CN116324032A - Electroless nickel deposition on copper without palladium activation - Google Patents
Electroless nickel deposition on copper without palladium activation Download PDFInfo
- Publication number
- CN116324032A CN116324032A CN202180053197.3A CN202180053197A CN116324032A CN 116324032 A CN116324032 A CN 116324032A CN 202180053197 A CN202180053197 A CN 202180053197A CN 116324032 A CN116324032 A CN 116324032A
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- concentration
- copper
- ligand
- reducing agent
- bath
- Prior art date
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- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 title claims abstract description 227
- 239000010949 copper Substances 0.000 title claims abstract description 138
- 229910052759 nickel Inorganic materials 0.000 title claims abstract description 108
- 229910052802 copper Inorganic materials 0.000 title claims abstract description 91
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 title claims abstract description 90
- 230000004913 activation Effects 0.000 title claims description 54
- 230000008021 deposition Effects 0.000 title abstract description 28
- KDLHZDBZIXYQEI-UHFFFAOYSA-N Palladium Chemical compound [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 title description 78
- 229910052763 palladium Inorganic materials 0.000 title description 39
- 238000000034 method Methods 0.000 claims abstract description 100
- 238000007747 plating Methods 0.000 claims abstract description 58
- 239000003638 chemical reducing agent Substances 0.000 claims abstract description 56
- 238000000151 deposition Methods 0.000 claims abstract description 37
- KWSLGOVYXMQPPX-UHFFFAOYSA-N 5-[3-(trifluoromethyl)phenyl]-2h-tetrazole Chemical compound FC(F)(F)C1=CC=CC(C2=NNN=N2)=C1 KWSLGOVYXMQPPX-UHFFFAOYSA-N 0.000 claims abstract description 23
- 229910001379 sodium hypophosphite Inorganic materials 0.000 claims abstract description 23
- RJTANRZEWTUVMA-UHFFFAOYSA-N boron;n-methylmethanamine Chemical compound [B].CNC RJTANRZEWTUVMA-UHFFFAOYSA-N 0.000 claims abstract description 18
- -1 sodium tetrahydroborate Chemical compound 0.000 claims abstract description 15
- JPVYNHNXODAKFH-UHFFFAOYSA-N Cu2+ Chemical class [Cu+2] JPVYNHNXODAKFH-UHFFFAOYSA-N 0.000 claims abstract description 14
- UOMBONFALRJTIP-UHFFFAOYSA-N morpholin-4-ylborane Chemical compound BN1CCOCC1 UOMBONFALRJTIP-UHFFFAOYSA-N 0.000 claims abstract description 10
- 239000012279 sodium borohydride Substances 0.000 claims abstract description 8
- 229910000033 sodium borohydride Inorganic materials 0.000 claims abstract description 8
- VMQMZMRVKUZKQL-UHFFFAOYSA-N Cu+ Chemical compound [Cu+] VMQMZMRVKUZKQL-UHFFFAOYSA-N 0.000 claims abstract description 7
- KGBXLFKZBHKPEV-UHFFFAOYSA-N boric acid Chemical compound OB(O)O KGBXLFKZBHKPEV-UHFFFAOYSA-N 0.000 claims abstract description 5
- 239000004327 boric acid Substances 0.000 claims abstract description 5
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims description 156
- 239000003446 ligand Substances 0.000 claims description 54
- 239000000203 mixture Substances 0.000 claims description 30
- DHMQDGOQFOQNFH-UHFFFAOYSA-N Glycine Chemical compound NCC(O)=O DHMQDGOQFOQNFH-UHFFFAOYSA-N 0.000 claims description 28
- LGQLOGILCSXPEA-UHFFFAOYSA-L nickel sulfate Chemical compound [Ni+2].[O-]S([O-])(=O)=O LGQLOGILCSXPEA-UHFFFAOYSA-L 0.000 claims description 25
- 229910000363 nickel(II) sulfate Inorganic materials 0.000 claims description 25
- 238000009713 electroplating Methods 0.000 claims description 22
- 230000008569 process Effects 0.000 claims description 21
- 150000001875 compounds Chemical class 0.000 claims description 20
- 229960002449 glycine Drugs 0.000 claims description 14
- RPNUMPOLZDHAAY-UHFFFAOYSA-N Diethylenetriamine Chemical compound NCCNCCN RPNUMPOLZDHAAY-UHFFFAOYSA-N 0.000 claims description 13
- 239000011734 sodium Substances 0.000 claims description 12
- 239000004471 Glycine Substances 0.000 claims description 10
- 239000005749 Copper compound Substances 0.000 claims description 9
- 239000002253 acid Substances 0.000 claims description 9
- KRKNYBCHXYNGOX-UHFFFAOYSA-N citric acid Chemical compound OC(=O)CC(O)(C(O)=O)CC(O)=O KRKNYBCHXYNGOX-UHFFFAOYSA-N 0.000 claims description 9
- 150000001880 copper compounds Chemical class 0.000 claims description 9
- 238000004090 dissolution Methods 0.000 claims description 9
- PIICEJLVQHRZGT-UHFFFAOYSA-N Ethylenediamine Chemical compound NCCN PIICEJLVQHRZGT-UHFFFAOYSA-N 0.000 claims description 8
- 229910001431 copper ion Inorganic materials 0.000 claims description 8
- QPLDLSVMHZLSFG-UHFFFAOYSA-N Copper oxide Chemical compound [Cu]=O QPLDLSVMHZLSFG-UHFFFAOYSA-N 0.000 claims description 7
- 150000003839 salts Chemical class 0.000 claims description 7
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 claims description 6
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 claims description 6
- YJROYUJAFGZMJA-UHFFFAOYSA-N boron;morpholine Chemical compound [B].C1COCCN1 YJROYUJAFGZMJA-UHFFFAOYSA-N 0.000 claims description 6
- NBIIXXVUZAFLBC-UHFFFAOYSA-N phosphoric acid Substances OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 claims description 6
- LJCNRYVRMXRIQR-OLXYHTOASA-L potassium sodium L-tartrate Chemical compound [Na+].[K+].[O-]C(=O)[C@H](O)[C@@H](O)C([O-])=O LJCNRYVRMXRIQR-OLXYHTOASA-L 0.000 claims description 6
- 229940074439 potassium sodium tartrate Drugs 0.000 claims description 6
- 229910052708 sodium Inorganic materials 0.000 claims description 6
- 235000011006 sodium potassium tartrate Nutrition 0.000 claims description 6
- 230000003647 oxidation Effects 0.000 claims description 5
- 238000007254 oxidation reaction Methods 0.000 claims description 5
- AKHNMLFCWUSKQB-UHFFFAOYSA-L sodium thiosulfate Chemical compound [Na+].[Na+].[O-]S([O-])(=O)=S AKHNMLFCWUSKQB-UHFFFAOYSA-L 0.000 claims description 5
- 239000005751 Copper oxide Substances 0.000 claims description 4
- QPCDCPDFJACHGM-UHFFFAOYSA-N N,N-bis{2-[bis(carboxymethyl)amino]ethyl}glycine Chemical compound OC(=O)CN(CC(O)=O)CCN(CC(=O)O)CCN(CC(O)=O)CC(O)=O QPCDCPDFJACHGM-UHFFFAOYSA-N 0.000 claims description 4
- 230000002378 acidificating effect Effects 0.000 claims description 4
- 229910000147 aluminium phosphate Inorganic materials 0.000 claims description 4
- 230000003197 catalytic effect Effects 0.000 claims description 4
- 238000001311 chemical methods and process Methods 0.000 claims description 4
- 239000003153 chemical reaction reagent Substances 0.000 claims description 4
- 150000001879 copper Chemical class 0.000 claims description 4
- 229910000431 copper oxide Inorganic materials 0.000 claims description 4
- 235000013905 glycine and its sodium salt Nutrition 0.000 claims description 4
- 229910052739 hydrogen Inorganic materials 0.000 claims description 4
- 239000001257 hydrogen Substances 0.000 claims description 4
- 238000005470 impregnation Methods 0.000 claims description 4
- 229960003330 pentetic acid Drugs 0.000 claims description 4
- 238000002791 soaking Methods 0.000 claims description 4
- FEWJPZIEWOKRBE-JCYAYHJZSA-N Dextrotartaric acid Chemical compound OC(=O)[C@H](O)[C@@H](O)C(O)=O FEWJPZIEWOKRBE-JCYAYHJZSA-N 0.000 claims description 3
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims description 3
- FEWJPZIEWOKRBE-UHFFFAOYSA-N Tartaric acid Natural products [H+].[H+].[O-]C(=O)C(O)C(O)C([O-])=O FEWJPZIEWOKRBE-UHFFFAOYSA-N 0.000 claims description 3
- NSOXQYCFHDMMGV-UHFFFAOYSA-N Tetrakis(2-hydroxypropyl)ethylenediamine Chemical compound CC(O)CN(CC(C)O)CCN(CC(C)O)CC(C)O NSOXQYCFHDMMGV-UHFFFAOYSA-N 0.000 claims description 3
- 229910021529 ammonia Inorganic materials 0.000 claims description 3
- 238000003421 catalytic decomposition reaction Methods 0.000 claims description 3
- 239000011975 tartaric acid Substances 0.000 claims description 3
- 235000002906 tartaric acid Nutrition 0.000 claims description 3
- 238000005979 thermal decomposition reaction Methods 0.000 claims description 3
- NQXGLOVMOABDLI-UHFFFAOYSA-N sodium oxido(oxo)phosphanium Chemical compound [Na+].[O-][PH+]=O NQXGLOVMOABDLI-UHFFFAOYSA-N 0.000 claims 1
- 238000000576 coating method Methods 0.000 abstract description 28
- 239000011248 coating agent Substances 0.000 abstract description 19
- 238000004519 manufacturing process Methods 0.000 abstract description 3
- 150000003016 phosphoric acids Chemical class 0.000 abstract 1
- 238000001994 activation Methods 0.000 description 48
- 239000010410 layer Substances 0.000 description 45
- 239000000243 solution Substances 0.000 description 30
- 229910052751 metal Inorganic materials 0.000 description 21
- 239000002184 metal Substances 0.000 description 21
- 230000004888 barrier function Effects 0.000 description 19
- 239000000463 material Substances 0.000 description 9
- 239000000758 substrate Substances 0.000 description 9
- 230000008901 benefit Effects 0.000 description 8
- 239000010931 gold Substances 0.000 description 8
- 239000003054 catalyst Substances 0.000 description 7
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 7
- 238000007772 electroless plating Methods 0.000 description 6
- 229910052737 gold Inorganic materials 0.000 description 6
- 238000010979 pH adjustment Methods 0.000 description 6
- ACVYVLVWPXVTIT-UHFFFAOYSA-M phosphinate Chemical compound [O-][PH2]=O ACVYVLVWPXVTIT-UHFFFAOYSA-M 0.000 description 6
- 238000006722 reduction reaction Methods 0.000 description 6
- 239000000126 substance Substances 0.000 description 6
- 238000005530 etching Methods 0.000 description 5
- 150000002500 ions Chemical class 0.000 description 5
- 238000001465 metallisation Methods 0.000 description 5
- 230000009467 reduction Effects 0.000 description 5
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 4
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 4
- 150000007513 acids Chemical class 0.000 description 4
- 229910052783 alkali metal Inorganic materials 0.000 description 4
- 230000015572 biosynthetic process Effects 0.000 description 4
- 238000006243 chemical reaction Methods 0.000 description 4
- 238000007654 immersion Methods 0.000 description 4
- ACVYVLVWPXVTIT-UHFFFAOYSA-N phosphinic acid Chemical compound O[PH2]=O ACVYVLVWPXVTIT-UHFFFAOYSA-N 0.000 description 4
- 239000004065 semiconductor Substances 0.000 description 4
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 description 3
- 229910018104 Ni-P Inorganic materials 0.000 description 3
- 229910018536 Ni—P Inorganic materials 0.000 description 3
- 230000003213 activating effect Effects 0.000 description 3
- 229910052796 boron Inorganic materials 0.000 description 3
- 239000000356 contaminant Substances 0.000 description 3
- 238000009792 diffusion process Methods 0.000 description 3
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 3
- 150000002739 metals Chemical group 0.000 description 3
- 229910052698 phosphorus Inorganic materials 0.000 description 3
- 239000011574 phosphorus Substances 0.000 description 3
- 239000003381 stabilizer Substances 0.000 description 3
- 229910000990 Ni alloy Inorganic materials 0.000 description 2
- FEBFYWHXKVOHDI-UHFFFAOYSA-N [Co].[P][W] Chemical compound [Co].[P][W] FEBFYWHXKVOHDI-UHFFFAOYSA-N 0.000 description 2
- 239000003929 acidic solution Substances 0.000 description 2
- 239000012790 adhesive layer Substances 0.000 description 2
- 150000001340 alkali metals Chemical class 0.000 description 2
- 239000012670 alkaline solution Substances 0.000 description 2
- 229910045601 alloy Inorganic materials 0.000 description 2
- 239000000956 alloy Substances 0.000 description 2
- 238000004140 cleaning Methods 0.000 description 2
- 239000010941 cobalt Substances 0.000 description 2
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 description 2
- 238000005137 deposition process Methods 0.000 description 2
- 238000006073 displacement reaction Methods 0.000 description 2
- 150000004679 hydroxides Chemical class 0.000 description 2
- 230000007246 mechanism Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 2
- 239000011347 resin Substances 0.000 description 2
- 229920005989 resin Polymers 0.000 description 2
- 238000004381 surface treatment Methods 0.000 description 2
- 238000005406 washing Methods 0.000 description 2
- 241000132028 Bellis Species 0.000 description 1
- KXDHJXZQYSOELW-UHFFFAOYSA-N Carbamic acid Chemical compound NC(O)=O KXDHJXZQYSOELW-UHFFFAOYSA-N 0.000 description 1
- 229910000531 Co alloy Inorganic materials 0.000 description 1
- 229910001111 Fine metal Inorganic materials 0.000 description 1
- YZCKVEUIGOORGS-UHFFFAOYSA-N Hydrogen atom Chemical compound [H] YZCKVEUIGOORGS-UHFFFAOYSA-N 0.000 description 1
- 229910018661 Ni(OH) Inorganic materials 0.000 description 1
- 229910021140 PdSi Inorganic materials 0.000 description 1
- 101150003085 Pdcl gene Proteins 0.000 description 1
- 206010070834 Sensitisation Diseases 0.000 description 1
- 150000001298 alcohols Chemical class 0.000 description 1
- 150000001412 amines Chemical class 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 230000006399 behavior Effects 0.000 description 1
- KKAXNAVSOBXHTE-UHFFFAOYSA-N boranamine Chemical class NB KKAXNAVSOBXHTE-UHFFFAOYSA-N 0.000 description 1
- 150000001639 boron compounds Chemical group 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 238000006555 catalytic reaction Methods 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 238000005234 chemical deposition Methods 0.000 description 1
- 238000009388 chemical precipitation Methods 0.000 description 1
- 239000011247 coating layer Substances 0.000 description 1
- 229910017052 cobalt Inorganic materials 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 238000006731 degradation reaction Methods 0.000 description 1
- 238000006356 dehydrogenation reaction Methods 0.000 description 1
- 239000008367 deionised water Substances 0.000 description 1
- 229910021641 deionized water Inorganic materials 0.000 description 1
- 238000007598 dipping method Methods 0.000 description 1
- 238000000454 electroless metal deposition Methods 0.000 description 1
- 230000008030 elimination Effects 0.000 description 1
- 238000003379 elimination reaction Methods 0.000 description 1
- 150000002148 esters Chemical class 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 230000006870 function Effects 0.000 description 1
- 150000002431 hydrogen Chemical class 0.000 description 1
- 238000006460 hydrolysis reaction Methods 0.000 description 1
- 125000002887 hydroxy group Chemical group [H]O* 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 238000011065 in-situ storage Methods 0.000 description 1
- 230000000977 initiatory effect Effects 0.000 description 1
- 238000005342 ion exchange Methods 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 238000004377 microelectronic Methods 0.000 description 1
- 125000000896 monocarboxylic acid group Chemical group 0.000 description 1
- BSIDXUHWUKTRQL-UHFFFAOYSA-N nickel palladium Chemical compound [Ni].[Pd] BSIDXUHWUKTRQL-UHFFFAOYSA-N 0.000 description 1
- 239000012811 non-conductive material Substances 0.000 description 1
- 238000005457 optimization Methods 0.000 description 1
- 239000007800 oxidant agent Substances 0.000 description 1
- 150000002927 oxygen compounds Chemical class 0.000 description 1
- JRKICGRDRMAZLK-UHFFFAOYSA-L peroxydisulfate Chemical compound [O-]S(=O)(=O)OOS([O-])(=O)=O JRKICGRDRMAZLK-UHFFFAOYSA-L 0.000 description 1
- 238000005554 pickling Methods 0.000 description 1
- 238000009832 plasma treatment Methods 0.000 description 1
- 239000004033 plastic Substances 0.000 description 1
- 229910052697 platinum Inorganic materials 0.000 description 1
- 229910021420 polycrystalline silicon Inorganic materials 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 229920005591 polysilicon Polymers 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 239000011241 protective layer Substances 0.000 description 1
- 238000006479 redox reaction Methods 0.000 description 1
- 230000008313 sensitization Effects 0.000 description 1
- 239000002356 single layer Substances 0.000 description 1
- 229910000679 solder Inorganic materials 0.000 description 1
- 238000001179 sorption measurement Methods 0.000 description 1
- 230000002269 spontaneous effect Effects 0.000 description 1
- 229910001432 tin ion Inorganic materials 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
Classifications
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- 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
- C23C18/1601—Process or apparatus
- C23C18/1603—Process or apparatus coating on selected surface areas
-
- 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
- C23C18/1601—Process or apparatus
- C23C18/1633—Process of electroless plating
- C23C18/1635—Composition of the substrate
- C23C18/1637—Composition of the substrate metallic substrate
-
- 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
- C23C18/1601—Process or apparatus
- C23C18/1633—Process of electroless plating
- C23C18/1646—Characteristics of the product obtained
- C23C18/165—Multilayered product
- C23C18/1651—Two or more layers only obtained by electroless plating
-
- 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
- C23C18/18—Pretreatment of the material to be coated
- C23C18/1803—Pretreatment of the material to be coated of metallic material surfaces or of a non-specific material surfaces
- C23C18/1824—Pretreatment of the material to be coated of metallic material surfaces or of a non-specific material surfaces by chemical pretreatment
- C23C18/1837—Multistep pretreatment
- C23C18/1844—Multistep pretreatment with use of organic or inorganic compounds other than metals, first
-
- 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
- C23C18/18—Pretreatment of the material to be coated
- C23C18/1803—Pretreatment of the material to be coated of metallic material surfaces or of a non-specific material surfaces
- C23C18/1848—Pretreatment of the material to be coated of metallic material surfaces or of a non-specific material surfaces by electrochemical pretreatment
-
- 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
- C23C18/32—Coating with nickel, cobalt or mixtures thereof with phosphorus or boron
- C23C18/34—Coating with nickel, cobalt or mixtures thereof with phosphorus or boron using reducing agents
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- 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
- C23C18/32—Coating with nickel, cobalt or mixtures thereof with phosphorus or boron
- C23C18/34—Coating with nickel, cobalt or mixtures thereof with phosphorus or boron using reducing agents
- C23C18/36—Coating with nickel, cobalt or mixtures thereof with phosphorus or boron using reducing agents using hypophosphites
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- 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
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- 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
- C23C28/00—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D
- C23C28/02—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D only coatings only including layers of metallic material
- C23C28/023—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D only coatings only including layers of metallic material only coatings of metal elements only
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- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D11/00—Electrolytic coating by surface reaction, i.e. forming conversion layers
- C25D11/02—Anodisation
- C25D11/34—Anodisation of metals or alloys not provided for in groups C25D11/04 - C25D11/32
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- 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
- C23C18/18—Pretreatment of the material to be coated
- C23C18/1803—Pretreatment of the material to be coated of metallic material surfaces or of a non-specific material surfaces
- C23C18/1824—Pretreatment of the material to be coated of metallic material surfaces or of a non-specific material surfaces by chemical pretreatment
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Abstract
The present invention relates to the selective deposition of nickel layers on copper surfaces. The invention can be used for the production of conductive areas of electronic circuits. The method for depositing nickel on a copper surface includes: the article to be deposited with the nickel layer is immersed in one or more baths, wherein at least one bath contains a reducing agent, and wherein at least one bath is adapted for (electroless) nickel plating. In order to expand the field of application and obtain a practically pure nickel coating, the reducing agent comprises boric acid or phosphoric acid compounds, which include morpholinoborane (C 4 H 9 BNO), or dimethylamine borane (C) 2 H 7 BN), or sodium tetrahydroborate (NaBH) 4 ) Or sodium hypophosphite (NaBH) 4 ) And the reducing agent directly or indirectly reduces insoluble copper (I) or copper (II) compounds on the copper surface.
Description
Technical Field
The present invention relates to the field of chemical processes for metal deposition in electronics, automobiles and other fields. In particular, the invention is useful for selectively depositing a nickel layer on a copper surface. The invention is of great importance in the production of conductive areas of electronic circuits, wherein a nickel barrier layer with excellent adhesion is formed on the conductive copper tracks to prevent unwanted diffusion of copper into other materials in contact with the conductive areas and elsewhere where final or intermediate coating of copper is required.
Background
The patent US 6180523 B1 (10, 13, 1998) to choan-Ying Lee discloses three options for forming Cu/Au contacts and bonds with a three-layer system using electroless metal deposition: an adhesive layer, a barrier layer, and a finishing layer. These three forms have different barrier layers for electroless deposition of Cu or Au. The adhesive layer is made of Ni, al, polysilicon or PdSi on non-conductive material x And (5) forming. A first barrier layer is electrolessly deposited on the adhesion layer. The first barrier layer is composed of Ni, pd, co or alloys of Ni, pd and Co. Using PdCl-containing materials 2 Is used to activate the first barrier layer. Finally, the top layer of Cu or Au is electroless coated.
A disadvantage of the known method is the use of a complex multi-layer deposition system. Ion activation with palladium is performed using expensive and rare materials. Palladium is a very active catalyst that not only adsorbs perfectly on the metal; thus, the selectivity of metal deposition may be lost and the coated metal may be deposited not only on the desired metal structure but also on the surface of the dielectric substrate in its vicinity.
Japanese patent application No. 9-307234 (1996, 5, 20) by yo. Funada et al (U.S. Pat. No. 5830563) describes a method for fabricating conductive areas on a printed circuit board in which palladium is deposited on a copper surface by an electro-displacement reaction of copper and palladium by immersion in a bath containing palladium. Palladium attached to the surface acts as a catalyst for electroless deposition of the metal. On the other hand, palladium activation has been known in the past for chemical (electroless) deposition of metals, in which palladium ions are reduced by oxidation of tin ions.
A disadvantage of the known method is that activation with palladium is performed, which uses expensive and rare materials. Palladium is a highly active catalyst that not only adsorbs perfectly to the metal, thus losing the surface selectivity of the metal deposition, and the coating metal can be deposited not only on the desired metal structure, but also on the surface of the dielectric substrate in its vicinity.
The invention of EP 2233608 B1 of Elisabeth Zettelmeyer et al (3/23/2009) relates to a final layer coating process for producing Printed Circuit Boards (PCBs). The present invention describes a method for electroless coating of nickel on copper surfaces. The method comprises the following steps: i) Activating the copper surface with palladium ions; (ii) Removing excess palladium ions or their precipitates by means of a special solution containing at least two different types of acids, one of which is an organic amino carboxylic acid; and (iii) depositing nickel without flowing.
A disadvantage of the known method is the use of palladium activation, which uses expensive and rare substances such as palladium. The pickling procedure is not compatible with many semiconductors, thus limiting the application of this technique. Washing palladium with an acidic solution consumes expensive and rare palladium.
Patent KR 101883249 B1 (11/13/2013) described by Tae Hyeon Lee and Tae Kwon Lee relates to a surface treatment for electroless deposition of nickel on copper, comprising the step of etching in a liquid etchant to clean and roughen the copper surface; after the etching process, treating the copper surface with a preparation solution containing an acid, water and a reducing agent; after this procedure, the prepared surface was activated with an ionic palladium solution.
A disadvantage of the known method is that the etching procedure severely limits the substrate (dielectric) material. A disadvantage of the known method is that the etching procedure severely limits the substrate (dielectric) material. Furthermore, the non-conductive surface may be roughened during etching so that active palladium ions may be adsorbed on the surface that should not be coated. Also, palladium is expensive and rare.
US 2010051387 A1 (8/10/2009) by tachibana, t.ito and y.mitsui describes a method for electroless plating of nickel-palladium-gold coatings on substrates, wherein fine metal structures are formed on organic resins; the method includes the steps of treating a metal structure with a palladium catalyst and then forming a nickel palladium gold layer on the structure. In the method, at least one surface treatment selected from the group consisting of treatment with a solution having a pH of 10 to 14 and plasma treatment is performed at an optional step after the step of providing a palladium catalyst and before the step of performing electroless palladium plating.
A disadvantage of the known method is that palladium is used not only for activation but also for forming the barrier layer by electroless deposition. This process uses a number of expensive palladium.
A common disadvantage of all the above methods (using palladium catalysis) is that palladium forms islands on the surface to be catalyzed, which can result in an uneven coating containing primed areas. Thus, the use of such palladium catalyst cores to grow a barrier layer will produce a non-uniform and heterogeneous barrier coating. In addition, in order to form a barrier layer as a continuous uniform coating layer on the entire metal surface, it is necessary to increase the thickness of the barrier layer, which depends on the density of the formed palladium islands. Palladium is also known to have very strong adsorption on any surface, which reduces the selectivity of the deposition of the metal layer. These problems make it difficult to control the process.
An electroless plating process for depositing nickel or cobalt on a non-conductive substrate without using palladium as a catalyst layer is described in U.S. patent No. 4,002,778 to bellis et al (1978, 08, 15). The non-conductive layer is activated by a solution of water and a reducing agent. Alkali metal borohydrides, alkali metal cyanoborohydrides and aminoboranes may be used as reducing agents in solution at a concentration of at least 0.5g/l of reducing agent. The coated article is then immersed in an electroless plating bath to chemically reduce the nickel, provided that the reducing agent in the activation solution is an alkali metal borohydride, which also acts as a reducing agent in the plating bath. It should be noted that an additional process step of electroless copper deposition, persulfate copper surface with aggressive oxidizing agents, is used.
Furthermore, in U.S. patent No. 4,002,778, a solution containing alkali metal salts is proposed, which is particularly undesirable in semiconductor processing. The deposition process is slow.
Patent application US 2008/0254205A1 (13/04/2007) claims electroless deposition of cobalt or nickel alloys from solutions comprising two stabilizers, namely hypophosphite and Mo (VI) compounds.
In the case of the present invention, no stabilizer is required. In some implementations, the hypophosphite acts as a reducing agent but not as a stabilizing agent. As boron-containing reducing agents we use morpholine borane or sodium borohydride not used in the above applications. Furthermore, according to patent application US 2008/0254205A1, only nickel alloys are plated, whereas the present application allows to obtain pure nickel coatings.
U.S. Pat. No.5,695,810 (09/12/1997) to Dubin et al describes a process in which a copper surface is coated with a composite cobalt-tungsten-phosphorus (Co-W-P) coating. This technique attempts to prevent copper diffusion by creating a barrier layer on the copper surface by forming layers and/or structures on the semiconductor wafer. In this method, a cobalt tungsten phosphorus coating is deposited by chemical deposition, activating the copper surface prior to the coating process.
This method is characterized by a low deposition rate, which can be improved by catalytic activation.
U.S. patent No. 6794288B1 (05/05/2003) to Kolics et al describes a method for selectively depositing a Co-W-P structural coating on copper without palladium activation by forming a hydrogen-rich complex on the surface of the metal and then depositing the metal. More specifically, the method involves forming a complex on the copper surface prior to electroless deposition of the Co-W-P system coating. This is achieved by contacting the copper surface with a reducing agent at high temperature for a short period of time. Such reducing agents include hypophosphorous acid or boron-containing reducing agents such as dimethylamine borane. Reduction with hypophosphorous acid is preferred because it is more compatible with chemical precipitation solutions. The method is applicable to phosphorus-containing coatings deposited by electroless plating procedures.
The disadvantage of this method is the fact that: the authors wash the activated copper surface with water, which is a significant disadvantage, as during the water wash hydrolysis reactions occur, the products of which adsorb and contaminate the coated surface. This is especially a problem when hypophosphorous acid is used. Furthermore, electroless plating processes are performed at high temperatures, which is not attractive from an industrial point of view.
Another disadvantage of the known method is that the activation is only used for phosphor-containing electroless deposition of the coating, which significantly limits the application of the barrier layer forming method.
U.S. patent application 2005/194255A1 (04/03/2004) to Tiwari Chandra s describes a method of metal plating to form interconnects on semiconductor components. Patent application US2005/194255A1 teaches a self-activation process for Ni electroless deposition on copper substrates using hypophosphite or dimethylamine borane as a reducing agent. The electroless Ni is deposited in an alkaline solution (pH>7) And temperature>85 ℃ (in the case of hypophosphites) or>55 ℃ (in the case of dimethylamine borane). The disadvantage of the present invention is that the initiation of nickel plating on copper surfaces is obtained only by reducing the copper oxide without binding it to the complex, whereby the reduced but still active copper can contaminate the plating bath by (again) forming copper contaminants such as hydroxyl or oxygen compounds on the surface or in the bath solution, thus reducing the quality of the plating and limiting the deposition rate. Another disadvantage is that the bath solution is limited to alkaline environments. Alkaline pH of electroless Ni deposition bath using hypophosphite as reducing agent: pH value>8, the temperature limit is higher than 85 ℃. In the metal plating, an alkaline solution is not preferable because surface contaminants such as oxides and hydroxides are formed on the metal surface. Since the filing of patent application US2005/194255A1, the understanding of electrochemical processes has changed, and is therefore described in [0024 ]]Similar to the medium-grade "… Ni + Ion-exchanged Cu ++ Ions, which cause a monolayer "of Ni … …" are now known to be wrong because there is no Ni in the bath + Ion (Ni only) ++ Ion) also free of Cu ++ Ion exchange. Furthermore, explanation of the mechanism of self-initiation therein [0030-0049]Not in compliance with the prior knowledge noted above. For the purpose of depositing nickel on surfaces of articles made of copper or having a copper layer thereonIt is desirable to have a sufficient understanding of the chemical and/or thermodynamic behavior, particularly in relation to the self-priming mechanism. It is known that in the case of spontaneous displacement reactions, only metals with more positive standard reduction potentials can be deposited during the redox reaction. For example, ni (E 0 ＝-0.25V)+Cu 2+ (E 0 ＝0.34V)
Cu+Ni 2+ (battery electromotive force EMF is 0.34- (-0.25) =0.59V). The thermodynamically opposite reaction cannot be performed. Thus, as described in patent application US2005/194255A1, ni is not possible from Ni 2+ Cu is replaced in the solution.
In EP2177646A1, boyle Mike et Al (17/10/2008) describe a method of electroless plating of a trimetallic coating on an Al or Cu surface: (a) a Ni-P layer, (b) a Pd layer, and optionally (c) an Au layer. The first Ni-P layer was deposited by electroless Ni using hypophosphite as a reducing agent.
A disadvantage of the present invention is that the mentioned method is not a self-activating method, since Pd activation is required before Ni-P deposition.
Technical problem to be solved
The object of the present invention is to create economically viable and rare materials, such as palladium saving techniques for forming nickel barriers on copper surfaces for conductive trace and contact production, so that the nickel barriers can be formed directly on the copper surfaces without the need for auxiliary activation of palladium or similar layer formation, thus reducing the number of process steps. In fact, in contrast to the methods described in the analogues, pure nickel coatings can be obtained by this method.
Disclosure of Invention
The essence of the solution according to the invention is, in a method for depositing nickel on the surface of an article produced from copper or having a copper layer on the article, comprising: immersing the article in one or more baths, at least one bath containing a reducing agent, at least one bath suitable for electroless nickel plating, wherein the reducing agent comprises a boric acid or phosphoric acid compound comprising morpholinoborane (C 4 H 9 BNO), or dimethylamine borane (C) 2 H 7 BN), or sodium tetrahydroborate (NaBH) 4 ) Or sodium hypophosphite (NaH) 2 PO 2 ) And the reducing agent directly or indirectly reduces insoluble copper (I) or copper (II) compounds on the surface of the article produced from copper or on the copper layer of the article; and at least one of the mentioned baths contains ligands or mixtures thereof, which promote their dissolution by combining an incompletely reduced insoluble copper compound, copper oxide, with a soluble complex, so that a substantially pure copper surface is present where the nickel is deposited.
The ligand or mixture thereof is comprised of any water-soluble compound capable of forming a sufficiently stable complex with copper ions, including glycine (C 2 H 5 NO 2 ) Nitrotriacetic acid (C) 6 H 9 NO 6 ) Diethylene triamine pentaacetic acid (C) 14 H 23 N 3 O 10 ) And salts, tartaric acid (C) 4 H 6 O 6 ) The method comprises the steps of carrying out a first treatment on the surface of the Citric acid (C) 6 H 8 O 7 ) And salts thereof; ammonia (NH) 3 ) Ethylenediamine (C) 2 H 8 N 2 ) Diethylenetriamine (C) 4 H 13 N 3 ) N, N, N ', N' -tetrakis (2-hydroxypropyl) ethylenediamine (C) 14 H 32 N 2 O 4 )。
The method further comprises the steps of:
(i) Immersing the article in an activation bath comprising a reducing agent and a ligand, wherein electrons occurring after anodic oxidation of the reducing agent from the activation bath activate the copper surface by reducing Cu (I) and Cu (II) oxides and/or oxyhydroxide compounds on the surface while anodic catalytic or thermal decomposition reactions take place, releasing hydrogen, also reacting as an active reducing agent with Cu (I) and Cu (II) compounds on the copper surface, leaving behind a substantially pure copper surface in which nickel is subsequently deposited; and
(ii) Immersing the article having the activated copper surface in a second electroless nickel plating bath, wherein nickel is electrolessly deposited on the copper surface,
wherein immersing the article in the second electroless nickel plating bath occurs after immersing the article in the activation bath without any intermediate steps.
The method includes a single step of immersing the article directly into an electroless nickel plating bath comprising: a reducing agent selected from the group consisting of boric acid or a phosphoric acid reducing compound, the concentration of which is selected to reduce insoluble copper (I) and copper (II) compounds present on the surface of an article produced from copper or having a copper layer; and a ligand or ligand mixture selected from the group of compounds, the concentration of the ligand or ligand mixture of compounds being selected such that the compound dissolves the incompletely reduced insoluble copper compound by combining the incompletely reduced insoluble copper compound with a soluble complex, thereby retaining a substantially pure copper surface of the deposited nickel.
The activation bath consists of sodium hypophosphite (NaH) with a concentration of 0.5M to the solubility limit 2 PO 2 ) The solution and the ligand or the mixture thereof with a concentration of 0.001M to the solubility limit, and the impregnation time is 1 to 15min at a temperature of 80-96 ℃.
The activation bath is composed of morpholine borane (C) with concentration of 0.01M to solubility limit 4 H 9 BNO) solution and a ligand or a mixture thereof at a concentration of 0.001M to solubility limit, and a soaking time of 1 to 15min at a temperature of 18-50 ℃.
The activation bath is composed of dimethylamine borane (C) with a concentration of 0.01M to the solubility limit 2 H 7 BN) a solution and a ligand or a mixture thereof in a concentration of 0.001M to solubility limit and a soaking time of 1 to 15min at a temperature of 18-50 ℃.
The activation bath consists of sodium tetrahydroborate (NaBH) with a concentration of 0.01M to the solubility limit 4 ) The solution and the ligand or mixture thereof at a concentration of 0.001M to solubility limit and the impregnation time at a temperature of 18-50 ℃ is 1 to 15min.
The electroless nickel plating bath is composed of nickel sulfate (NiSO) with a concentration of 0.05-0.5M 4 ) Sodium hypophosphite reducing agent (NaH) with concentration of 0.25-3M 2 PO 2 ) Aminoacetic acid (C) at a concentration of 0.25-1M 2 H 5 NO 2 ) And sodium hydroxide (NaOH) at a concentration sufficient to adjust the desired pH.
The surface of an article produced from copper is nickel plated using a series of two different nickel plating baths, the first nickel plating bath containing sodium hypophosphite as a reducing agent, the article to be metallized is first immersed in an alkaline electroless nickel plating bath having a pH in the range 8.5-10.0, and then the article is immersed in a second nickel plating bath, which is an acidic electroless nickel plating bath having a pH in the range 4.0-6.0.
The electroless nickel plating bath is composed of nickel sulfate (NiSO) with a concentration of 0.05-0.5M 4 ) Morpholinoborane (C) at a concentration of 0.01-1M 4 H 9 BNO), diethylenetriamine (C) at a concentration of 0.001-0.5M 4 H 13 N 3 ) A ligand of (2), sodium hydroxide (NaOH) in a concentration sufficient to adjust the pH to a pH of 5.0 to 7.8; and electroplating is carried out at a temperature of 18-35 ℃.
The electroless nickel plating bath is composed of nickel sulfate (NiSO) with a concentration of 0.05-0.5M 4 ) Dimethylamine borane (C) at a concentration of 0.01-1M 2 H 7 BN), diethylenetriamine (C) at a concentration of 0.001-0.5M 4 H 13 N 3 ) A ligand of (2), sodium hydroxide (NaOH) in a concentration sufficient to adjust the pH to a pH of 5.0 to 7.8; electroplating is carried out at a temperature of 18-35 ℃.
The electroless nickel plating bath is composed of nickel sulfate (NiSO) with a concentration of 0.05-0.5M 4 ) Sodium tetrahydroborane (NaBH) with a concentration of 0.01-0.5M 4 ) And ethylenediamine (C) at a concentration of 0.001-0.5M 2 H 8 N 2 ) Is a ligand of (1) potassium sodium tartrate (KNaC) with concentration of 0.05-0.2M 4 H 4 O 6 ) Ligand of (2), disodium thiosulfate (Na) with concentration of 0.001-0.01M 2 S 2 O 3 ) Sodium hydroxide (NaOH) at a concentration sufficient to adjust the pH to a pH of 12.0-13.0; electroplating is carried out at a temperature of 18-35 ℃.
The electroless nickel plating bath is made of nickel sulfate (NiSO 4 ) Sodium hydroxide (NaOH), glycine (C) 2 H 5 NO 2 ) Ligand and sodium hypophosphite reductant (NaH) at a concentration exceeding 0.8M 2 PO 2 ) Composition is prepared.
The electroless nickel plating bath is composed of nickel sulfate (NiSO) with a concentration of 0.05-0.5M 4 ) Sodium hypophosphite reducing agent (NaH) with concentration of 0.8-3M 2 PO 2 ) Aminoacetic acid (C) at a concentration of 0.25-1M 2 H 5 NO 2 ) A ligand of (2), sodium hydroxide (NaOH) in a concentration sufficient to adjust the pH to a pH of 4.0-6.0; and electroplating is performed at a temperature of 80-96 ℃.
The electroless nickel plating bath is composed of nickel sulfate (NiSO) with a concentration of 0.05-0.5M 4 ) Morpholinoborane (C) at a concentration of 0.1-1M 4 H 9 BNO), diethylenetriamine (C) at a concentration of 0.001-0.5M 4 H 13 N 3 ) A ligand of (2), sodium hydroxide (NaOH) in a concentration sufficient to adjust the pH to a pH of 5.0 to 7.8; and electroplating is carried out at a temperature of 18-35 ℃.
The electroless nickel plating bath is composed of nickel sulfate (NiSO) with a concentration of 0.05-0.5M 4 ) Reducing agent of dimethylamine borane (C2H 7 BN) with concentration of 0.1-1M, diethylenetriamine (C) with concentration of 0.001-0.5M 4 H 13 N 3 ) A ligand of (2), sodium hydroxide (NaOH) in a concentration sufficient to adjust the pH to a pH of 5.0 to 7.8; and electroplating is carried out at a temperature of 18-35 ℃.
The electroless nickel plating bath is composed of nickel sulfate (NiSO) with a concentration of 0.05-0.5M 4 ) Sodium tetrahydroborane (NaBH) with a concentration of 0.02-0.5M 4 ) And ethylenediamine (C) at a concentration of 0.001-0.5M 2 H 8 N 2 ) Is a ligand of (1) potassium sodium tartrate (KNaC) with concentration of 0.05-0.2M 4 H 4 O 6 ) Ligand of (2), disodium thiosulfate (Na) with concentration of 0.001-0.01M 2 S 2 O 3 ) Sodium hydroxide (NaOH) at a concentration sufficient to adjust the pH to a pH of 12.0-13.0; and electroplating is carried out at a temperature of 18-35 ℃.
The method comprises the following steps: determining the concentration and/or the process time experimentally or in a computer-implemented or semi-automated manner from the read and loaded information about the quality of the deposited nickel layer of the article and the concentration of the reagent in the bath; and calculating the concentration of the bath and/or the time of the chemical process required for the process on site.
THE ADVANTAGES OF THE PRESENT INVENTION
The present invention relates to the formation of nickel barriers on copper surfaces on microelectronic or decorative coatings without the use of palladium activation. The practical advantage of the present invention is the elimination of the use of noble and rare metals such as palladium. The proposed method significantly improves the quality of barrier layer formation and the spatially selective resolution of the deposited conductive areas, since no palladium activation is used. Palladium is a very active metal so that it not only absorbs and activates the desired area, but also activates the substrate next to it. As a result, nickel may then deposit on unwanted areas and create shorts in the electronic circuit. This method also allows the copper surface to be activated faster than the other methods described above for nickel plating due to the use of the ligand with the reducing agent. Another essential advantage of the method is that nickel is formed directly on the copper surface, thus reducing the number of process steps and thus also the duration. Unlike the alternative method of palladium-free copper surface activation mentioned in the similar, this method allows the deposition of pure (without contamination by-products) nickel coatings.
Description of the invention and embodiments
The conductive areas in the electronic device are mainly formed of copper, since copper has one of the highest conductivities (higher than gold), is relatively inexpensive, and can be easily deposited on a dielectric substrate such as a fiber reinforced resin, a polymer or even a ceramic. However, copper atoms diffuse into other materials (such as solder), which results in degradation of the copper layer. In addition, copper is prone to oxidation. For these reasons, a barrier layer is deposited. It is most convenient to form a nickel barrier layer in which diffusion of copper atoms does not occur and a thin oxide protective layer of gold or platinum and a conductive layer can be easily deposited on the layer by immersion. Electroless nickel plating baths using phosphorus-containing compounds are virtually impossible to deposit nickel onto copper surfaces or are prolonged processes without additional activation or sensitization, thus introducing a surface activation step. Activation is typically performed with palladium, but this process is expensive and it is difficult to control the spatial selectivity of the deposition.
The present invention is directed to activating copper surfaces for electroless deposition of nickel from a bath. This process can be implemented in two ways. First, by using a reducing agent containing boron or phosphorusAnd an activation solution (bath) comprising copper ion ligands or mixtures thereof activates the desired metallized areas, and then the activated copper surface is immersed in an electroless nickel plating bath, wherein a nickel layer is selectively formed directly on the copper surface to be coated. Another option is: using morpholine borane (C) 4 H 9 BNO) or dimethylamine borane (C) 2 H 7 BN) or sodium tetraborane (NaBH) 4 ) Or sodium hypophosphite (NaH) at higher concentrations (exceeding 0.8M) 2 PO 2 ) As a reducing agent in electroless nickel plating baths, nickel may be deposited directly on the copper surface without the need for an additional surface activation step.
Firstly, sulfuric acid H with concentration of 0.5-4M is used 2 SO 4 The surface is washed or wiped for 3-15 minutes. If the surface is strongly oxidized, this step is performed. If all other multi-layer coating steps are performed immediately (within 5 minutes) after electroless deposition of copper, this step may be omitted. The surface is then activated by an activation bath, optionally by immersion, using one of the following activation methods:
a) Sodium hypophosphite (NaH) at a concentration of 0.5M to the solubility limit and comprising one or more copper ion ligands 2 PO 2 ) Solutions, which are at a concentration of from 0.01M to the solubility limit and which have a dipping time of 1 to 15 minutes at a temperature of 80-96 ℃. After activation, with 0.5M NaH 2 PO 2 The solution was washed at 80-96 ℃ for 1 second.
b) 0.01M to solubility limit and containing one or more copper ion ligands, the concentration being 0.01M to solubility limit and the immersion time being 1 to 15 minutes at a temperature of 18-50 ℃. After activation, the surface was washed with water at 80-96 ℃ for 1 second.
c) Dimethylamine borane solution having a concentration of 0.01M to the solubility limit and containing one or more copper ion ligands, is immersed for a time of 1 to 15 minutes at a temperature of 18 to 50 ℃. After activation, the surface was washed with water at 80-96 ℃ for 1 second.
d) With sodium tetrahydroborate (NaBH) at a concentration of 0.01M to the solubility limit 4 ) And one or more copper ion ligands at a concentration of 0.01M to the solubility limitThe method comprises the steps of carrying out a first treatment on the surface of the The treatment time is 1-15 minutes at 18-50 ℃; after activation, the surface was washed with deionized water at 80-96 ℃ for 1 second.
Examples of activation baths:
composition and coating conditions of bath No. 1:
0.5M sodium hypophosphite (NaH) 2 PO 2 )；
0.01M-N, N, N ', N' -tetrakis (2-hydroxypropyl) ethylenediamine;
sodium hydroxide (NaOH) in a concentration sufficient to adjust the pH of the solution to 9.2;
last 5 minutes at 88 ℃.
Composition and coating conditions of bath No. 2:
0.5M morpholinoborane (C) 4 H 9 BNO)；
0.01M diethylenetriamine pentaacetic acid (C) 14 H 23 N 3 O 10 )；
Sodium hydroxide (NaOH), in a concentration sufficient to adjust the pH of the solution to 7;
last 5 minutes at 30 ℃.
Further, after the electroless deposition of nickel by immersing the article in a No. 3 chemical metallization bath (deposition rate of about 9.2 μm/h), which is alkaline to initiate the deposition process, the coating process was performed for 1-10 minutes, and then the article was immersed in a No. 4 bath (acidic) in which the nickel layer became thicker, deposition rate of about 3.7 μm/h.
Composition and conditions of bath No. 3:
0.1M Nickel sulfate (NiSO) 4 )；
0.5M sodium hypophosphite (NaH) 2 PO 2 )；
0.6M glycine (C) 2 H 5 NO 2 )；
Sodium hydroxide (NaOH) was added for pH adjustment to pH 9.2;
electroplating at a temperature of 85-92 ℃.
Composition and conditions of bath No. 4:
0.1M Nickel sulfate (NiSO) 4 )；
0.25M sodium hypophosphite (NaH) 2 PO 2 )；
0.4M glycine (C) 2 H 5 NO 2 )；
Sodium hydroxide (NaOH) was added for pH adjustment to pH 5.2;
electroplating at a temperature of 85-95 ℃.
Activation route a). The advantages are that: after activation, no cleaning of the parts is required; it can be immersed directly into a nickel plating bath containing the same reducing agent, sodium hypophosphite.
Activation routes b), c) and d). The advantages are that: the process is performed at room temperature, using low reagent concentrations; electroplating in a phosphorus-free electroless nickel plating bath using morpholine borane or dimethylamine borane as a reducing agent; a virtually pure nickel coating is deposited.
The described bath has the advantage that the activation can be carried out in any bath and then the nickel plating can also be carried out in any bath. In addition, acidic (non-alkaline) baths of electroless Ni deposition solutions using hypophosphite as a reducing agent use pH 4-6 at lower temperatures of 80 ℃. Acidic solutions are preferred because no surface contaminants such as oxides and hydroxides are formed on the metal surface due to their dissolution.
Examples:
NiO+2H + →Ni 2+ +H 2 O
Ni(OH) 2 +2H + →Ni 2+ +2H 2 O
another advantage is that a bath in which the reducing agent is a boron compound can be used to deposit a pure nickel coating free of phosphorus impurities.
Principle of operation: electrons formed during anodic oxidation of the reducing agent in solution activate the copper surface by reducing copper (I) and copper (II) oxides and oxyhydroxides on the surface to metallic copper. Atomic hydrogen (latin) formed during the release process is adsorbed on the surface at the same time as thermal and/or catalytic decomposition (dehydrogenation) of the reducing agent takes place. Hydrogen formed during release is known to be a very active reducing agent, thus further cleaning the copper surface to give it catalytic properties. Furthermore, the added ligands help to dissolve the incompletely reduced insoluble copper compounds by binding them to the soluble complexes. Electroless nickel plating processes on pure copper surfaces are easy to begin when the activated article is immersed in an electroless nickel plating bath.
Reaction during copper surface activation:
with sodium hypophosphite
2H 2 PO 2 - +2OH - →2H 2 PO 3 - +H 2 ↑+2e -
Cu 2+ +2e - →Cu 0
Cu + +e - →Cu 0
H 2 PO 2 - +H 2 O→H 2 PO 3 - +2H (ads)
Cu 2+ +2H (ads) →Cu 0 +2H +
Cu + +H (ads) →Cu 0 +H +
With morpholine borane
2C 4 H 8 O-NH·BH 3 +8OH - →2BO 2 - +2C 4 H 8 O-NH+4H 2 O+3H 2 ↑+6e -
Cu 2+ +2e - →Cu 0
Cu + +e - →Cu 0
C 4 H 8 O-NH·BH 3 +4OH - →BO 2 - +C 4 H 8 O-NH+2H 2 O+3H (ads) +3e -
Cu 2+ +2H (ads) →Cu 0 +2H +
Cu + +H (ads) →Cu 0 +H +
With dimethylamine borane
2(CH 3 ) 2 NH·BH 3 +8OH - →2BO 2 - +2(CH 3 ) 2 NH+4H 2 O+3H 2 ↑+6e -
Cu 2+ +2e - →Cu 0
Cu + +e - →Cu 0
(CH 3 ) 2 NH·BH 3 +4OH - →BO 2 - +(CH 3 ) 2 NH+2H 2 O+3H (ads) +3e -
Cu 2+ +2H (ads) →Cu 0 +2H +
Cu + +H (ads) →Cu 0 +H +
With tetrahydroboric acid esters
BH 4 - +4OH - →BO 2 - +2H 2 O+2H 2 ↑+4e -
Cu 2+ +2e - →Cu 0
Cu + +e - →Cu 0
BH 4 - +3OH - →BO 2 - +H 2 O+5H (ads) +3e -
Cu 2+ +2H (ads) →Cu 0 +2H +
Cu + +H (ads) →Cu 0 +H +
Advantages compared to other activation baths: when using a typical activation solution with Pd (II) salts, only the copper surface is activated and then nickel plated. The entire surface of the component is activated and nickel is deposited not only on copper but also on the plastic surface.
In one approach, the nickel coating may be deposited on the copper surface by skipping treatment with an activation bath. If an electroless nickel plating solution containing at least one of the following reducing agents is used: higher concentrations (greater than 0.8M) of morpholinoborane (C) 4 H 9 BNO), dimethylamine borane (C) 2 H 7 BN), sodium tetrahydroborate (NaBH) 4 ) Or sodium hypophosphite (NaH) 2 PO 2 ) The copper can be coated with nickel or its alloys without additional activation and washing steps.
Initially, the mixture is treated with 0.5-4M sulfuric acid H 2 SO 4 The surface is washed or wiped for 3-15 minutes. If the surface is strongly oxidized, this step is performed. If all other multi-layer coating steps are performed immediately after each step (within 5 minutes), this step may be omitted. Subsequently, electroless deposition of nickel is performed by immersing the article in an electroless metallization bath No.5 or No. 6 or No. 7.
Composition and conditions of bath No. 5:
0.05M Nickel sulfate (NiSO) 4 )；
0.1M morpholinoborane (C) 4 H 9 BNO)；
0.015M diethylenetriamine (C) 4 H 13 N 3 )；
Sodium hydroxide (NaOH) was added for pH adjustment to pH 7.0;
electroplating at a temperature of 30 ℃.
Composition and conditions of bath No. 6:
0.05M Nickel sulfate (NiSO) 4 )；
0.1M dimethylamine borane (C) 2 H 7 BNO)；
0.015M diethylenetriamine (C) 4 H 13 N 3 )；
Sodium hydroxide (NaOH) was added for pH adjustment to pH 7.0;
electroplating at a temperature of 30 ℃.
Composition and conditions of bath No. 7:
0.125M Nickel sulfate (NiSO) 4 )；
0.125M sodium tetrahydroborane (NaBH) 4 )；
0.25M ethylenediamine (C) 2 H 8 N 2 )；
0.15M Potassium sodium tartrate (KNaC) 4 H 4 O 6 )；
0.008M disodium thiosulfate (Na 2 S 2 O 3 )；
Sodium hydroxide (NaOH) was added for pH adjustment to pH 12.5;
electroplating at a temperature of 30 ℃.
Another example without an activation step may be given for electroless nickel plating baths, in which sodium hypophosphite is used as a reducing agent, and if a metal is used in the bath consisting of nickel sulfate (NiSO 4 ) Sodium hydroxide (NaOH), glycine (C) 2 H 5 NO 2 ) And sodium hypophosphite (NaH) 2 PO 2 ) NaH in electroless nickel plating bath of composition 2 PO 2 The activation step may be skipped if the concentration of (c) exceeds 0.8M.
Composition and conditions of bath No. 8:
0.1M Nickel sulfate (NiSO) 4 )；
1M sodium hypophosphite (NaOH);
0.4M glycine (C) 2 H 5 NO 2 )；
Sodium hydroxide (NaOH) was added for pH adjustment to pH 5.2;
electroplating at 92 ℃.
In electroless nickel baths of this type (nos. 5-8), no additional chemical activation is required, as the concentration of reducing agent already present in the solution is sufficient to prepare and activate the copper surface. Ni in electroless nickel plating bath 2+ The ions do not interfere with the copper activation process, diethylenetriamine (C 4 H 13 N 3 ) Ethylenediamine (C) 2 H 8 N 2 ) Glycine (C) 2 H 5 NO 2 ) And potassium sodium tartrate (KNaC) 4 H 4 O 6 ) It is also possible to participate in the transfer (dissolution) of copper as copper (II) ligands, e.g. copper oxide (CuO) and glycine (C) 2 H 5 NO 2 )：
CuO+2H 2 NCH 2 COOH→Cu(H 2 NCH 2 COO - ) 2 +H 2 O
The ligands in the bath promote their dissolution by binding the incompletely reduced insoluble copper compounds with the soluble complexes, leaving a substantially pure copper surface where the nickel is subsequently deposited. The ligand generates a complex with insoluble copper (from copper oxide) and thus achieves a completely different function with respect to the prior art methods.
These ligands may be selected from, but are not limited to, the following Cu (II) ligand groups: amines, polyhydroxy alcohols, polycarboxylic acids, hydroxy-polycarboxylic acids, polyamine-polycarboxylic acids. The ligand or mixture thereof is comprised of any water-soluble compound capable of forming a sufficiently stable complex with copper ions at a high rate, including but not limited to (C 2 H 5 NO 2 ) Nitrotriacetic acid (C) 6 H 9 NO 6 ) Diethylene triamine pentaacetic acid (C) 14 H 23 N 3 O 10 ) And salts, tartaric acid (C) 4 H 6 O 6 ) The method comprises the steps of carrying out a first treatment on the surface of the Citric acid (C) 6 H 8 O 7 ) And salts thereof; ammonia (NH) 3 ) N, N, N ', N' -tetrakis (2-hydroxypropyl) ethylenediamine (C) 14 H 32 N 2 O 4 )。
The optimal concentration of the reagent in the bath and the duration of the treatment may be determined using automated methods for determining the concentration of the solution and/or the duration of the treatment, using equipment that indicates and loads information to a computer regarding the surface of the article and the conditions of the bath and calculates the concentration of the bath and/or the data of the chemical treatment in situ based on the loaded information. Optimization by iteration (looping) can be performed in this way.
As a final consideration, it is worth emphasizing that the present invention describes a method for depositing nickel on the surface of an article produced from copper or having a copper layer thereon, the method comprising the steps of reduction, dissolution and electroplating.
In one embodiment of the invention, the steps may occur one after the other in a sequential manner, and it is possible to implement such a sequence by changing the bath between the steps.
However, in alternative embodiments of the invention, these steps may also occur in parallel or substantially simultaneously. Although the chemical process of course requires that at least some reduction must occur before dissolution occurs, it is in fact quite simultaneous that the reduction of the insoluble copper compounds and the dissolution of such insoluble compounds by the formation of soluble complex compounds occur because the rate of the reduction reaction is much higher (preferably at least two or more orders of magnitude) than the rate of the dissolution reaction. The advantage of this embodiment is that all methods occur in a single bath (single step) because the electroless nickel plating bath contains all the mentioned compounds: a reducing agent and a ligand (and thus a suitable mixture of all the required components). The present invention has been described in terms of specific embodiments, which should be considered as examples only and not limiting the true scope of the invention. Thus, any changes and modifications to the process, materials, and reactions are possible, provided that such changes and modifications do not depart from the definition of the invention of this patent.
Claims (19)
1. A method for depositing nickel on a surface of an article produced from copper or having a copper layer on the article, comprising:
immersing the article in one or more baths,
o at least one bath containing a reducing agent,
o at least one bath suitable for electroless nickel plating;
wherein,,
the reducing agent comprises a boric acid or phosphoric acid compound including morpholinoborane (C 4 H 9 BNO), or dimethylamine borane (C) 2 H 7 BN), or sodium tetrahydroborate (NaBH) 4 ) Or sodium hypophosphite (NaH) 2 PO 2 ) And the reducing agent directly or indirectly reduces insoluble copper (I) or copper (II) compounds on the surface of the article produced from copper or on a copper layer of the article; and is also provided with
At least one of the baths contains ligands or mixtures thereof, which promote dissolution of the incompletely reduced insoluble copper compounds (copper oxide) by combining them with soluble complexes, so that a substantially pure copper surface is present where the nickel is deposited.
2. The method according to claim 1, wherein the ligand or mixture thereof consists of any water-soluble compound capable of forming a sufficiently stable complex with copper ions, said compound comprising glycine (C 2 H 5 NO 2 ) Nitrotriacetic acid (C) 6 H 9 NO 6 ) Diethylene triamine pentaacetic acid (C) 14 H 23 N 3 O 10 ) And salts, tartaric acid (C) 4 H 6 O 6 ) The method comprises the steps of carrying out a first treatment on the surface of the Citric acid (C) 6 H 8 O 7 ) And salts thereof; ammonia (NH) 3 ) Ethylenediamine (C) 2 H 8 N 2 ) Diethylenetriamine (C) 4 H 13 N 3 ) N, N, N ', N' -tetrakis (2-hydroxypropyl) ethylenediamine (C) 14 H 32 N 2 O 4 )。
3. The method of claim 1, wherein the method further comprises:
(i) Immersing the article in an activation bath comprising the reducing agent and the ligand, wherein electrons occurring after anodic oxidation of the reducing agent from the activation bath activate the copper surface by reducing Cu (I) and Cu (II) oxides and/or oxyhydroxide compounds on the surface while anodic catalytic or thermal decomposition reactions occur, releasing hydrogen which also reacts as an active reducing agent with Cu (I) and Cu (II) compounds on the copper surface, leaving behind a substantially pure copper surface in which nickel is subsequently deposited; and
(ii) Immersing the article having the activated copper surface in a second electroless nickel plating bath, wherein nickel is electrolessly deposited on the copper surface,
wherein immersing the article in the second electroless nickel plating bath occurs after immersing the article in the activation bath without any intermediate steps.
4. The method of claim 1, wherein the method comprises a single step of immersing the article directly into an electroless nickel plating bath comprising: a reducing agent selected from the group consisting of the boric acid or phosphoric acid reducing compound, the concentration of which is selected to reduce insoluble copper (I) and copper (II) compounds present on the surface of the article produced from copper or having a copper layer; and said ligand or ligand mixture selected from the group of said compounds, the concentration of said ligand or ligand mixture being selected such that said compound dissolves said incompletely reduced insoluble copper compound by combining said incompletely reduced insoluble copper compound with a soluble complex, thereby preserving a substantially pure copper surface of the deposited nickel.
5. A process according to claim 3, wherein the activation bath consists of sodium hypophosphite (NaH 2 PO 2 ) The solution and the ligand or mixture thereof at a concentration of 0.001M to solubility limit and the impregnation time is 1 to 15min at a temperature of 80-96 ℃.
6. A process according to claim 3, wherein the activation bath is composed of morpholine borane (C) at a concentration of 0.01M to the solubility limit 4 H 9 BNO) solution and said ligand or mixture thereof in a concentration of 0.001M to solubility limit and for a soaking time of 1 to 15min at a temperature of 18-50 ℃.
7. A process according to claim 3, wherein the activation bath is composed of dimethylamine borane (C) at a concentration of 0.01M to the solubility limit 2 H 7 BN) a solution and said ligand or mixture thereof in a concentration of 0.001M to solubility limit and a soaking time of 1 to 15min at a temperature of 18-50 ℃.
8. A method according to claim 3, which comprisesIn the activation bath, the concentration of sodium tetrahydroborate (NaBH) is 0.01M to the solubility limit 4 ) The solution and the ligand or mixture thereof at a concentration of 0.001M to solubility limit and the impregnation time is 1 to 15min at a temperature of 18-50 ℃.
9. The method of claim 1, wherein the electroless nickel plating bath consists of nickel sulfate (NiSO) at a concentration of 0.05-0.5M 4 ) Sodium hypophosphite reducing agent (NaH) with concentration of 0.25-3M 2 PO 2 ) Aminoacetic acid (C) at a concentration of 0.25-1M 2 H 5 NO 2 ) And sodium hydroxide (NaOH) at a concentration sufficient to adjust the desired pH.
10. The method according to claim 1, wherein the surface of the article produced from copper is nickel plated using a series of two different nickel plating baths, a first nickel plating bath containing sodium hypophosphite as the reducing agent, the article to be metallized is first immersed in an alkaline electroless nickel plating bath having a pH in the range of 8.5-10.0, and then the article is immersed in a second nickel plating bath, which is an acidic electroless nickel plating bath having a pH in the range of 4.0-6.0.
11. The method according to claim 1, wherein the electroless nickel plating bath consists of nickel sulfate (NiSO) at a concentration of 0.05-0.5M 4 ) Morpholinoborane (C) at a concentration of 0.01-1M 4 H 9 BNO) reducing agent, diethylenetriamine (C) at a concentration of 0.001-0.5M 4 H 13 N 3 ) A ligand of (2), sodium hydroxide (NaOH) in a concentration sufficient to adjust the pH to a pH of 5.0 to 7.8; and electroplating is carried out at a temperature of 18-35 ℃.
12. The method according to claim 1, wherein the electroless nickel plating bath consists of nickel sulfate (NiSO) at a concentration of 0.05-0.5M 4 ) Dimethylamine borane (C) at a concentration of 0.01-1M 2 H 7 BN), diethylenetriamine (C) at a concentration of 0.001-0.5M 4 H 13 N 3 ) Is of sufficient concentrationTo adjust the pH to pH 5.0-7.8; and electroplating is carried out at a temperature of 18-35 ℃.
13. The method according to claim 1, wherein the electroless nickel plating bath consists of nickel sulfate (NiSO) at a concentration of 0.05-0.5M 4 ) Sodium tetrahydroborane (NaBH) with a concentration of 0.01-0.5M 4 ) And ethylenediamine (C) at a concentration of 0.001-0.5M 2 H 8 N 2 ) Is a ligand of (1) potassium sodium tartrate (KNaC) with concentration of 0.05-0.2M 4 H 4 O 6 ) Ligand of (2), disodium thiosulfate (Na) with concentration of 0.001-0.01M 2 S 2 O 3 ) Sodium hydroxide (NaOH) at a concentration sufficient to adjust the pH to a pH of 12.0-13.0; and electroplating is carried out at a temperature of 18-35 ℃.
14. The method of claim 4, wherein the electroless nickel plating bath is formed from nickel sulfate (NiSO 4 ) Sodium hydroxide (NaOH), glycine (C) 2 H 5 NO 2 ) Ligand of (2) and sodium hypophosphite (NaH) at a concentration exceeding 0.8M 2 PO 2 ) Is composed of a reducing agent.
15. The method according to any one of claims 4 and 14, wherein the electroless nickel plating bath consists of nickel sulfate (NiSO) at a concentration of 0.05-0.5M 4 ) Sodium hypophosphite reducing agent (NaH) with concentration of 0.8-3M 2 PO 2 ) Aminoacetic acid (C) at a concentration of 0.25-1M 2 H 5 NO 2 ) A ligand of (2), sodium hydroxide (NaOH) in a concentration sufficient to adjust the pH to a pH of 4.0-6.0; and electroplating is performed at a temperature of 80-96 ℃.
16. The method of claim 4, wherein the electroless nickel plating bath consists of nickel sulfate (NiSO 4 ) Morpholinoborane (C) at a concentration of 0.1-1M 4 H 9 BNO) reducing agent, diethylenetriamine (C) at a concentration of 0.001-0.5M 4 H 13 N 3 ) Is a ligand of (2), sodium hydroxide (Na) in a concentration sufficient to adjust the pH to a pH of 5.0-7.8OH); and electroplating is carried out at a temperature of 18-35 ℃.
17. The method of claim 4, wherein the electroless nickel plating bath consists of nickel sulfate (NiSO 4 ) Dimethylamine borane (C) at a concentration of 0.1-1M 2 H 7 BN), diethylenetriamine (C) at a concentration of 0.001-0.5M 4 H 13 N 3 ) A ligand of (2), sodium hydroxide (NaOH) in a concentration sufficient to adjust the pH to a pH of 5.0 to 7.8; and electroplating is carried out at a temperature of 18-35 ℃.
18. The method of claim 4, wherein the electroless nickel plating bath consists of nickel sulfate (NiSO 4 ) Sodium tetrahydroborane (NaBH) with a concentration of 0.02-0.5M 4 ) And ethylenediamine (C) at a concentration of 0.001-0.5M 2 H 8 N 2 ) Potassium sodium tartrate ligand (KNaC) with concentration of 0.05-0.2M 4 H 4 O 6 ) The method comprises the steps of carrying out a first treatment on the surface of the Disodium thiosulfate (Na) with concentration of 0.001-0.01M 2 S 2 O 3 ) Sodium hydroxide (NaOH) at a concentration sufficient to adjust the pH to a pH of 12.0-13.0; and electroplating is carried out at a temperature of 18-35 ℃.
19. The method according to any one of claims 1 and 18, wherein the method comprises: determining the concentration and/or the process time by experimental or computer-implemented or semi-automatic means from the read and loaded information about the quality of the deposited nickel layer of the article and the concentration of the reagent in the bath; and calculating the concentration of the bath and/or the time of the chemical process required for the process on site.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| LT2020542A LT6899B (en) | 2020-08-27 | 2020-08-27 | Method for electroless nickel deposition onto copper without activation with palladium |
| LTLT2020542 | 2020-08-27 | ||
| PCT/IB2021/057786 WO2022043889A1 (en) | 2020-08-27 | 2021-08-25 | Method for electroless nickel deposition onto copper without activation with palladium |
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| CN116324032A true CN116324032A (en) | 2023-06-23 |
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| US (1) | US20220064801A1 (en) |
| EP (1) | EP4204599A1 (en) |
| JP (1) | JP2023538951A (en) |
| KR (1) | KR20230056751A (en) |
| CN (1) | CN116324032A (en) |
| LT (1) | LT6899B (en) |
| WO (1) | WO2022043889A1 (en) |
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| US4002778A (en) | 1973-08-15 | 1977-01-11 | E. I. Du Pont De Nemours And Company | Chemical plating process |
| US5235139A (en) * | 1990-09-12 | 1993-08-10 | Macdermid, Incorprated | Method for fabricating printed circuits |
| TW341022B (en) | 1995-11-29 | 1998-09-21 | Nippon Electric Co | Interconnection structures and method of making same |
| JP2828032B2 (en) | 1996-05-20 | 1998-11-25 | 日本電気株式会社 | Method for manufacturing multilayer wiring structure |
| US5695810A (en) | 1996-11-20 | 1997-12-09 | Cornell Research Foundation, Inc. | Use of cobalt tungsten phosphide as a barrier material for copper metallization |
| US6180523B1 (en) | 1998-10-13 | 2001-01-30 | Industrial Technology Research Institute | Copper metallization of USLI by electroless process |
| US6794288B1 (en) | 2003-05-05 | 2004-09-21 | Blue29 Corporation | Method for electroless deposition of phosphorus-containing metal films onto copper with palladium-free activation |
| US20050194255A1 (en) * | 2004-03-04 | 2005-09-08 | Tiwari Chandra S. | Self-activated electroless metal deposition |
| AU2007224643B2 (en) * | 2006-03-16 | 2012-10-11 | Takeda Pharmaceutical Company Limited | Compositions and methods using serine protease inhibiting peptides for treating ophthalmic disorders |
| US20080254205A1 (en) | 2007-04-13 | 2008-10-16 | Enthone Inc. | Self-initiated alkaline metal ion free electroless deposition composition for thin co-based and ni-based alloys |
| ATE503037T1 (en) * | 2008-10-17 | 2011-04-15 | Atotech Deutschland Gmbh | STRESS-REDUCED NI-P/PD STACKS FOR WAFER SURFACE |
| EP2233608B1 (en) | 2009-03-23 | 2016-03-23 | ATOTECH Deutschland GmbH | Pre-treatment process for electroless nickel plating |
| JP5573429B2 (en) | 2009-08-10 | 2014-08-20 | 住友ベークライト株式会社 | Electroless nickel-palladium-gold plating method, plated product, printed wiring board, interposer, and semiconductor device |
| EP2671969A1 (en) * | 2012-06-04 | 2013-12-11 | ATOTECH Deutschland GmbH | Plating bath for electroless deposition of nickel layers |
| KR101883249B1 (en) | 2017-03-31 | 2018-08-30 | (주)엠케이켐앤텍 | A pretreating-activating solution for an electroless nickel plating, a method for electroless plating a thin-nickel and a method for surface-treating using the same, and a printed circuit board comprising an electroless thin-nickel |
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- 2020-08-27 LT LT2020542A patent/LT6899B/en unknown
- 2020-12-15 US US17/122,269 patent/US20220064801A1/en not_active Abandoned
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- 2021-08-25 EP EP21759163.5A patent/EP4204599A1/en active Pending
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| Publication number | Publication date |
|---|---|
| US20220064801A1 (en) | 2022-03-03 |
| WO2022043889A1 (en) | 2022-03-03 |
| EP4204599A1 (en) | 2023-07-05 |
| LT2020542A (en) | 2022-03-10 |
| KR20230056751A (en) | 2023-04-27 |
| WO2022043889A4 (en) | 2022-04-21 |
| JP2023538951A (en) | 2023-09-12 |
| LT6899B (en) | 2022-04-11 |
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