a hydroxyl group, a carboxyl group, or a sulfonic acid group.

[0033] R 4 and R 5 are each independently hydrogen, an aliphatic hydrocarbon group having 1 to 20 carbon atoms, an alicyclic hydrocarbon group having 5 to 8 carbon atoms, or an optionally substituted aryl group having 6 to 14 carbon atoms. Q may be the same or different and is NH, NR 3 or O, and R 3 has the definition set forth above.

[0034] Furthermore, R 6 are the same or different, and (C n H 2n )-SO3H (wherein n=0, 1, 2, 3 or 4), (C n H 2n )—OH (wherein n=0, 1, 2, 3 or 4), (C n H 2n )-PO3H2 (wherein n=0, 1, 2, 3 or 4), (C n H 2n )-OPO3H2 (wherein n=0, 1, 2, 3, or 4), (C6H4)-SO3H, (C6H4)-PO3H2, (C6H4)-OPO3H2, and (C n H 2n )-NR 8 b (wherein n=0, 1, 2, 3 or 4, and b=2 or 3).

[0035] R 7 H,-COOM a , -CO-O(C q H 2q O) r -R 3 or -CO-NH-(C q H 2q O) r -R 3 and M a , R 3 , q and r have the definitions set forth above.

[0036] R 8 is hydrogen, an aliphatic hydrocarbon group having 1 to 10 C atoms, an alicyclic hydrocarbon group having 5 to 8 C atoms, or an optionally substituted aryl group having 6 to 14 C atoms.

[0037] In another preferred embodiment, the ethylenically unsaturated monomer (I) is a monomer having the general formula of the following group (Ia), (Ib) and (Ic):

[0038] [ka] [In the formula, R 1 and R 2 are, independently of one another, hydrogen or an aliphatic hydrocarbon group having 1 to 20 C atoms, Y, H, -COOM a , -CO-O(C q H 2q O) r -R 3 or -CO-NH-(C q H 2q O) r -R 3 and M is hydrogen, a monovalent or divalent metal cation, an ammonium ion, or an organic amine group; a is 1 / 2 or 1, R 3is hydrogen, an aliphatic hydrocarbon group having 1 to 20 C atoms, an alicyclic hydrocarbon group having 5 to 8 C atoms, or an optionally substituted aryl group having 6 to 14 C atoms, q is the q H 2q O) are independently identical or different at each occurrence in the unit and are 2, 3, or 4; r is 0 to 200; Z is 0 or NR 3 is],

[0039] [ka] [In the formula, R 4 and R 5 are each independently hydrogen, or an aliphatic hydrocarbon group having 1 to 20 C atoms, an alicyclic hydrocarbon group having 5 to 8 C atoms, or an optionally substituted aryl group having 6 to 14 C atoms, Q may be the same or different and may be NH, NR 3 or O, and R 3 has the definition set forth above, R 6 are the same or different, and (C n H 2n )-SO3H (wherein n=0, 1, 2, 3 or 4), (C n H 2n )—OH (wherein n=0, 1, 2, 3 or 4), (C n H 2n )-PO3H2 (wherein n=0, 1, 2, 3 or 4), (C n H 2n )-OPO3H2 (wherein n=0, 1, 2, 3, or 4), (C6H4)-SO3H, (C6H4)-PO3H2, (C6H4)-OPO3H2, and (C n H 2n )-NR 8 b wherein n=0, 1, 2, 3, or 4, and b=2 or 3. R 7 H,-COOMa , -CO-O(C q H 2q O) r -R 3 or -CO-NH-(C q H 2q O) r -R 3 and M a , R 3 , q and r have the definitions set forth above; R 8 is hydrogen, an aliphatic hydrocarbon group having 1 to 10 C atoms, an alicyclic hydrocarbon group having 5 to 8 C atoms, or an optionally substituted aryl group having 6 to 14 C atoms] is represented by at least one of:

[0040] Suitable examples of ethylenically unsaturated monomers (I) are salts of (meth)acrylic acid, salts of itaconic acid, methacrylic anhydride, maleic anhydride, fumaric anhydride, itaconic anhydride.

[0041] In a preferred form, the ethylenically unsaturated monomer (I) contains at least one group from the series of carboxylic acids, carboxylic acid salts and carboxylic acid amides.

[0042] In another preferred embodiment, the ethylenically unsaturated monomer (I) is a carboxylate, a carboxylic acid, or a carboxylic acid anhydride. In another preferred embodiment, the ethylenically unsaturated monomer (I) is a salt of (meth)acrylic acid.

[0043] In another preferred embodiment, the ethylenically unsaturated monomer (I) is a carboxylic acid amide, such as N,N-dimethylacrylamide, N,N-dimethylmethacrylamide, N,N-diethylacrylamide, or N,N-diethylmethacrylamide. In another preferred embodiment, the ethylenically unsaturated monomer (I) is N,N-dimethylacrylamide.

[0044] In one preferred form, the ethylenically unsaturated monomer (II) has the following general formula:

[0045] [ka] [In the formula, p is an integer of 0 to 6, y is 0 or 1, v is an integer of 3 to 500, and w is each (C w H 2w each occurrence in the O) unit is independently the same or different and is an integer from 2 to 18, and T is oxygen or a chemical bond. It is expressed by R 1 , R 2 and R 3 has the definition set forth above.

[0046] In a preferred embodiment of the monomer (II), R 3 is an aliphatic hydrocarbon group having 1 to 20 C atoms, preferably methyl, ethyl, propyl or butyl.

[0047] In a preferred embodiment, in the general formula (II), p is an integer of 0 to 4, v is an integer of 5 to 250, and w is each (C w H 2w O) are independently the same or different at each occurrence in the unit and are 2 or 3.

[0048] In a particularly preferred embodiment, in the general formula (II), p is 4, v is an integer of 10 to 120, and w is each (C w H 2w O) units are independently the same or different at each occurrence and are 2 or 3, T is oxygen, and y is 0. In this case, it is particularly preferred that at least one subdomain is formed from a random ethylene oxide / propylene oxide copolymer, and that the molar fraction of propylene oxide units is preferably 10 to 30 mol %, based on the sum of ethylene oxide and propylene oxide units in the random ethylene oxide / propylene oxide copolymer or in the corresponding subdomain.

[0049] More specifically, the at least one ethylenically unsaturated monomer having a polyalkylene oxide group (II) may be a compound of formula (III): Block A is composed of polyethylene oxide units, and n is preferably a number from 20 to 30. Block B is composed of random ethylene oxide / propylene oxide copolymer units, and k is preferably a number from 5 to 10, and l is preferably a number from 20 to 35.

[0050] [ka]

[0051] In a further preferred embodiment of the present invention, the ethylenically unsaturated monomer (II) is represented by the general formulas (IV), (V), (VI) and (VII):

[0052] [ka] [In the formula, R 10 , R 11 and R 12 are each identical or different and are represented independently of one another by H and / or an unbranched or branched C1-C4 alkyl group, preferably H and / or CH3, E are identical or different and are an unbranched or branched C1-C6 alkylene group, more particularly a cyclohexyl group, CH2-CH6, which is present in ortho-, meta- or para-substituted form by C1, C2, C3, C4, C5 or C6, preferably by C2 and C4, although it is clear that this is typical in each case. 10 , represented by C6H4 and / or by the absent unit, i.e., E is absent, G is the same or different and is represented by O, NH and / or CO-NH, provided that if E is a non-existent unit, then G is also a non-existent unit, i.e. G is absent; A is the same or different, and C x H 2xwhere x=2, 3, 4 and / or 5, preferably x=2, and / or CH2CH(C6H5), n is the same or different and is represented by 0, 1, 2, 3, 4 and / or 5; a is the same or different and is represented by an integer of 2 to 350, preferably 10 to 200; R 13 are the same or different and are represented by H, an unbranched or branched C1-C4 alkyl group, CO—NH2 and / or COCH3, preferably H or CH3;

[0053] [ka] [In the formula, R 14 are the same or different and are represented by H and / or unbranched or branched C1-C4 alkyl groups, preferably H, E are identical or different and are unbranched or branched C1-C6 alkylene groups, preferably cyclohexyl groups present in ortho, meta or para substituted form by C2H4, CH2-C6H 10 , represented by C6H4 and / or by the absent unit, i.e. E is absent, G is the same or different and is represented by the absent units O, NH and / or CO-NH, provided that if E is an absent unit, then G is also an absent unit, i.e. G is absent; A is the same or different, and C x H 2x where x=2, 3, 4 and / or 5, preferably x=2, and / or CH2CH(C6H5), n is the same or different and is represented by 0, 1, 2, 3, 4 and / or 5; a is the same or different and is represented by an integer of 2 to 350, preferably 10 to 200; D is the same or different and is represented by a non-existent unit, i.e., D is absent or represented by NH and / or O, provided that when D is a non-existent unit, b=0, 1, 2, 3 or 4, and c=0, 1, 2, 3 or 4, and b+c=3 or 4; provided that when D is NH and / or O, b=0, 1, 2 or 3, c=0, 1, 2 or 3, and b+c=2 or 3; R 15 are the same or different and are represented by H, unbranched or branched C1-C4 alkyl groups, CO—NH2 and / or COCH3, preferably H;

[0054] [ka] [In the formula, R 16 , R 17 and R 18 are each the same or different and independently represent H and / or an unbranched or branched C1-C4 alkyl group, preferably H and / or CH3, E are the same or different and independently represent an unbranched or branched C1-C6 alkylene group, preferably a cyclohexyl group, CH2-C6H, which is present in ortho-, meta- or para-substituted form by C2H4 or C4H8; 10 , represented by C6H4 and / or by the absent unit, i.e. E is absent, A is the same or different, and C x H 2x where x=2, 3, 4 and / or 5, preferably x=2, and / or CH2CH(C6H5), n is the same or different and is represented by 0, 1, 2, 3, 4 and / or 5; L is the same or different, and C x H 2x where x=2, 3, 4 and / or 5, preferably x=2, and / or CH2CH(C6-H5), a is the same or different and is represented by an integer of 2 to 350, preferably 10 to 200; d is the same or different and is represented by an integer of 1 to 350, preferably 10 to 200; R 19 are the same or different and are represented by H and / or unbranched or branched C1-C4 alkyl groups, preferably H, R 20 are the same or different and are represented by H and / or unbranched C1-C4 alkyl groups, preferably H;

[0055] [ka] [In the formula, R 27 , R 28 and R 29 are the same or different and are each independently H and / or an unbranched or branched C1-C4 alkyl group, A is the same or different, and C x H 2x where x=2, 3, 4 and / or 5, and / or CHCH(C6H5), a is the same or different and is an integer of 2 to 350; R 30 are the same or different and are H and / or unbranched or branched C1-C4 alkyl groups. The compound contains at least one of the following compounds:

[0056] Generally, the polyalkoxy side chains (AO) of polyether macromonomers a is very preferably a pure polyethoxy side chain, but it can be said that mixed polyalkoxy side chains, more particularly those containing both propoxy and ethoxy groups, may also be present.

[0057] In practice, frequently used polyether macromonomers are alkoxylated isoprenols, i.e., alkoxylated 3-methyl-3-buten-1-ol and / or alkoxylated hydroxybutyl vinyl ethers and / or alkoxylated (meth)allyl alcohols, allyl alcohols being preferred to methallyl alcohols, in each case usually having an arithmetic average number of oxyalkylene groups of 4 to 350. Particularly preferred are alkoxylated hydroxybutyl vinyl ethers.

[0058] It is considered preferred herein that the monomer (II) has a molecular weight of 500 to 10,000 g / mol. In another embodiment, the monomer (II) has a molecular weight of 500 to 6,000 g / mol, preferably 800 to 5,000 g / mol, in particular 1,000 to 4,000 g / mol. In another embodiment, the monomer (II) has a molecular weight of at least 500, 700, 900, 1,000, 1,500, 2,000, 2,500, or 3,000 g / mol. In another embodiment, the monomer (II) has a molecular weight of up to 8,000, 7,000, 6,000, 5,000, or 4,000 g / mol. The molecular weight of the monomer (II) can be determined by the OH number of the base polyalkylene glycol.

[0059] In addition to monomers (I) and (II), further types of monomers may be used in the copolymers of the present invention. However, in one particularly preferred embodiment, the copolymers of the present invention do not contain styrene or derivatives of styrene as monomers.

[0060] The molar fractions of monomers (I) and (II) in the copolymer of the present invention can be freely selected within wide limits. The proportion of monomer (I) in the polycarboxylate ether is usually 5 to 95 mol %, preferably 30 to 95 mol %, and in particular 55 to 95 mol %.

[0061] The proportion of the monomer (II) in the polycarboxylate ether is usually 1 to 89 mol %, preferably 1 to 55 mol %, particularly preferably 1 to 30 mol %.

[0062] The molar ratio of monomer (II) to monomer (I) may range from 1:1 to 1:10, preferably from 1:2 to 1:6.

[0063] The weight ratio of monomer (II) to monomer (I) may range from 37 / 63 to 98 / 2, preferably from 39 / 61 to 97 / 3, more preferably from 45 / 55 to 96 / 4, and especially from 48 / 52 to 95 / 5.

[0064] The polycarboxylate ether may have a molecular weight, Mw, determined by gel permeation chromatography against polyethylene glycol standards, of 1,000 to 100,000 g / mol, preferably 12,000 to 75,000 g / mol. In another embodiment, the polycarboxylate ether may have a molecular weight, Mw, determined by gel permeation chromatography against polyethylene glycol standards, of 5,000 to 60,000 g / mol, preferably 15,000 to 40,000 g / mol.

[0065] The polycarboxylate ether may have a charge density of 0.5 to 5.0, preferably 0.9 to 3.0, especially 1.1 to 2.0. The charge density can be determined by conductometric titration.

[0066] Water is a particularly suitable solvent when preparing polycarboxylate ethers. It is also possible to use a mixture of water and an organic solvent, but in this case, the solvent should be largely inert to the radical polymerization reaction. As for the organic solvent, the organic solvents already identified above are considered to be particularly suitable.

[0067] The polymerization reaction is preferably carried out in a temperature range of 0 to 180°C, more preferably 10 to 100°C, and also under atmospheric pressure or elevated or reduced pressure. The polymerization may optionally be carried out under an inert gas atmosphere, preferably under nitrogen.

[0068] To initiate the polymerization, high-energy electromagnetic radiation, mechanical energy, or chemical polymerization initiators, such as organic peroxides, can be used, such as benzoyl peroxide, tert-butyl hydroperoxide, methyl ethyl ketone peroxide, cumoyl peroxide, dilauroyl peroxide, or azo initiators, such as azodiisobutyronitrile, azobisamidopropyl hydrochloride, and 2,2'-azobis(2-methylbutyronitrile). Also suitable are inorganic peroxy compounds, such as ammonium peroxodisulfate, potassium peroxodisulfate, or hydrogen peroxide, optionally in combination with a reducing agent (e.g., sodium bisulfite, ascorbic acid, iron(II) sulfate) or a redox system containing an aliphatic or aromatic sulfonic acid (e.g., benzenesulfonic acid, toluenesulfonic acid) as the reducing component. Particularly preferred are mixtures of at least one sulfuric acid and at least one iron(III) salt, and / or ascorbic acid and at least one iron(III) salt.

[0069] The chain transfer agent used is the conventional compound for controlling molecular weight.Such suitable known agent is for example alcohol, for example methanol, ethanol, propanol, isopropanol, n-butanol, sec-butanol and amyl alcohol, aldehyde, ketone, alkyl thiol, for example dodecyl thiol and tert-dodecyl thiol, for example thioglycolic acid, isooctyl thioglycolate, 2-mercaptoethanol, 2-mercaptopropionic acid, 3-mercaptopropionic acid, and some halogen compounds, for example carbon tetrachloride, chloroform and methylene chloride.

[0070] Polycarboxylate ethers can also be prepared by polymer-analogous reactions, in which a polymer containing latent or free carboxyl groups is reacted with one or more compounds containing amine or hydroxyl functional groups under conditions leading to at least partial amidation or esterification of the carboxyl groups, respectively.

[0071] The polycarboxylate ether is typically present in an amount ranging from 1 to 10,000 mg / L, preferably from 500 to 5,000 mg / L, based on the weight of the bath. In alternative embodiments, the polycarboxylate ether is typically present in an amount ranging from 10 to 5,000 mg / L, 20 to 1,000 mg / L, or 20 to 200 mg / L.

[0072] The metal plating baths may include one or more optional additives. The metal baths may contain one or more accelerators, additional suppressors, leveling agents, sources of halide ions, grain refiners, and mixtures thereof.

[0073] Suitable accelerators are organic additives that increase the plating rate of a metal plating bath, such as compounds containing one or more sulfur atoms and sulfonic / phosphonic acids or salts thereof.

[0074] Preferred promoters have the general structure M A O3X A -R A1 -(S) a -R A2 [In the formula, -M A is hydrogen or an alkali metal (preferably Na or K), - X A is P or S, - a=1~6, -R A1 is selected from a C1-C8 alkyl or heteroalkyl group, an aryl group, or a heteroaromatic group, where the heteroalkyl group has one or more heteroatoms (N, S, O) and 1-12 carbons, the carbocyclic aryl group is a typical aryl group, e.g., phenyl, naphthyl, and the heteroaromatic group is also a suitable aryl group, containing one or more N, O, or S atoms and 1-3 separate or fused rings; -R A2 is H or (-SR A1' XO3M) and R A1' is R A1 the same or different from the

[0075] More specifically, useful accelerators are of the formula: X A O3S-R A1 -SH X A O3S-R A1 -SSR A1 -SO3X A X A O3S-Ar-SS-Ar-SO3X A (In the formula, R A1 is as defined above and Ar is aryl. Includes:

[0076] Particularly preferred accelerators are SPS: bis-(3-sulfopropyl)-disulfide disodium salt, MPS: 3-mercapto-1-propanesulfonic acid sodium salt, is.

[0077] Other examples of accelerators used alone or in mixtures include, but are not limited to, MES (2-mercaptoethanesulfonic acid sodium salt), DPS (N,N-dimethyldithiocarbamic acid (3-sulfopropyl ester) sodium salt), UPS (3-[(amino-iminomethyl)-thio]-1-propylsulfonic acid), ZPS (3-(2-benzthiazolylthio)-1-propanesulfonic acid sodium salt), 3-mercapto-propylsulfonic acid-(3-sulfopropyl)ester, methyl-(ω-sulfopropyl)-disulfide disodium salt, methyl-(ω-sulfopropyl)-trisulfide disodium salt.

[0078] Such accelerators are typically used in an amount of about 0.1 to about 3000 mg / L based on the total weight of the plating bath. Particularly suitable amounts of accelerator are 1 to 500 mg / L, more particularly 2 to 100 mg / L.

[0079] Suitable leveling agents include one or more of polyalkanolamines and their derivatives, polyethyleneimine and its derivatives, quaternized polyethyleneimine, polyglycine, poly(allylamine), polyaniline, polyurea, polyacrylamide, poly(melamine-co-formaldehyde), reaction products of amines and epichlorohydrin, reaction products of amines, epichlorohydrin and polyalkylene oxides, reaction products of amines and polyepoxides, polyvinylpyridine, polyvinylimidazole, polyvinylpyrrolidone, or copolymers thereof, nigrosine, pentamethyl-para-rosaniline hydrohalide, hexamethyl-pararosaniline hydrohalide, or compounds containing a functional group of the formula NRS (wherein R is 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. 20 ) aryl, preferably (C6-C 10 ) aryl. Such aryl groups may further contain heteroatoms such as sulfur, nitrogen, and oxygen. Preferably, the aryl group is phenyl or naphthyl. Compounds containing a functional group of formula NRS are generally known, generally commercially available, and can be used without further purification.

[0080] In compounds containing such NRS functional groups, sulfur ("S") and / or nitrogen ("N") can be attached to such compounds by a single bond or a double bond. When sulfur is attached to such compounds by a single bond, the sulfur may have another substituent, such as hydrogen, (C1-C 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 one or more substituents, such as hydrogen, (C1-C 12) Alkyl, (C2-C 12 ) alkenyl, (C7-C 10 ) aryl, etc. NRS functional groups can 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.

[0081] Generally, the total amount of leveling agent in the electroplating bath is 0.5 to 10,000 mg / L based on the total weight of the plating bath. The leveling agent is typically used in a total amount of about 0.1 to about 1,000 mg / L, more typically 1 to 100 mg / L, based on the total weight of the plating bath, although greater or lesser amounts may be used.

[0082] All percentages, ppm or equivalent values ​​refer to weight based on total weight of the corresponding composition unless otherwise indicated.

[0083] In addition to the polycarboxylate ether inhibitor according to the present invention, further inhibitors can be used. Suitable further inhibitors include polyethylene glycol copolymers, particularly polyethylene glycol-polypropylene glycol copolymers. The arrangement of ethylene oxide and propylene oxide in suitable inhibitors can be block, gradient, or random. Polyalkylene glycols may contain further alkylene oxide building blocks, such as butylene oxide. Preferably, the average molecular weight of suitable inhibitors is greater than about 2000 g / mol. Suitable polyalkylene glycol starter molecules may be alkyl alcohols such as methanol, ethanol, propanol, n-butanol, etc., aryl alcohols such as phenol and bisphenol, alkaryl alcohols such as benzyl alcohol, polyol starters such as glycol, glycerin, trimethylolpropane, pentaerythritol, sorbitol, carbohydrates such as sucrose, etc., amines and oligoamines such as alkylamines, arylamines such as aniline, triethanolamine, ethylenediamine, etc., amides, lactams, heterocyclic amines such as imidazole, and carboxylic acids. Optionally, the polyalkylene glycol inhibitor may be functionalized with ionic groups such as sulfate, sulfonate, ammonium, etc.

[0084] If an additional inhibitor is used, it is typically present in an amount ranging from 1 to 10000 mg / l, preferably from 500 to 5000 mg / l, based on the weight of the bath.

[0085] [Example] Inhibitor: PCE-1: Polycarboxylate ether based on acrylic acid and 4-hydroxybutyl vinyl ether-polyethylene glycol HBVE-PEG (molar weight of the polyethylene glycol side chains is 3000 g / mol), with an acrylic acid to HBVE-PEG ratio of 1:2.7, total molar weight Mw=36200 g / mol, Mn=3350 g / mol. PCE-2: Polycarboxylate ether based on acrylic acid and HBVE-PEG (polyethylene glycol side chain molar weight of 1100 g / mol) with a charge density of 1.61 and a total molar weight Mw=19290 g / mol. PCE-3: Polycarboxylate ether based on N,N-dimethylacrylamide and HBVE-PEG (with a molar weight of the polyethylene glycol side chains of 3000 g / mol), with a ratio of N,N-dimethylacrylamide to HBV-PEG of 5:1, a charge density of 1.4 mmol / g, and a total molar weight Mw=39000 g / mol. The molar weight of the polycarboxylate ether was determined by GPC (against Na-PAA standards). The charge density was determined by conductometric titration.

[0086] [Example 1] Deposition quality of the metal layer An acid copper plating bath was prepared containing: CuSO4 * 5H2O 200g / l H2SO4(95%) 70g / l NaCl 100mg / l Wetting agent 80 mg / l (Plurafac® LF 1430 from BASF, an alkoxylated fatty alcohol) Accelerator 8 mg / l (SPS, bis-(3-sulfopropyl)-disulfide disodium salt) Leveling agent 24 mg / l (Lugalvan® IZE from BASF, a product of imidazole and epichlorohydrin) The amount of polycarboxylate ether inhibitors PCE-1, PCE-2 and PCE-3 was 40 mg / L.

[0087] The inhibitor candidates were tested for initial plating performance in a Hull cell (2 A, 10 minutes, 30°C on polished brass panels). The panels were visually rated on a scale of 1 to 10 (deposition quality, gloss, and leveling: 1 = poor, 10 = perfect), and the results are summarized in Table 1.

[0088] The areas on the panel with different current densities are referred to as follows: HCD=high current density MCD=medium current density LCD=low current density

[0089] The concentration of each component was set 50% lower than the standard industrial use to make the inhibition effect more clearly visible. The results demonstrated that polycarboxylate ethers provided good deposition quality.

[0090] [Table 1]

[0091] [Example 2] Electrochemical stability of plating baths The applied parameters in the electrochemical stability evaluation were: 250 ml of the easily formulated electrolyte of Example 1 was exposed to a 2 A current for 2 hours at 30° C. This stimulates the electrochemical decomposition of the organic components in the plating bath.

[0092] Normal plating in the same electrolyte is then carried out as in Example 1 (2 A, 10 minutes, 30°C). These deposits are evaluated. All components are then re-dosed to the desired starting levels, and another 10-minute deposition is carried out. This indicates that if the electrolyte still works (or does not), the intensity of the failure in the current exposure run is due to decomposition alone.

[0093] The panels were visually evaluated according to a ranking scale of 1 to 10 (1 = very poor, 10 = very good), and the results are summarized in Table 2. For comparison, the commercial inhibitor Pluriol E9000 (polyethylene glycol, molar mass 9000 g / mol) was used instead of the polycarboxylate ether.

[0094] The results demonstrated that polycarboxylate ethers improved the electrochemical stability of the plating bath.

[0095] [Table 2]

[0096] [Example 3] polarization Laser drilling of microvias and subsequent copper filling is a standard manufacturing technique for high density interconnects. The present invention's objective of depositing a metal layer can be used for copper electroplating of microvias, where high filling performance and minimal surface thickness of the microvias (typically cavities with a diameter of approximately 20 μm, also called bottom-up filling) are desired. This was evaluated as follows:

[0097] Galvanostatic measurements were performed on a Gamry potentiostat with the following parameters: Amount: 700ml CuSO4×5H2O: 200g / l NaCl: 0.1 g / L (equivalent to 60 mg / L chloride) H2SO4:70g / l Inhibitor: 80mg / l Accelerator bis-(3-sulfopropyl)-disulfide disodium salt SPS: 8 mg / l

[0098] Cathode area: 5,812cm 2 Cathode material: Cu-ETP (E-Cu, 2.0060) Anode: Platinum Reference electrode: Calomel Electrolyte transfer: Air agitation

[0099] The basic electrolyte salt was added to the volumetric flask and measurements were started at the predetermined currents listed in Table 3. The potential was measured for approximately 500 seconds until it became constant. The inhibitor was added and the resulting potential was recorded. After an additional 200 seconds, SPS was added and the potential was measured after an additional 1000 seconds. The average values ​​of these potentials are listed in Tables 3a and 3b.

[0100] [Table 3]

[0101] The results in Table 3a show that the absolute value of polarization was reduced for bottom-up filling, which means that the electrons were slowed down less, which was desirable for achieving high microvia filling performance.

[0102] [Table 4]

[0103] The results in Table 3b show that electroplating the surface increased the absolute value of the polarization, which means that the electrons were slowed down more, which was desirable to achieve a minimum surface thickness outside the microvia.

[0104] The combination of both results, high microvia filling capability and minimal surface thickness, results in improved interconnect leveling.

Claims

1. a) contacting the substrate with a metal plating bath containing a source of metal ions and a suppressor; and b) applying a current density to the substrate; 1. A method for depositing a metal layer on a substrate by: The inhibitor is (I) at least one ethylenically unsaturated monomer (I) containing at least one group from the series of carboxylic acids, carboxylic acid salts, carboxylic acid esters, carboxylic acid amides, carboxylic acid anhydrides, and carboxylic acid imides; and (II) at least one ethylenically unsaturated monomer having a polyalkylene oxide group (II) is a polycarboxylate ether obtained by polymerizing a mixture of monomers comprising method.

2. 10. The method of claim 1, wherein the ethylenically unsaturated monomer (I) comprises at least one group from the series of carboxylic acids, carboxylic acid salts, and carboxylic acid amides.

3. The ethylenically unsaturated monomer (I) is of the general formula (Ia), (Ib) and (Ic) groups: 【Chemistry 1】 [In the formula, R 1 and R 2 are, independently of one another, hydrogen or an aliphatic hydrocarbon group having 1 to 20 C atoms, Y, H, -COOM a , -CO-O(C q H 2q O) r -R 3 or -CO-NH-(C q H 2q O) r -R 3 and M is hydrogen, a monovalent or divalent metal cation, an ammonium ion, or an organic amine group; a is 1 / 2 or 1, R 3 is hydrogen, an aliphatic hydrocarbon group having 1 to 20 C atoms, an alicyclic hydrocarbon group having 5 to 8 C atoms, or an optionally substituted aryl group having 6 to 14 C atoms, q is the q H 2q O) are independently identical or different at each occurrence in the unit and are 2, 3, or 4; r is between 0 and 200; Z is 0 or NR 3 is], 【Chemistry 2】 [In the formula, R 4 and R 5 are, independently of one another, hydrogen or an aliphatic hydrocarbon group having 1 to 20 C atoms, an alicyclic hydrocarbon group having 5 to 8 C atoms or an optionally substituted aryl group having 6 to 14 C atoms, Q may be the same or different and may be NH, NR 3 or O, and R 3 has the definition set forth above, R 6 are the same or different, and (C n H 2n )-SO 3 H (wherein n=0, 1, 2, 3 or 4), (C n H 2n )—OH (wherein n=0, 1, 2, 3 or 4), (C n H 2n )-PO 3 H 2 (wherein n=0, 1, 2, 3 or 4), (C n H 2n )-OPO 3 H 2 (wherein n=0, 1, 2, 3 or 4), (C 6 H 4 )-SO 3 H, (C 6 H 4 )-PO 3 H 2 , (C 6 H 4 )-OPO 3 H 2 , and (C n H 2n )-NR 8 b wherein n=0, 1, 2, 3, or 4, and b=2 or 3; R 7 ,H,-COOM a , -CO-O(C q H 2q O) r -R 3 or -CO-NH-(C q H 2q O) r -R 3 and M a , R 3 , q and r have the definitions set forth above; R 8 is hydrogen, an aliphatic hydrocarbon group having 1 to 10 C atoms, an alicyclic hydrocarbon group having 5 to 8 C atoms, or an optionally substituted aryl group having 6 to 14 C atoms] 3. The method of claim 1 or 2, wherein the method is represented by at least one of:

4. The ethylenically unsaturated monomer (II) has the following general formula: 【Transformation 3】 [In the formula, p is an integer from 0 to 6, y is 0 or 1; v is an integer from 3 to 500; w is the w H 2w O) each occurrence is independently the same or different and is an integer from 2 to 18; T is oxygen or a chemical bond; R 1 , R 2 and R 3 have the definitions set forth above] 4. The method according to claim 1, wherein the method is represented by:

5. In the ethylenically unsaturated monomer (II), p is an integer of 0 to 4, v is an integer of 5 to 250, and w is each (C w H 2w 0) units are independently the same or different at each occurrence and are 2 or 3.

6. In the ethylenically unsaturated monomer (II), R 3 The method according to claim 4 or 5, wherein is an aliphatic hydrocarbon group having 1 to 20 C atoms.

7. 7. The process according to claim 1, wherein the ethylenically unsaturated monomer (II) has a molecular weight of 500 to 10,000 g / mol.

8. 8. The method according to claim 1, wherein the polycarboxylate ether has a molecular weight of 1,000 to 100,000 g / mol.

9. 9. The method according to claim 1, wherein the proportion of monomer (I) in the copolymer is from 5 to 95 mol %.

10. 10. The process according to claim 1, wherein the monomer (I) is a carboxylic acid amide, such as N,N-dimethylacrylamide, N,N-dimethylmethacrylamide, N,N-diethylacrylamide or N,N-diethylmethacrylamide.

11. 11. The method according to claim 1, wherein the proportion of monomer (II) in the copolymer is from 1 to 89 mol%.

12. 12. The method of any one of claims 1 to 11, wherein the polycarboxylate ether is present in the range of 1 to 10,000 mg / l based on the weight of the bath.

13. 13. The method of claim 1, wherein the source of metal ions comprises a copper salt.

14. 14. The method of any one of claims 1 to 13, wherein the metal plating bath comprises an accelerator which is a compound containing one or more sulfur atoms and a sulfonic / phosphonic acid or a salt thereof.

15. 15. A metal plating bath comprising a source of metal ions and a suppressor which is a polycarboxylate ether as defined in any one of claims 1 to 14.

16. 15. Use of a suppressor which is a polycarboxylate ether as defined in any one of claims 1 to 14 in a metal plating bath for depositing a metal layer on a substrate.

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