Alkaline compositions for copper electroplating containing defect reducing agents

Abstract

The present invention provides a composition for depositing copper on a semiconductor substrate, the composition comprising: (a) copper ions; (b) an additive of formula S1; [Formula 1] TIFF2025503562000029.tif19108 (in the formula, R S1 -X S -Y S Selected from; R S2 is R S1 and R S3 Selected from; X S is linear or branched C1-C 10 Alkanediyl, linear or branched C2-C 10 Alkenyl, linear or branched C2-C 10 Alkynediyl, and -X S6 -(O-C2H3R S6 ) m - Selected from; Y S OR S3 , N.R. S3 R S4 , N + R S3 R S4 R S5 NH-(C=O)-R S3 Selected from; R S3 , R S4 , R S5 are the same or different, (i) H, (ii) C5-C 20 Aryl, (iii) C1-C 10 Alkyl, (iv) C-C 20 arylalkyl, (v) C6 to C6 optionally substituted with OH, SO3H, COOH or a combination thereof 20 Alkylaryl, and (vi) -(C2H3R S6 -O) n -R S6 where R S3 and R S4 Together, O or NR S7 forming a ring system which may be interrupted by; XS6 is C1-C6 alkanediyl; m and n are independently an integer selected from 1 to 30; R S6 is selected from H and C1-C5 alkyl; R S7 is R S6 , and [Case 2] TIFF2025503562000030.tif1551) (c) a complexing agent; and (d) optionally a buffer or base to adjust the pH to between 7 and 13; Including, The pH of the composition is between 7 and 13, and the composition is cyanide-free.

Description

[Technical field]

[0001] The present invention relates to an alkaline composition for depositing a copper layer on a semiconductor substrate, a method for its use, and a deposition method by using such a composition. [Background technology]

[0002] The filling of small features such as vias and trenches by metal electroplating is a critical part of the semiconductor manufacturing process. It is well known that the presence of organic materials as additives in electroplating baths is crucial in achieving uniform metal deposition on the substrate surface and avoiding defects such as voids and seams in the metal lines.

[0003] Void-free, bottom-up filling of sub-micrometer sized interconnect features by using an acid copper electroplating bath with a copper seed is well known in the art.

[0004] Filling of interconnects with copper becomes particularly challenging as the opening size of features such as vias or trenches shrinks to less than 5 nanometers and even less than 3 nanometers, respectively, especially at the top of the opening, as copper seed deposition prior to copper electroplating exhibits non-uniformity and incompatibility. The smaller the feature size and the higher the aspect ratio of the feature, the more difficult it becomes to obtain a continuous seed on the sidewall of the feature without significant seed overhang.

[0005] To avoid these difficulties, non-copper seeds such as cobalt or ruthenium have been proposed in WO 2019 / 199614 A1. An acidic electroplating solution for plating copper on a non-copper liner layer includes a low copper concentration, an acidic pH, an organic additive, and bromide ions as a copper complexing agent. WO 2022 / 012932 also discloses an acidic copper electroplating bath containing bromide.

[0006] However, cobalt is a less noble metal than copper and corrodes rapidly in the presence of acid and oxygen, especially in the presence of copper. On the other hand, alkaline electroplating baths, which are less corrosive to cobalt, use complexing agents necessary to keep the copper in solution, which results in poor filling and contamination of the copper fill.

[0007] Also, alkaline compositions for electroplating copper onto copper or other metal seeds are generally known in the art. For example, WO 2015 / 086180 discloses a copper electroplating bath comprising copper ions and a promoter for nucleation of metallic copper on the substrate, where the promoter for nucleation of copper is selected from the group consisting of 2,2'-bipyridine, imidazole, and cesium (Cs) to improve the nucleation of copper on the most resistant materials that act as barriers to copper diffusion, such as ruthenium or cobalt. 2+ ), alkylammonium, and mixtures thereof.

[0008] CN 112 126 952 A discloses a copper electroplating solution for heterojunction solar cells, which contains a copper salt, such as copper sulfate, a complexing agent, such as potassium citrate, a conductive salt, such as sodium chloride, a crystal refining agent, such as a combination of saccharin, sodium propynylsulfonate, and polyvinyl alcohol, a stress reliever, such as a combination of 2-amino-6-mercaptopurine, 1,4-butylenediamine, and polyethyleneimine, a brightener, such as a combination of nicotinic acid and sodium phenyldithiopropanesulfonate, and a pH stabilizer, such as boric acid.

[0009] CN 105 543 908 B discloses a cyanide-free alkaline bright roll copper plating solution containing brighteners which may be 1,4-butynediol (BOZ), pyridinium hydroxypropanesulfonate (PPS-OH), propynol propoxylate (PAP), propynyl alcohol (PA), pyridinium propanesulfonate (PPS), propyl alcohol ethoxylate (PME), N,N-diethylpropynylamine (DEP), N,N-diethylpropynylamine formate (PABS), N,N-diethylpropargylamine propanesulfonate (DEPS), butynediol ethoxylate (BEO), and butynediol propoxylate (BMP).

[0010] There remains a need for copper electroplating compositions that enable void-free deposition of copper in small recessed features such as vias or trenches in semiconductor substrates. [Prior art documents] [Patent documents]

[0011] [Patent Document 1] WO 2019 / 199614 A1 [Patent Document 2] WO 2022 / 012932 [Patent Document 3] WO 2015 / 086180 [Patent Document 4] CN 112 126 952 A [Patent Document 5] CN 105 543 908 B Summary of the Invention [Problem to be solved by the invention]

[0012] It is therefore an object of the present invention to provide electroplating compositions capable of providing substantially void-free filling of nanometer and / or micrometer scale features with copper over non-copper metal seeds, particularly cobalt seeds. It is also an object of the present invention to provide electroplating compositions capable of depositing homogeneous, smooth, void-free copper seed layers over non-copper metal seeds, particularly cobalt seeds.

[0013] For resistivity reasons, it is also beneficial for the copper layer deposited on the cobalt seed layer to exhibit low resistivity. The low resistivity of the copper deposition is supported by low impurity levels in the deposited copper film, which means that very little C, N, S, O, H, Cl, P or other elements other than copper are incorporated into the copper film during copper electroplating. [Means for solving the problem]

[0014] Summary of the Invention The present invention provides copper electroplating baths that can be used in two general ways: 1. This bath deposits a copper seed layer onto a semiconductor substrate, allowing each recessed feature to be filled using state-of-the-art acid copper plating baths; and 2. The bath allows for direct, void-free filling of recessed features and ideally also bottom-up filling to be achieved.

[0015] Accordingly, the present invention provides a composition for depositing copper on a semiconductor substrate, the composition comprising: (a) copper ions; (b) an additive of formula S1; [ka] (In the formula, R S1 -X S -Y S Selected from; R S2 is R S1 and R S3 Selected from; X S is linear or branched C 1 ~C 10 Alkanediyl, linear or branched C 2 ~C 10 Alkenyl, linear or branched C 2 ~C 10 Alkynediyl, and -X S6 -(OC 2 H 3 R S6 ) m - Selected from; Y S OR S3 , N.R. S3 R S4 , N + R S3 R S4 R S5 NH-(C=O)-R S3 Selected from; R S3 , R S4 , R S5 are the same or different, (i) H, (ii) C 5 ~C 20 aryl, (iii) C 1 ~C 10 alkyl, (iv) C 6 ~C 20 Aryl alkyl, (v) OH, SO 3 C, which may be substituted by H, COOH or a combination thereof 6 ~C 20 Alkylaryl, and (vi)-(C 2 H 3 R S6 -O) n -R S6 where R S3 and R S4 Together, O or NR S7 forming a ring system which may be interrupted by; X S6 is C 1 ~C 6 It is an alkanediyl; m and n are independently an integer selected from 1 to 30; R S6 H and C1 ~C 5 alkyl; R S7 is R S6 , and [ka] (selected from (c) a complexing agent; and (d) optionally a buffer or base to adjust the pH to between 7 and 13; Including, The pH of the composition is between 7 and 13, and the composition is cyanide-free.

[0016] The present invention further relates to methods of using metal plating baths comprising the compositions defined herein to deposit copper essentially void-free, preferably by bottom-up fill, on substrates containing recess features having opening sizes of 50 nanometers or less, 15 nanometers or less, 10 nanometers or less, or 5 nanometers or less.

[0017] The present invention further relates to a method of depositing copper on a semiconductor substrate including a recessed feature having an opening size of 50 nm or less, preferably 15 nm or less, the recessed feature including a metal seed, the method comprising: (a) contacting a composition described herein with a metal seed; (b) applying a current for a time sufficient to deposit a continuous seed of copper on the surface of the recessed feature or for a time sufficient to completely fill the recessed feature with copper; Includes.

[0018] The alkaline copper electroplating compositions according to the present invention provide substantially void-free filling of nanometer and / or micrometer scale features with copper over non-copper metal seeds, particularly cobalt seeds. They also allow for the deposition of homogeneous, smooth, void-free seed layers over non-copper metal seeds, particularly cobalt seeds. A further advantage of the present invention is that the deposited copper, e.g., completely filled recessed features or continuous seeds, has much lower impurity levels. [Brief description of the drawings]

[0019] [Figure 1] FIG. 1 shows the FIB / SEM inspected wafers used for copper electroplating in Comparative Example 2c, and Examples 2d, 2e and 3e. [Diagram 2] FIG. 2 shows the FIB / SEM inspected wafers used for copper electroplating in Comparative Example 3c and Example 3d. [Diagram 3] FIG. 3 shows a FIB / SEM inspected wafer electroplated with copper according to Comparative Example 2a. [Figure 4] FIG. 4 shows a FIB / SEM inspected wafer electroplated with copper according to Example 2b. [Diagram 5] FIG. 5 shows a FIB / SEM inspected wafer electroplated with copper according to Comparative Example 2c. [Figure 6] FIG. 6 shows a FIB / SEM inspected wafer electroplated with copper according to Example 2d. [Figure 7] FIG. 7 shows a FIB / SEM inspected wafer electroplated with copper according to Example 2e. [Figure 8] FIG. 8 shows a FIB / SEM inspected wafer electroplated with copper according to Example 3a. [Figure 9] FIG. 9 shows a FIB / SEM inspected wafer electroplated with copper according to Example 3b. [Figure 10] FIG. 10 shows a FIB / SEM inspected wafer electroplated with copper according to Comparative Example 3c. [Figure 11] FIG. 11 shows a FIB / SEM inspected wafer electroplated with copper according to Example 3d. [Figure 12] FIG. 12 shows a FIB / SEM inspected wafer electroplated with copper according to Example 3e. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Detailed Description of the Invention The composition according to the present invention comprises copper ions and an additive of formula S1 described below (also referred to herein as a defect reducing agent).

[0021] Defect reducing agent The additive of formula S1 is [ka] It has been found to be a particularly useful additive for alkaline electroplating of copper onto semiconductor substrates, especially those containing sub-micrometer sized recess features, most especially those having nanometer or micrometer scale opening sizes, preferably opening sizes of 50 nanometers or less, 15 nanometers or less, 10 nanometers or less, or even 5 nanometers or less.

[0022] SIMS measurements of copper films plated with a defect reducing agent in the plating bath show that the amount of C, N, S, O, H, Cl, P or elements other than copper incorporated into the copper film during copper electroplating is less than that of copper films plated without a defect reducing agent in the plating bath.

[0023] In the additive of formula S1, R S1 X S -Y S where X is S is linear or branched C 1 ~C 10 Alkanediyl, linear or branched C 2 ~C 10 Alkenyl, linear or branched C 2 ~C 10 Alkynediyl, and -X S6 -(OC 2 H 3 R S6 ) m - is a divalent spacer group selected from the group consisting of m and m, which is an integer selected from 1 to 30, preferably 1 to 15, more preferably 1 to 10, and most preferably 1 to 5. Spacer X S6 is C 1 ~C 6Alkanediyl is preferably methanediyl, ethanediyl, propanediyl or butanediyl, most preferably methanediyl or ethanediyl.

[0024] In a first preferred embodiment, X S is linear or branched C 1 ~C 6 Alkanediyl, preferably C 1 ~C 4 alkanediyl.

[0025] In a second preferred embodiment, X S is selected from methanediyl, ethane-1,1-diyl and ethane-1,2-diyl. S is selected from propane-1,1-diyl, butane-1,1-diyl, pentane-1,1-diyl, and hexane-1,1-diyl. S is selected from propane-2,2-diyl, butane-2,2-diyl, pentane-2,2-diyl, and hexane-2,2-diyl.

[0026] In a fifth preferred embodiment, X S is selected from propane-1,2-diyl, butane-1,2-diyl, pentane-1,2-diyl, and hexane-1,2-diyl. S is selected from propane-1,3-diyl, butane-1,3-diyl, pentane-1,3-diyl, and hexane-1,3-diyl.

[0027] Y S is a monovalent group, OR S3 where R S3 are (i) H, (ii) C 5 ~C 20 Aryl, preferably C 5 , C 6 and C 10 aryl, (iii) C 1 ~C 10 Alkyl, preferably C1 ~C 6 Alkyl, most preferably C 1 ~C 4 alkyl, (iv) C 6 ~C 20 Aryl alkyl, preferably C 6 ~C 10 Aryl alkyl, (v) OH, SO 3 C, which may be substituted by H, COOH or a combination thereof 6 ~C 20 Alkylaryl, and (vi)-(C 2 H 3 R S6 -O) n -R S6 In a preferred embodiment, R S3 is C 1 ~C 6 R may be alkyl or H. S6 are independently H and C 1 ~C 5 Alkyl, preferably H and C 1 ~C 4 It may be selected from alkyl, most preferably H, methyl or ethyl.

[0028] As used herein, aryl includes carbocyclic aromatic groups and heterocyclic aromatic groups in which one or more carbon atoms are replaced by one or more N or O atoms. As used herein, arylalkyl refers to an alkyl group substituted with one or more aryl groups, such as, but not limited to, benzyl and methylpyridine. As used herein, alkylaryl refers to an aryl group substituted with one or more alkyl groups, such as, but not limited to, toluyl.

[0029] In another preferred embodiment, R S3 is selected from H to form a hydroxy group. In another preferred embodiment, R S3 is the formula -(C 2 H 3 R S6 -O) n -R S6R S6 H and C 1 ~C 5 Alkyl, preferably H and C 1 ~C 4 In particular embodiments, polyoxymethylene, polyoxypropylene, or poly(oxymethylene-co-oxypropylene) may be used. In another preferred embodiment, R S3 is C 1 ~C 10 Alkyl, preferably C 1 ~C 6 It may be selected from alkyl, most preferably methyl and ethyl.

[0030] Furthermore, Y S is the amine group NR S3 R S4 where R S3 and R S4 may be the same or different, and the above OR S3 R S3 It may have the meaning:

[0031] In a preferred embodiment, R S3 and R S4 is selected from H, NH 2 In another preferred embodiment, R S3 and R S4 At least one, preferably both, of the formula -(C 2 H 3 R S6 -O) n -R S6 R S6 are independently H and C 1 ~C 5 Alkyl, preferably H and C 1 ~C 4and most preferably selected from H, methyl or ethyl. In yet another preferred embodiment, R S3 and R S4 At least one of, and preferably both of, 1 ~C 10 Alkyl, preferably C 1 ~C 6 It is selected from alkyl, most preferably from methyl and ethyl.

[0032] R S3 and R S4 Together, O or NR S7 It is also possible to form ring systems which may be interrupted by R S7 is R S6 and [ka] Preferably, the ring system has two substituents R S3 and R S4 Such ring systems preferably contain 4 or 5 carbon atoms to form 5- or 6-membered carbocyclic ring systems, in which one or two carbon atoms may be replaced by oxygen atoms.

[0033] Furthermore, Y S is a positively charged ammonium group N + R S3 R S4 R S5 R S3 , R S4 , R S5 may be the same or different, and the above OR S3 and N.R. S3 R S4 R S3 In a preferred embodiment, R S3 , R S4 and R S5 is independently selected from H, methyl or ethyl. S3 , RS4 and R S5 At least one, preferably two, and most preferably all, of the formula -(C 2 H 3 R S6 -O) n -R S6 The polyoxyalkylene group is selected from the group consisting of the following polyoxyalkylene groups:

[0034] m is an integer selected from 1 to 30, preferably 1 to 15, even more preferably 1 to 10, and most preferably 1 to 5.

[0035] In the additive of formula S1, R S2 is the above-mentioned R S1 or R S3 R S2 R S1 If R S1 is a symmetric compound (both R S1 are the same) or asymmetric compounds (two R S1 may be selected to form a

[0036] In a preferred embodiment, R S2 is H.

[0037] Particularly preferred aminoalkynes are: (a)R S1 isX S -NR S3 R S4 and R S2 is H; (b)R S1 isX S -NR S3 R S4 and R S2 isX S -NR S3 R S4 where X S is a straight chain C 1 ~C 4 Alkanediyl and branched C 3 ~C 6 Selected from alkanediyls.

[0038] Particularly preferred hydroxyalkynes or alkoxyalkynes are:

[0039] (a)R S1 isX S -OR S3 and R S2 is H; (b)R S1 isX S -OR S3 and R S2 isX S -OR S3 where X S is a straight chain C 1 ~C 4 Alkanediyl and branched C 3 ~C 6 Selected from alkanediyls.

[0040] Particularly preferred alkynes containing amino and hydroxy groups are R S1 isX S -OR S3 , especially X S -OH and R S2 isX S -NR S3 R S4 where X S are independently linear C 1 ~C 4 Alkanediyl and branched C 3 ~C 6 The alkanediyl is selected from the group consisting of alkanediyl.

[0041] The amine groups in the additive are primary amine groups (R S3 , R S4 is H), secondary amine groups (R S3 or R S4 is H), and tertiary amine groups (R S3 and R S4 and n is not H).

[0042] The alkyne may contain one or more terminal triple bonds or one or more non-terminal triple bonds (alkyne functional groups). Preferably, the alkyne contains one or more terminal triple bonds, in particular one to three triple bonds, most preferably one terminal triple bond.

[0043] Particularly preferred primary aminoalkynes are:

[0044] [ka]

[0045] Particularly preferred secondary aminoalkynes are:

[0046] [ka]

[0047] Particularly preferred tertiary aminoalkynes are:

[0048] [ka]

[0049] Other preferred additives include the residue R S3 and R S4 Together, they form O or NR S3 Preferably, the residue R S3 and R S4 Together, C 5 Or C 6 in which one or two, preferably one, carbon atom is O or NR S7 where R S7 is selected from hydrogen, methyl or ethyl.

[0050] Examples of such compounds are:

[0051] [ka]

[0052] It is obtained by reaction of propargylamine with formaldehyde and morpholine.

[0053] Further preferred additives containing saturated heterocyclic ring systems are:

[0054] [ka]

[0055] In this case, R S3 and R S4 Together, the two NR S3 forms a ring system interrupted by groups, where R S3 CH 2 -C≡CH. The additive contains three terminal triple bonds.

[0056] The amino groups in the additive may be further quaternized by reaction with an alkylating agent, for example, but not limited to, a dialkyl sulfate such as DMS, DES or DPS, benzyl chloride or chloromethylpyridine. Particularly preferred quaternized additives are:

[0057] [ka]

[0058] Particularly preferred pure hydroxyalkynes are:

[0059] [ka]

[0060] Particularly preferred aminoalkynes containing an OH group are:

[0061] [ka]

[0062] Also in this case, residue R S3 and R S4 Together, O or NR S3 Preferably, the residue R S3 and R S4 Together, C 5 Or C 6 in which one or two, preferably one, carbon atom is O or NR S7 where R S7 is selected from hydrogen, methyl or ethyl.

[0063] Examples of such compounds are:

[0064] [ka]

[0065] These can be obtained by reaction of propargyl alcohol with formaldehyde and piperidine or morpholine, respectively.

[0066] The mixture of additives can be formed by partial reaction with an alkylating agent. In one embodiment, such a mixture can be obtained by reaction of 1 mole of diethylaminopropyne with 0.5 moles of epichlorohydrin, 1 mole of diethylaminopropyne with 0.5 moles of benzyl chloride, 1 mole of diethylaminopropyne with 0.9 moles of dimethyl sulfate, 1 mole of dimethylpropyneamine with 0.33 moles of dimethyl sulfate, or 1 mole of dimethylpropyneamine with 0.66 moles of dimethyl sulfate. In another embodiment, such a mixture can be obtained by reaction of 1 mole of dimethylpropyneamine with 1.5, 1.9, or 2.85 moles of dimethyl sulfate, 1 mole of dimethylpropyneamine with 0.5 moles of epichlorohydrin, 1 mole of dimethylpropyneamine with 2.85 moles of diethyl sulfate, or 1 mole of dimethylpropyneamine with 1.9 moles of dipropyl sulfate.

[0067] In a further embodiment, the additive is SO 3 H (sulfonate) or COOH (carboxy) groups. Specific sulfonated additives include, but are not limited to, butynoxyethanesulfonic acid, propynoxyethanesulfonic acid, 1,4-di-(β-sulfoethoxy)-2-butyne, 3-(β-sulfoethoxy)-propyne.

[0068] In one embodiment, a single additive may be used in the copper electroplating baths, while in another embodiment, two or more additives may be used in combination.

[0069] In general, the additives are usually used in an amount of about 0.1 ppm to about 30,000 ppm based on the total weight of the plating bath. Particularly suitable amounts of the defect reducing agent useful in the present invention are 1 to 10,000 ppm, more particularly 10 to 1,000 ppm. Other amounts can also be used as needed.

[0070] Complexing Agent Copper electroplating compositions also contain complexing agents to keep the copper ions in solution and prevent their precipitation.

[0071] The complexing agent may in particular be chosen from polyamines, aminocarboxylic acids, aminophosphonic acids, aminoalcohols, polyalcohols, hydroxycarboxylic acids, hydroxyphosphonic acids, thioureas, and polycarboxylic acids.

[0072] Useful polyamines include, but are not limited to, methylenediamine, ethylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, diethylenetriamine, tetraethylenepentamine, pentaethylenehexamine, hexaethyleneheptamine, or combinations thereof.

[0073] Useful amino carboxylic acids include, but are not limited to, ethylenediaminetetraacetic acid (EDTA), hydroxyethylethylenediaminetriacetic acid (HEDTA), diethylenetriaminepentaacetic acid (DTPA), triethylenetetraaminehexaacetic acid (TTHA), ethylenediaminetetrapropionic acid, nitrilotriacetic acid (NTA), iminodiacetic acid (IDA), iminodipropionic acid (IDA), metaphenylenediaminetetraacetic acid, 1,2-diaminocyclohexane-N,N,N',N'-tetraacetic acid, diaminopropionic acid, combinations thereof, or salts thereof.

[0074] Useful amino alcohols include, but are not limited to, monoethanolamine, diethanolamine, triethanolamine, monopropanolamine, dipropanolamine, tripropanolamine, or combinations thereof.

[0075] Useful hydroxycarboxylic acids include, but are not limited to, tartaric acid, citric acid, malic acid, gluconic acid, glycolic acid, lactic acid, glucoheptonic acid, combinations thereof, or salts thereof.

[0076] Useful hydroxyphosphonic acids include, but are not limited to, 1-hydroxyethylidene-1,1-diphosphonic acid (etidronic acid), combinations thereof, or salts thereof.

[0077] Thiourea is thiourea and thiourea derivatives.

[0078] A useful, but non-limiting, polyhydric alcohol is sorbitol.

[0079] Preferred complexing agents are hydroxycarboxylic acids, including but not limited to citric acid, tartaric acid, and hydroxyphosphonic acids, including but not limited to etidronic acid.

[0080] The complexing agents may be used alone or in any combination. The content of the complexing agent in the plating bath is usually 0.01 to 2 mol / l, preferably 0.1 to 0.6 mol / l.

[0081] Buffers / Bases The composition optionally includes a buffer or base (also called a "pH adjuster") to adjust the pH to between 7 and 13.

[0082] Exemplary bases include, but are not limited to, hydroxides, carbonates, NH 4 OH, alkyl ammonium hydroxides, etc. Preferred are metal hydroxides, especially alkaline earth metal hydroxides. Most preferred bases are NaOH, KOH and combinations thereof.

[0083] The alkyl ammonium ion is, for example, represented by the formula (NR B1 R B2 R B3 R B4 ) + wherein R B1 , R B2 , R B3 , and R B4 are independently H and C 1 ~C 4 alkyl, with the proviso that RB1 , R B2 , R B3 , and R B4 At least one of them is C 1 ~C 4 It is an alkyl.

[0084] C 1 ~C 4 Alkyl is, for example, methyl, ethyl, n-propyl or n-butyl. Preferred alkylammonium ions include tetraalkylammonium, such as tetramethylammonium, tetraethylammonium, tetrapropylammonium or tetrabutylammonium, methyltriethylammonium and ethyltrimethylammonium.

[0085] The cation is provided in the form of a salt, for example a sulfate, in which the counterion of the cation is preferably the same as the counterion of the copper(II) salt.

[0086] Crystal Refining Agent The copper electroplating compositions may optionally include a grain refiner.

[0087] Preferred crystal refiners are of formula G1a or G1b, or salts thereof: [ka] (In the formula, R G1 , H, C 1 ~C 4 Carboxyl, C 1 ~C 4 Alkyl, C 1 ~C 6 selected from one or more of alkoxy, halogen, and CN; R G2 , H, C 1 ~C 4 Carboxyl, C 1 ~C 4 Alkyl, C 1 ~C 6 selected from one or more of alkoxy, halogen, and CN; XG1 is C 1 ~C 6 Alkanediyl or group -X G11 -C(O)-OX G12 - Selected from; X G11 is a chemical bond or C 1 ~C 4 Selected from alkanediyls; X G12 is a chemical bond or C 1 ~C 4 Selected from alkanediyls; Here, R G1 or R G2 At least one C 1 ~C 4 Contains a carboxyl group or a group X G1 -X G11 -C(O)-OX G12 -).

[0088] In a first preferred embodiment, the crystal refiner is a compound of formula G1 or a salt thereof, wherein R G1 , H, C 1 ~C 4 Carboxyl, C 1 ~C 4 Alkyl, C 1 ~C 6 selected from one or more of alkoxy, halogen, and CN; R G2 , H, C 1 ~C 4 Carboxyl, C 1 ~C 4 Alkyl, C 1 ~C 6 selected from one or more of alkoxy, halogen, and CN; X G1 is C 1 ~C 6 It is an alkanediyl, X G1 Or X G2 At least one C 1 ~C 4 Contains a carboxyl group.

[0089] Particularly preferred crystal refiners of the first embodiment are of formula G2a or G2b, or salts thereof: [ka] (In the formula, R G21 , H, C 1 ~C 3 Alkyl, C 1 ~C 4 selected from one or more of alkoxy, halogen, and CN; R G22 , H, C 1 ~C 4 Alkyl, C 1 ~C 6 selected from one or more of alkoxy, halogen, and CN; X G1 is methanediyl, ethanediyl, propanediyl or butanediyl).

[0090] A particularly preferred crystal refiner of formula G2b is 3-carboxy-1-phenylmethylpyridinium (inner salt).

[0091] In a second preferred embodiment, the crystal refiner is a compound of formula G1 or a salt thereof, wherein R G1 , H, C 1 ~C 4 Carboxyl, C 1 ~C 4 Alkyl, C 1 ~C 6 selected from one or more of alkoxy, halogen, and CN; R G2 , H, C 1 ~C 4 Carboxyl, C 1 ~C 4 Alkyl, C 1 ~C 6 selected from one or more of alkoxy, halogen, and CN; X G1 is the group -X G11 -C(O)-OX G12 - and X G11 , X G12 is independently 1 ~C 4 alkanediyl.

[0092] Particularly preferred crystal refiners of the second embodiment are of formula G3a, G3b, G3c, or salts thereof:

[0093] [ka] (In the formula, R G31 , H, C 1 ~C 4 Carboxyl, C 1 ~C 4 Alkyl, C 1 ~C 6 selected from one or more of alkoxy, halogen, and CN; R G32 , H, C 1 ~C 4 Carboxyl, C 1 ~C 4 Alkyl, C 1 ~C 6 Alkoxy, C 1 ~C 6 selected from one or more of carboxy, halogen, and CN; X G32 is a chemical bond or C 1 ~C 4 alkanediyl).

[0094] Particularly preferred crystal refiners of formula G3b are 4-(methoxycarbonyl)benzylpyridine-3-carboxylate and benzylpyridine-3-carboxylate.

[0095] Generally, the total amount of the grain refiner in the electroplating bath is 0.5 ppm to 10000 ppm based on the total weight of the plating bath. The additive according to the present invention is typically used in a total amount of about 0.1 ppm to about 1000 ppm, more typically 1 to 100 ppm, based on the total weight of the plating bath, although greater or lesser amounts may be used.

[0096] SIMS measurements of copper films plated with a crystal refiner in the plating bath show that less C, N, S, O, H, Cl, P or elements other than copper are incorporated into the copper film during copper electroplating compared to copper films plated without a crystal refiner in the plating bath.

[0097] Other Additives A wide variety of additional additives can typically be used in the bath to provide the desired surface finish to the copper plated metal. Typically, multiple additives are used, with each additive performing a desired function. Advantageously, the electroplating bath can contain one or more wetting agents or surfactants, such as Lutensol®, Plurafac®, or Pluronic® (available from BASF), to remove trapped air or hydrogen bubbles, and the like. Additional components that can be added include stress relief agents, levelers, and mixtures thereof.

[0098] In a further embodiment, a surfactant may be present in the electroplating composition to improve wetting. The wetting agent may be selected from nonionic surfactants, anionic surfactants, and cationic surfactants.

[0099] In a preferred embodiment, a non-ionic surfactant is used. Typical non-ionic surfactants are fluorinated surfactants, polyglycols, or polyoxyethylene and / or oxypropylene containing molecules.

[0100] In a preferred embodiment, the composition is free of polyethyleneimine, sulfur-containing additives, or both.

[0101] composition A wide variety of metal plating baths can be used in the present invention. Metal electroplating baths typically comprise or consist essentially of a source of copper ions, a defect reducing agent, a complexing agent, optionally a grain refiner, optionally a base or buffer, optionally an electrolyte, and optionally further additives as described above.

[0102] Typically, the plating bath is aqueous. The term "aqueous" means that the plating bath is based on water. 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. Preferably, the plating bath is an aqueous solution of the compounds described herein. Preferably, the water is electronic grade deionized water. Small amounts of other solvents besides water may be present, but preferably water is the only solvent.

[0103] The metal ion source may be any compound capable of releasing a sufficient amount of copper ions into the electroplating bath, i.e., at least partially dissolving in the electroplating bath. In another preferred embodiment, the metal comprises copper and less than 0.1 g / l, preferably less than 0.01 g / l, of tin, and most preferably no tin. Most preferably, there are essentially no alloying metal ions other than copper ions in the composition. In this context, "alloying metal" means a metal that can be electroplated with copper as an alloying metal from an aqueous solution. Without being limited thereto, typical alloying metals are subgroup metals, such as, but not limited to, Sn (forming bronze), Zn (forming brass), Ni, Co, Mn, Ag, W, Au, and Pb. Typical non-alloying metals are Group I metals, such as sodium or potassium, or Group II metals, such as magnesium or calcium. Most preferably, no metal ions are present in the composition, except those present in a buffer, base, or any electrolyte. In particular, for copper deposition into features having an opening size of 15 or less, the additional cations, especially metal ions, are detrimental because the lower conductivity of the composition results in more uniform deposition into the feature.

[0104] In a preferred embodiment, the composition does not contain boric acid.

[0105] In another preferred embodiment, the electroplating composition does not include a reducing agent that reduces copper ions to metallic copper.

[0106] The copper ion source is preferably soluble in the plating bath to release 100% of the metal ion. Suitable copper ion sources are metal salts, including but not limited to metal sulfates, metal halides, metal acetates, metal nitrates, metal fluoroborates, metal alkylsulfonates, metal arylsulfonates, metal sulfamates, metal gluconates, and the like. It is preferred that the metal is copper. More preferred are copper ion sources such as 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.

[0107] The copper ion source may be used in the present invention in an amount that provides sufficient metal ions for electroplating onto a substrate.

[0108] Copper is typically present in an amount ranging from about 0.2 to about 300 g / L of the plating solution. In general, defect reducing agents are useful in low copper, medium copper, and high copper baths. By low copper, it is meant copper concentrations of about 0.3 to about 20 g / L. Even lower concentrations of about 0.1 to about 5 g / L, and 0.1 to 1 g / L, are advantageous from the standpoint of cobalt corrosion.

[0109] The pH of the electroplating composition ranges from about 7 to about 13, preferably from about 8 to about 13, more preferably from about 8 to about 12, and most preferably from about 9 to about 11.

[0110] The electroplating composition is cyanide ion free.

[0111] In a preferred embodiment, the composition is essentially free of chloride ions, except for those present in the defect reducing agent (e.g., if positively charged) or any grain refiner (e.g., if an inner salt is used). Essentially free of chloride means less than 1 ppm, especially less than 0.1 ppm, of additional chloride. Most preferably, the composition contains no additional anions, especially chloride ions, except for those present in the defect reducing agent or any grain refiner. In particular, for copper deposition into features having an aperture size of 15 or less, any additional anions are detrimental, since the lower electrical conductivity of the composition results in more uniform deposition into the features.

[0112] In another preferred embodiment, the electroplating composition consists essentially of, or consists of: (a) copper ions; (b) Defective reducing agent of formula S1

[0113] [ka] (c) complexing agents, especially hydroxycarboxylic acids, most especially citric acid; (d) optionally a buffer or base to adjust the pH to between 7 and 13; (e) optionally a crystal refiner, particularly a crystal refiner of formula G1a or G1b; and (f) optionally, a non-ionic surfactant.

[0114] In yet another preferred embodiment, the electroplating composition consists essentially of, or consists of: (a) copper ions; (b) Defective reducing agent of formula S1 [ka] (c) complexing agents, especially hydroxycarboxylic acids, most especially citric acid; (d) a base, especially a hydroxide, to raise the pH to 7-13; and (e) A crystal refiner of formula G1a or G1b.

[0115] In yet another preferred embodiment, the electroplating composition consists essentially of, or consists of: (a) copper ions; (b) Defective reducing agent of formula S1 [ka] (c) hydroxycarboxylic acids, most particularly citric acid; (d) hydroxides, especially NaOH or KOH, to raise the pH to 7-13; and (e) A crystal refiner of formula G1a or G1b.

[0116] method According to one embodiment of the present invention, alkaline copper electroplating baths comprising the compositions described herein can be used to deposit copper on substrates containing recessed features having an opening size of 50 nanometers or less, the features preferably containing seeds of cobalt, iridium, osmium, palladium, platinum, rhodium, ruthenium, molybdenum, or alloys thereof, preferably cobalt or ruthenium seeds, and most preferably cobalt seeds.

[0117] According to the present invention, an electrolytic bath is prepared, which includes copper ions, a complexing agent, and at least one additive. A dielectric substrate having a seed layer is placed in the electrolytic bath, where the electrolytic bath contacts at least one outer surface and, in the case of a dielectric substrate, the three-dimensional pattern having the seed layer. A counter electrode is placed in the electrolytic bath, and a current is passed through the electrolytic bath between the seed layer on the substrate and the counter electrode. At least a portion of the copper is deposited on at least a portion of the three-dimensional pattern, and the deposited copper is substantially free of voids.

[0118] The present invention is useful for depositing layers including copper on a variety of substrates, particularly substrates having nanometer and various size openings. For example, the present invention is particularly suited for depositing copper on integrated circuit substrates, such as semiconductor devices, having small diameter vias, trenches, or other recessed features. In one embodiment, semiconductor devices are plated according to the present invention. Such semiconductor devices include, but are not limited to, wafers used in the manufacture of integrated circuits.

[0119] In order to deposit copper on a substrate including a dielectric surface, it is necessary to apply a seed layer to the surface. Such a seed layer can consist of cobalt, iridium, osmium, palladium, platinum, rhodium, ruthenium, or an alloy containing such metals. Preferably, copper is deposited on a cobalt seed. Seed layers are described in detail, for example, in US20140183738 A.

[0120] The underlying seed layer may be deposited or grown by chemical vapor deposition (CVD), atomic layer deposition (ALD), physical vapor deposition (PVD), electroplating, electroless plating, or other suitable process for depositing a conformal thin film. In one embodiment, the cobalt seed layer is deposited to form a high quality conformal layer that adequately and uniformly covers all exposed surfaces within the openings and the top surface. In one embodiment, the high quality seed layer may be formed by depositing the cobalt seed material at a low deposition rate to deposit the conformal seed layer uniformly and consistently. Forming the seed layer in a conformal manner may improve compatibility of the subsequently formed fill material with the underlying structure. In particular, the seed layer may aid the deposition process by providing a suitable surface energy for deposition thereon.

[0121] In one embodiment, the substrate includes sub-micrometer sized features and the copper deposition is performed to fill the sub-micrometer sized features. Most preferably, the sub-micrometer sized features have an (effective) opening size of 10 nm or less and / or an aspect ratio of 4 or more. More preferably, the features have an opening size of 7 nanometers or less, most preferably 5 nanometers or less. Preferably, the features have a cobalt seed layer onto which the copper is electroplated.

[0122] In another embodiment, a copper seed is deposited on a seed surface of a substrate, preferably the substrate includes recess features having an opening size of 50 nm or less and / or an aspect ratio of 4 or greater. Preferably the substrate has a cobalt seed layer onto which the copper seed layer is electroplated.

[0123] As used herein, "copper seed" refers to a continuous thin layer of copper metal having a thickness of about 5 nm to about 15 nm.

[0124] Aperture size according to the present invention refers to the smallest diameter or free distance of a feature before plating, i.e. after seed deposition. In this specification, the terms "aperture" and "opening" are used interchangeably.

[0125] The current density of the electroplating should be selected to promote void-free filling behavior. For this purpose, a current density of 0.1 to 40 mA / cm2 should be used. 2 In a particular example, the current density is in the range of 1 to 10 mA / cm 2 In another particular example, the current density can range from 0.5 to 5 mA / cm 2 The range can be:

[0126] Typically, a substrate is electroplated by contacting it with a plating bath of the present invention. The substrate typically functions as the cathode. The plating bath contains an anode, which may be soluble or insoluble. Optionally, the cathode and anode may be separated by a membrane. Typically, an electrical potential is applied to the cathode. A sufficient current density is applied and plating is carried out for a time sufficient to deposit a metal layer, such as a copper layer, having a desired thickness on the substrate. Suitable current densities are between 1 and 250 mA / cm. 2 Typically, when used to deposit copper in the manufacture of integrated circuits, the current density is in the range of 1 to 60 mA / cm. 2 The current density ranges from 10° C. to 50° C. The specific current density will depend on the substrate being plated, the reagents and additives selected, etc. Selection of such current density is within the ability of one skilled in the art. The applied current may be direct current (DC), pulsed current (PC), pulsed reverse current (PRC), or other suitable current. Pulsed current is preferred. Typical temperatures used for copper electroplating are 10° C. to 50° C., preferably 20° C. to 40° C., and most preferably 20° C. to 35° C.

[0127] Generally, when the present invention is used to deposit metal on a substrate such as a wafer used in the manufacture of integrated circuits, the 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, sparging with inert gas or air, agitating the workpiece, impingement, and the like. Such methods are well known to those skilled in the art. When the present invention is used to plate an integrated circuit substrate such as a wafer, the wafer may be rotated, for example, at 1-300 RPM, and the plating solution may be contacted with the rotating wafer, for example, by a pump or spray. Alternatively, if the flow of the plating bath is sufficient to provide the desired metal deposition, the wafer need not be rotated.

[0128] Copper is deposited in recessed features in accordance with the present invention without forming substantial voids in the metal deposit.

[0129] In this specification, void-free filling is ensured by growing copper in a very significant bottom-up manner while completely suppressing sidewall copper growth, both resulting in a flat growth front, thus providing a substantially defect-free trench / via filling (so-called bottom-up filling), or by so-called V-fill.

[0130] As used herein, the term "substantially void-free" means that at least 95% of the plated openings are void-free. Preferably, at least 98% of the plated openings are void-free, and most preferably, all of the plated openings are void-free. As used herein, the term "substantially seam-free" means that at least 95% of the plated openings are seam-free. Preferably, at least 98% of the plated openings are seam-free, and most preferably, all of the plated openings are seam-free.

[0131] Plating equipment for plating semiconductor substrates is well known. The plating equipment includes an electrolytic plating tank containing a Cu electrolyte, which is made of a suitable material, such as plastic or other material that is inert to the electrolytic plating solution. The tank may be cylindrical, particularly for wafer plating. The cathode is horizontally positioned at the top of the tank and may be any type of substrate, such as a silicon wafer with openings, such as trenches and vias. The wafer substrate is typically coated with a seed layer or metal-containing layer of Cu or other metal, on which plating begins. The anode is also preferably circular for wafer plating and is horizontally positioned at the bottom of the tank forming a space between the anode and the cathode. The anode is typically a soluble anode.

[0132] These bath additives are useful in combination with membrane technology being developed by various tool manufacturers. In this system, the anode can be separated from the organic bath additives by a membrane. The purpose of separating the anode and the organic bath additives is to minimize oxidation of the organic bath additives.

[0133] The cathode substrate and the anode are electrically connected by wiring, and each is connected to a rectifier (power supply). Because the cathode substrate for direct current or pulsed current has a net negative charge, Cu ions in the solution are reduced at the cathode substrate, forming plated Cu metal on the cathode surface. An oxidation reaction occurs at the anode. The cathode and anode are positioned horizontally or vertically in the tank.

[0134] Although the method of the present invention has been generally described in the context of semiconductor manufacturing, it should be understood that the present invention is useful in any electrolytic process where substantially void-free copper deposition is desired. Such processes include the manufacture of printed wiring boards. For example, the plating baths of the present invention are useful for plating vias, pads or traces on printed wiring boards, and bump plating on wafers. Other suitable processes include the manufacture of packaging and interconnects. Thus, suitable substrates include lead frames, interconnects, printed wiring boards, and the like.

[0135] All percentages, ppm or equivalent values ​​refer to weight relative to the total weight of the respective composition unless otherwise specified. All citations are incorporated herein by reference.

[0136] The following examples further illustrate the invention without limiting its scope. EXAMPLES

[0137] 3-Carboxy-1-phenylmethylpyridinium (Na) used in the examples + and Cl - (inner salt having the formula:

[0138] Example 1 Example 1a: Synthesis of defective reducing agent 1

[0139] [ka] Propargyl alcohol (280.3 g) and triphenylphosphine (2.0 g) were placed in a 3.5 l autoclave. After nitrogen neutralization, the pressure was adjusted to 1.5 bar and the mixture was homogenized at 60° C. for 1 h. Ethylene oxide (220.3 g) was then added at 60° C. over 4 h, reaching a maximum pressure of 3.5 bar. The reaction mixture was then heated to 80° C. over 30 min, reaching a maximum pressure of 4 bar. To complete the reaction, the mixture was reacted at 80° C. for 6 h. The temperature was then reduced to 40° C. Volatile compounds were removed in vacuum at 60° C. Defective reducing agent 1 was obtained as a yellowish liquid (494.4 g) with a hydroxyl value of 569 mg / g.

[0140] Example 1b: Synthesis of defective reducing agent 2

[0141] [ka] 3-Hexyne-2,5-diol (456.6 g) and imidazole (2.5 g) were placed in a 3.5 l autoclave. After nitrogen neutralization, the pressure was adjusted to 1.0 bar and the mixture was homogenized at 70° C. for 1 h. Ethylene oxide (176.2 g) was then added at 70° C. over 1 h, reaching a maximum pressure of 3.5 bar. To complete the reaction, the mixture was reacted at 70° C. for 6 h. The temperature was then reduced to 60° C. Volatile compounds were removed in vacuum at 60° C. Defective reducing agent 2 was obtained as an orange liquid (630.8 g) with a hydroxyl value of 709 mg / g.

[0142] Example 1c: Synthesis of defective reducing agent 3

[0143] [ka] 2-Methyl-3-butyn-2-ol (420.6 g) and imidazole (3.4 g) were placed in a 3.5 l autoclave. After nitrogen neutralization, the pressure was adjusted to 1.5 bar and the mixture was homogenized at 70° C. for 1 h. Ethylene oxide (440.5 g) was then added at 70° C. over 8 h, reaching a maximum pressure of 3.5 bar. To complete the reaction, the mixture was reacted at 70° C. for 6 h. The temperature was then reduced to 60° C. Volatile compounds were removed in vacuum at 60° C. Intermediate 1 (=2-Methyl-3-butyn-2-ol + 2EO) was obtained as an orange liquid (835.3 g) with a hydroxyl value of 325 mg / g.

[0144] Intermediate 1 (300 g) and imidazole (0.7 g) were placed in a 3.5 l autoclave. After nitrogen neutralization, the pressure was adjusted to 2.2 bar and the mixture was homogenized at 70° C. for 1 h. Then propylene oxide (202.4 g) was added at 70° C. over 7 h, reaching a maximum pressure of 3.2 bar. To complete the reaction, the mixture was reacted at 70° C. for 6 h. Then the temperature was reduced to 60° C. Volatile compounds were removed in vacuum at 60° C. Defective reducing agent 3 was obtained as a dark orange liquid (488.5 g).

[0145] Example 1d: Synthesis of defective reducing agent 4

[0146] [ka] The reaction was carried out in a 2 liter, 4-neck flask equipped with a stirrer, condenser, thermometer, and nitrogen inlet. Diethylamine (240 g) and water (324 g) were added to the flask and heated to 40°C. Protectol KCL (1.3 g) and propargyl chloride (342.3 g) were then added over 2 hours and 50 minutes, reaching a maximum temperature of 56°C. The reaction mixture was then stirred at 50°C for 3.5 hours. During this time, the pH value was adjusted to above 10 with sodium hydroxide (50%). The mixture was placed in a separatory funnel. The aqueous phase was separated. Water (100 g) was added to the organic phase and the pH was adjusted to 3.5 with hydrochloric acid (222 g). The lower aqueous phase was separated; the organic phase was discarded. The aqueous phase, containing the product in the form of the hydrochloride, was adjusted to pH=9.5-10 with 50% NaOH (186.8 g). The product was discharged as the organic phase and the aqueous phase was discarded. For further purification, the product was distilled at an internal temperature of 50° C. and 35 mbar. The product was obtained as a colorless liquid (175 g).

[0147] 1H-NMR (400 MHz, D2O): δ (ppm) = 1.25 (6H, -CH3), 2.54 (4H, -CH2), 3.41 (2H, -CH2), 4.8 (1H, CH).

[0148] Copper electroplating experiment In some plating experiments, a blanket wafer substrate with a 100 Å CVD Co seed on a 30 Å TaN layer was used.

[0149] In some plating experiments, a patterned wafer substrate was used as shown in Figure 1. The wafer substrate had a 100 A Co seed on a 30 A TaN layer with features having a diameter of 24 nm at the top of the opening and a diameter of 20 nm at half the height of the feature. The feature height was about 105 nm, thus the aspect ratio was about 5.25.

[0150] In some plating experiments, a patterned wafer substrate was used as shown in Figure 2. The wafer substrate had a 50 A Co seed on a 30 A TaN layer with features having a diameter of 18 nm at half the feature height. The feature height was about 110 nm, and therefore the aspect ratio was about 6.

[0151] Example 2: Cu electrodeposition using defect reducing agent Comparative example 2a A plating bath was prepared by combining DI water, 0.5 g / l copper as copper sulfate, citric acid at a 2:1 molar ratio to Cu, and a solution of sodium hydroxide or potassium hydroxide to adjust the pH to 9. The wafer substrate was contacted with the plating bath and plated at −2.0 mA / cm at 25° C. 2 A copper layer was electroplated on a blanket wafer substrate having a cobalt seed layer by applying a DC current of 1000 V for 2000 s. The thus electroplated copper layer was annealed in forming gas at 400 °C for 5 min and examined by FIB / SEM inspection.

[0152] The results are shown in Figure 3, which provides an SEM image of the electroplated copper film, showing that the electroplated copper has defects such as holes and voids.

[0153] Example 2b The experiment described in Example 2a was repeated, with 1 ml / l of a 0.9 wt. % solution of defect reducer 1 in DI water being added to the plating bath.

[0154] The results are shown in Figure 4, which provides SEM images of the electroplated copper film. Figure 4 shows that the electroplated copper film has significantly fewer defects.

[0155] Example 2c A plating bath was prepared by combining DI water, 0.5 g / l copper as copper sulfate, an aqueous solution of citric acid at a 2:1 molar ratio to Cu, and sodium or potassium hydroxide to adjust the pH to 9. The wafer substrate was contacted with the plating bath and plated at −2.0 mA / cm at 25° C.2 A copper layer was electroplated on the patterned wafer substrate as shown in Figure 1 by applying a DC current of 0.01 V for 125 seconds. The copper layer thus electroplated was examined by FIB / SEM inspection.

[0156] The results are shown in Figure 5, which provides an SEM image of the electroplated copper film, showing conformal Cu deposition inside features that exhibit a rough and non-uniform Cu surface.

[0157] Example 2d The experiment described in Example 2c was repeated, with 25 ml / l of a 0.9 wt. % solution of defect reducer 1 in DI water being added to the plating bath.

[0158] The results are shown in Figure 6, which provides an SEM image of the electroplated copper film, showing a continuous and smooth metal film inside the features.

[0159] Example 2e The experiment described in Example 2c was repeated, but 10 ml / l of a 0.9 wt. % solution of defect reducer 4 in DI water was added to the plating bath.

[0160] The results are shown in Figure 7, which provides an SEM image of the electroplated copper film. Figure 7 shows conformal Cu deposition inside the features. The surface of the deposited Cu is less rough than the case without the additive shown in Figure 5.

[0161] Example 3: Cu electrodeposition using defect reducing agent and grain refiner 3-Carboxy-1-phenylmethylpyridinium was used as a grain refiner in combination with a defect reducer in an alkaline Cu electroplating bath. The grain refiner helps to reduce the roughness of the electroplated copper layer, and as a result, it can also prevent the formation of defects in the electroplated Cu film.

[0162] Example 3a A plating bath was prepared by combining DI water, 0.5 g / l copper as copper sulfate, citric acid at a 2:1 molar ratio to Cu, and a solution of sodium or potassium hydroxide to adjust the pH to 9. 10 ml / l of a 0.9 wt. % solution of defect reducer 1 in DI water and 0.5 ml / l of a 0.9 wt. % solution of 3-carboxy-1-phenylmethylpyridinium in DI water were added to the electrolyte. A wafer substrate was contacted with the plating bath and plated at -2.0 mA / cm at 25°C. 2 A copper layer was electroplated on a blanket wafer substrate having a cobalt seed layer by applying a DC current of 1000 V for 1000 s. The thus electroplated copper layer was annealed in forming gas at 400 °C for 5 min and examined by FIB / SEM inspection.

[0163] The results are shown in Figure 8, which provides SEM images of the electroplated copper film, showing that the electroplated copper film is largely defect-free.

[0164] Example 3b A plating bath was prepared by combining DI water, 0.5 g / l copper as copper sulfate, citric acid at a 2:1 molar ratio to Cu, and a solution of sodium or potassium hydroxide to adjust the pH to 9. 10 ml / l of a 0.9 wt. % solution of defect reducer 1 in DI water and 1.0 ml / l of a 0.9 wt. % solution of 3-carboxy-1-phenylmethylpyridinium in DI water were added to the electrolyte. A wafer substrate was contacted with the plating bath and plated at -1.0 mA / cm at 25°C. 2 A copper layer was electroplated on the patterned wafer substrate as shown in Figure 2 by applying a DC current of 0.01 V for 250 seconds. The copper layer thus electroplated was examined by FIB / SEM inspection.

[0165] The results are shown in Figure 9, which provides SEM images of the Cu-filled features, and shows that the electroplated copper film is largely defect-free.

[0166] Comparative example 3c A plating bath was prepared by combining DI water, 0.5 g / l copper as copper sulfate, citric acid at a 2:1 molar ratio to Cu, and a solution of sodium hydroxide or potassium hydroxide to adjust the pH to 9. The wafer substrate was contacted with the plating bath and plated at −1.0 mA / cm at 22° C. 2 A copper layer was electroplated on the patterned wafer substrate as shown in Figure 2 by applying a DC current of 0.1 V for 50 seconds. The copper layer thus electroplated was examined by FIB / SEM inspection.

[0167] The results are shown in Figure 10, which provides an SEM image of the electroplated copper film, showing an amorphous, rough metal film inside the features.

[0168] Example 3d The experiment described in Example 3c was repeated, adding 10 ml / l of a 0.9 wt. % solution of defect reducing agent 2 in DI water and 1.0 ml / l of a 0.9 wt. % solution of 3-carboxy-1-phenylmethylpyridinium in DI water to the plating bath.

[0169] The wafer substrate was then placed in contact with the plating bath and exposed to -1.0 mA / cm at 22°C. 2 A copper layer was electroplated on the patterned wafer substrate as shown in Figure 2 by applying a DC current of 0.1 V for 100 seconds. The copper layer thus electroplated was examined by FIB / SEM inspection.

[0170] The results are shown in Figure 11, which provides an SEM image of the electroplated copper film, showing a continuous and smooth metal film inside the features.

[0171] Example 3e A plating bath was prepared by combining DI water, 0.5 g / l copper as copper sulfate, citric acid at a 2:1 molar ratio to Cu, and a solution of sodium or potassium hydroxide to adjust the pH to 9. 10 ml / l of a 0.9 wt. % solution of defect reducer 3 in DI water and 1.0 ml / l of a 0.9 wt. % solution of 3-carboxy-1-phenylmethylpyridinium in DI water were added to the plating bath. A wafer substrate was contacted with the plating bath and plated at -1.0 mA / cm at 25°C. 2 A copper layer was electroplated on the patterned wafer substrate as shown in Figure 1 by applying a DC current of 0.01 V for 250 seconds. The copper layer thus electroplated was examined by FIB / SEM inspection.

[0172] The results are shown in Figure 12, which provides an SEM image of the Cu-filled features, which show that the features are largely defect-free.

Claims

1. 1. A composition for depositing copper on a semiconductor substrate, comprising: (a) copper ions; (b) a defect reducing agent of formula S1; 【Chemistry 1】 (In the formula, R Ｓ１ , X Ｓ -Y Ｓ Selected from: R Ｓ２ is R Ｓ１ and R Ｓ３ Selected from: X Ｓ is a linear or branched C １ ~C １０ Alkanediyl, linear or branched C ２ ~C １０ Alkenyl, linear or branched C ２ ~C １０ Alkynediyl, and -X Ｓ６ -(O-C ２ H ３ R Ｓ６ ) ｍ - selected from; Y Ｓ is OR Ｓ３ , N.R. Ｓ３ R Ｓ４ , N ＋ R Ｓ３ R Ｓ４ R Ｓ５ and NH-(C=O)-R Ｓ３ Selected from: R Ｓ３ , R Ｓ４ , R Ｓ５ are the same or different, (i) H, (ii) C ５ ~C ２０ aryl, (iii) C １ ~C １０ alkyl, (iv) C ６ ~C ２０ Aryl alkyl, (v) OH, SO ３ C, which may be substituted by H, COOH or a combination thereof ６ ~C ２０ alkylaryl, and (vi)-(C ２ H ３ R Ｓ６ -O) ｎ -R Ｓ６ where R Ｓ３ and R Ｓ４ are taken together as O or NR Ｓ７ forming a ring system which may be interrupted by X Ｓ６ is C １ ~C ６ alkanediyl; m, n are independently integers selected from 1 to 30; R Ｓ６ is H and C １ ~C ５ alkyl; R Ｓ７ is R Ｓ６ , and 【Chemistry 2】 (selected from (c) a complexing agent; and (d) optionally a buffer or base to adjust the pH to between 7 and 13; Including, A composition, wherein the pH of the composition is between 7 and 13, and the composition is free of cyanide ions.

2. X Ｓ But, C １ ~C ６ 2. The composition according to claim 1, wherein the alkanediyl is selected from alkanediyl, in particular from methanediyl, or from 1,1 or 1,2 ethanediyl.

3. X Ｓ is selected from propane-1,1-diyl, butane-1,1-diyl, pentane-1,1-diyl, hexane-1,1-diyl, propane-2,2-diyl, butane-2,2-diyl, pentane-2,2-diyl, and hexane-2,2-diyl; and is selected from propane-1,2-diyl, butane-1,2-diyl, pentane-1,2-diyl, hexane-1,2-diyl, propane-1,3-diyl, butane-1,3-diyl, pentane-1,3-diyl, and hexane-1,3-diyl.

4. R Ｓ２ The composition of claim 1 , wherein

5. Y Ｓ OR Ｓ３ and R Ｓ３ The composition of claim 1 , wherein

6. Y Ｓ OR Ｓ３ and R Ｓ３ Formula -(C ２ H ３ R Ｓ６ -O) ｎ -R Ｓ６ 5. The composition according to claim 1 , wherein the polyoxyalkylene group is selected from the group consisting of:

7. Y Ｓ is NR Ｓ３ R Ｓ４ and R Ｓ３ and R Ｓ４ The composition of claim 1 , wherein is independently selected from H, methyl and ethyl.

8. Y Ｓ is NR Ｓ３ R Ｓ４ where R Ｓ３ and R Ｓ４ is H or R Ｓ３ and R Ｓ４ The composition of claim 1 , wherein one of is H.

9. Y Ｓ is NR Ｓ３ R Ｓ４ and R Ｓ３ and R Ｓ４ At least one, preferably both, of the formula -(C ２ H ３ R Ｓ６ -O) ｎ -R Ｓ６ 5. The composition according to claim 1 , wherein the polyoxyalkylene group is selected from the group consisting of:

10. Y Ｓ N ＋ R Ｓ３ R Ｓ４ R Ｓ５ and R Ｓ３ , R Ｓ４ and R Ｓ５ The composition of claim 1 , wherein is independently selected from H, methyl or ethyl.

11. Y Ｓ N ＋ R Ｓ３ R Ｓ４ R Ｓ５ and R Ｓ３ and R Ｓ４ At least one, preferably two, and most preferably all of the formula -(C ２ H ３ R Ｓ６ -O) ｎ -R Ｓ６ 7. The composition according to claim 1, wherein the polyoxyalkylene group is selected from the group consisting of:

12. 12. The composition of claim 1 further comprising a crystal refiner of formula G1 or a salt thereof. 【Chemistry 3】 (In the formula, R Ｇ１ is H, C １ ~C ４ Carboxyl, C １ ~C ４ Alkyl, C １ ~C ６ selected from one or more of alkoxy, halogen, and CN; R Ｇ２ is H, C １ ~C ４ Carboxyl, C １ ~C ４ Alkyl, C １ ~C ６ selected from one or more of alkoxy, halogen, and CN; X Ｇ１ is C １ ~C ６ Alkanediyl or group -X Ｇ１１ -C(O)-O-X Ｇ１２ - selected from; X Ｇ１１ is a chemical bond or C １ ~C ４ alkanediyl; X Ｇ１２ is a chemical bond or C １ ~C ４ alkanediyl; Here, R Ｇ１ Or R Ｇ２ At least one C １ ~C ４ Contains a carboxyl group or a group X Ｇ１ Ha-X Ｇ１１ -C(O)-O-X Ｇ１２ -).

13. 13. The composition of any one of claims 1 to 12, essentially free of alloying metal ions.

14. 14. A composition according to any one of claims 1 to 13, which does not contain any chloride ions other than those present in the defect reducing agent, in the buffer or base, if present, or in the crystal refining agent, if present.

15. 15. The composition of any one of claims 1 to 14, wherein the buffer or base is a hydroxide.

16. (a) copper ions; (b) a defect reducing agent of formula S1, and 【Chemistry 4】 (c) a complexing agent; (d) optionally a base to adjust the pH to 7-13; (e) optionally a grain refiner of formula G1a or G1b, and (f) optionally, a non-ionic surfactant 16. The composition of any one of claims 1 to 15, consisting essentially of

17. 17. Use of a composition according to any one of claims 1 to 16 for depositing copper on a semiconductor substrate containing recess features having an opening size of 50 nanometers or less, in particular 15 nanometers or less.

18. 1. A method of depositing copper on a semiconductor substrate including recess features having an opening size of 50 nm or less, preferably 15 nm or less, said recess features including a metal seed, said method comprising: (a) contacting the composition of any one of claims 1 to 16 with the metal seeds; (b) applying a current for a time sufficient to deposit a continuous seed of copper onto the metal seed in the recessed feature or for a time sufficient to completely fill the recessed feature; A method comprising:

19. 20. The method of claim 18, wherein the seeds are comprised of cobalt, iridium, osmium, palladium, platinum, rhodium, ruthenium, molybdenum, and alloys thereof.

20. The method of claim 18 , wherein the seeds comprise cobalt.

21. The method of claim 18 , wherein the seeds are comprised of ruthenium.

22. 22. The method of any one of claims 18 to 21, wherein the recessed feature is completely filled with copper.

23. 22. The method of any one of claims 18 to 21, wherein a continuous seed of copper is deposited on the metal seed of the recessed feature.

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