Patent Description:
One class of additives are the so-called levelers. Levelers are used to provide a substantially planar surface over the filled features. In literature, a variety of different leveling compounds has been described. In most cases, leveling compounds are N-containing and optionally substituted and/or quaternized polymers, such as polyethylene imine, polyglycine, poly(allylamine), polyaniline (sulfonated), polyurea, polyacrylamide, poly(melamine-co-formaldehyde) (<CIT>), reaction products of amines with epichlorohydrin (<CIT>), reaction products of an amine, epichlorohydrin, and polyalkylene oxide (<CIT>), reaction products of an amine with a polyepoxide (<CIT>), polyvinylpyridine, polyvinylimidazole (<CIT>), polyvinylpyrrolidone (<CIT>), polyalkoxylated polyamides and polyalkanolamines (unpublished <CIT>). However, none of these documents cited discloses the use of polyaminoamide, alkoxylated polyaminoamide, functionalized polyaminoamide, or functionalized alkoxylated polyaminoamide as additives for copper electroplating baths.

<CIT> discloses leveling agents comprising the reaction product of polyaminoamides and epihalohydrins, dihalohydrins and <NUM>-halogen-<NUM>,<NUM>-propanediols, respectively.

<CIT> discloses leveling agents comprising polyethoxylated polyamides or polyethoxylated polyaminoamides. In the examples the end groups are both polyalkoxylated with <NUM>, <NUM> or <NUM> alkoxy repeating units.

It is an object of the present invention to provide a copper electroplating additive having good leveling properties, in particular leveling agents capable of providing a substantially planar copper layer and filling features on the nanometer and on the micrometer scale without substantially forming defects, such as but not limited to voids, with a copper electroplating bath.

It has been found, that polyaminoamides, alkoxylated polyaminoamides, functionalized polyaminoamides, and functionalized and alkoxylated polyaminoamides can be used as additives, in particular leveling agents, in copper electroplating baths showing an improved performance.

Therefore the present invention provides a composition comprising a source of copper ions and at least one additive comprising at least one polyaminoamide of formula I
<CHM>
or derivatives of a polyaminoamide of formula I obtainable by complete or partial protonation,
wherein.

It has been found that the use of compositions according to the present invention for electroplating provides deposited copper layers, having reduced overplating, particularly reduced mounding. The copper layers provided by the present invention are substantially planar, even on substrates exhibiting apertures of a very wide range of different aperture sizes (scale: below or equal <NUM> nanometers to <NUM> micrometers). Furthermore it has been found that the present invention provides copper layers substantially without the formation of added defects, such as voids, in the features.

The agents/additives according to the present invention can further advantageously be used for electroplating of copper in through silicon vias (TSV). Such vias normally have diameters of several micrometers up to <NUM> micrometers and large aspect ratios of at least <NUM>, sometimes above <NUM>.

Furthermore the agents/additives according to the present invention can advantageously be used in bonding technologies such as the manufacture of copper pillars of typically <NUM> to <NUM> micrometers height and diameter for the bumping process, in circuit board technologies like the manufacture of high-density-interconnects on printed circuit boards using microvia plating or plated-through-hole technologies, or in other packaging processes for electronic circuits.

A further significant advantage of this leveling effect is that less material has to be removed in post-deposition operations. For example, chemical mechanical polishing (CMP) is used to reveal the underlying features. The more level deposit of the invention corresponds to a reduction in the amount of copper which must be deposited, therefore resulting in less removal later by CMP. There is a reduction in the amount of scrapped copper and, more significantly, a reduction in the time required for the CMP operation. The material removal operation is also less severe which, coupled with the reduced duration, corresponds to a reduction in the tendency of the material removal operation to impart defects.

In contrast to the prior art leveling agents the leveling agents according to the present inventions are alkoxylated or polyalkoxylated with a low average degree of alkoxylation of <NUM> to <NUM>. A higher degree of alkoxylation leads to a much lower nitrogen content in the leveling agent. Without being bound to any theory it is believed that that a high nitrogen content in the leveling agent is responsible for a good leveling performance on substrates comprising micrometer or nanometer sized features.

Preferably D<NUM> is, for each repeating unit <NUM> to p independently, selected from a chemical bond or a C<NUM>-C<NUM>-alkanediyl group. More preferably D<NUM> is, for each repeating unit <NUM> to p independently, selected from a chemical bond or a linear C<NUM>-C<NUM>-alkanediyl group, more preferably from a linear C3-, C4-, and C5-alkanediyl, most preferably from a linear butanediyl group.

Preferably, D<NUM>, D<NUM> are independently selected from straight chain or branched C1 to C6 alkanediyl, more preferably from (CH<NUM>)m, wherein m is an integer from <NUM> to <NUM>, preferably <NUM> or <NUM>, most preferably <NUM>. Most preferably D<NUM>, D<NUM> are independently selected from (CH<NUM>)<NUM> or (CH<NUM>)<NUM>.

The polyaminoamide is alkoxylated or polyalkoxylated up to an average degree of alkoxylation q of <NUM> and R<NUM> is, for each repeating unit <NUM> to n independently, selected from -R<NUM>. As used herein "average degree of alkoxylation" means the number of alkoxy groups CR<NUM>R<NUM>-CR<NUM>R<NUM>-O averaged over the the polymer units <NUM> to n, e.g. a number of <NUM> means that there is one alkoxy group per nine hydrogen atoms in the polymer.

In a preferred embodiment the polyaminoamide is (poly)alkoxylated and functionalized.

q is a number from <NUM> to <NUM>, preferably from <NUM> to <NUM>, more preferably from <NUM> to <NUM>, most preferably from <NUM> to <NUM>.

Preferably, m is <NUM> or <NUM>, most preferably <NUM>.

Preferably, n is an integer from <NUM> to <NUM>, more preferably <NUM> to <NUM>, more preferably <NUM> to <NUM>, most preferably <NUM> or <NUM>.

Preferably p is an integer from <NUM> to <NUM>, more preferably from <NUM> to <NUM>, most preferably from <NUM> to <NUM>. p corresponds to the degree of polymerization. In average non-integer numbers are possible.

Generally, the nucleophilically displaceable leaving group X may be any functional group being nucleophilically displaceable. Preferred nucleophilically displaceable leaving group X are selected from OH, alkoxy, and halogen, most preferably from OH, OCH<NUM>, OCH<NUM>CH<NUM>, and Cl.

In a preferred polyaminoamide R<NUM> is R<NUM> and R<NUM>, R<NUM>, and R<NUM> are hydrogen and R<NUM> is hydrogen or methyl. It is even more preferred if R<NUM>, R<NUM>, R<NUM> and R<NUM> are hydrogen. Furthermore, it is preferred if R<NUM> is a copolymer of at least two alkylene oxides, particularly if R<NUM> is a copolymer of ethylene oxide and propylene oxide. R<NUM> preferably may have a block, random or gradient structure or combinations thereof.

Particularly preferred polyaminoamides are those, wherein.

In a preferred embodiment of the present invention the at least one polyaminoamide is obtainable by reacting at least one polyalkylenepolyamine with at least one dicarboxylic acid. In particular, the at least one polyalkylenepolyamine is selected from the group of diethylenetriamine, triethylenetetramine, tetraethylenpentamine, pentaethylenehexamine, diaminopropylethylenediamine, ethylenepropylenetriamine, <NUM>-(<NUM>-aminoethyl)aminopropylamine, dipropylenetriamine, polyethyleneimines, and mixtures thereof. In particular, the at least one dicarboxylic acid is selected from the group of oxalic acid, malonic acid, succinic acid, tartaric acid, maleic acid, itaconic acid, glutaric acid, adipic acid, suberic acid, sebacic acid, phthalic acid and terephthalic acid, iminodiacetic acid, aspartic acid, glutamic acid, and mixtures thereof.

A further embodiment of the present invention is the use of polyaminoamides as described herein in a bath for depositing copper containing layers.

Yet another embodiment of the present invention is a process for depositing a copper layer on a substrate by contacting a plating solution as described herein with the substrate, and applying a current to the substrate to deposit a copper layer onto the substrate. The process is particularly useful for depositing copper layers on substrate comprising micrometer and/or submicrometer-sized features.

Due to its strong leveling performance the additives according to the present inventions are also referred to as leveling agent or leveler. Although the additive according to the present invention has strong leveling properties in electroplating of submicron-sized features, the use and performance of the additives according to the present invention is not limited to its leveling properties and may advantageously be used in other copper plating applications, e.g. for depositing through silicon vias (TSV), for other purposes.

As used herein, "feature" refers to the geometries on a substrate, such as, but not limited to, trenches and vias. "Apertures" refer to recessed features, such as vias and trenches. As used herein, the term "plating" refers to copper electroplating, unless the context clearly indicates otherwise. "Deposition" and "plating" are used interchangeably throughout this specification. The term "alkyl" means C1 to C30 alkyl and includes linear, branched and cyclic alkyl. "Substituted alkyl" means that one or more of the hydrogens on the alkyl group is replaced with another substituent group, such as, but not limited to, cyano, hydroxy, halo, (C1-C6)alkoxy, (C1-C6)alkylthio, thiol, and nitro. By "substituted aryl" is meant that one or more hydrogens on the aryl ring are replaced with one or more substituent groups, such as, but not limited to, cyano, hydroxy, halo, (C1-C6)alkoxy, (C1-C6)alkyl, (C2-C6)alkenyl, (C1-C6)alkylthio, thiol, and nitro. As used herein "aryl" includes carbocyclic and heterocyclic aromatic systems, such as, but not limited to, phenyl, and naphthyl.

"Accelerator" refers to an organic additive that increases the plating rate of the electroplating bath. The terms "accelerator" and "accelerating agent" are used interchangeably throughout this specification. In literature, sometimes the accelerator component is also named "brightener" or "brightening agent". "Suppressor" refers to an organic compound that decreases the plating rate of the electroplating bath. The terms "suppressors" and "suppressing agents" are used interchangeably throughout this specification. "Leveler" refers to an organic compound that is capable of providing a substantially planar copper layer. The terms "levelers", "leveling agents" and "leveling additive" are used interchangeably throughout this specification. As used herein, "acylation" means a substitution by an acyl group, e.g. CH<NUM>C(O)-. As used herein "polymer" means any compound comprising at least two monomeric units i.e. the term polymer includes dimers, trimers, etc., oligomers as well as high molecular weight polymers.

The present invention provides a plated copper layer, on a substrate containing features on the nanometer and/or micrometer scale wherein the copper layer has reduced overplating and all features are substantially free of added voids, and preferably substantially free of voids. "Overplating" refers to a thicker copper deposit over dense feature areas as compared to areas free of features or at least containing relatively few features. "Dense feature areas" means an area exhibiting smaller distances between neighboring features compared to a comparative area containing apertures with a relatively large distance in between. Smaller distances means distances below <NUM> micrometer, and preferably below <NUM> micrometer, and even more preferably below <NUM>. Such difference in the plating thickness over dense feature areas as compared to the plating thickness over areas free of features or containing relatively few features is referred to as "step height" or "mounding".

Suitable substrates are any used in the manufacture of electronic devices, such as integrated circuits. Such substrates typically contain a number of features, particularly apertures, having a variety of sizes. Particularly suitable substrates are those having apertures on the nanometer and on the micrometer scale.

The present invention is achieved by combining one or more additives capable of providing a substantially planar copper layer and filling features on the nanometer and on the micrometer scale without substantially forming defects, such as but not limited to voids, with a copper electroplating bath.

Suitable additives are polyaminoamides, alkoxylated polyaminoamides, functionalized polyaminoamides, or functionalized alkoxylated polyaminoamides or particular derivatives thereof.

Polyaminoamides are known to be polymers whose backbone chain contains both amino functionalities (NH) and amide functionalities (NH-C(O)). They are obtainable by reacting polyalkylenepolyamines with dicarboxylic acids, preferably in a molar ratio of <NUM>:<NUM> to <NUM>:<NUM>. In general polyaminoamides are linear or branched. Linear polyaminoamides are preferred. Polyaminoamides may be polymers of the formula I as defined above.

Polyalkylenepolyamines are to be understood as meaning compounds which consist of a saturated hydrocarbon chain with terminal amino functions which is interrupted by at least one secondary amino group. Suitable polyalkylenepolyamines include but are not limited to diethylenetriamine, triethylenetetramine, tetraethylenpentamine, pentaethylenehexamine, diaminopropylethylenediamine (=N,N'-bis(<NUM>-aminopropyl)-<NUM>,<NUM>-diaminoethane)-, ethylenepropylenetriamine, <NUM>-(<NUM>-aminoethyl)aminopropylamine, dipropylenetriamine, and polyethyleneimines with molar masses of preferably <NUM> to <NUM>, in particular from <NUM> to <NUM><NUM>, and mixtures thereof. Preference is given to poly-C <NUM>-C <NUM>-alkyleneamines with <NUM> to <NUM> nitrogen atoms. Of these, particular preference is given to diethylenetriamine, <NUM>-(<NUM>-aminoethyl)aminopropylamine, dipropylenetriamine, diaminopropylethylenediamine, and mixtures thereof.

Suitable dicarboxylic acids are, in particular, those with <NUM> to <NUM> carbon atoms, such as oxalic acid, malonic acid, succinic acid, tartaric acid, maleic acid, itaconic acid, glutaric acid, adipic acid, suberic acid, sebacic acid, phthalic acid and terephthalic acid, and mixtures thereof. Also suitable are dibasic amino acids, such as iminodiacetic acid, aspartic acid and glutamic acid. Preferred acids are adipic acid, glutaric acid, aspartic acid, iminodiacetic acid, and mixtures thereof.

The dicarboxylic acids can be used in the form of the free acids or as carboxylic acid derivatives, such as anhydrides, esters, amides or acid halides, in particular chlorides. Examples of such derivatives are anhydrides, such as maleic anhydride, succinic anhydride, phthalic anhydride and itaconic anhydride; adipic dichloride; esters with, preferably, C <NUM>-C <NUM>-alcohols, such as dimethyl adipate, diethyl adipate, dimethyl tartrate and dimethyl iminodiacetate; amides, such as adipic acid diamide, adipic acid monoamide and glutaric acid diamide. Preference is given to using the free carboxylic acids or the carboxylic anhydrides.

The polycondensation of the polyamine and of the dicarboxylic acid usually takes place by heating the polyamine and the dicarboxylic acid, e.g. to temperatures of from <NUM> to <NUM> degrees C. , preferably <NUM> to <NUM> degrees C, and distilling off the water of reaction which forms in the condensation. If said carboxylic acid derivatives are used, the condensation can also be carried out at temperatures lower than those given. The preparation of the polyaminoamides can be carried out without the addition of a catalyst, or else with the use of an acidic or basic catalyst. Suitable acidic catalysts are, for example, acids, such as Lewis acids, e.g. sulfuric acid, p-toluenesulfonic acid, phosphorous acid, hypophosphorous acid, phosphoric acid, methanesulfonic acid, boric acid, aluminum chloride, boron trifluoride, tetraethyl orthotitanate, tin dioxide, tin butyldilaurate or mixtures thereof. Suitable basic catalysts are, for example, alkoxides, such as sodium methoxide or sodium ethoxide, alkali metal hydroxides, such as potassium hydroxide, sodium hydroxide or lithium hydroxide, alkaline earth metal oxides, such as magnesium oxide or calcium oxide, alkali metal and alkaline earth metal carbonates, such as sodium, potassium and calcium carbonate, phosphates, such as potassium phosphate and complex metal hydrides, such as sodium borohydride. Where used, the catalyst is generally used in an amount of from <NUM> to <NUM>% by weight, preferably <NUM> to <NUM>% by weight, based on the total amount of the starting materials.

The reaction can be carried out in a suitable solvent or preferably in the absence of a solvent. If a solvent is used, suitable examples are hydrocarbons, such as toluene or xylene, nitriles, such as acetonitrile, amides, such as N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, ethers, such as diethylene glycol dimethyl ether, ethylene glycol dimethyl ether, ethylene carbonate, and propylene carbonate.

The solvent is generally distilled off during the reaction or when the reaction is complete. This distillation can optionally be carried out under a protective gas, such as nitrogen or argon.

The (Poly)alkoxylated polyaminoamides containing polyether side chains, which are attached to the amino nitrogen atoms of the polymer backbone and, if present, to the amino nitrogen atoms of the end-groups of the polymer, are known e.g. from <CIT>, <CIT>, <CIT>, <CIT> and <CIT>.

(Poly)alkoxylated polyaminoamides are polymers wherein at least part of R<NUM> is -(CR<NUM> R<NUM>-CR<NUM>R<NUM>-O)q-H, with R<NUM>, R<NUM>, R<NUM>, and R<NUM>, for each repeating unit <NUM> to q independently, being selected from hydrogen, C<NUM>-C<NUM>-alkyl, CH<NUM>-O-alkyl, such as CH<NUM>-O-tert-Bu, or CH<NUM>-O-aryl, such as CH<NUM>-O-phenyl, and q is as defined above. R<NUM>, R<NUM>, and R<NUM> are preferably hydrogen and R<NUM> is preferably hydrogen or methyl.

The (Poly)alkoxylated polyaminoamides can be obtained by (poly)alkoxylating polyaminoamides with C<NUM>- to C<NUM>-alkylene oxides, styrene oxide, or glycidyl ethers with the proviso that the average degree of (poly)alkoxylation is from <NUM> to <NUM> per secondary amino group and - where present - <NUM> to <NUM> per primary amino group. In this reaction, alkoxylated side chains form on all or some of the amino groups of the polyaminoamides. The average value q is determined according to the molar amount of epoxide, based on the amine nitrogen atoms within the polyaminoamide which are available.

It is possible to use C<NUM>- to C<NUM>-alkylene oxides, styrene oxide, or glycidyl ethers such as glycidyl tert-butyl ether. Examples of corresponding alkylene oxides comprise ethylene oxide and propylene oxide and also <NUM>-butene oxide, <NUM>,<NUM>-butene oxide, <NUM>-methyl-<NUM>,<NUM>-propene oxide (isobutene oxide), <NUM>-pentene oxide, <NUM>,<NUM>-pentene oxide, <NUM>-methyl-<NUM>,<NUM>-butene oxide, <NUM>-methyl-<NUM>,<NUM>-butene oxide, <NUM>,<NUM>-hexene oxide, <NUM>,<NUM>-hexene oxide, <NUM>-methyl-<NUM>,<NUM>-pentene oxide, <NUM>-ethyl-<NUM>,<NUM>-butene oxide, <NUM>-methyl-<NUM>,<NUM>-pentene oxide, decene oxide, <NUM>-methyl-<NUM>,<NUM>-pentene oxide or styrene oxide.

Preference is given to using ethylene oxide and/or propylene oxide and/ or butylene oxide. Higher alkylene oxides are generally used, at most, in small amounts for fine adjustment of the properties. In general, the amount of ethylene oxide and/or propylene oxide and/ or butylene oxide is at least <NUM>% by weight, preferably <NUM>% by weight and more preferably <NUM>% by weight based on the sum of all alkylene oxides used.

The average degree of alkoxylation is from <NUM> to <NUM>, more preferably from <NUM> to <NUM>, most preferably from <NUM> to <NUM> and, for example, <NUM> to <NUM> oxyalkylene units per secondary amino group. The average degree of alkoxylation per terminal primary amino group is from <NUM> to <NUM>, more preferably from <NUM> to <NUM>, most preferably from <NUM> to <NUM> and, for example <NUM> to <NUM> oxyalkylene units.

When two or more different alkylene oxides are used, the polyoxyalkylene groups formed may be random copolymers, gradient copolymers, block copolymers or alternating copolymers.

The synthesis of alkylene oxide units is known to those skilled in the art. Comprehensive details are given, for example, in "<NPL>.

When q is from <NUM> to <NUM> preference is given to undertaking the alkoxylation in the presence of water being used as a catalyst. For q greater <NUM> preference is given to undertaking the alkoxylation in the presence of a customary basic catalyst, for example alkali metal hydroxides, preferably potassium hydroxide, or alkali metal alkoxides, for example, sodium methoxide or potassium tert-butylate. In addition, it is also possible to use double metal cyanide catalysts (DMC catalysts). Suitable DMC catalysts are disclosed, for example, in <CIT>, especially paragraphs [<NUM>] to [<NUM>] and the literature cited therein. The alkoxylation can be undertaken, in a manner known in principle, in a pressure reactor at from <NUM> to <NUM> degree C, preferably from <NUM> to <NUM> degree C and more preferably from <NUM> to <NUM> degree C. For the correct metered addition of the alkylene oxides, it is advisable, before the alkoxylation, to determine the number (secondary) amine groups of the polyaminoamide.

The (poly)alkoxylated polyaminoamides can optionally be functionalized in a further reaction step. An additional functionalization can serve to modify the properties of the alkoxylated polyaminoamides. To this end, the hydroxyl groups and/or amino groups present in the alkoxylated polyaminoamides are converted by means of suitable agents which are capable of reaction with hydroxyl groups and/or amino groups. This forms functionalized alkoxylated polyaminoamides.

For example, the amino groups present in the alkoxylated polyaminoamide can be protonated or functionalized by means of suitable alkylating agents.

Examples for suitable alkylating agents are organic compounds which contain active halogen atoms, such as the aralkyl halides, the alkyl, alkenyl and alkynyl halides.

Additionally, compounds such as the alkyl sulfates, alkyl sultones, epoxides, alkyl suphites, dialkyl carbonates, methyl formiate may also be used Examples of corresponding alkylating agents comprise benzyl chloride, propane sultone, dimethyl sulphate, dimethyl sulphite, dimethyl carbonate, (<NUM>-chloro-<NUM>-hydroxypropyl)trimethylammonium chloride.

Preference is given to using dimethyl sulphate and/or benzyl chloride.

The terminal hydroxyl groups of the alkoxylated polyaminoamide can be reacted with suitable reagents for derivatization, which forms groups of the general formula - (alkoxy)q-Y where X is any desired group. The type of functionalization depends on the desired end use. According to the functionalizing agent, the chain end can be hydrophobized or more strongly hydrophilized.

The terminal hydroxyl groups can be esterified, for example, with sulfuric acid or derivatives thereof, so as to form products with terminal sulfate groups. Analogously, products having terminal phosphorus groups can be obtained with phosphoric acid, phosphorous acid, polyphosphoric acid, POCl<NUM> or P<NUM>O<NUM>.

In addition, the terminal OH groups may also be etherified, so as to form ether-terminated polyalkoxy groups of the general formula -(alkoxy)n-O-R<NUM>, where R<NUM> is an alkyl, alkenyl, alkynyl, alkaryl, or aryl group.

It will be appreciated by those skilled in the art that more than one leveling agent may be used. When two or more leveling agents are used, at least one of the leveling agents is a polyaminoamide or a derivative thereof as described herein. It is preferred to use only one polyaminoamide leveling agent in the plating composition.

Suitable additional leveling agents include, but are not limited to, one or more of polyalkanolamine and derivatives thereof, polyethylene imine and derivatives thereof, quaternized polyethylene imine, polyglycine, poly(allylamine), polyaniline, polyurea, polyacrylamide, poly(melamine-co-formaldehyde), reaction products of amines with epichlorohydrin, reaction products of an amine, epichlorohydrin, and polyalkylene oxide, reaction products of an amine with a polyepoxide, polyvinylpyridine, polyvinyl imidazole, polyvinylpyrrolidone, or copolymers thereof, nigrosines, pentamethyl-para-rosaniline hydrohalide, hexamethyl-pararosaniline hydrohalide, or compounds containing a functional group of the formula N-R-S, where R is a substituted alkyl, unsubstituted alkyl, substituted aryl or unsubstituted aryl. Typically, the alkyl groups are (C1-C6)alkyl and preferably (C1-C4)alkyl. In general, the aryl groups include (C6-C20)aryl, preferably (C6-C10)aryl. Such aryl groups may further include heteroatoms, such as sulfur, nitrogen and oxygen. It is preferred that the aryl group is phenyl or napthyl. The compounds containing a functional group of the formula N-R-S are generally known, are generally commercially available and may be used without further purification.

In such compounds containing the N-R-S functional group, the sulfur ("S") and/or the nitrogen ("N") may be attached to such compounds with single or double bonds. When the sulfur is attached to such compounds with. a single bond, the sulfur will have another substituent group, such as but not limited to hydrogen, (C1-C12)alkyl, (C2-C12)alkenyl, (C6-C20)aryl, (C1-C12)alkylthio, (C2-C12)alkenylthio, (C6-C20)arylthio. Likewise, the nitrogen will have one or more substituent groups, such as but not limited to hydrogen, (C1-C12)alkyl, (C2-C12)alkenyl, and (C7-C10)aryl.

The N-R-S functional group may be acyclic or cyclic. Compounds containing cyclic N-R-S functional groups include those having either the nitrogen or the sulfur or both the nitrogen and the sulfur within the ring system.

In general, the total amount of leveling agents in the electroplating bath is from <NUM> ppm to <NUM> ppm based on the total weight of the plating bath. The leveling agents according to the present invention are typically used in a total amount of from <NUM> ppm to <NUM> ppm based on the total weight of the plating bath and more typically from <NUM> to <NUM> ppm, although greater or lesser amounts may be used.

The electroplating baths according to the present invention may include one or more optional additives. Such optional additives include, but are not limited to, accelerators, suppressors, and surfactants.

Such suppressors and accelerators are generally known in the art. It will be clear to one skilled in the art which suppressors and/or accelerators to use and in what amounts.

A large variety of additives may typically be used in the bath to provide desired surface finishes for the Cu plated metal. Usually more than one additive is used with each additive forming a desired function. Advantageously, the electroplating baths may contain one or more of accelerators, suppressors, sources of halide ions, grain refiners and mixtures thereof. Most preferably the electroplating bath contains both, an accelerator and a suppressor in addition to the leveling agent according to the present invention. Other additives may also be suitably used in the present electroplating baths.

Any accelerators may be advantageously used in the present invention. Accelerators useful in the present invention include, but are not limited to, compounds comprising one or more sulphur atom and a sulfonic/phosphonic acid or their salts.

The generally preferred accelerators have the general structure MAO<NUM>XA-RA1-(S)a-RA2, with:.

More specifically, useful accelerators include those of the following formulae:.

with RA1 as defined above and Ar is Aryl.

Particularly prefered accelerating agents are:.

Other examples of accelerators, used alone or in mixture, include, but are not limited to: MES (<NUM>-Mercaptoethanesulfonic acid, sodium salt); DPS (N,N-dimethyldithiocarbamic acid (<NUM>-sulfopropylester), sodium salt); UPS (<NUM>-[(amino-iminomethyl)-thio]-<NUM>-propylsulfonic acid); ZPS (<NUM>-(<NUM>-benzthiazolylthio)-<NUM>-propanesulfonic acid, sodium salt); <NUM>-mercapto-propylsulfonicacid-(<NUM>-sulfopropyl)ester; methyl-(w-sulphopropyl)-disulfide, disodium salt; methyl-(w-sulphopropyl)-trisulfide, disodium salt.

Such accelerators are typically used in an amount of <NUM> ppm to <NUM> ppm, based on the total weight of the plating bath. Particularly suitable amounts of accelerator useful in the present invention are <NUM> to <NUM> ppm, and more particularly <NUM> to <NUM> ppm.

Any suppressor may be advantageously used in the present invention. Suppressors useful in the present invention include, but are not limited to, polymeric materials, particularly those having heteroatom substitution, and more particularly oxygen substitution. It is preferred that the suppressor is a polyalkyleneoxide. Suitable suppressors include polyethylene glycol copolymers, particularly polyethylene glycol polypropylene glycol copolymers. The arrangement of ethylene oxide and propylene oxide of suitable suppressors may be block, gradient, or random. The polyalkylene glycol may comprise further alkylene oxide building blocks such as butylene oxide. Preferably, the average molecular weight of suitable suppressors exceeds <NUM>/mol. The starting molecules of suitable polyalkylene glycol may be alkyl alcohols such as methanol, ethanol, propanol, n-butanol, aryl alcohols such as phenols and bisphenols, alkaryl alcohols such as benzyl alcohol, polyol starters such as glycol, glycerin, trimethylol propane, pentaerythritol, sorbitol, carbohydrates such as saccharose, amines and oligoamines such as alkyl amines, aryl amines such as aniline, triethanol amine, ethylene diamine, amides, lactams heterocyclic amines such as imidazol and carboxylic acids. Optionally, polyalkylene glycol suppressors may be functionalized by ionic groups such as sulfate, sulfonate, and ammonium.

Particularly useful suppressing agents in combination with the levelers according to the present inventions are:.

Preferably spacer groups XS and YS are independently, and XS for each repeating unit independently, selected from C2 to C4 alkylene. Most preferably XS and YS are independently, and XS for each repeating unit independently, selected from ethylene (-C<NUM>H<NUM>-) or propylene (-C<NUM>H<NUM>-).

Preferably ZS is selected from C2 to C4 alkylene, most preferably from ethylene or propylene.

Preferably s is an integer from <NUM> to <NUM>, more preferably from <NUM> to <NUM>, most preferably from <NUM> to <NUM>. Preferably t is an integer from <NUM> to <NUM>, more preferably from <NUM> to <NUM>, most preferably from <NUM> to <NUM>.

In another preferred embodiment the C3 to C4 alkylene oxide is selected from propylene oxide (PO). In this case EO/PO copolymer side chains are generated starting from the active amino functional groups.

The content of ethylene oxide in the copolymer of ethylene oxide and the further C3 to C4 alkylene oxide can generally be from <NUM> % by weight to <NUM> % by weight preferably from <NUM> % by weight to <NUM> % by weight, particularly preferably between <NUM> % by weight to <NUM> % by weight.

The compounds of formula (S1) are prepared by reacting an amine compound with one ore more alkylene oxides. Preferably the amine compound is selected from ethylene diamine, <NUM>,<NUM>-diaminopropane, <NUM>,<NUM>-diaminobutane, <NUM>,<NUM>-diaminopentane, <NUM>,<NUM>-diaminohexane, neopentanediamine, isophoronediamine, <NUM>,<NUM>-dioxadecane-<NUM>,<NUM>-diamine, <NUM>,<NUM>,<NUM>-trioxatridecane-<NUM>,<NUM>-diamine, triethylene glycol diamine, diethylene triamine, (<NUM>-(<NUM>-aminoethyl)amino)propylamine, <NUM>,<NUM>'-iminodi(propylamine), N,N-bis(<NUM>-aminopropyl)methylamine, bis(<NUM>-dimethylaminopropyl)amine, triethylenetetraamine and N, N '-bis(<NUM>-aminopropyl)ethylenediamine.

The molecular weight Mw of the suppressing agent of formula S1 may be between <NUM>/mol to <NUM>/mol. Preferably the molecular weight Mw should be <NUM>/mol or more, preferably from <NUM>/mol to <NUM>/mol more preferably from <NUM>/mol to <NUM>/mol, and most preferably from <NUM>/mol to <NUM>/mol. Preferred total amounts of alkylene oxide units in the suppressing agent may be from <NUM> to <NUM>, preferably from <NUM> to <NUM>, most preferably from <NUM> to <NUM>.

Typical total amounts of alkylene oxide units in the suppressing agent may be <NUM> ethylene oxide units (EO) and <NUM> propylene oxide units (PO), <NUM> EO and <NUM> PO, <NUM> EO and <NUM> PO, <NUM> EO and <NUM> PO, <NUM> EO and <NUM> PO <NUM> EO and <NUM> PO, <NUM> EO and <NUM> PO, <NUM> EO and <NUM> PO, <NUM> EO and <NUM> PO, <NUM> EO and <NUM> butylene oxide (BuO) units, <NUM> EO and <NUM> BO, <NUM> EO and <NUM> BO, <NUM> EO and <NUM> BO, <NUM> EO and <NUM> BO or <NUM> EO and <NUM> BO to <NUM> EO and <NUM> PO units, <NUM> EO and <NUM> PO <NUM> EO and <NUM> PO, <NUM> EO and <NUM> PO, <NUM> EO and <NUM> PO <NUM> EO and <NUM> PO, <NUM> EO and <NUM> PO, <NUM> EO and <NUM> PO <NUM> EO and <NUM> PO, <NUM> EO and <NUM> butylene oxide (BuO) units, <NUM> EO and <NUM> BO, <NUM> EO and <NUM> BO, <NUM> EO and <NUM> BO, <NUM> EO and <NUM> BO, or <NUM> EO and <NUM> BO. (e) Suppressing agent obtainable by reacting a polyhydric alcohol condensate compound derived from at least one polyalcohol of formula (S2) XS(OH)u by condensation with at least one alkylene oxide to form a polyhydric alcohol condensate comprising polyoxyalkylene side chains, wherein u is an integer from <NUM> to <NUM> and XS is an u-valent linear or branched aliphatic or cycloaliphatic radical having from <NUM> to <NUM> carbon atoms, which may be substituted or unsubstituted, as described in <CIT>.

Preferred polyalcohol condensates are selected from compounds of formulae
<CHM>
<CHM>
<CHM>
wherein YS is an u-valent linear or branched aliphatic or cycloaliphatic radical having from <NUM> to <NUM> carbon atoms, which may be substituted or unsubstituted, a is an integer from <NUM> to <NUM>, b may be the same or different for each polymer arm u and is an integer from <NUM> to <NUM>, c is an integer from <NUM> to <NUM>, and n is an integer from <NUM> to <NUM>. Most preferred Polyalcohols are glycerol condensates and/or pentaerythritol condensates. (f) Suppressing agent obtainable by reacting a polyhydric alcohol comprising at least <NUM> hydroxyl functional groups with at least one alkylene oxide to form a polyhydric alcohol comprising polyoxyalkylene side chains as described in <CIT>. Preferred polyalcohols are linear or cyclic monosaccharide alcohols represented by formula (S3a) or (S3b).

wherein v is an integer from <NUM> to <NUM> and w is an integer form <NUM> to <NUM>. Most preferred monosaccharide alcohols are sorbitol, mannitol, xylitol, ribitol and inositol. Further preferred polyalcohols are monosaccharides of formula (S4a) or (S4b).

CH<NUM>OH-(CHOHy-CO-(CHOH)z-CH<NUM>OH     (S4b).

wherein x is an integer of <NUM> to <NUM>, and y, z are integers and y + z is <NUM> or <NUM>. Most preferred monosaccharide alcohols are selected from the aldoses allose, altrose, galactose, glucose, gulose, idose, mannose, talose, glucoheptose, mannoheptose or the ketoses fructose, psicose, sorbose, tagatose, mannoheptulose, sedoheptulose, taloheptulose, alloheptulose.

These are particularly effective, strong suppressing agents that cope with the seed overhang issue and provide substantially defect free trench filling despite a non-conformal copper seed.

When suppressors are used, they are typically present in an amount in the range of from <NUM> to <NUM>,<NUM> ppm based on the weight of the bath, and preferably from <NUM> to <NUM>,<NUM> ppm.

The copper ion source may be any compound capable of releasing copper ions to be deposited in the electroplating bath in sufficient amount, i. e is at least partially soluble in the electroplating bath. It is preferred that the copper ion source is soluble in the plating bath. Suitable copper ion sources are copper salts and include, but are not limited to, copper sulfates, copper halides, copper acetates, copper nitrates, copper fluoroborates, copper alkylsulfonates, copper arylsulfonates, copper sulfamates, copper gluconates.

It is preferred that the source of copper ions is copper sulfate, copper chloride, copper acetate, copper citrate, copper nitrate, copper fluoroborate, copper methane sulfonate, copper phenyl sulfonate and copper p-toluene sulfonate. Copper sulfate pentahydrate and copper methane sulfonate are particularly preferred. Such copper salts are generally commercially available and may be used without further purification.

Besides copper electroplating the compositions may be used in electroless deposition of copper containing layers.

The copper ion source may be used in the present invention in any amount that provides sufficient copper ions for electroplating on a substrate. The copper salt is typically present in an amount in the range of from <NUM> to <NUM>/l of plating solution. It will be appreciated mixtures of copper salts may be electroplated according to the present invention. Thus, alloys, such as copper-tin having up to <NUM> percent by weight tin, may be advantageously plated according to the present invention. The amounts of each of the metal salts in such mixtures depend upon the particular alloy to be plated and is well known to those skilled in the art.

In general, besides the copper ion source and at least one of the leveling agents (S2) to (S4), further referred to as polyalkanolamines, the present copper electroplating compositions preferably include electrolyte, i. acidic or alkaline electrolyte, one or more sources of copper ions, optionally halide ions, and optionally other additives like accelerators and/or suppressors. Such baths are typically aqueous. The water may be present in a wide range of amounts. Any type of water may be used, such as distilled, deionized or tap.

The electroplating baths of the present invention may be prepared by combining the components in any order. It is preferred that the inorganic components such as copper salts, water, electrolyte and optional halide ion source, are first added to the bath vessel followed by the organic components such as leveling agents, accelerators, suppressors, and surfactants.

Typically, the plating baths of the present invention may be used at any temperature from <NUM> to <NUM> degrees C or higher. It is preferred that the temperature of the plating baths is from <NUM> to <NUM> degrees C and more preferably from <NUM> degrees to <NUM> degrees C.

Suitable electrolytes include such as, but not limited to, sulfuric acid, acetic acid, fluoroboric acid, alkylsulfonic acids such as methanesulfonic acid, ethanesulfonic acid, propanesulfonic acid and trifluoromethane sulfonic acid, arylsulfonic acids such as phenyl sulfonic acid and toluenesulfonic acid, sulfamic acid, hydrochloric acid, phosphoric acid, tetraalkylammonium hydroxide, preferably tetramethylammonium hydroxide, sodium hydroxide, potassium hydroxide.

Acids are typically present in an amount in the range of from <NUM> to <NUM>/L, alkaline electrolytes are typically present in an amount of <NUM> to <NUM>/L or to yield a pH of <NUM> to <NUM> respectively, and more typically to yield a pH of <NUM> to <NUM>.

Such electrolytes may optionally contain a source of halide ions, such as chloride ions as in copper chloride or hydrochloric acid. A wide range of halide ion concentrations may be used in the present invention such as from <NUM> to <NUM> ppm Typically, the halide ion concentration is in the range of from <NUM> to <NUM> ppm based on the plating bath. It is preferred that the electrolyte is sulfuric acid or methanesulfonic acid, and preferably a mixture of sulfuric acid or methanesulfonic acid and a source of chloride ions. The acids and sources of halide ions useful in the present invention are generally commercially available and may be used without further purification.

A particular advantage of the present invention is that overplating, particularly mounding, is reduced or substantially eliminated. Such reduced overplating means less time and effort is spent in removing copper, during subsequent chemical-mechanical planarization (CMP) processes, particularly in semiconductor manufacture. A further advantage of the present invention is that a wide range of aperture sizes may be filled within a single substrate resulting in a substantially even surface having a ratio a/b of <NUM> or less, preferably <NUM> or less, most preferably <NUM> or less. Thus, the present invention is particularly suitable to evenly filling apertures in a substrate having a variety of aperture sizes, such as from <NUM> micrometer to <NUM> micrometer or even larger.

A further significant advantage of this leveling effect is that less material has to be removed in post-deposition operations. For example, chemical mechanical planarization (CMP) is used to reveal the underlying features. The more level deposit of the invention corresponds to a reduction in the amount of copper which must be deposited, therefore resulting in less removal later by CMP. There is a reduction in the amount of scrapped copper and, more significantly, a reduction in the time required for the CMP operation. The material removal operation is also less severe which, coupled with the reduced duration, corresponds to a reduction in the tendency of the material removal operation to impart defects.

Copper, is deposited in apertures according to the present invention without substantially forming voids within the copperdeposit. By the term "without substantially forming voids", it is meant that <NUM> % of the plated apertures are void-free. It is preferred that the plated apertures are void-free.

Typically, substrates are electroplated by contacting the substrate with the plating baths of the present invention. The substrate typically functions as the cathode. The plating bath contains an anode, which may be soluble or insoluble. Optionally, cathode and anode may be separated by a membrane. Potential is typically applied to the cathode. Sufficient current density is applied and plating performed for a period of time sufficient to deposit a copper layer, having a desired thickness on the substrate. Suitable current densities, include, but are not limited to, the range of <NUM> to <NUM> mA/cm<NUM>. Typically, the current density is in the range of <NUM> to <NUM> mA/cm<NUM> when used to deposit copper in the manufacture of integrated circuits. The specific current density depends upon the substrate to be plated, the leveling agent selected and the like. Such current density choice is within the abilities of those skilled in the art. The applied current may be a direct current (DC), a pulse current (PC), a pulse reverse current (PRC) or other suitable current.

In general, when the present invention is used to deposit copper on a substrate such as a wafer used in the manufacture of an integrated circuit, the plating baths are agitated during use. Any suitable agitation method may be used with the present invention and such methods are well-known in the art. Suitable agitation methods include, but are not limited to, inert gas or air sparging, work piece agitation, impingement and the like. Such methods are known to those skilled in the art. When the present invention is used to plate an integrated circuit substrate, such as a wafer, the wafer may be rotated such as from <NUM> to <NUM> RPM and the plating solution contacts the rotating wafer, such as by pumping or spraying. In the alternative, the wafer need not be rotated where the flow of the plating bath is sufficient to provide the desired copper deposit.

Copper, is deposited in apertures according to the present invention without substantially forming voids within the copper deposit. By the term "without substantially forming voids", it is meant that <NUM>% of the plated apertures are void-free. It is preferred that the plated apertures are void-free.

While the process of the present invention has been generally described with reference to semiconductor manufacture, it will be appreciated that the present invention may be useful in any electrolytic process where an essentially level or planar copper deposit having high reflectivity is desired, and where reduced overplating and copper filled small features that are substantially free of voids are desired. Such processes include printed wiring board manufacture. For example, the present plating baths may be useful for the plating of vias, pads or traces on a printed wiring board, as well as for bump plating on wafers. Other suitable processes include packaging and interconnect manufacture. Accordingly, suitable substrates include lead frames, interconnects, printed wiring boards.

Plating equipment for plating semiconductor substrates are well known. Plating equipment comprises an electroplating tank which holds Cu electrolyte and which is made of a suitable material such as plastic or other material inert to the electrolytic plating solution. The tank may be cylindrical, especially for wafer plating. A cathode is horizontally disposed at the upper part of tank and may be any type substrate such as a silicon wafer having openings such as trenches and vias. The wafer substrate is typically coated with a seed layer of Cu or other metal to initiate plating thereon. A Cu seed layer may be applied by chemical vapor deposition (CVD), physical vapor deposition (PVD), or the like. An anode is also preferably circular for wafer plating and is horizontally disposed at the lower part of tank forming a space between the anode and cathode. The anode is typically a soluble anode.

These bath additives are useful in combination with membrane technology being developed by various tool manufacturers. In this system, the anode may be isolated from the organic bath additives by a membrane. The purpose of the separation of the anode and the organic bath additives is to minimize the oxidation of the organic bath additives.

The cathode substrate and anode are electrically connected by wiring and, respectively, to a rectifier (power supply). The cathode substrate for direct or pulse current has a net negative charge so that Cu ions in the solution are reduced at the cathode substrate forming plated Cu metal on the cathode surface. An oxidation reaction takes place at the anode. The cathode and anode may be horizontally or vertically disposed in the tank.

The present invention is useful for depositing a copper layer, on a variety of substrates, particularly those having variously sized apertures. For example, the present invention is particularly suitable for depositing copper on integrated circuit substrates, such as semiconductor devices, with small diameter vias, trenches or other apertures. 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.

While the process of the present invention has been generally described with reference to semiconductor manufacture, it will be appreciated that the present invention may be useful in any electrolytic process where an essentially level or planar copper deposit having high reflectivity is desired. Accordingly, suitable substrates include lead frames, interconnects, printed wiring boards.

All percent, ppm or comparable values refer to the weight with respect to the total weight of the respective composition except where otherwise indicated.

The following examples shall further illustrate the present invention without restricting the scope of this invention.

The amine number was determined according to DIN <NUM> by titration of a solution of the polymer in acetic acid with perchloric acid.

The acid number was determined according to DIN <NUM> by titration of a solution of the polymer in water with aqueous sodium hydroxide solution.

The molecular weight (Mw) was determined by size exclusion chromatography using hexafluoroisopropanol containing <NUM> % potassium trifluoroacetat as eluent, hexafluoroisopropanol-packed (HFIP) gel columns as stationary phase and polymethylmethacrylate (PMMA) standards for determination of the molecular weights.

Diethylenetriamine (<NUM>, <NUM> mol) was introduced into a <NUM> I apparatus and stirred under a constant nitrogen stream. Water (<NUM>) was added resulting in a temperature increase up to <NUM> degree C. The solution was heated to <NUM> and adipic acid was added in portions during <NUM>. During this time the temperature increased up to <NUM> degree C. Then the reaction mixture was stirred for <NUM> at <NUM> degree C, the color turning into orange. Subsequently, the temperature was increased to <NUM> degree C and water and traces of diethylenetriamine were destilled off for <NUM>. Then the nitrogen stream was intensified to remove residual traces of water. The resulting distillate (<NUM>) showed an amine number of <NUM> mmol/g, indicating a <NUM> diethylenetriamine content in the distillate. The heating was turned off and when the temperature reached <NUM> degree C, water (<NUM>) was added slowly resulting in a temperature drop to <NUM> degree C. After cooling to room temperature, again water (<NUM>) was added, resulting in a yellow-green solution of polyaminoamide (<NUM>). The aqueous solution of the polyaminoamide showed a water content of <NUM>% according to Karl-Fischer-titration, an amine number of <NUM> mmol/g and an acid number of <NUM> mmol/g. Gel permeation chromatography revealed an average molecular weight of Mw = <NUM>/mol and a polydispersity of Mw/Mn = <NUM>.

The aqueous solution of polyaminoamide from example <NUM> (<NUM>; water content according to Karl-Fischer-titration: <NUM>%) was placed into a <NUM> autoclave and heated at <NUM> degree C under nitrogen at <NUM> bar. Ethylene oxide (<NUM>, <NUM> mol) was added in portions at <NUM> degree C over a period of <NUM>. To complete the reaction, the mixture was allowed to post-react overnight. The reaction mixture was stripped with nitrogen. Alkoxylated polyaminoamide was obtained as an aqueous solution showing a water content of <NUM>% and an amine number of <NUM> mmol/g.

The aqueous solution of polyaminoamide from example <NUM> (<NUM>; water content according to Karl-Fischer-titration: <NUM>%) was placed into a <NUM> autoclave and heated at <NUM> degree C under nitrogen at <NUM> bar. Propylene oxide (<NUM>, <NUM> mol) was added in portions at <NUM> degree C over a period of <NUM>. To complete the reaction, the mixture was allowed to post-react overnight. The reaction mixture was stripped with nitrogen. Alkoxylated polyaminoamide was obtained as an aqueous solution showing a water content of <NUM>% and an amine number of <NUM> mmol/g.

N,N'-bis(<NUM>-aminopropyl)-<NUM>,<NUM>-diaminoethane (<NUM>, <NUM> mol) was introduced into a <NUM> apparatus and heated to <NUM> degree C under a constant nitrogen stream. A solution of adipic acid (<NUM>, <NUM> mol) and N,N'-bis(<NUM>-aminopropyl)-<NUM>,<NUM>-diaminoethane (<NUM>, <NUM> mol) in water (<NUM>) was added dropwise. Then the reaction mixture was stirred for <NUM> at <NUM> degree C. Subsequently, the temperature was increased to <NUM> degree C and water (<NUM>) was destilled off for <NUM>. The heating was turned off and when the temperature reached <NUM> degree C, water (<NUM>) was added slowly. The aqueous solution of polyaminoamide showed a water content of <NUM>% according to Karl-Fischer-titration, an amine number of <NUM> mmol/g and an acid number of <NUM> mmol/g. Gel permeation chromatography revealed an average molecular weight of Mw = <NUM>/mol and a polydispersity of Mw/Mn = <NUM>.

The aqueous solution of polyaminoamide from example <NUM> (<NUM>; water content according to Karl-Fischer-titration: <NUM>%) and additional water (<NUM>) were placed into a <NUM> apparatus and dimethyl sulphate (<NUM>, <NUM> mmol) was added slowly by a syringe pump. When the temperature increased to <NUM> degree C the reaction mixture was cooled to room temperature again by an ice bath. The reaction mixture showed an amine number of <NUM> mmol/g, indicating incomplete quaternization of the amine atoms. Thus, an additional portion of dimethyl sulphate (<NUM>, <NUM> mmol) was added slowly. The resulting brown solution showed an amine number of <NUM> mmol/g, indicating complete quaternization of all amine atoms present in the polyaminoamide starting material. The aqueous solution of quaternized polyaminoamide showed a water content of <NUM>%.

After copper seed deposition the smaller trenches had a width of <NUM> to <NUM> nanometer at the trench opening, a width of <NUM> to <NUM> nanometer at half height of the trench, and were <NUM> nanometer deep. The trenches had a width of <NUM>.

A plating bath was prepared by combining DI water, <NUM>/l copper as copper sulfate, <NUM>/l sulfuric acid, <NUM>/l chloride ion as HCl, <NUM>/l of SPS and <NUM>/l of a <NUM> wt % solution in DI water of a EO/PO copolymer suppressor having a molecular weight Mw of below <NUM>/mole and terminal hydroxyl groups.

A copper layer was electroplated onto a wafer substrate with feature sizes provided with a copper seed layer by contacting the wafer substrate with the above described plating bath at <NUM> degrees C applying a direct current of -<NUM> mA/cm<NUM> for <NUM> and -<NUM> mA/cm<NUM> for <NUM> followed by -<NUM> mA/cm<NUM> for <NUM> respectively. The thus electroplated copper layer was cross-sectioned and investigated by SEM inspection.

SEM images of fully filled trenches did not exhibit any defects like voids or seams. Enhanced copper deposition above the fully filled trenches resulting in bump formation in contrast to the decreased copper deposition above the dielectric was abserved.

The procedure of example <NUM> was repeated except that <NUM>/l of a <NUM> % by weight aqueous solution of polyaminoamide from example <NUM> was added to the plating bath.

A copper layer was electroplated onto a wafer substrate as described in example <NUM>. The thus electroplated copper layer was cross-sectioned and investigated by SEM inspection.

The <NUM> to <NUM> nanometer wide trenches were completely filled without exhibiting any defects like voids or seams thus showing that there is not any interference in the gap filling by the leveling agent. A balanced Cu deposition above the trenches and the dielectric was observed.

The procedure of example <NUM> was repeated except that <NUM>/l of a <NUM> % by weight aqueous solution of the quaternized polyaminoamide from example <NUM> was added to the plating bath.

The <NUM> to <NUM> nanometer wide trenches were completely filled without exhibiting any defects like voids or seams thus showing that there is not any interference in the gap filling by the leveling agent.

A copper plating bath was prepared by combining <NUM>/l copper as copper sulfate, <NUM>/l sulfuric acid, <NUM>/l chloride ion as HCl, <NUM>/l of an EO/PO copolymer suppressor, and <NUM>/l of SPS and DI water. The EO/PO copolymer suppressor had a molecular weight of <<NUM>/mole and terminal hydroxyl groups.

A copper layer was electroplated onto a structured silicon wafer purchased from SKW Associate Inc. containing trenches. These trenches varied in width ranging from <NUM> to several microns with a depth of approximately <NUM> and a separation ranging from <NUM> to several micrometers. Such wafer substrates were brought into contact with the above described plating bath at <NUM> degrees C and a direct current of - <NUM> mA/cm2 for <NUM> followed by -<NUM> mA/cm2 for <NUM> was applied.

The thus electroplated copper layer was investigated by profilometry inspection with a Dektak <NUM>, Veeco Instruments Inc. In the case of <NUM> and <NUM> feature sizes a field of nested wires was scanned and the height difference between the unstructured and structured area was measured. In the case of the <NUM> micrometer trenches the profilometer P16+, KLA Tencor GmbH was used and the height difference between the trench and the ridge was measured. The mean values of the height differences were calculated of at least from <NUM> height differences.

A higher copper deposition rate on the structured area in contrast to the unstructured area was observed. This phenomenon is well known as mounding and is strongly pronounced over the <NUM> and <NUM> micrometer trenches. A significant groove depth, which is comparable to the non-plated substrate, was observed. The measured values for the <NUM> micrometer, <NUM> micrometer and <NUM> micrometer features are depicted in table <NUM>.

The procedure of example <NUM> was repeated except that <NUM>/l of a stock solution containing <NUM> % (w/w) of the active leveling agent of example <NUM> was added to the plating bath.

A copper layer was electroplated onto a wafer substrate as described in example <NUM>. The thus electroplated copper layer was investigated by profilometry as described in example <NUM>.

A cross-sectional scan of <NUM> micrometer features showed a significant reduction of the mounding compared to prior art. A noteworthy reduction of the groove depth compared to prior art was observed. The measured values are depicted in table <NUM>.

The values obtained from profilometry, as depicted in table <NUM>, show a significant reduction of the mounding as well as a reduction of the groove depth compared to example <NUM> without a leveling agent.

Claim 1:
A composition comprising a source of copper ions and at least one additive comprising at least one polyaminoamide represented by formula I
<CHM>
or derivatives of a polyaminoamide of formula I obtainable by complete or partial protonation or acylation,
wherein
D<NUM> is, for each repeating unit <NUM> to p independently, selected from a chemical bond or a divalent group selected from C<NUM>-C<NUM>-alkanediyl group which may optionally be interrupted by a double bond and/or an imino group and/or is optionally, completely or partially, a constituent of one or more saturated or unsaturated carbocyclic <NUM>- to <NUM>-membered rings,
D<NUM>, D<NUM> are independently selected from straight chain or branched C1 to C6 alkanediyl,
R<NUM> is R<NUM>,
R<NUM> is -(CR<NUM>R<NUM>-CR<NUM>R<NUM>-O)q-H or hydrogen,
R<NUM>, R<NUM>, R<NUM>, R<NUM> are each independently selected from hydrogen, C<NUM>-C<NUM>-alkyl, CH<NUM>-O-alkyl,
E<NUM>, E<NUM> are independently selected from
(a) a nucleophilically displaceable leaving group X,
(b) NH-C<NUM>-C<NUM>-alkyl or NH-C<NUM>-C<NUM>-alkenyl,
(c) H-{NH-[D<NUM>-NR<NUM>]n-D<NUM>-NH} or R<NUM>-{NR<NUM>-[D<NUM>-NR<NUM>]n-D<NUM>-NH},
(d) C<NUM>-C<NUM>-alkyl-CO-{NH-[D<NUM>-NR<NUM>]n-D<NUM>-NH}, and
(e) C<NUM>-C<NUM>-alkenyl-CO-{NH-[D<NUM>-NR<NUM>]n-D<NUM>-NH},
n is an integer from <NUM> to <NUM>,
p is an integer from <NUM> to <NUM>,
q is the number of alkoxy groups CR<NUM>R<NUM>-CR<NUM>R<NUM>-O averaged over the polymer units <NUM> to n and is from <NUM> to <NUM>.