EP2764135A2 - Solution pour cuivrage autocatalytique exempte de formaldéhyde - Google Patents

Solution pour cuivrage autocatalytique exempte de formaldéhyde

Info

Publication number
EP2764135A2
EP2764135A2 EP12766668.3A EP12766668A EP2764135A2 EP 2764135 A2 EP2764135 A2 EP 2764135A2 EP 12766668 A EP12766668 A EP 12766668A EP 2764135 A2 EP2764135 A2 EP 2764135A2
Authority
EP
European Patent Office
Prior art keywords
acid
copper plating
plating solution
copper
electroless
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP12766668.3A
Other languages
German (de)
English (en)
Inventor
Edith STEINHÄUSER
Sandra RÖSELER
Stefanie WIESE
Tang Cam Lai NGUYEN
Lutz Stamp
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Atotech Deutschland GmbH and Co KG
Original Assignee
Atotech Deutschland GmbH and Co KG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Atotech Deutschland GmbH and Co KG filed Critical Atotech Deutschland GmbH and Co KG
Priority to EP12766668.3A priority Critical patent/EP2764135A2/fr
Publication of EP2764135A2 publication Critical patent/EP2764135A2/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C18/00—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating
    • C23C18/16—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating by reduction or substitution, e.g. electroless plating
    • C23C18/31—Coating with metals
    • C23C18/38—Coating with copper
    • C23C18/40—Coating with copper using reducing agents

Definitions

  • the present invention relates to an electroless copper plating solution, a method for electroless copper plating utilizing said solution and the use of the solution for the plating of substrates.
  • Electroless plating is the controlled autocatalytic deposition of a continuous film of metal without the assistance of an external supply of electrons.
  • Non-metallic surfaces may be pretreated to make them receptive or catalytic for deposition. All or selected portions of a surface may suitably be pretreated.
  • the main components of electroless copper baths are the copper salt, a complexing agent, a reducing agent, and, as optional ingredients, an alkaline, and additives, as for example stabilizers.
  • Complexing agents are used to chelate the copper being deposited and prevent the copper from being precipitated from solution (i.e. as the hydroxide and the like). Chelating copper renders the copper available to the reducing agent which converts the copper ions to metallic form.
  • US 20020064592 discloses an electroless bath comprising a source of copper ions, glyoxylic acid or formaldehyde as reducing agent, and EDTA, tartrate or alkanol amine as complexing agent.
  • US 20080223253 discloses an electroless copper plating solution including a copper salt, a reductant that may be selected from the group consisting of formaldehyde,
  • EDTA ethylenediamine tetraacetic acid
  • HEDTA hydroxyethyl ethylene diamine triacetic acid
  • cyclohexanediamine tetraacetic acid diethylenetriamine pentaacetic acid
  • Performance of a copper plating solution is generally not predictable and strongly depends on its constituents, especially the complexing agent and the reducing agent, and the molar ratio of its constituents.
  • An object of the present invention was to provide with an electroless copper plating solution that is formaldehyde-free. Another object was to provide with an electroless copper plating solution with improved performance, for example an improved copper deposition rate.
  • Another object of the invention was an electroless copper plating solution that employs a biodegradable complexing agent for copper.
  • the present invention provides with an electroless copper plating solution, comprising
  • a source of glyoxylic acid as reducing agent and - at least one polyamino disuccinic acid or at least one polyamino monosuccinic acid, or a mixture of at least one polyamino disuccinic acid and at least one polyamino monosuccinic acid, as complexing agent,
  • the molar ratio of the complexing agent to copper ions is in the range of 1 .1 :1 to 5:1 .
  • the solution of claim 1 is formaldehyde-free and shows an improved copper deposition rate. Deposition rates of 0.15 - 1 .0 ⁇ /10 min, 0.15 - 1 .5 ⁇ /10 min or even 0.15 - 2.0 ⁇ /10 min may be reached.
  • monosuccinic acid to copper ions leads to beneficial properties of the plating solution, which are suppressed copper hydroxide precipitation, bath stability and suppressed formation of blisters in copper plating process, as further explained below and in the working examples.
  • the molar ratio of glyoxylic acid to complexing agent is ⁇ 4.6 : 1 . It is shown in the present invention that such molar ratio has beneficial effects on the quality of a copper deposition on a substrate, as for example coverage, backlight and passivation. Further beneficial molar ratios of glyoxylic acid to complexing agent, particularly EDDS, are ⁇ 4.5:1 , ⁇ 4.2:1 , ⁇ 4.0:1 , ⁇ 3.8:1 , ⁇ 3.6:1 . Preferable lower limits of molar ratios of glyoxylic acid to complexing agent, particularly EDDS, are 0.45:1 , or 0.7:1 , 1 :1 or 2:1 .
  • preferable ranges of molar ratios of glyoxylic acid to complexing agent, particularly EDDS are 0.45:1 to 4.5:1 , 0.45:1 to 4.2:1 , 0.45:1 to 4.0:1 , 0.45:1 to 3.8:1 , or 0.45:1 to 3.6:1 .
  • Other preferable ranges are 1 :1 to 4.5:1 , 1 :1 to 4.2:1 , 1 :1 to 4.0:1 , 1 :1 to 3.8:1 , or 1 :1 to 3.6:1 .
  • Still other preferable ranges of molar ratios of glyoxylic acid to complexing agent, particularly EDDS, are 2:1 to 4.5:1 , 2:1 to 4.2:1 , 2:1 to 4.0:1 , 2:1 to 3.8:1 , or 2:1 to 3.6:1 .
  • the ratio is related to the molar amount of complexing agent, which means in this connection the total molar amount of complexing agents, if more than one complexing agent is used.
  • the molar concentration of glyoxylic acid is preferably at least as high as the molar concentration of copper in the solution, more preferably higher.
  • the molar ratio of glyoxylic acid to Cu is preferably ⁇ 1 :1 , preferably ⁇ 1 .5:1 , more preferably ⁇ 2:1 .
  • Polyamino disuccinic acids and polyamino monosuccinic acids show a very good or even high biodegradability.
  • the plating solution of the present invention is free from
  • EDTA ethylenediamine tetraacetic acid
  • HEDTA N'-(2-Hydroxyethyl)-ethylenediamine-N,N,N'- triacetic acid
  • tetrakis(2-hydroxypropyl)ethylenediamine tetrakis(2-hydroxypropyl)ethylenediamine
  • the solution according to the invention and the process according to the invention are preferably used for the coating of printed circuit boards, chip carriers and semiconductor wafers or also of any other circuit carriers and interconnect devices.
  • the solution is used in particular in printed circuit boards and chip carriers, but also in semiconductor wafers, to plate surfaces, trenches, blind micro vias, through hole vias (through holes) and similar structures with copper.
  • the solution of the invention or the process of the invention can be used for deposition of copper on surfaces, in trenches, blind-micro-vias, through-hole-vias, and comparable structures in printed circuit boards, chips, carriers, wafers, and various other interconnect devices.
  • through hole vias or “through holes”, as used in the present invention, encompasses all kinds of through hole vias and includes so-called “through silicon vias” in silicon wafers.
  • Another application that is envisaged for the solution is metallization of display applications.
  • copper is deposited particularly on glass substrate, particularly flat glass surfaces.
  • Wet electroless copper deposition on glass substrate is beneficial in comparison to metal sputtering processes that have been used so far.
  • Benefits that can be reached with wet electroless deposition in comparison to sputtering techniques are, inter alia, reduced internal stress and reduced bending of a glass substrate, reduced equipment maintenance, effective use of metal, reduced material waste.
  • a high copper deposition rate on glass substrate is reached with the solution of the invention, especially on glass substrates that are pretreated with relatively few metal seeds.
  • the solution of the invention is an aqueous solution.
  • aqueous solution means that the prevailing liquid medium, which is the solvent in the solution, is water. Further liquids, that are miscible with water, as for example alcohols and other polar organic liquids, that are miscible with water, may be added.
  • the solution of the present invention may be prepared by dissolving all components in aqueous liquid medium, preferably in water.
  • the solution contains a copper ion source, which may for example be any water soluble copper salt. Copper may for example, and without limitation, be added as copper sulphate, copper chloride, copper nitrate, copper acetate, copper methane sulfonate ((CH 3 0 3 S) 2 Cu), copper hydroxide; or hydrates thereof.
  • a copper ion source which may for example be any water soluble copper salt. Copper may for example, and without limitation, be added as copper sulphate, copper chloride, copper nitrate, copper acetate, copper methane sulfonate ((CH 3 0 3 S) 2 Cu), copper hydroxide; or hydrates thereof.
  • Electroless copper baths using reducing agents mentioned above preferably employ a relatively high pH, usually between 1 1 and 14, or 12.5 and 14, preferably between 12.5 and 13.5, or 12.8 and 13.3.
  • the pH is adjusted generally by potassium hydroxide (KOH), sodium hydroxide (NaOH), lithium hydroxide (LiOH), ammonium hydroxide or tetramethylammonium hydroxide (TMAH).
  • KOH potassium hydroxide
  • NaOH sodium hydroxide
  • LiOH lithium hydroxide
  • TMAH tetramethylammonium hydroxide
  • the solution may contain a source of hydroxide ions, as for example and without limitation one or more of the compounds listed above.
  • a source of hydroxide is for example added if an alkaline pH of the solution is desired and if the pH is not already in the alkaline range by other constituents.
  • potassium hydroxide because the solubility of potassium oxalate is high.
  • Oxalate anions are formed in the solution by the oxidation of the glyoxylic acid that is used as the reducing agent.
  • Glyoxylic acid is the reducing agent for the reduction of copper ions to elementary copper.
  • the term "glyoxylic acid” includes non-dissociated glyoxylic acid as well as glyoxylate ions.
  • non-dissociated glyoxylic acid and glyoxylate-ions may be present.
  • the exact nature of the species, acid or salt, present will depend in the pH of the solution. The same consideration applies to other weak acids and bases.
  • source of glyoxylic acid encompasses glyoxylic acid and all compounds that can be converted to glyoxylic acid in aqueous solution.
  • aqueous solution the aldehyde containing acid is in equilibrium with its hydrate.
  • a suitable source of glyoxylic acid is dihaloacetic acid, such as dichloroacetic acid, which will hydrolyse in an aqueous medium to the hydrate of glyoxylic acid.
  • An alternative source of glyoxylic acid is the bisulphite adduct as is a hydrolysable ester or other acid derivative. The bisulphite adduct may be added to the composition or formed in situ.
  • the bisulphite adduct may be made from glyoxylate and either bisulphite, sulphite or metabisulphite.
  • One or more further reducing agents may be added, if desired, as for example hypophosphoric acid, glycolic acid or formic acid, or salts of aforementioned acids.
  • the solution of the invention does, however, not contain formaldehyde. Thus, the solution is free of formaldehyde.
  • the further reducing agent is preferably an agent that acts as reducing agent but cannot be used as the sole reducing agent (cf. US 7,220,296, col. 4, 1. 20-43 and 54-62).
  • a further reducing agent is in this sense also called an "enhancer".
  • Polyamino disuccinic acids are compounds having two or more nitrogen atoms, wherein 2 of the nitrogens are bonded to a succinic acid (or salt) group, preferably only two nitrogen atoms each have one succinic acid (or salt) group attached thereto.
  • succinic acid includes salts thereof.
  • the compound has at least 2 nitrogen atoms, and due to the commercial availability of the amine, preferably has no more than about 10 nitrogen atoms, more preferably no more than about 6, most preferably 2 nitrogen atoms. Nitrogen atoms which do not have a succinic acid moiety attached most preferably are substituted with hydrogen atoms.
  • the succinic acid groups are on terminal nitrogen atoms, most preferably each of which nitrogens also have a hydrogen substituent.
  • terminal it is meant the first or last nitrogen atom which is present in the compound, irrespective of other substituents.
  • Another definition of a terminal nitrogen is a primary amine nitrogen, before a succinic acid moiety is attached. The terminal nitrogen is transferred to a secondary amine nitrogen after a succinic acid moiety was attached. Because of steric hindrance of two succinic groups on one nitrogen, it is preferred that each nitrogen having a succinic group has only one such group.
  • Remaining bonds on nitrogens having a succinic acid group are preferably filled by hydrogens or alkyl or alkylene groups (linear, branched or cyclic including cyclic structures joining more than one nitrogen atom or more than one bond of a single nitrogen atom, preferably linear) or such groups having ether or thioether linkages, all of preferably from 1 to 10 carbon atoms, more preferably from 1 to 6, most preferably from 1 to 3 carbon atoms, but most preferably hydrogen.
  • Preferred alkyl groups are methyl, ethyl and propyl groups.
  • the nitrogen atoms are linked by alkylene groups, preferably each of from 2 to12 carbon atoms, more preferably from 2 to 10 carbon atoms, even more preferably from 2 to 8, most preferably from 2 to 6 carbon atoms, namely ethylene, propylene, butylene, pentylene or hexylene.
  • the polyamino disuccinic acid compound preferably has at least about 10 carbon atoms and preferably has at most about 50, more preferably at most about 40, most preferably at most about 30 carbon atoms.
  • succinic acid is used herein for the acid and salts thereof; the salts include metal cation (e.g. potassium, sodium) and ammonium or amine salts.
  • Polyamino disuccinic acids useful in the practice of the invention are unsubstituted
  • inert substituents include alkyl groups (preferably of from 1 to 6 carbon atoms); aryl groups including arylalkyl and alkylaryl groups (preferably of from 6 to 12 carbon atoms), with alkyl groups preferred among these and methyl and ethyl groups preferred among alkyl groups.
  • Inert substituents are suitably on any portion of the molecule, preferably on carbon atoms, more preferably on alkylene groups, for example alkylene groups between nitrogen atoms or between carboxylic acid groups, most preferably on alkylene groups between nitrogen groups.
  • Preferred polyamino disuccinic acids include ethylenediamine-N,N'-disuccinic acid (EDDS), diethylenetriamine-N,N"-disuccinic acid, triethylenetetraamine-N,N"'-disuccinic acid, 1 ,6 hexamethylenediamine ⁇ , ⁇ '-disuccinic acid, tetraethylenepentamine-N,N""-disuccinic acid, 2-hydroxypropylene-1 ,3-diamine-N,N'-disuccinic acid, 1 ,2 propylenediamine-N,N'-disuccinic acid, 1 ,3-propylenediamine-N,N"-disuccinic acid, cis-cyclohexanediamine-N,N'-disuccinic acid, transcyclohexanediamine-N,N'-disuccinic acid, and ethylenebis(oxyethylenenitrilo)- ⁇ , ⁇ '
  • Such polyamino disuccinic acids can be prepared, for instance, by the process disclosed by Kezerian et al. in U.S. Patent 3,158,635 which is incorporated herein by reference in its entirety.
  • Kezerian et al disclose reacting maleic anhydride (or ester or salt) with a polyamine corresponding to the desired polyamino disuccinic acid under alkaline conditions.
  • the reaction yields a number of optical isomers, for example, the reaction of ethylenediamine with maleic anhydride yields a mixture of three optical isomers [R,R], [S,S] and [S,R] ethylenediamine disuccinic acid (EDDS) because there are two asymmetric carbon atoms in ethylenediamine disuccinic acid.
  • EDDS ethylenediamine disuccinic acid
  • [S,S] isomers are prepared by reaction of such acids as L-aspartic acid with such
  • Polyamino monosuccinic acids are compounds having at least two nitrogen atoms to which a succinic acid (or salt) moiety is attached to one of the nitrogen atoms.
  • the compound has at least 2 nitrogen atoms, and due to the commercial availability of the amine, preferably has no more than about 10 nitrogen atoms, more preferably no more than about 6, most preferably 2 nitrogen atoms.
  • Remaining nitrogen atoms, those which do not have a succinic acid moiety attached preferably are substituted with hydrogen atoms.
  • the succinic acid moiety may be attached to any of the amines, preferably the succinic acid group is attached to a terminal nitrogen atom.
  • terminal it is meant the first or last amine which is present in the compound, irrespective of other substituents.
  • Another definition of a terminal nitrogen is a primary amine nitrogen, before a succinic acid moiety is attached. The terminal nitrogen is transferred to a secondary amine nitrogen after a succinic acid moiety was attached.
  • the remaining bonds on the nitrogen having a succinic acid group are preferably filled by hydrogens or alkyl or alkylene groups (linear, branched or cyclic including cyclic structures joining more than one nitrogen atom or more than one bond of a single nitrogen atom, preferably linear) or such groups having ether or thioether linkages, all of preferably from 1 to 10 carbon atoms, more preferably from 1 to 6, most preferably from 1 to 3 carbon atoms, but most preferably hydrogen.
  • Preferred alkyl groups are methyl, ethyl and propyl groups.
  • the nitrogen atoms are linked by alkylene groups, each of from 2 to 12 carbon atoms, preferably from 2 to 10 carbon atoms, more preferably from 2 to 8, and most preferably from 2 to 6 carbon atoms, namely ethylene, propylene, butylene, pentylene or hexylene.
  • the polyamino monosuccinic acid compound preferably has at least about 6 carbon atoms and preferably has at most about 50, more preferably at most about 40, and most preferably at most about 30 carbon atoms.
  • Polyamino monosuccinic acids useful in the practice of the invention are unsubstituted (preferably) or inertly substituted as described above for polyamino disuccinic acid compounds.
  • Preferred polyamino monosuccinic acids include ethylenediamine monosuccinic acid, diethylenetriamine monosuccinic acid, triethylenetetraamine monosuccinic acid, 1 ,6- hexamethylenediamine monosuccinic acid, tetraethylenepentamine monosuccinic acid, 2 hydroxypropylene-1 ,3-diamine monosuccinic acid, 1 ,2-propylenediamine monosuccinic acid, 1 ,3-propylenediamine monosuccinic acid, ciscyclohexanediamine monosuccinic acid, trans- cyclohexanediamine monosuccinic acid and ethylenebis(oxyethylenenitrilo) monosuccinic acid.
  • the preferred polyamino monosuccinic acid is ethylenediamine monosuccinic acid.
  • Such polyamino monosuccinic acids can be prepared for instance, by the process of
  • Bersworth et al. in U.S. Patent 2,761 ,874, the disclosure of which is incorporated herein by reference, and as disclosed in Jpn. Kokai Tokkyo Koho JP 57,1 16,031 .
  • Bersworth et al. disclose reacting alkylene diamines and dialkylene triamines under mild conditions with maleic acid esters under mild conditions (in an alcohol) to yield amino derivatives of N-alkyl substituted aspartic acid. The reaction yields a mixture of the R and S isomers.
  • the solution contains a mixture of a polyamino disuccinic acid and a polyamino monosuccinic acid
  • the polyamino substituent of the polyamino disuccinic acid and the polyamino monosuccinic acid are the same.
  • the polyamino disuccinic acid is ethylenediamine-N,N'-disuccinic acid
  • the polyamine monosuccinic acid is ethylenediamine monosuccinic acid.
  • ethylenediamine-N,N'-disuccinic acid (EDDS) is used as complexing agent.
  • EDDS is a preferred complexing agent because of its high
  • the solution of the present invention is free of toxic co-metals.
  • the solution of the present invention is preferably free of nickel.
  • the present inventors have found out that a considerably improved copper deposition rate is obtained in solutions of the invention, comprising glyoxylic acid and EDDS. This is an unexpected result because in comparison examples employing formaldehyde, the copper deposition is not or only marginally improved when a formaldehyde-EDDS-combination is compared with formaldehyde-EDTA.
  • EDDS includes racemic EDDS or all optically active isomers thereof, such as (S,S)-EDDS, and salts and derivatives thereof.
  • EDDS may be prepared by the process of PCT/GB94/02397. In the solution, ethylenediaminedisuccinic acid and ethylenediaminedisuccinate-ions may be present, depending on the pH of the solution.
  • the solution of the invention in one embodiment contains copper ions, complexing agent, which is preferably EDDS, and glyoxylic acid in following concentrations:
  • glyoxylic acid 2-20 g/l corresponding to 0.027-0.270 mol/l
  • the solution of the invention more preferably contains copper ions, complexing agent, which is preferably EDDS, and glyoxylic acid in following concentrations: Cu-ions: 2-3 g/l, corresponding to 0.031 -0.047 mol/l complexing agent: 20-40 g/l, corresponding to 0.068-0.137 mol/l
  • the molar ratio of complexing agent which means in this connection the total amount of complexing agent(s) (i.e. sum of moles of all complexing agents, if more than one complexing agent is used), to copper ions is in the range of 1 .1 :1 to 5:1 , more preferably 1 .5:1 to 5:1 . It has been shown that the solutions of the invention have a better performance when this molar ratio is used, i.e. when the complexing agent, particularly EDDS, is used in molar excess with respect to copper.
  • a molar ratio of complexing agent, particularly EDDS, to copper of at least 1 .1 :1 is necessary to complex the copper ions.
  • a molar ratio ⁇ 1 :1 leads to copper hydroxide precipitation and no copper plating is possible.
  • a molar ratio of >5:1 leads to bath instability and high blister formation on the surface of a substrate in the copper plating process.
  • the molar ratio of complexing agent which means in this connection the total amount of complexing agent(s) to copper ions is 2:1 to 5:1 , more preferably 3:1 to 5:1 .
  • a further reducing agent also called “enhancer”
  • the further reducing agent is preferably selected from glycolic acid, hypophosphoric acid, or formic acid, most preferably glycolic acid.
  • the solution of the present invention may comprise - and does not necessarily comprise - further components, as for example stabilizers, surfactants, additives, as rate controlling additives, grain refining additives, pH buffers, pH adjusters, and enhancers.
  • further components are for example described in following documents, which are incorporated by reference in their entirety: US 4,617,205 (particularly disclosure in col. 6, 1. 17 - col. 7, 1. 25), US 7,220,296 (particularly col. 4, 1. 63 - col. 6, I. 26), US 2008/0223253 (cf. particularly paragraphs 0033 and 0038).
  • Stabilizers are compounds that stabilize the electroless plating solution against unwanted outplating in the bulk solution.
  • the term "outplating" means unspecific and/or uncontrolled deposition of copper. Reduction of copper(ll) should only occur on the desired substrate surface and not unspecific in the whole bath.
  • a Stabilizing function can for example be accomplished by substances acting as catalyst poison (for example sulfur or other chalcogenide containing compounds) or by compounds forming copper(l)-complexes, thus inhibiting the formation of copper(l)oxide.
  • Suitable stabilizers are, without limitation, dipyridyls (2,2'-dipyridyl, 4,4'dipyridyl),
  • DP 2,2'-dipyridyl
  • the stabilizer is chosen, mainly for environmental and occupational health reasons, from a stabilizer that is free of cyanides.
  • the solution of the present invention is preferably free of cyanides.
  • 2,2'-dipyridyl is a preferred stabilizer. Dipyridyl is prefably added in an amount of 1 - 10 mg/l.
  • European application EP1876262 discloses an electroless copper bath that contains as a necessary component one or more thiocarboxylic acids.
  • the thio compounds mentioned in EP1876262 include compounds having a formula HS-(CX1 )r-(CHX2)s-COOH, wherein X1 is -H or -COOH; X2 is -H or -SH; r and s are positive integers where r is 0 to 2, or 0 or 1 ; and s is 1 or 2.
  • Specific examples of thio compounds, mentioned in EP1876262 are thioglycolic acid, thiopropionic acid, thiomalic acid and dithiodisuccinic acid.
  • such thiocarboxylic acids are compatible with glyoxylic acid and its salts and stabilize the electroless copper compositions by preventing the formation of copper oxide.
  • the necessary minimum amount of a thio compound according to EP1876262 is 0.01 ppm.
  • performance of an electroless copper bath is better when a thiocarboxylic acid component, as generically and specifically mentioned in EP1876262, is avoided or at least below the limit mentioned in EP1876262.
  • Trace amounts of thiocarboxylic acid as generically and specifically mentioned in EP1876262 may be present, as long as the amount is below 0.01 ppm. It is however preferred that no thiocarboxylic acid is added to the solution of the invention, i.e. that the bath does not contain any thiocarboxylic acid as generically and specifically mentioned in EP1876262.
  • the present invention relates to a process for electroless copper plating, the process comprising contacting a substrate with an electroless copper plating solution as described above.
  • the substrate may be dipped or immersed in the solution of the invention.
  • a whole surface of a substrate may be plated with copper, or only selected portions.
  • the solution be agitated during use.
  • work- and/or solution- agitation may be used.
  • a preferred kind of agitation is air agitation of the solution. Air agitation may be achieved by bubbling air through the solution in use.
  • the process will be carried out for a sufficient time to yield a deposit of the thickness required, which in turn will depend on the particular application.
  • the electroless deposition of copper according to the process of the invention can particularly be used for the through-plating of holes, surfaces, trenches, blind micro vias in printed circuit boards.
  • Double sided or multilayer boards may be plated by means of the present invention.
  • the process of the invention may be useful in providing electroless copper deposits with a thickness in the range of 0.1 to 25 ⁇ , preferably between 0.25 and 3 ⁇ .
  • Substrates that are generally used for printed circuit board manufacture are most frequently epoxy resins or epoxy glass composites. But other substances, notably phenolic resins, polytetrafluoroethylene (PTFE), polyimides, polyphenyleneoxides, bismaleintriazine-resins (BT-resins), cyanate esters and polysulphones can be used.
  • non-conductive substrates including plastics, such as acrylonitrile butadiene styrene (ABS) and polycarbonate; ceramics and glass.
  • ABS acrylonitrile butadiene styrene
  • the process is carried out at a temperature in the range of 20 - 60 °C, preferably 20 - 55 ⁇ €, more preferably 20 - 50 ⁇ €, even more preferably 20 - 45 °C, and most preferably 20 - 40 ' ⁇ .
  • This embodiment is very beneficial since with formaldehyde based solutions of the state of the art higher temperatures are necessary for a good plating performance, especially for a sufficient copper deposition rate.
  • the substrate i.e. the surfaces of the substrate that are to be plated with copper, particularly non-metallic surfaces, may be pretreated by means within the skill in the art (as for example described in US 4,617,205, col 8) to make it/them more receptive or autocatalytic for copper deposition. All or selected portions of a surface may be pretreated.
  • a pretreatment is, however, not necessary in every case and depends on the kind of substrate and surface. Within the pretreatment, it is possible to sensitise substrates prior to the deposition of electroless copper on them. This may be achieved by the adsorption of a catalysing metal (such as a noble metal, for example palladium) onto the surface of the substrate.
  • a catalysing metal such as a noble metal, for example palladium
  • a pretreatment process strongly depends on parameters as the substrate, the desired application, and the desired properties of the copper surface
  • An exemplary and non-limiting pretreatment process especially for printed circuit board laminates and other suitable substrates, may comprise following steps
  • an activator solution that contains colloidal or ionic catalysing metal, such as a noble metal, preferably palladium, causing the substrate's surface to become catalytic,
  • the activator contains ionic catalysing metal
  • the activator contains colloidal catalysing metal
  • the cleaner may also contain additional substances (conditioners) that prepare the surface for an activation step, i.e. enhance the adsorption of the catalyst and lead to a more uniformly activated surface.
  • Etching the substrate to remove oxides from the surface of the copper, especially from inner layers in holes. This may be done by persulphate or peroxide based etching systems.
  • a pre-dip solution such as a hydrochloric acid solution or sulfuric acid solution, optionally with an alkali metal salt, such as sodium chloride, also in the pre-dip solution.
  • the pre-dip serves to protect an activator from drag-in and contaminations.
  • a permanganate etching step is employed.
  • Desmear process using a permanganate etching step, is described in the appended examples. The Desmear process may be combined with the above described steps.
  • the Desmear process may be performed before step a) of the above described pretreatment process, or before above-mentioned steps i)-iii) in case that one or more of steps i)-iii) is performed.
  • the desmear process may also be performed instead of steps i) and ii).
  • a surface is only contacted with a pre- dip solution and an activator solution and then with the solution of the invention.
  • Contacting with a cleaning solution and an adhesion enhancer before the pre-dip step are optional steps that can be carried out in advance.
  • Still another process, which is often used for glass substrates, may be carried out with following steps before copper plating:
  • a glass surface that is to be plated exhibits metal particles as seeds.
  • the metal particles may be brought onto the surface by sputtering techniques.
  • Exemplary seeds are particles composed of copper, titanium, molybdenum, zirconium, aluminium, chromium, tungsten, niobium, tantalum or a mixture or alloy thereof.
  • Another seed may be a metal oxide, or a mixed metal oxide, as for example indium tin oxide.
  • This process can also be used for plastic substrates, as for example substrates made from polyethylene terephthalate.
  • Said pretreated glass surface is contacted with an activator solution that contains ionic catalysing metal, such as a noble metal, preferably palladium, causing the surface to become catalytic.
  • ionic catalysing metal such as a noble metal, preferably palladium
  • the ionic catalysing metal is reduced onto the surface by the seed metal.
  • addition of a further reducer may be omitted.
  • This process is especially used in copper plating of glass substrates for display applications.
  • the exemplary pretreatment processes, or single steps thereof, may be combined to alternative pretreatment processes, if found necessary.
  • the present invention relates to the use of the electroless copper plating solution as described above for the plating of printed circuit boards, wafers, Integrated circuit substrates, MID (molded interconnect device) components, displays, such as liquid crystal displays, TFT-displays, plasma displays, electroluminescent displays (ELD), and
  • ECD electrochromic displays
  • displays particularly displays for electronic devices or TVs, display components, flat sensors, such as X-ray imaging devices, or plastic parts, such as plastic parts for functional or decorative purposes.
  • Fig. 2 Steps of the plating through hole process for activation, Fig. 3 Reference samples for backlight measurement, showing results from D1 to D10, Fig. 4 copper thickness on glass substrates, using baths with different complexing agents.
  • the coverage of the electroless copper plating into the through holes can be assessed using an industry standard Backlight Test, in which an electroless plated coupon is sectioned, so as to allow areas of incomplete coverage to be detected as bright spots when viewed over a strong light source [US 2008/0038450 A1 ].
  • the quality of the copper deposit is determined by the amount of light that is observed under a conventional optical microscope.
  • test samples are treated in a common Desmear process to clean the hole wall surfaces and the inner layer copper surfaces.
  • resin surface is roughened to achieve a good copper adhesion.
  • the Desmear process is a multi-stage process, whose steps are shown in Fig. 1 .
  • the Sweller is made of a mixture of organic solvents. During this step the drill smear and other impurities are removed. The high temperature of 60 - 80 °C promotes the infiltration of the Sweller which lead to a swelled surface. Therefore a stronger attack of the subsequently applied permanganate solution is possible. Afterwards the Reduction Solution (reaction conditioner) removes the manganese dioxides produced during the permanganate step from the surfaces.
  • Reduction Solution reaction conditioner
  • the non conductive material is prepared for the copper deposition.
  • the activation steps of the PTH process are shown in Fig. 2.
  • the cleaner is used to remove organics and condition the surface for the next activation steps.
  • the Etch Cleaner removes the oxides from the surface of the copper inner layers in the holes.
  • Substances used as etch cleaner are selected from a mixture of sulfuric acid and hydrogen peroxide, or from peroxodisulfates, or from peroxomonosulfate.
  • Etch cleaning solutions may, in addition to the etching component, also contain additives and/or stabilizers.
  • the activation of the panel and hole surfaces with palladium takes place in the activator that contains colloidal or ionic catalysing metal, such as a noble metal, preferably palladium, causing the surface to become catalytic.
  • the activator contains palladium ions complexed by an organic ligand.
  • the prefixed Predip should protect the activator from drag-in and contaminations.
  • the last step of the activation process is the Reducer.
  • the palladium ions are reduced to elemental palladium with high catalytic activity.
  • electroless copper deposition with a solution of the invention is carried out.
  • the reducer is used in combination with ionic metal compounds as activators. It employs reducing agents like hypophosphites, boranates, aminoboranes.
  • the bath make up was made by adding the bath components in the order outlined in table 1 to the suited amount of water. Air agitation was used. The operation temperature was varied from 38 - 50 'C. Also the deposition time was set from 10 - 60 minutes to achieve the required copper thickness.
  • test panels run through the Desmear process (below table).
  • Comparison example 2.1 HEDTA (N'-(2-Hvdroxyethyl)-ethylenediamine-N,N,N'-triacetic acid)
  • Bath composition 1 solution of the invention with glyoxylic acid/ EDDS
  • the copper plating bath containing EDDS was twice as fast as the bath containing EDTA with respect to copper deposition rate under the same plating conditions. Moreover, a better coverage was reached with EDDS.
  • Reducing agent glyoxylic acid 8 g/L
  • the molar ratio EDDS: Cu of 1 .1 :1 is at least necessary to complex the copper ions in alkaline solutions.
  • the molar ratio ⁇ 1 .1 :1 leads to copper hydroxide precipitation. Thus, no copper plating is possible.
  • the molar ratio > 5:1 leads to bath instability and high blister tendency on PCB material.
  • the deposition color is dark salmon pink and the backlight is under the required value of D7.
  • Uncontrolled copper deposition on the beaker can be found after electroless copper plating with bath 6 (molar ratio EDDS:Cu of 6:1 ).
  • the bath stability is unsufficient.
  • Example 5 Plating solutions with different molar ratios of glyoxylic acid to EDDS
  • test panels run through the Desmear process (Tab. 2) and the activation process based on an ionic activator system (tab. 3) as described in Example 1 .
  • the following parameters were applied for electroless plating in the electroless copper bath
  • test panels made of the following materials were used.
  • ABS short desmeared: 2 ' ,4 ' ,2 '
  • R1755C desmeared: 5 ' , 10 ' , 5 '
  • the bath stability decreases after one day in all baths. Next day, the precipitation of copper hydroxide occurs.
  • a ratio of EDDS to copper of at least 1 .1 : 1 is recommended. But the present experiments show influence of the molar ratio of glyoxylic acid:EDDS on the quality of the copper deposition on a substrate.
  • the reduction process with the copper-glyoxylic acid complex seems to be clammed.
  • the formation of a copper-glyoxylic acid complex causes bath instability together with passivation on copper clad material. Passivation means here the copper surface becomes inactive towards the electroless copper plating process; the electroless copper plating process terminates on a passive surface.
  • the copper deposition quality decreases when the molar ratio of glyoxylic acid:EDDS is 4.6:1 or higher.
  • the initial reactivity, the copper coverage and the passivation depend on the molar ratio of glyoxylic acid : EDDS.
  • the complexing agent plays an important part in the electroless copper plating process. The reduction process is not possible with every complexing agent.
  • the complexing agent EDDS forms with copper a complex that can be easily reduced.
  • the deposition qualities (coverage, backlight) are very good at a ratio glyoxylic acid : EDDS of below 4.6:1 , particularly at 3.6 : 1 or below.
  • Thioglycolic acid leads to a dark color of the electroless copper deposition.
  • the deposition rate decreases with using thioglycolic acid in the electroless copper bath.

Landscapes

  • Chemical & Material Sciences (AREA)
  • General Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Chemically Coating (AREA)

Abstract

La présente invention porte sur une solution aqueuse pour cuivrage autocatalytique, comprenant une source d'ions cuivre, une source d'acide glyoxylique servant d'agent réducteur et au moins un acide polyaminodisuccinique ou au moins un acide polyaminomonosuccinique, ou un mélange d'au moins un acide polyaminodisuccinique et d'au moins un acide polyaminomonosuccinique servant d'agent complexant, ainsi que sur un procédé pour le cuivrage autocatalytique utilisant ladite solution et sur l'utilisation de la solution pour le placage de substrats.
EP12766668.3A 2011-10-05 2012-10-01 Solution pour cuivrage autocatalytique exempte de formaldéhyde Withdrawn EP2764135A2 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP12766668.3A EP2764135A2 (fr) 2011-10-05 2012-10-01 Solution pour cuivrage autocatalytique exempte de formaldéhyde

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
EP11183991 2011-10-05
PCT/EP2012/069388 WO2013050332A2 (fr) 2011-10-05 2012-10-01 Solution pour cuivrage autocatalytique exempte de formaldéhyde
EP12766668.3A EP2764135A2 (fr) 2011-10-05 2012-10-01 Solution pour cuivrage autocatalytique exempte de formaldéhyde

Publications (1)

Publication Number Publication Date
EP2764135A2 true EP2764135A2 (fr) 2014-08-13

Family

ID=46963736

Family Applications (1)

Application Number Title Priority Date Filing Date
EP12766668.3A Withdrawn EP2764135A2 (fr) 2011-10-05 2012-10-01 Solution pour cuivrage autocatalytique exempte de formaldéhyde

Country Status (7)

Country Link
US (1) US20140242264A1 (fr)
EP (1) EP2764135A2 (fr)
JP (1) JP6180419B2 (fr)
KR (1) KR101953940B1 (fr)
CN (1) CN104040026B (fr)
TW (1) TWI557271B (fr)
WO (1) WO2013050332A2 (fr)

Families Citing this family (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2784181B1 (fr) * 2013-03-27 2015-12-09 ATOTECH Deutschland GmbH Solution de dépôt de cuivre chimique
KR102165629B1 (ko) * 2013-09-25 2020-10-15 아토테크더치랜드게엠베하 배리어 층에 구리 시드 층을 증착하기 위한 방법 및 구리 도금 욕
WO2015111291A1 (fr) * 2014-01-27 2015-07-30 奥野製薬工業株式会社 Bain formant un film conducteur
JP6539992B2 (ja) * 2014-11-14 2019-07-10 凸版印刷株式会社 配線回路基板、半導体装置、配線回路基板の製造方法、半導体装置の製造方法
US20160145745A1 (en) * 2014-11-24 2016-05-26 Rohm And Haas Electronic Materials Llc Formaldehyde-free electroless metal plating compositions and methods
EP3035122B1 (fr) 2014-12-16 2019-03-20 ATOTECH Deutschland GmbH Procédé de fabrication de lignes fines
EP3035375B1 (fr) * 2014-12-19 2017-05-03 ATOTECH Deutschland GmbH Module de traitement d'un appareil pour traiter chimiquement et horizontalement des substrats de grande taille
CN109072438B (zh) 2016-05-04 2021-08-13 德国艾托特克公司 沉积金属或金属合金到衬底表面及包括衬底表面活化的方法
KR102428755B1 (ko) * 2017-11-24 2022-08-02 엘지디스플레이 주식회사 파장 변환이 가능한 광섬유 및 이를 사용하는 백라이트 유닛
EP3578683B1 (fr) 2018-06-08 2021-02-24 ATOTECH Deutschland GmbH Bain de placage de cuivre ou d'alliage de cuivre autocatalytique et procédé de galvanoplastie
EP3670698B1 (fr) 2018-12-17 2021-08-11 ATOTECH Deutschland GmbH Solution de prétraitement alcalin aqueux à utiliser avant le dépôt d'une couche d'activation de palladium, son procédé et son utilisation
TWI764121B (zh) 2019-04-04 2022-05-11 德商德國艾托特克公司 活化用於金屬化之非傳導或含碳纖維之基材表面的方法
EP3839092A1 (fr) 2019-12-20 2021-06-23 ATOTECH Deutschland GmbH Procédé d'activation d'au moins une surface, composition d'activation et utilisation de la composition d'activation pour activer une surface de dépôt autocatalytique
US20230340673A1 (en) 2020-08-27 2023-10-26 Atotech Deutschland GmbH & Co. KG A method for activating a surface of a non-conductive or carbon-fibres containing substrate for metallization
CN114507850A (zh) * 2021-12-06 2022-05-17 华东理工大学 一种喷墨打印在陶瓷基板上非甲醛化学镀铜的环保型镀液的化学配方
CN115679305B (zh) * 2023-01-03 2023-03-10 湖南源康利科技有限公司 一种印制板用铝箔表面化学镀铜处理工艺

Family Cites Families (23)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2761874A (en) 1954-09-30 1956-09-04 Dow Chemical Co Amino derivatives of n-alkyl substituted aspartic acids and their functional derivatives
US3158635A (en) 1959-03-18 1964-11-24 Stauffer Chemical Co Bis-adduction products and methods of preparing same
US3632704A (en) * 1967-12-04 1972-01-04 Stauffer Chemical Co Method for modifying electrically nonconductive surfaces for electroless plating
US4315045A (en) * 1978-12-19 1982-02-09 Crown City Plating Co. Conditioning of polyamides for electroless plating
JPS57116031A (en) 1981-01-13 1982-07-19 Tokyo Organ Chem Ind Ltd N-substituted polyamine and its preparation
US4668532A (en) * 1984-09-04 1987-05-26 Kollmorgen Technologies Corporation System for selective metallization of electronic interconnection boards
US4617205A (en) 1984-12-21 1986-10-14 Omi International Corporation Formaldehyde-free autocatalytic electroless copper plating
GB9422762D0 (en) * 1994-11-11 1995-01-04 Ass Octel Use of a compound
JPH0949084A (ja) * 1995-05-31 1997-02-18 Nitto Chem Ind Co Ltd ジアミン型生分解性キレート剤を用いた無電解Ｃｕメッキ浴
US5741555A (en) * 1995-05-22 1998-04-21 The Dow Chemical Company Succinic acid derivative degradable chelants, uses and compositions thereof
US5733858A (en) * 1995-08-30 1998-03-31 The Dow Chemical Company Succinic acid derivative degradable chelants, uses and compositions thererof
CA2230282C (fr) * 1995-08-30 2008-07-08 The Dow Chemical Company Chelatants degradables derives de l'acide succinique, leurs utilisations et compositions
JP3444276B2 (ja) * 2000-06-19 2003-09-08 株式会社村田製作所 無電解銅めっき浴、無電解銅めっき方法および電子部品
US20020064592A1 (en) 2000-11-29 2002-05-30 Madhav Datta Electroless method of seed layer depostion, repair, and fabrication of Cu interconnects
KR100529371B1 (ko) * 2003-07-29 2005-11-21 주식회사 엘지화학 촉매전구체 수지조성물 및 이를 이용한 투광성 전자파차폐재 제조방법
EP1681372A4 (fr) * 2003-10-17 2008-07-16 Nippon Mining Co Solution de cuivrage par depot autocatalytique et procede de cuivrage par depot autocatalytique
WO2005048674A1 (fr) * 2003-11-14 2005-05-26 Bridgestone Corporation Materiau de fenetre electromagnetiquement blindant et phototransmetteur, et procede de production
TW200707640A (en) * 2005-03-18 2007-02-16 Applied Materials Inc Contact metallization scheme using a barrier layer over a silicide layer
KR100702797B1 (ko) * 2005-12-09 2007-04-03 동부일렉트로닉스 주식회사 반도체소자의 구리배선막 형성방법
US7220296B1 (en) 2005-12-15 2007-05-22 Intel Corporation Electroless plating baths for high aspect features
EP1876262A1 (fr) 2006-07-07 2008-01-09 Rohm and Haas Electronic Materials, L.L.C. Compositions de dépôt autocatalytique sans danger pour lýenvironnement
KR20080083790A (ko) 2007-03-13 2008-09-19 삼성전자주식회사 무전해 구리 도금액, 그의 제조방법 및 무전해 구리도금방법
CN102191491A (zh) * 2010-03-10 2011-09-21 比亚迪股份有限公司 一种化学镀铜液及一种化学镀铜方法

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO2013050332A2 *

Also Published As

Publication number Publication date
CN104040026A (zh) 2014-09-10
JP6180419B2 (ja) 2017-08-16
WO2013050332A8 (fr) 2013-07-11
WO2013050332A2 (fr) 2013-04-11
WO2013050332A3 (fr) 2014-03-13
TWI557271B (zh) 2016-11-11
US20140242264A1 (en) 2014-08-28
JP2014528517A (ja) 2014-10-27
KR20140090145A (ko) 2014-07-16
KR101953940B1 (ko) 2019-03-04
TW201323654A (zh) 2013-06-16
CN104040026B (zh) 2019-01-01

Similar Documents

Publication Publication Date Title
US20140242264A1 (en) Formaldehyde-free electroless copper plating solution
EP2784181B1 (fr) Solution de dépôt de cuivre chimique
JP2018119209A (ja) 無電解銅めっき組成物
EP3034650B1 (fr) Compositions de bain de placage pour un dépôt autocatalytique de métaux et d'alliages métalliques
US20160145745A1 (en) Formaldehyde-free electroless metal plating compositions and methods
WO2014154702A1 (fr) Solution de cuivrage autocatalytique
US11512394B2 (en) Electroless gold plating bath
EP3578683B1 (fr) Bain de placage de cuivre ou d'alliage de cuivre autocatalytique et procédé de galvanoplastie

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

17P Request for examination filed

Effective date: 20140217

AK Designated contracting states

Kind code of ref document: A2

Designated state(s): AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

DAX Request for extension of the european patent (deleted)
STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION HAS BEEN WITHDRAWN

18W Application withdrawn

Effective date: 20171101