EP3945144A1 - Electroless palladium plating bath - Google Patents
Electroless palladium plating bath Download PDFInfo
- Publication number
- EP3945144A1 EP3945144A1 EP21187838.4A EP21187838A EP3945144A1 EP 3945144 A1 EP3945144 A1 EP 3945144A1 EP 21187838 A EP21187838 A EP 21187838A EP 3945144 A1 EP3945144 A1 EP 3945144A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- palladium
- compound
- acid
- plating bath
- plating
- 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.)
- Granted
Links
- 238000007747 plating Methods 0.000 title claims abstract description 173
- KDLHZDBZIXYQEI-UHFFFAOYSA-N Palladium Chemical compound [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 title claims description 212
- 229910052763 palladium Inorganic materials 0.000 title claims description 100
- 239000003381 stabilizer Substances 0.000 claims abstract description 31
- 150000001875 compounds Chemical group 0.000 claims abstract description 26
- 150000002894 organic compounds Chemical group 0.000 claims abstract description 22
- 239000003638 chemical reducing agent Substances 0.000 claims abstract description 20
- 125000000623 heterocyclic group Chemical group 0.000 claims abstract description 18
- 239000008139 complexing agent Substances 0.000 claims abstract description 16
- 150000003464 sulfur compounds Chemical group 0.000 claims abstract description 15
- 125000003396 thiol group Chemical group [H]S* 0.000 claims abstract description 11
- 150000002941 palladium compounds Chemical class 0.000 claims abstract description 10
- LSDPWZHWYPCBBB-UHFFFAOYSA-N Methanethiol Chemical compound SC LSDPWZHWYPCBBB-UHFFFAOYSA-N 0.000 claims description 18
- IOJUPLGTWVMSFF-UHFFFAOYSA-N benzothiazole Chemical compound C1=CC=C2SC=NC2=C1 IOJUPLGTWVMSFF-UHFFFAOYSA-N 0.000 claims description 18
- JUJWROOIHBZHMG-UHFFFAOYSA-N Pyridine Chemical compound C1=CC=NC=C1 JUJWROOIHBZHMG-UHFFFAOYSA-N 0.000 claims description 12
- YTPLMLYBLZKORZ-UHFFFAOYSA-N Thiophene Chemical compound C=1C=CSC=1 YTPLMLYBLZKORZ-UHFFFAOYSA-N 0.000 claims description 8
- GLUUGHFHXGJENI-UHFFFAOYSA-N Piperazine Chemical compound C1CNCCN1 GLUUGHFHXGJENI-UHFFFAOYSA-N 0.000 claims description 7
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 claims description 7
- 239000011593 sulfur Substances 0.000 claims description 7
- 229910052717 sulfur Inorganic materials 0.000 claims description 7
- QMMFVYPAHWMCMS-UHFFFAOYSA-N Dimethyl sulfide Chemical compound CSC QMMFVYPAHWMCMS-UHFFFAOYSA-N 0.000 claims description 6
- RWRDLPDLKQPQOW-UHFFFAOYSA-N Pyrrolidine Chemical compound C1CCNC1 RWRDLPDLKQPQOW-UHFFFAOYSA-N 0.000 claims description 6
- YPWFISCTZQNZAU-UHFFFAOYSA-N Thiane Chemical compound C1CCSCC1 YPWFISCTZQNZAU-UHFFFAOYSA-N 0.000 claims description 6
- RAXXELZNTBOGNW-UHFFFAOYSA-N imidazole Natural products C1=CNC=N1 RAXXELZNTBOGNW-UHFFFAOYSA-N 0.000 claims description 6
- KOUKXHPPRFNWPP-UHFFFAOYSA-N pyrazine-2,5-dicarboxylic acid;hydrate Chemical compound O.OC(=O)C1=CN=C(C(O)=O)C=N1 KOUKXHPPRFNWPP-UHFFFAOYSA-N 0.000 claims description 6
- UMJSCPRVCHMLSP-UHFFFAOYSA-N pyridine Natural products COC1=CC=CN=C1 UMJSCPRVCHMLSP-UHFFFAOYSA-N 0.000 claims description 6
- RMVRSNDYEFQCLF-UHFFFAOYSA-N thiophenol Chemical compound SC1=CC=CC=C1 RMVRSNDYEFQCLF-UHFFFAOYSA-N 0.000 claims description 6
- OGYGFUAIIOPWQD-UHFFFAOYSA-N 1,3-thiazolidine Chemical compound C1CSCN1 OGYGFUAIIOPWQD-UHFFFAOYSA-N 0.000 claims description 5
- HYZJCKYKOHLVJF-UHFFFAOYSA-N 1H-benzimidazole Chemical compound C1=CC=C2NC=NC2=C1 HYZJCKYKOHLVJF-UHFFFAOYSA-N 0.000 claims description 5
- FHTDDANQIMVWKZ-UHFFFAOYSA-N 1h-pyridine-4-thione Chemical compound SC1=CC=NC=C1 FHTDDANQIMVWKZ-UHFFFAOYSA-N 0.000 claims description 5
- KOODSCBKXPPKHE-UHFFFAOYSA-N propanethioic s-acid Chemical compound CCC(S)=O KOODSCBKXPPKHE-UHFFFAOYSA-N 0.000 claims description 5
- SHLSSLVZXJBVHE-UHFFFAOYSA-N 3-sulfanylpropan-1-ol Chemical compound OCCCS SHLSSLVZXJBVHE-UHFFFAOYSA-N 0.000 claims description 4
- IAZDPXIOMUYVGZ-UHFFFAOYSA-N Dimethylsulphoxide Chemical compound CS(C)=O IAZDPXIOMUYVGZ-UHFFFAOYSA-N 0.000 claims description 4
- NQRYJNQNLNOLGT-UHFFFAOYSA-N Piperidine Chemical compound C1CCNCC1 NQRYJNQNLNOLGT-UHFFFAOYSA-N 0.000 claims description 4
- KYQCOXFCLRTKLS-UHFFFAOYSA-N Pyrazine Chemical compound C1=CN=CC=N1 KYQCOXFCLRTKLS-UHFFFAOYSA-N 0.000 claims description 4
- KAESVJOAVNADME-UHFFFAOYSA-N Pyrrole Chemical compound C=1C=CNC=1 KAESVJOAVNADME-UHFFFAOYSA-N 0.000 claims description 4
- AIILTVHCLAEMDA-UHFFFAOYSA-N S-Methyl propanethioate Chemical compound CCC(=O)SC AIILTVHCLAEMDA-UHFFFAOYSA-N 0.000 claims description 4
- FZWLAAWBMGSTSO-UHFFFAOYSA-N Thiazole Chemical compound C1=CSC=N1 FZWLAAWBMGSTSO-UHFFFAOYSA-N 0.000 claims description 4
- DNJIEGIFACGWOD-UHFFFAOYSA-N ethanethiol Chemical compound CCS DNJIEGIFACGWOD-UHFFFAOYSA-N 0.000 claims description 4
- AWJUIBRHMBBTKR-UHFFFAOYSA-N isoquinoline Chemical compound C1=NC=CC2=CC=CC=C21 AWJUIBRHMBBTKR-UHFFFAOYSA-N 0.000 claims description 4
- SUVIGLJNEAMWEG-UHFFFAOYSA-N propane-1-thiol Chemical compound CCCS SUVIGLJNEAMWEG-UHFFFAOYSA-N 0.000 claims description 4
- KJRCEJOSASVSRA-UHFFFAOYSA-N propane-2-thiol Chemical compound CC(C)S KJRCEJOSASVSRA-UHFFFAOYSA-N 0.000 claims description 4
- RAOIDOHSFRTOEL-UHFFFAOYSA-N tetrahydrothiophene Chemical compound C1CCSC1 RAOIDOHSFRTOEL-UHFFFAOYSA-N 0.000 claims description 4
- VLLMWSRANPNYQX-UHFFFAOYSA-N thiadiazole Chemical compound C1=CSN=N1.C1=CSN=N1 VLLMWSRANPNYQX-UHFFFAOYSA-N 0.000 claims description 4
- CWERGRDVMFNCDR-UHFFFAOYSA-N thioglycolic acid Chemical compound OC(=O)CS CWERGRDVMFNCDR-UHFFFAOYSA-N 0.000 claims description 4
- 229930192474 thiophene Natural products 0.000 claims description 4
- DGVVWUTYPXICAM-UHFFFAOYSA-N β‐Mercaptoethanol Chemical compound OCCS DGVVWUTYPXICAM-UHFFFAOYSA-N 0.000 claims description 4
- JYEUMXHLPRZUAT-UHFFFAOYSA-N 1,2,3-triazine Chemical compound C1=CN=NN=C1 JYEUMXHLPRZUAT-UHFFFAOYSA-N 0.000 claims description 2
- ZOASGOXWEHUTKZ-UHFFFAOYSA-N 1-(Methylthio)-propane Chemical compound CCCSC ZOASGOXWEHUTKZ-UHFFFAOYSA-N 0.000 claims description 2
- JUIQOABNSLTJSW-UHFFFAOYSA-N 2-Methyl-4,5-dihydro-1,3-thiazole Chemical compound CC1=NCCS1 JUIQOABNSLTJSW-UHFFFAOYSA-N 0.000 claims description 2
- ULIKDJVNUXNQHS-UHFFFAOYSA-N 2-Propene-1-thiol Chemical compound SCC=C ULIKDJVNUXNQHS-UHFFFAOYSA-N 0.000 claims description 2
- WBBPRCNXBQTYLF-UHFFFAOYSA-N 2-methylthioethanol Chemical compound CSCCO WBBPRCNXBQTYLF-UHFFFAOYSA-N 0.000 claims description 2
- AJPGNQYBSTXCJE-UHFFFAOYSA-N 2-methylthiolane Chemical compound CC1CCCS1 AJPGNQYBSTXCJE-UHFFFAOYSA-N 0.000 claims description 2
- BCHZICNRHXRCHY-UHFFFAOYSA-N 2h-oxazine Chemical compound N1OC=CC=C1 BCHZICNRHXRCHY-UHFFFAOYSA-N 0.000 claims description 2
- DKIDEFUBRARXTE-UHFFFAOYSA-N 3-mercaptopropanoic acid Chemical compound OC(=O)CCS DKIDEFUBRARXTE-UHFFFAOYSA-N 0.000 claims description 2
- WVDYBOADDMMFIY-UHFFFAOYSA-N Cyclopentanethiol Chemical compound SC1CCCC1 WVDYBOADDMMFIY-UHFFFAOYSA-N 0.000 claims description 2
- WRYCSMQKUKOKBP-UHFFFAOYSA-N Imidazolidine Chemical compound C1CNCN1 WRYCSMQKUKOKBP-UHFFFAOYSA-N 0.000 claims description 2
- PCNDJXKNXGMECE-UHFFFAOYSA-N Phenazine Natural products C1=CC=CC2=NC3=CC=CC=C3N=C21 PCNDJXKNXGMECE-UHFFFAOYSA-N 0.000 claims description 2
- WTKZEGDFNFYCGP-UHFFFAOYSA-N Pyrazole Chemical compound C=1C=NNC=1 WTKZEGDFNFYCGP-UHFFFAOYSA-N 0.000 claims description 2
- CZPWVGJYEJSRLH-UHFFFAOYSA-N Pyrimidine Chemical compound C1=CN=CN=C1 CZPWVGJYEJSRLH-UHFFFAOYSA-N 0.000 claims description 2
- OATSQCXMYKYFQO-UHFFFAOYSA-N S-methyl thioacetate Chemical compound CSC(C)=O OATSQCXMYKYFQO-UHFFFAOYSA-N 0.000 claims description 2
- WQAQPCDUOCURKW-UHFFFAOYSA-N butanethiol Chemical compound CCCCS WQAQPCDUOCURKW-UHFFFAOYSA-N 0.000 claims description 2
- UFULAYFCSOUIOV-UHFFFAOYSA-N cysteamine Chemical compound NCCS UFULAYFCSOUIOV-UHFFFAOYSA-N 0.000 claims description 2
- LJSQFQKUNVCTIA-UHFFFAOYSA-N diethyl sulfide Chemical compound CCSCC LJSQFQKUNVCTIA-UHFFFAOYSA-N 0.000 claims description 2
- MTNDZQHUAFNZQY-UHFFFAOYSA-N imidazoline Chemical compound C1CN=CN1 MTNDZQHUAFNZQY-UHFFFAOYSA-N 0.000 claims description 2
- IOPLHGOSNCJOOO-UHFFFAOYSA-N methyl 3,4-diaminobenzoate Chemical compound COC(=O)C1=CC=C(N)C(N)=C1 IOPLHGOSNCJOOO-UHFFFAOYSA-N 0.000 claims description 2
- WCPAKWJPBJAGKN-UHFFFAOYSA-N oxadiazole Chemical compound C1=CON=N1 WCPAKWJPBJAGKN-UHFFFAOYSA-N 0.000 claims description 2
- USPWKWBDZOARPV-UHFFFAOYSA-N pyrazolidine Chemical compound C1CNNC1 USPWKWBDZOARPV-UHFFFAOYSA-N 0.000 claims description 2
- PBMFSQRYOILNGV-UHFFFAOYSA-N pyridazine Chemical compound C1=CC=NN=C1 PBMFSQRYOILNGV-UHFFFAOYSA-N 0.000 claims description 2
- ZERULLAPCVRMCO-UHFFFAOYSA-N sulfure de di n-propyle Natural products CCCSCCC ZERULLAPCVRMCO-UHFFFAOYSA-N 0.000 claims description 2
- 150000003536 tetrazoles Chemical class 0.000 claims description 2
- BRNULMACUQOKMR-UHFFFAOYSA-N thiomorpholine Chemical compound C1CSCCN1 BRNULMACUQOKMR-UHFFFAOYSA-N 0.000 claims description 2
- 150000003852 triazoles Chemical class 0.000 claims description 2
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 98
- 229910052759 nickel Inorganic materials 0.000 description 46
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 25
- 239000011574 phosphorus Substances 0.000 description 25
- 229910052698 phosphorus Inorganic materials 0.000 description 25
- 238000000151 deposition Methods 0.000 description 22
- 238000012545 processing Methods 0.000 description 21
- 230000008021 deposition Effects 0.000 description 20
- -1 palladium ions Chemical class 0.000 description 19
- BDAGIHXWWSANSR-UHFFFAOYSA-N methanoic acid Natural products OC=O BDAGIHXWWSANSR-UHFFFAOYSA-N 0.000 description 14
- 150000003839 salts Chemical class 0.000 description 14
- 239000010931 gold Substances 0.000 description 13
- 238000000034 method Methods 0.000 description 13
- 239000000203 mixture Substances 0.000 description 13
- 239000000758 substrate Substances 0.000 description 13
- 150000003573 thiols Chemical class 0.000 description 13
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 12
- 229910052737 gold Inorganic materials 0.000 description 12
- 230000000052 comparative effect Effects 0.000 description 10
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 8
- 239000000872 buffer Substances 0.000 description 8
- OSWFIVFLDKOXQC-UHFFFAOYSA-N 4-(3-methoxyphenyl)aniline Chemical compound COC1=CC=CC(C=2C=CC(N)=CC=2)=C1 OSWFIVFLDKOXQC-UHFFFAOYSA-N 0.000 description 7
- 229910045601 alloy Inorganic materials 0.000 description 7
- 239000000956 alloy Substances 0.000 description 7
- 235000019253 formic acid Nutrition 0.000 description 7
- 239000000126 substance Substances 0.000 description 7
- PIICEJLVQHRZGT-UHFFFAOYSA-N Ethylenediamine Chemical compound NCCN PIICEJLVQHRZGT-UHFFFAOYSA-N 0.000 description 6
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 6
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 6
- 239000010949 copper Substances 0.000 description 6
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 5
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 5
- 239000002253 acid Substances 0.000 description 5
- 229910052802 copper Inorganic materials 0.000 description 5
- 229910017604 nitric acid Inorganic materials 0.000 description 5
- 239000002245 particle Substances 0.000 description 5
- 235000011007 phosphoric acid Nutrition 0.000 description 5
- NLJMYIDDQXHKNR-UHFFFAOYSA-K sodium citrate Chemical compound O.O.[Na+].[Na+].[Na+].[O-]C(=O)CC(O)(CC([O-])=O)C([O-])=O NLJMYIDDQXHKNR-UHFFFAOYSA-K 0.000 description 5
- KCXVZYZYPLLWCC-UHFFFAOYSA-N EDTA Chemical compound OC(=O)CN(CC(O)=O)CCN(CC(O)=O)CC(O)=O KCXVZYZYPLLWCC-UHFFFAOYSA-N 0.000 description 4
- 239000000654 additive Substances 0.000 description 4
- 229910052782 aluminium Inorganic materials 0.000 description 4
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 4
- KRKNYBCHXYNGOX-UHFFFAOYSA-N citric acid Chemical compound OC(=O)CC(O)(C(O)=O)CC(O)=O KRKNYBCHXYNGOX-UHFFFAOYSA-N 0.000 description 4
- 238000007772 electroless plating Methods 0.000 description 4
- PIBWKRNGBLPSSY-UHFFFAOYSA-L palladium(II) chloride Chemical compound Cl[Pd]Cl PIBWKRNGBLPSSY-UHFFFAOYSA-L 0.000 description 4
- NWONKYPBYAMBJT-UHFFFAOYSA-L zinc sulfate Chemical compound [Zn+2].[O-]S([O-])(=O)=O NWONKYPBYAMBJT-UHFFFAOYSA-L 0.000 description 4
- ZZUQWNYNSKJLPI-UHFFFAOYSA-N 2-(1,3-benzothiazol-2-ylsulfanyl)acetic acid Chemical compound C1=CC=C2SC(SCC(=O)O)=NC2=C1 ZZUQWNYNSKJLPI-UHFFFAOYSA-N 0.000 description 3
- PGUPJAPHYIEKLT-UHFFFAOYSA-N 2-pyridin-4-ylsulfanylacetic acid Chemical compound OC(=O)CSC1=CC=NC=C1 PGUPJAPHYIEKLT-UHFFFAOYSA-N 0.000 description 3
- XGJOFCCBFCHEHK-UHFFFAOYSA-N 4-pyridin-4-ylsulfanylpyridine Chemical compound C=1C=NC=CC=1SC1=CC=NC=C1 XGJOFCCBFCHEHK-UHFFFAOYSA-N 0.000 description 3
- 0 CC(CCC=C1)=*1N Chemical compound CC(CCC=C1)=*1N 0.000 description 3
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 description 3
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 3
- 229910052783 alkali metal Inorganic materials 0.000 description 3
- 229910000147 aluminium phosphate Inorganic materials 0.000 description 3
- 239000003795 chemical substances by application Substances 0.000 description 3
- 238000006197 hydroboration reaction Methods 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 238000002156 mixing Methods 0.000 description 3
- 239000003002 pH adjusting agent Substances 0.000 description 3
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 3
- 238000006722 reduction reaction Methods 0.000 description 3
- 230000002829 reductive effect Effects 0.000 description 3
- 239000011734 sodium Substances 0.000 description 3
- 239000004094 surface-active agent Substances 0.000 description 3
- BJEPYKJPYRNKOW-REOHCLBHSA-N (S)-malic acid Chemical compound OC(=O)[C@@H](O)CC(O)=O BJEPYKJPYRNKOW-REOHCLBHSA-N 0.000 description 2
- YXIWHUQXZSMYRE-UHFFFAOYSA-N 1,3-benzothiazole-2-thiol Chemical compound C1=CC=C2SC(S)=NC2=C1 YXIWHUQXZSMYRE-UHFFFAOYSA-N 0.000 description 2
- OCKJFOHZLXIAAT-UHFFFAOYSA-N 2-methylsulfanyl-1h-benzimidazole Chemical compound C1=CC=C2NC(SC)=NC2=C1 OCKJFOHZLXIAAT-UHFFFAOYSA-N 0.000 description 2
- VLQBSKLZRSUMTJ-UHFFFAOYSA-N 2-methylsulfanylpyridine Chemical compound CSC1=CC=CC=N1 VLQBSKLZRSUMTJ-UHFFFAOYSA-N 0.000 description 2
- UTBVIMLZIRIFFR-UHFFFAOYSA-N 2-methylthio-1,3-benzothiazole Chemical compound C1=CC=C2SC(SC)=NC2=C1 UTBVIMLZIRIFFR-UHFFFAOYSA-N 0.000 description 2
- UYHSQVMHSFXUOA-UHFFFAOYSA-N 2-methylthiouracil Chemical compound CSC1=NC=CC(O)=N1 UYHSQVMHSFXUOA-UHFFFAOYSA-N 0.000 description 2
- NMHKBABHRKQHOL-UHFFFAOYSA-N 2-phenylsulfanylisoindole-1,3-dione Chemical compound O=C1C2=CC=CC=C2C(=O)N1SC1=CC=CC=C1 NMHKBABHRKQHOL-UHFFFAOYSA-N 0.000 description 2
- DXSBAOMLHPFLMW-UHFFFAOYSA-N 3-(1,3-benzothiazol-2-ylsulfanyl)propanoic acid Chemical compound C1=CC=C2SC(SCCC(=O)O)=NC2=C1 DXSBAOMLHPFLMW-UHFFFAOYSA-N 0.000 description 2
- AEXCUJUYEZIWJV-UHFFFAOYSA-N 4-hydroxy-2-methylsulfanyl-1h-pyrimidin-6-one Chemical compound CSC1=NC(O)=CC(=O)N1 AEXCUJUYEZIWJV-UHFFFAOYSA-N 0.000 description 2
- GONFBOIJNUKKST-UHFFFAOYSA-N 5-ethylsulfanyl-2h-tetrazole Chemical compound CCSC=1N=NNN=1 GONFBOIJNUKKST-UHFFFAOYSA-N 0.000 description 2
- ZBXNFTFKKOSPLD-UHFFFAOYSA-N 5-methylsulfanyl-2h-tetrazole Chemical compound CSC1=NN=NN1 ZBXNFTFKKOSPLD-UHFFFAOYSA-N 0.000 description 2
- RKXYTFTZODXDEF-UHFFFAOYSA-N 5-methylsulfanylthiophene-2-carbaldehyde Chemical compound CSC1=CC=C(C=O)S1 RKXYTFTZODXDEF-UHFFFAOYSA-N 0.000 description 2
- ISUXMAHVLFRZQU-UHFFFAOYSA-N 6-chloro-2-methylsulfanylpyrimidin-4-amine Chemical compound CSC1=NC(N)=CC(Cl)=N1 ISUXMAHVLFRZQU-UHFFFAOYSA-N 0.000 description 2
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 2
- CIWBSHSKHKDKBQ-JLAZNSOCSA-N Ascorbic acid Chemical compound OC[C@H](O)[C@H]1OC(=O)C(O)=C1O CIWBSHSKHKDKBQ-JLAZNSOCSA-N 0.000 description 2
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 description 2
- 101100133719 Caenorhabditis elegans npr-18 gene Proteins 0.000 description 2
- FEWJPZIEWOKRBE-JCYAYHJZSA-N Dextrotartaric acid Chemical compound OC(=O)[C@H](O)[C@@H](O)C(O)=O FEWJPZIEWOKRBE-JCYAYHJZSA-N 0.000 description 2
- ROSDSFDQCJNGOL-UHFFFAOYSA-N Dimethylamine Chemical compound CNC ROSDSFDQCJNGOL-UHFFFAOYSA-N 0.000 description 2
- WSFSSNUMVMOOMR-UHFFFAOYSA-N Formaldehyde Chemical compound O=C WSFSSNUMVMOOMR-UHFFFAOYSA-N 0.000 description 2
- DHMQDGOQFOQNFH-UHFFFAOYSA-N Glycine Chemical compound NCC(O)=O DHMQDGOQFOQNFH-UHFFFAOYSA-N 0.000 description 2
- OAKJQQAXSVQMHS-UHFFFAOYSA-N Hydrazine Chemical compound NN OAKJQQAXSVQMHS-UHFFFAOYSA-N 0.000 description 2
- OFOBLEOULBTSOW-UHFFFAOYSA-N Malonic acid Chemical compound OC(=O)CC(O)=O OFOBLEOULBTSOW-UHFFFAOYSA-N 0.000 description 2
- BAVYZALUXZFZLV-UHFFFAOYSA-N Methylamine Chemical compound NC BAVYZALUXZFZLV-UHFFFAOYSA-N 0.000 description 2
- AFCARXCZXQIEQB-UHFFFAOYSA-N N-[3-oxo-3-(2,4,6,7-tetrahydrotriazolo[4,5-c]pyridin-5-yl)propyl]-2-[[3-(trifluoromethoxy)phenyl]methylamino]pyrimidine-5-carboxamide Chemical compound O=C(CCNC(=O)C=1C=NC(=NC=1)NCC1=CC(=CC=C1)OC(F)(F)F)N1CC2=C(CC1)NN=N2 AFCARXCZXQIEQB-UHFFFAOYSA-N 0.000 description 2
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 description 2
- 239000004280 Sodium formate Substances 0.000 description 2
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 2
- FEWJPZIEWOKRBE-UHFFFAOYSA-N Tartaric acid Natural products [H+].[H+].[O-]C(=O)C(O)C(O)C([O-])=O FEWJPZIEWOKRBE-UHFFFAOYSA-N 0.000 description 2
- HAXFWIACAGNFHA-UHFFFAOYSA-N aldrithiol Chemical compound C=1C=CC=NC=1SSC1=CC=CC=N1 HAXFWIACAGNFHA-UHFFFAOYSA-N 0.000 description 2
- BJEPYKJPYRNKOW-UHFFFAOYSA-N alpha-hydroxysuccinic acid Natural products OC(=O)C(O)CC(O)=O BJEPYKJPYRNKOW-UHFFFAOYSA-N 0.000 description 2
- 150000003863 ammonium salts Chemical class 0.000 description 2
- 238000001479 atomic absorption spectroscopy Methods 0.000 description 2
- 239000002585 base Substances 0.000 description 2
- WGQKYBSKWIADBV-UHFFFAOYSA-N benzylamine Chemical compound NCC1=CC=CC=C1 WGQKYBSKWIADBV-UHFFFAOYSA-N 0.000 description 2
- 229910052796 boron Inorganic materials 0.000 description 2
- 150000001639 boron compounds Chemical class 0.000 description 2
- RJTANRZEWTUVMA-UHFFFAOYSA-N boron;n-methylmethanamine Chemical compound [B].CNC RJTANRZEWTUVMA-UHFFFAOYSA-N 0.000 description 2
- 230000003197 catalytic effect Effects 0.000 description 2
- 235000015165 citric acid Nutrition 0.000 description 2
- 230000006866 deterioration Effects 0.000 description 2
- XBDQKXXYIPTUBI-UHFFFAOYSA-N dimethylselenoniopropionate Natural products CCC(O)=O XBDQKXXYIPTUBI-UHFFFAOYSA-N 0.000 description 2
- 238000007654 immersion Methods 0.000 description 2
- 239000001630 malic acid Substances 0.000 description 2
- 235000011090 malic acid Nutrition 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 150000002940 palladium Chemical class 0.000 description 2
- ACVYVLVWPXVTIT-UHFFFAOYSA-N phosphinic acid Chemical compound O[PH2]=O ACVYVLVWPXVTIT-UHFFFAOYSA-N 0.000 description 2
- XNGIFLGASWRNHJ-UHFFFAOYSA-N phthalic acid Chemical compound OC(=O)C1=CC=CC=C1C(O)=O XNGIFLGASWRNHJ-UHFFFAOYSA-N 0.000 description 2
- SIOXPEMLGUPBBT-UHFFFAOYSA-N picolinic acid Chemical compound OC(=O)C1=CC=CC=N1 SIOXPEMLGUPBBT-UHFFFAOYSA-N 0.000 description 2
- 239000011591 potassium Substances 0.000 description 2
- 229910052700 potassium Inorganic materials 0.000 description 2
- KIDHWZJUCRJVML-UHFFFAOYSA-N putrescine Chemical compound NCCCCN KIDHWZJUCRJVML-UHFFFAOYSA-N 0.000 description 2
- 239000012279 sodium borohydride Substances 0.000 description 2
- 229910000033 sodium borohydride Inorganic materials 0.000 description 2
- HLBBKKJFGFRGMU-UHFFFAOYSA-M sodium formate Chemical compound [Na+].[O-]C=O HLBBKKJFGFRGMU-UHFFFAOYSA-M 0.000 description 2
- 235000019254 sodium formate Nutrition 0.000 description 2
- 159000000000 sodium salts Chemical class 0.000 description 2
- 230000000087 stabilizing effect Effects 0.000 description 2
- 239000011975 tartaric acid Substances 0.000 description 2
- 235000002906 tartaric acid Nutrition 0.000 description 2
- ISIJQEHRDSCQIU-UHFFFAOYSA-N tert-butyl 2,7-diazaspiro[4.5]decane-7-carboxylate Chemical compound C1N(C(=O)OC(C)(C)C)CCCC11CNCC1 ISIJQEHRDSCQIU-UHFFFAOYSA-N 0.000 description 2
- GETQZCLCWQTVFV-UHFFFAOYSA-N trimethylamine Chemical compound CN(C)C GETQZCLCWQTVFV-UHFFFAOYSA-N 0.000 description 2
- YHMYGUUIMTVXNW-UHFFFAOYSA-N 1,3-dihydrobenzimidazole-2-thione Chemical compound C1=CC=C2NC(S)=NC2=C1 YHMYGUUIMTVXNW-UHFFFAOYSA-N 0.000 description 1
- SKIIKRJAQOSWFT-UHFFFAOYSA-N 2-[3-[1-(2,2-difluoroethyl)piperidin-4-yl]oxy-4-[2-(2,3-dihydro-1H-inden-2-ylamino)pyrimidin-5-yl]pyrazol-1-yl]-1-(2,4,6,7-tetrahydrotriazolo[4,5-c]pyridin-5-yl)ethanone Chemical compound FC(CN1CCC(CC1)OC1=NN(C=C1C=1C=NC(=NC=1)NC1CC2=CC=CC=C2C1)CC(=O)N1CC2=C(CC1)NN=N2)F SKIIKRJAQOSWFT-UHFFFAOYSA-N 0.000 description 1
- XDVOLDOITVSJGL-UHFFFAOYSA-N 3,7-dihydroxy-2,4,6,8,9-pentaoxa-1,3,5,7-tetraborabicyclo[3.3.1]nonane Chemical compound O1B(O)OB2OB(O)OB1O2 XDVOLDOITVSJGL-UHFFFAOYSA-N 0.000 description 1
- WLHCBQAPPJAULW-UHFFFAOYSA-N 4-methylbenzenethiol Chemical compound CC1=CC=C(S)C=C1 WLHCBQAPPJAULW-UHFFFAOYSA-N 0.000 description 1
- GXGKKIPUFAHZIZ-UHFFFAOYSA-N 5-benzylsulfanyl-2h-tetrazole Chemical compound C=1C=CC=CC=1CSC=1N=NNN=1 GXGKKIPUFAHZIZ-UHFFFAOYSA-N 0.000 description 1
- QTBSBXVTEAMEQO-UHFFFAOYSA-M Acetate Chemical compound CC([O-])=O QTBSBXVTEAMEQO-UHFFFAOYSA-M 0.000 description 1
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 description 1
- RPNUMPOLZDHAAY-UHFFFAOYSA-N Diethylenetriamine Chemical compound NCCNCCN RPNUMPOLZDHAAY-UHFFFAOYSA-N 0.000 description 1
- 239000004471 Glycine Substances 0.000 description 1
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 1
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 1
- 229910002651 NO3 Inorganic materials 0.000 description 1
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 description 1
- 229910001096 P alloy Inorganic materials 0.000 description 1
- 229910019142 PO4 Inorganic materials 0.000 description 1
- 229910001252 Pd alloy Inorganic materials 0.000 description 1
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 1
- 230000002159 abnormal effect Effects 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 150000007513 acids Chemical class 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 150000001340 alkali metals Chemical class 0.000 description 1
- 229910052784 alkaline earth metal Inorganic materials 0.000 description 1
- 229910021529 ammonia Inorganic materials 0.000 description 1
- 235000011114 ammonium hydroxide Nutrition 0.000 description 1
- 239000002280 amphoteric surfactant Substances 0.000 description 1
- 125000000129 anionic group Chemical group 0.000 description 1
- 239000003945 anionic surfactant Substances 0.000 description 1
- 235000010323 ascorbic acid Nutrition 0.000 description 1
- 229960005070 ascorbic acid Drugs 0.000 description 1
- 239000011668 ascorbic acid Substances 0.000 description 1
- 229910000085 borane Inorganic materials 0.000 description 1
- WVMHLYQJPRXKLC-UHFFFAOYSA-N borane;n,n-dimethylmethanamine Chemical compound B.CN(C)C WVMHLYQJPRXKLC-UHFFFAOYSA-N 0.000 description 1
- QDWJUBJKEHXSMT-UHFFFAOYSA-N boranylidynenickel Chemical compound [Ni]#B QDWJUBJKEHXSMT-UHFFFAOYSA-N 0.000 description 1
- KGBXLFKZBHKPEV-UHFFFAOYSA-N boric acid Chemical compound OB(O)O KGBXLFKZBHKPEV-UHFFFAOYSA-N 0.000 description 1
- 239000004327 boric acid Substances 0.000 description 1
- 230000003139 buffering effect Effects 0.000 description 1
- 159000000007 calcium salts Chemical class 0.000 description 1
- 150000001735 carboxylic acids Chemical class 0.000 description 1
- 125000002091 cationic group Chemical group 0.000 description 1
- 239000003093 cationic surfactant Substances 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 229910017052 cobalt Inorganic materials 0.000 description 1
- 239000010941 cobalt Substances 0.000 description 1
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- AFZSMODLJJCVPP-UHFFFAOYSA-N dibenzothiazol-2-yl disulfide Chemical compound C1=CC=C2SC(SSC=3SC4=CC=CC=C4N=3)=NC2=C1 AFZSMODLJJCVPP-UHFFFAOYSA-N 0.000 description 1
- VBDQNUWZQXYUDP-UHFFFAOYSA-L dichloropalladium;ethane-1,2-diamine Chemical compound [Cl-].[Cl-].[Pd+2].NCCN.NCCN VBDQNUWZQXYUDP-UHFFFAOYSA-L 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- XPPKVPWEQAFLFU-UHFFFAOYSA-N diphosphoric acid Chemical compound OP(O)(=O)OP(O)(O)=O XPPKVPWEQAFLFU-UHFFFAOYSA-N 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 150000002429 hydrazines Chemical class 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 239000011777 magnesium Substances 0.000 description 1
- 229910052749 magnesium Inorganic materials 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- RTWNYYOXLSILQN-UHFFFAOYSA-N methanediamine Chemical compound NCN RTWNYYOXLSILQN-UHFFFAOYSA-N 0.000 description 1
- 239000002736 nonionic surfactant Substances 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- MUJIDPITZJWBSW-UHFFFAOYSA-N palladium(2+) Chemical compound [Pd+2] MUJIDPITZJWBSW-UHFFFAOYSA-N 0.000 description 1
- YJVFFLUZDVXJQI-UHFFFAOYSA-L palladium(ii) acetate Chemical compound [Pd+2].CC([O-])=O.CC([O-])=O YJVFFLUZDVXJQI-UHFFFAOYSA-L 0.000 description 1
- OFNHPGDEEMZPFG-UHFFFAOYSA-N phosphanylidynenickel Chemical compound [P].[Ni] OFNHPGDEEMZPFG-UHFFFAOYSA-N 0.000 description 1
- 235000021317 phosphate Nutrition 0.000 description 1
- ACVYVLVWPXVTIT-UHFFFAOYSA-M phosphinate Chemical compound [O-][PH2]=O ACVYVLVWPXVTIT-UHFFFAOYSA-M 0.000 description 1
- 150000003013 phosphoric acid derivatives Chemical class 0.000 description 1
- 150000003016 phosphoric acids Chemical class 0.000 description 1
- OJMIONKXNSYLSR-UHFFFAOYSA-N phosphorous acid Chemical compound OP(O)O OJMIONKXNSYLSR-UHFFFAOYSA-N 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 229910052697 platinum Inorganic materials 0.000 description 1
- 159000000001 potassium salts Chemical class 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 235000019260 propionic acid Nutrition 0.000 description 1
- 229940005657 pyrophosphoric acid Drugs 0.000 description 1
- 150000003242 quaternary ammonium salts Chemical class 0.000 description 1
- IUVKMZGDUIUOCP-BTNSXGMBSA-N quinbolone Chemical compound O([C@H]1CC[C@H]2[C@H]3[C@@H]([C@]4(C=CC(=O)C=C4CC3)C)CC[C@@]21C)C1=CCCC1 IUVKMZGDUIUOCP-BTNSXGMBSA-N 0.000 description 1
- 238000006479 redox reaction Methods 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 229910052709 silver Inorganic materials 0.000 description 1
- 239000004332 silver Substances 0.000 description 1
- 238000010129 solution processing Methods 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 238000004381 surface treatment Methods 0.000 description 1
- JBQYATWDVHIOAR-UHFFFAOYSA-N tellanylidenegermanium Chemical compound [Te]=[Ge] JBQYATWDVHIOAR-UHFFFAOYSA-N 0.000 description 1
- 150000003512 tertiary amines Chemical class 0.000 description 1
- WJCNZQLZVWNLKY-UHFFFAOYSA-N thiabendazole Chemical compound S1C=NC(C=2NC3=CC=CC=C3N=2)=C1 WJCNZQLZVWNLKY-UHFFFAOYSA-N 0.000 description 1
- UORVGPXVDQYIDP-UHFFFAOYSA-N trihydridoboron Substances B UORVGPXVDQYIDP-UHFFFAOYSA-N 0.000 description 1
- ASTWEMOBIXQPPV-UHFFFAOYSA-K trisodium;phosphate;dodecahydrate Chemical compound O.O.O.O.O.O.O.O.O.O.O.O.[Na+].[Na+].[Na+].[O-]P([O-])([O-])=O ASTWEMOBIXQPPV-UHFFFAOYSA-K 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
- 238000004876 x-ray fluorescence Methods 0.000 description 1
- 239000011701 zinc Substances 0.000 description 1
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
- C23C18/42—Coating with noble metals
- C23C18/44—Coating with noble metals using reducing agents
-
- 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
- C23C18/31—Coating with metals
- C23C18/32—Coating with nickel, cobalt or mixtures thereof with phosphorus or boron
Definitions
- the present disclosure relates to an electroless palladium plating bath.
- an electroless nickel (Ni)/electroless palladium (Pd)/immersion gold (Au) has been used as a surface treatment for mounts or terminals of printed circuit boards or IC packages.
- ENEPIG electroless nickel
- Au immersion gold
- the palladium film exhibits a good electrical conductivity and a high corrosion resistance, and moreover has the function of avoiding the diffusion of underlying nickel onto the gold surface due to thermal history.
- the palladium film plays an important role in the ENEPIG process described above.
- the plating bath is required to be highly stable.
- an ethylenediaminetetraacetic acid or a salt thereof, for example is used as a stabilizer.
- the plating bath is easily biodegradable and is therefore not sufficiently stable.
- an electroless palladium plating bath having an organic compound containing divalent sulfur blended therein has been proposed. It is described (see, e.g., Japanese Patent No. 3972158 ) that the stability of a plating bath improves by using an organic compound containing divalent sulfur.
- the typical plating bath described above has improved stability by blending the organic compound containing divalent sulfur, but has a problem of lower deposition properties of palladium onto a nickel plating film.
- Niobium plating films having a concentration of phosphorus in the film ranging from 4% to 8% nickel plating films having a concentration of phosphorus in the film ranging from 4% to 8%.
- P nickel plating films having a concentration of phosphorus in the film ranging from 4% to 8%.
- the typical plating bath described above has the problem in particular that the deposition properties of palladium onto a nickel plating film having a lower phosphorus content is reduced significantly. Development of an electroless palladium plating bath applicable to nickel plating films having a lower phosphorus content is therefore desired.
- an electroless palladium plating bath at least contains: a palladium compound; a reducing agent; a complexing agent; and a stabilizer.
- the stabilizer is an organic compound in which a divalent sulfur compound is bonded to a compound with a heterocyclic structure, and the organic compounds contains neither a thiol group nor a disulfide bond.
- the present disclosure provides a plating bath with improved stability, while reducing the deterioration in the deposition properties of palladium onto a nickel plating film.
- the electroless palladium plating bath according to the present disclosure contains a palladium compound, a reducing agent, a complexing agent, and a stabilizer.
- the palladium compound is a palladium ion source for palladium plating.
- the palladium compound may be at least water soluble.
- Examples of the palladium compound include: water-soluble inorganic palladium salts such as palladium chloride, palladium sulfate, and palladium acetate; and water-soluble organic palladium salts such as tetraamminepalladium hydrochloride, tetraamminepalladium sulfate, tetraamminepalladium acetate, tetraamminepalladium nitrate, and bis(ethylenediamine)palladium(II)chloride. Note that these palladium compounds may be used alone or two or more kinds may be used in a mixture.
- the concentration of the palladium ions in the electroless palladium plating bath is not particularly limited. However, a too low concentration of the palladium ions may significantly lower the rate of deposition of the plating film.
- the concentration is thus preferably 0.1 g/L or more, more preferably 0.3 g/L or more, and still more preferably 0.5 g/L or more.
- a too high concentration of the palladium ions may cause abnormal deposition which deteriorates the physical properties of the film.
- the concentration is thus preferably 10 g/L or less, more preferably 5 g/L or less, and still more preferably 3 g/L or less.
- the concentration of the palladium ions can be measured by atomic absorption spectrometry (AAS) using an atomic absorption spectrophotometer.
- AAS atomic absorption spectrometry
- the reducing agent has the function of depositing palladium in an electroless palladium plating bath.
- various known kinds of reducing agent can be used.
- the reducing agent include formic acid and salts thereof, hydrazines, hypophosphorous acid and salts thereof, phosphorous acid and salts thereof, amine borane compounds, hydroboration compounds, formalin, and ascorbic acid and salts thereof.
- salts examples include: alkali metal salts such as potassium and sodium salts; alkaline earth metal salts such as magnesium and calcium salts; ammonium salts; quaternary ammonium salts; and amine salts containing primary to tertiary amines.
- amine borane compounds examples include dimethylamine borane (DMAB) and trimethylamine borane (TMAB).
- hydroboration compounds include alkali metal borohydride salts such as sodium borohydride (SBH) and potassium borohydride (KBH).
- reducing agents formic acid or a salt thereof (e.g., sodium formate) is used in one preferred embodiment in view of achieving both the stability of the plating bath and the deposition properties of the plating film.
- reducing agents may be used alone or two or more kinds may be used in a mixture.
- the content of the reducing agent in the electroless palladium plating bath may be adjusted as appropriate in consideration of the rate of deposition in the plating processing and the stability of the plating bath.
- the lower limit is preferably 1 g/L or more, more preferably 3 g/L or more, still more preferably 5 g/L or more, and particularly preferably 10 g/L or more.
- the upper limit of the content of the reducing agent is preferably 100 g/L or less, more preferably 80 g/L or less, and still more preferably 50 g/L or less.
- the complexing agent has the main function of stabilizing the solubility of palladium in the electroless palladium plating bath.
- the complexing agent various known kinds of complexing agent can be used.
- the complexing agent include at least one selected from the group consisting of ammonia and amine compounds, among which an amine compound is selected in a more preferred embodiment.
- the amine compounds include methylamine, dimethylamine, trimethylamine, benzylamine, methylenediamine, ethylenediamine, ethylenediamine derivatives, tetramethylenediamine, diethylenetriamine, ethylenediaminetetraacetic acid (EDTA) or alkali metal salts thereof, EDTA derivatives, and glycine.
- These complexing agents may be used alone or two or more kinds may be used in a mixture.
- the content of the complexing agent in the electroless palladium plating bath may be adjusted as appropriate in consideration of the stable solubility of palladium.
- the lower limit is preferably 0.1 g/L or more, more preferably 1 g/L or more, and still more preferably 3 g/L or more.
- the upper limit of the content of the complexing agent is preferably 15 g/L or less and more preferably 10 g/L or less.
- an organic compound represented by the following Formula (1) can be used in which a divalent sulfur compound (i.e., a compound containing divalent sulfur) is bonded to a compound with a heterocyclic structure.
- a divalent sulfur compound i.e., a compound containing divalent sulfur
- R 1 -R 2 a compound with the heterocyclic structure
- R 1 -R 2 represents an organic compound with neither a thiol group nor a disulfide bond.
- Examples of the compound R 1 with a heterocyclic structure include compounds with a nitrogen-containing heterocyclic structure or a sulfur-containing heterocyclic structure such as imidazole, imidazolidine, imidazoline, oxadiazole, oxazine, thiadiazole, thiazole, thiazolidine, tetrazole, triazine, triazole, piperazine, piperidine, pyrazine, pyrazole, pyrazolidine, pyridine, pyridazine, pyrimidine, pyrrole, pyrrolidine, benzothiazole, benzimidazole, isoquinoline, thiophene, tetrahydrothiophene, pentamethylene sulfide, and derivatives thereof.
- a nitrogen-containing heterocyclic structure or a sulfur-containing heterocyclic structure such as imidazole, imidazolidine, imidazoline, oxadiazole, oxazine
- divalent sulfur compound R 2 examples include thiadiazole, thiazole, thiazolidine, benzothiazole, thiophene, tetrahydrothiophene, methanethiol, benzenethiol, pentamethylene sulfide, dimethyl sulfide, methyl mercaptan, ethyl mercaptan, allyl mercaptan, thiopropionic acid, thioacetic acid, ethyl methyl sulfide, 1-propanethiol, 2-propanethiol, 2-aminoethanethiol, 2-mercaptoethanol, 4-mercaptopyridine, dimethyl sulfoxide, S-methyl thioacetate, ethyl sulfide, methylpropyl sulfide, 1-butanethiol, thioglycolic acid, 2-(methylthio)ethanol, 3-mercapto-1-propanol, 2-(
- Examples of the stabilizer represented by Formula (1) include 2-(4-thiazolyl)benzimidazole, 2-(methylthio)benzimidazole, 2-(methylthio)benzothiazole, (2-benzothiazolylthio)acetic acid, 3-(2-benzothiazolylthio)propionic acid, 2-(methylthio)pyridine, (4-pyridylthio)acetic acid, 4,4'-dipyridyl sulfide, 2-methylthio-4-pyrimidinol, S-methylthiobarbituric acid, 4-amino-6-chloro-2-(methylthio)pyrimidine, 5-(methylthio)-1H-tetrazole, 5-(ethylthio)-1H-tetrazole, N-(phenylthio)phthalimide, and 5-(methylthio)thiophene-2-carboxaldehyde. Note that these stabilizers may be used alone or two or more kinds may be used in a mixture. Chemical formula
- the organic compound (R 1 -R 2 ) used as the stabilizer in the electroless palladium plating bath according to the present disclosure includes an organic compound in which the divalent sulfur compound R 2 bonded to the compound R 1 with the heterocyclic structure derives from a thiol (-SH) group-containing compound.
- the 2-(methylthio)benzimidazole is an organic compound (R 1 -R 2 ) in which benzimidazole as R 1 and methanethiol as R 2 are bonded.
- the compound contains no thiol (-SH) group in the state of R 1 -R 2 as shown in the chemical formula.
- R 2 i.e., methanethiol
- R 2 bonded to R 1 derives from the compound (i.e., methanethiol) containing the thiol (-SH) group.
- (2-benzothiazolylthio)acetic acid contains no thiol (-SH) group in the state of R 1 -R 2 (where R 1 is benzothiazole and R 2 is thioacetic acid) as shown in the chemical formula.
- R 2 i.e., thioacetic acid
- R 2 bonded to R 1 derives from the compound (i.e., thioacetic acid) containing the thiol (-SH) group.
- (4-pyridylthio)acetic acid where R 1 is pyridine and R 2 is thioacetic acid).
- 3-(2-benzothiazolylthio)propionic acid contains no thiol (-SH) group in the state of R 1 -R 2 (where R 1 is benzothiazole and R 2 is thiopropionic acid) as shown in the chemical formula.
- R 2 i.e., thiopropionic acid
- R 2 bonded to R 1 derives from the compound (i.e., thiopropionic acid) containing the thiol (-SH) group.
- 4,4'-dipyridyl sulfide contains no thiol (-SH) in the state of R 1 -R 2 (where R 1 is pyridine and R 2 is 4-mercaptopyridine) as shown in the chemical formula.
- R 2 i.e., 4-mercaptopyridine
- R 2 bonded to R 1 derives from the compound (i.e., 4-mercaptopyridine) containing the thiol (-SH) group.
- the plating bath has improved stability by blending the organic compound containing divalent sulfur, but has the problem of lower deposition properties of palladium onto the nickel plating film.
- the present inventors have studied the above problem and found the following: Using a stabilizer made of an organic compound in which a divalent sulfur compound is bonded to a compound with a heterocyclic structure (i. e., R 1 -R 2 described above) reduces a reduction in the deposition properties of palladium on the nickel plating film and improves the stability of the plating bath.
- a stabilizer made of an organic compound in which a divalent sulfur compound is bonded to a compound with a heterocyclic structure i. e., R 1 -R 2 described above
- the present inventors also have found the following: Using an organic compound having a thiol group or a disulfide bond, among organic compounds in which a divalent sulfur compound is bonded to a compound with a heterocyclic structure, alters the thiol group or the disulfide bond due to an oxidation-reduction reaction in the plating bath (i.e., a disulfide bond is generated by an oxidation reaction of the thiol group, and a thiol group is generated by a reduction reaction of the disulfide bond), which changes the deposition properties of palladium and reduces the stability of the plating bath.
- the content of the stabilizer in the electroless palladium plating bath may be adjusted as appropriate in consideration of the deposition properties of palladium in the plating processing and the stability of the plating bath.
- the lower limit is preferably 0.01 mg/L or more, more preferably 0.03 mg/L or more, and still more preferably 0.05 mg/L or more.
- the upper limit of the content of the stabilizer is preferably 10 mg/L or less, more preferably 5 mg/L or less, and still more preferably 1 mg/L or less.
- additives usually used in the field of plating bath can be added in addition to the components described above.
- examples of such additives include a pH adjuster, a buffer, and a surfactant.
- the pH adjuster is an additive that having the function of adjusting the pH of the plating bath.
- the pH adjuster include: acids such as hydrochloric acid, sulfuric acid, nitric acid, citric acid, malonic acid, malic acid, tartaric acid, and phosphoric acid; and alkalis such as sodium hydroxide, potassium hydroxide, and ammonia water. Note that these pH adjusters may be used alone or two or more kinds may be used in a mixture.
- the electroless palladium plating bath according to the present disclosure may have a pH preferably ranging from 4 to 10, and more preferably from 5 to 8.
- a buffer with a buffering function may be added.
- the buffer include: carboxylic acids such as citric acids (e.g., trisodium citrate dihydrate), tartaric acid, malic acid, and phthalic acid; phosphoric acids such as orthophosphoric acid, phosphorous acid, hypophosphorous acid, and pyrophosphoric acid; phosphates thereof such as potassium salts, sodium salts (e.g., trisodium phosphate dodecahydrate), and ammonium salts; boric acid; and tetraboric acid.
- carboxylic acids such as citric acids (e.g., trisodium citrate dihydrate), tartaric acid, malic acid, and phthalic acid
- phosphoric acids such as orthophosphoric acid, phosphorous acid, hypophosphorous acid, and pyrophosphoric acid
- phosphates thereof such as potassium salts, sodium salts (e.g., trisodium phosphate dodecahydrate), and ammonium salts
- boric acid and
- a surfactant is added as necessary to improve the stability, avoid pits, improve the appearance of the plate, and for other purposes.
- the surfactant is not particularly limited. Various kinds such as nonionic, cationic, anionic, and amphoteric surfactants can be used.
- the electroless palladium plating bath according to the present disclosure is applicable to, for example, a multilayer plating film including a palladium plating film and a gold plating film.
- the underlayer on which the palladium plating film is formed is not particularly limited.
- the underlayer include: various known base materials such as aluminum (Al), aluminum-based alloys, copper (Cu), and copper-based alloys; and plating films obtained by coating base materials with metal, such as iron (Fe), cobalt (Co), nickel (Ni), copper, zinc (Zn), silver (Ag), gold, platinum (Pt), and alloys thereof, having catalytic properties for reductive deposition of a palladium plating film. Even metal with no catalytic properties can be used as an object to be plated by various methods.
- the electroless palladium plating bath according to the present disclosure is applicable to an ENEPIG process.
- a multilayer plating film i.e., the electroless nickel/palladium/gold plating film
- the electroless nickel/palladium/gold plating film is obtained which includes a nickel plating film, the palladium plating film described above, and a gold plating film, in this order on aluminum, an aluminum-based alloy, copper, or a copper-based alloy constituting electrodes.
- Each of the plating films may be formed by a commonly used method.
- a method of producing a multilayer plating film including the palladium plating film formed in the electroless palladium plating bath according to the present disclosure will be described based on the ENEPIG process described above.
- the conditions for forming the palladium plating film are not limited to those described in the following description and changeable as appropriate based on known techniques.
- the plating conditions and plating equipment for electroless nickel plating using an electroless nickel plating bath are not particularly limited.
- Various known methods can be selected as appropriate.
- an object to be plated may be brought into contact with an electroless nickel plating bath at a temperature ranging from 50°C to 95°C for about 15 to 60 minutes.
- the thickness of the nickel plating film may be set as appropriate in accordance with required characteristics, and usually ranges from about 3 ⁇ m to about 7 ⁇ m.
- Various known compositions such as the nickel-phosphorus alloy and the nickel-boron (B) alloy can be used for the electroless nickel plating bath.
- the plating conditions and plating equipment for electroless palladium plating using an electroless palladium plating bath according to the present disclosure are not particularly limited. Various known methods can be selected as appropriate. For example, an object to be plated including a nickel plating film may be brought into contact with an electroless palladium plating bath at a temperature ranging from 50°C to 95°C for about 15 to 60 minutes. The thickness of the palladium plating film may be set as appropriate in accordance with required characteristics, and usually ranges from about 0.001 ⁇ m to about 1.0 ⁇ m.
- the plating conditions and plating equipment for electroless gold plating using an electroless gold plating bath are not particularly limited. Various known methods can be selected as appropriate. For example, an object to be plated including a palladium plating film may be brought into contact with an electroless gold plating bath at a temperature ranging from 40°C to 90°C for about 3 to 20 minutes.
- the thickness of the gold plating film may be set as appropriate in accordance with required characteristics, and usually ranges from about 0.001 ⁇ m to about 2 ⁇ m.
- the electroless palladium plating bath according to the present disclosure is also useful for electronic device components having a plating film.
- the electronic device components include components, such as a chip component, a crystal oscillator, a bump, a connector, a lead frame, a hoop material, a semiconductor package, and a printed board, that constitute an electronic device.
- the palladium plating film according to the present disclosure is obtained using the electroless palladium plating bath according to the present disclosure described above.
- the palladium plating film includes both of a pure palladium film and a palladium alloy plating film containing an alloy component. This is because elements other than palladium may be contained in the palladium plating film depending on the type of the reducing agent to be used. In some cases, components derived from the various additives may also be contained.
- the rest of the palladium plating film includes palladium and inevitable impurities.
- a pure palladium film is obtained.
- a phosphoric acid compound such as hypophosphite or phosphite is used as the reducing agent other than the formic acid or the salt thereof, a palladium plating film containing phosphorus is obtained.
- a boron compound such as an amine borane compound or a hydroboration compound is used, a palladium plating film containing boron is obtained.
- both of a phosphoric acid compound and a boron compound are used, a palladium plating film containing both of phosphorus and boron is obtained.
- the plating bath of each of Examples 1 to 18, Comparative Examples 1 to 8, and Reference Example 1 (i.e., an example containing no stabilizer) was prepared by mixing and stirring a palladium compound (i.e., palladium salt), ethylenediamine as the complexing agent, trisodium citrate dihydrate as the buffer, sodium formate as the reducing agent, and a stabilizer at concentrations shown in Tables 2 to 4.
- the plating bath was set to a temperature (i.e., temperature of the plating processing) of 60°C, and the pH was set to 6.0.
- the substrate was subjected sequentially to Pretreatment Steps 1 to 5 shown in Table 1.
- Step 1 Using MCL-16 (trade name: EPITHAS MCL-16 manufactured by C. Uyemura & Co., Ltd.), the substrate (a Si or TEG wafer) was subjected to cleaner treatment.
- MCL-16 trade name: EPITHAS MCL-16 manufactured by C. Uyemura & Co., Ltd.
- Step 2 Then, acid rinse treatment was performed using 30 mass% of a nitric acid solution to form an oxide film on the surface of the substrate.
- Step 3 After that, using MCT-51 (trade name: EPITHAS MCT-51 manufactured by C. Uyemura & Co., Ltd.), the substrate was subjected to primary zincate treatment.
- MCT-51 trade name: EPITHAS MCT-51 manufactured by C. Uyemura & Co., Ltd.
- Step 4 Next, the substrate was subjected to acid rinse treatment using 30 mass% of a nitric acid solution to remove a Zn substitution film, thereby forming an oxide film on the surface of the substrate.
- Step 5 Then, using MCT-51 (trade name: EPITHAS MCT-51 manufactured by C. Uyemura & Co., Ltd.), the substrate was subjected to secondary zincate treatment.
- MCT-51 trade name: EPITHAS MCT-51 manufactured by C. Uyemura & Co., Ltd.
- the substrate subjected to the pretreatment described above was subjected to Plating Processing Step 6 shown in Table 1 to form an electroless nickel plating film on the substrate. More specifically, using a nickel plating bath (trade name: NIMUDEN NPR-18 manufactured by C. Uyemura & Co., Ltd.), electroless plating processing was performed to form an electroless nickel plating film containing phosphorus (a nickel plating film having a concentration of phosphorus in the film ranging from 4% to 8%) on the substrate. Similarly, using a nickel plating bath (trade name: NIMUDEN NLL-1 manufactured by C. Uyemura & Co., Ltd.), electroless plating processing was performed to form a nickel plating film with a low phosphorus content (a nickel plating film having a concentration of phosphorus in the film being less than 4%) on the substrate.
- a nickel plating bath trade name: NIMUDEN NPR-18 manufactured by C. Uyemura & Co., Ltd.
- the substrate having the above-described nickel plating film thereon was subjected to Plating Processing Step 7 shown in Table 1 (i.e., the electroless plating processing using the palladium plating baths of Examples 1 to 18, Comparative Examples 1 to 8, and Reference Example 1) to form a palladium plating film on the surface of the nickel plating film (a pad of 100 ⁇ m ⁇ 100 ⁇ m and a pad of 2 mm ⁇ 3 mm) on the substrate.
- Plating Processing Step 7 shown in Table 1 i.e., the electroless plating processing using the palladium plating baths of Examples 1 to 18, Comparative Examples 1 to 8, and Reference Example 1 to form a palladium plating film on the surface of the nickel plating film (a pad of 100 ⁇ m ⁇ 100 ⁇ m and a pad of 2 mm ⁇ 3 mm) on the substrate.
- the present disclosure is particularly advantageously used for a multilayer plating film including a palladium plating film and a gold plating film, and an electroless palladium plating bath used in an ENEPIG process or other processing.
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Abstract
Description
- The present disclosure relates to an electroless palladium plating bath.
- In the field of electronic industry, for example, an electroless nickel (Ni)/electroless palladium (Pd)/immersion gold (Au) (ENEPIG) has been used as a surface treatment for mounts or terminals of printed circuit boards or IC packages. Using this ENEPIG process, a plating film sequentially including an electroless nickel plating film, an electroless palladium plating film, and an immersion gold plating film is obtained.
- The palladium film exhibits a good electrical conductivity and a high corrosion resistance, and moreover has the function of avoiding the diffusion of underlying nickel onto the gold surface due to thermal history. Thus, the palladium film plays an important role in the ENEPIG process described above.
- In general, the plating bath is required to be highly stable. In a typical electroless palladium plating bath, an ethylenediaminetetraacetic acid or a salt thereof, for example, is used as a stabilizer. However, the plating bath is easily biodegradable and is therefore not sufficiently stable.
- To address the problem, an electroless palladium plating bath having an organic compound containing divalent sulfur blended therein has been proposed. It is described (see, e.g.,
Japanese Patent No. 3972158 - Here, the typical plating bath described above has improved stability by blending the organic compound containing divalent sulfur, but has a problem of lower deposition properties of palladium onto a nickel plating film.
- There are devices that address the problem by using nickel plating films containing phosphorus (P) (nickel plating films having a concentration of phosphorus in the film ranging from 4% to 8%). In recent years, however, with an increase in the guaranteed operating temperatures of the devices, there is an increasing demand for a nickel plating film with a lower phosphorus content (a nickel plating film having a concentration of phosphorus in the film being less than 4%) that is applicable to a device with a high guaranteed operating temperature. The typical plating bath described above has the problem in particular that the deposition properties of palladium onto a nickel plating film having a lower phosphorus content is reduced significantly. Development of an electroless palladium plating bath applicable to nickel plating films having a lower phosphorus content is therefore desired.
- In view of the above problems, it is an objective of the present disclosure to provide an electroless palladium plating bath enabling improvement in stability of a plating bath, while reducing the deterioration in the deposition properties of palladium onto a nickel plating film.
- In order to achieve the above objective, an electroless palladium plating bath according to the present disclosure at least contains: a palladium compound; a reducing agent; a complexing agent; and a stabilizer. The stabilizer is an organic compound in which a divalent sulfur compound is bonded to a compound with a heterocyclic structure, and the organic compounds contains neither a thiol group nor a disulfide bond.
- The present disclosure provides a plating bath with improved stability, while reducing the deterioration in the deposition properties of palladium onto a nickel plating film.
- Now, an electroless palladium plating bath according to the present disclosure will be described.
- The electroless palladium plating bath according to the present disclosure contains a palladium compound, a reducing agent, a complexing agent, and a stabilizer.
- The palladium compound is a palladium ion source for palladium plating. The palladium compound may be at least water soluble. Examples of the palladium compound include: water-soluble inorganic palladium salts such as palladium chloride, palladium sulfate, and palladium acetate; and water-soluble organic palladium salts such as tetraamminepalladium hydrochloride, tetraamminepalladium sulfate, tetraamminepalladium acetate, tetraamminepalladium nitrate, and bis(ethylenediamine)palladium(II)chloride. Note that these palladium compounds may be used alone or two or more kinds may be used in a mixture.
- The concentration of the palladium ions in the electroless palladium plating bath is not particularly limited. However, a too low concentration of the palladium ions may significantly lower the rate of deposition of the plating film. The concentration is thus preferably 0.1 g/L or more, more preferably 0.3 g/L or more, and still more preferably 0.5 g/L or more. On the other hand, a too high concentration of the palladium ions may cause abnormal deposition which deteriorates the physical properties of the film. The concentration is thus preferably 10 g/L or less, more preferably 5 g/L or less, and still more preferably 3 g/L or less.
- The concentration of the palladium ions can be measured by atomic absorption spectrometry (AAS) using an atomic absorption spectrophotometer.
- The reducing agent has the function of depositing palladium in an electroless palladium plating bath. As the reducing agent, various known kinds of reducing agent can be used. Examples of the reducing agent include formic acid and salts thereof, hydrazines, hypophosphorous acid and salts thereof, phosphorous acid and salts thereof, amine borane compounds, hydroboration compounds, formalin, and ascorbic acid and salts thereof.
- Examples of the above mentioned salts include: alkali metal salts such as potassium and sodium salts; alkaline earth metal salts such as magnesium and calcium salts; ammonium salts; quaternary ammonium salts; and amine salts containing primary to tertiary amines.
- Examples of the amine borane compounds include dimethylamine borane (DMAB) and trimethylamine borane (TMAB). Examples of the hydroboration compounds include alkali metal borohydride salts such as sodium borohydride (SBH) and potassium borohydride (KBH).
- Among these reducing agents, formic acid or a salt thereof (e.g., sodium formate) is used in one preferred embodiment in view of achieving both the stability of the plating bath and the deposition properties of the plating film. These reducing agents may be used alone or two or more kinds may be used in a mixture.
- The content of the reducing agent in the electroless palladium plating bath (i.e., the single amount where the agent is used alone, and the total amount where two or more kinds are used in a mixture) may be adjusted as appropriate in consideration of the rate of deposition in the plating processing and the stability of the plating bath. The lower limit is preferably 1 g/L or more, more preferably 3 g/L or more, still more preferably 5 g/L or more, and particularly preferably 10 g/L or more. The upper limit of the content of the reducing agent is preferably 100 g/L or less, more preferably 80 g/L or less, and still more preferably 50 g/L or less.
- The complexing agent has the main function of stabilizing the solubility of palladium in the electroless palladium plating bath. As the complexing agent, various known kinds of complexing agent can be used. Examples of the complexing agent include at least one selected from the group consisting of ammonia and amine compounds, among which an amine compound is selected in a more preferred embodiment. Examples of the amine compounds include methylamine, dimethylamine, trimethylamine, benzylamine, methylenediamine, ethylenediamine, ethylenediamine derivatives, tetramethylenediamine, diethylenetriamine, ethylenediaminetetraacetic acid (EDTA) or alkali metal salts thereof, EDTA derivatives, and glycine. These complexing agents may be used alone or two or more kinds may be used in a mixture.
- The content of the complexing agent in the electroless palladium plating bath (i.e., the single amount where the agent is used alone, and the total amount where two or more types are used in a mixture) may be adjusted as appropriate in consideration of the stable solubility of palladium. The lower limit is preferably 0.1 g/L or more, more preferably 1 g/L or more, and still more preferably 3 g/L or more. The upper limit of the content of the complexing agent is preferably 15 g/L or less and more preferably 10 g/L or less.
- The stabilizer is added for the purpose of stabilizing the plating bath, improving appearance after the plating, adjusting the rate of forming a plating film, and other purposes. In the electroless palladium plating bath according to the present disclosure, an organic compound represented by the following Formula (1) can be used in which a divalent sulfur compound (i.e., a compound containing divalent sulfur) is bonded to a compound with a heterocyclic structure. [Chemical 1]
R1-R2... (1)
where R1 is the compound with the heterocyclic structure, and R2 is the divalent sulfur compound. R1-R2 represents an organic compound with neither a thiol group nor a disulfide bond. - Examples of the compound R1 with a heterocyclic structure include compounds with a nitrogen-containing heterocyclic structure or a sulfur-containing heterocyclic structure such as imidazole, imidazolidine, imidazoline, oxadiazole, oxazine, thiadiazole, thiazole, thiazolidine, tetrazole, triazine, triazole, piperazine, piperidine, pyrazine, pyrazole, pyrazolidine, pyridine, pyridazine, pyrimidine, pyrrole, pyrrolidine, benzothiazole, benzimidazole, isoquinoline, thiophene, tetrahydrothiophene, pentamethylene sulfide, and derivatives thereof.
- Examples of the divalent sulfur compound R2 include thiadiazole, thiazole, thiazolidine, benzothiazole, thiophene, tetrahydrothiophene, methanethiol, benzenethiol, pentamethylene sulfide, dimethyl sulfide, methyl mercaptan, ethyl mercaptan, allyl mercaptan, thiopropionic acid, thioacetic acid, ethyl methyl sulfide, 1-propanethiol, 2-propanethiol, 2-aminoethanethiol, 2-mercaptoethanol, 4-mercaptopyridine, dimethyl sulfoxide, S-methyl thioacetate, ethyl sulfide, methylpropyl sulfide, 1-butanethiol, thioglycolic acid, 2-(methylthio)ethanol, 3-mercapto-1-propanol, 2-methylthiazoline, cyclopentanethiol, 2-methyltetrahydrothiophene, pentamethylene sulfide, thiomorpholine, S-methyl thiopropionate, 3-mercaptopropionic acid, and derivatives thereof.
- Examples of the stabilizer represented by Formula (1) include 2-(4-thiazolyl)benzimidazole, 2-(methylthio)benzimidazole, 2-(methylthio)benzothiazole, (2-benzothiazolylthio)acetic acid, 3-(2-benzothiazolylthio)propionic acid, 2-(methylthio)pyridine, (4-pyridylthio)acetic acid, 4,4'-dipyridyl sulfide, 2-methylthio-4-pyrimidinol, S-methylthiobarbituric acid, 4-amino-6-chloro-2-(methylthio)pyrimidine, 5-(methylthio)-1H-tetrazole, 5-(ethylthio)-1H-tetrazole, N-(phenylthio)phthalimide, and 5-(methylthio)thiophene-2-carboxaldehyde. Note that these stabilizers may be used alone or two or more kinds may be used in a mixture. Chemical formulas of these stabilizers are as follows.
- The organic compound (R1-R2) used as the stabilizer in the electroless palladium plating bath according to the present disclosure includes an organic compound in which the divalent sulfur compound R2 bonded to the compound R1 with the heterocyclic structure derives from a thiol (-SH) group-containing compound.
- More specifically, for example, the 2-(methylthio)benzimidazole is an organic compound (R1-R2) in which benzimidazole as R1 and methanethiol as R2 are bonded. The compound contains no thiol (-SH) group in the state of R1-R2 as shown in the chemical formula. However, since R2 (i.e., methanethiol) before being bonded to R1 contains the thiol (-SH) group, R2 bonded to R1 derives from the compound (i.e., methanethiol) containing the thiol (-SH) group. The same applies to 2-(methylthio)benzothiazole (where R1 is benzothiazole and R2 is methanethiol) and 2-(methylthio)pyridine, (where R1 is pyridine and R2 is methanethiol).
- For example, (2-benzothiazolylthio)acetic acid contains no thiol (-SH) group in the state of R1-R2 (where R1 is benzothiazole and R2 is thioacetic acid) as shown in the chemical formula. However, since R2 (i.e., thioacetic acid) before being bonded to R1 contains the thiol (-SH) group, R2 bonded to R1 derives from the compound (i.e., thioacetic acid) containing the thiol (-SH) group. The same applies to (4-pyridylthio)acetic acid (where R1 is pyridine and R2 is thioacetic acid).
- For example, 3-(2-benzothiazolylthio)propionic acid contains no thiol (-SH) group in the state of R1-R2 (where R1 is benzothiazole and R2 is thiopropionic acid) as shown in the chemical formula. However, since R2 (i.e., thiopropionic acid) before being bonded to R1 contains the thiol (-SH) group, R2 bonded to R1 derives from the compound (i.e., thiopropionic acid) containing the thiol (-SH) group.
- For example, 4,4'-dipyridyl sulfide contains no thiol (-SH) in the state of R1-R2 (where R1 is pyridine and R2 is 4-mercaptopyridine) as shown in the chemical formula. However, since R2 (i.e., 4-mercaptopyridine) before being bonded to R1 contains the thiol (-SH) group, R2 bonded to R1 derives from the compound (i.e., 4-mercaptopyridine) containing the thiol (-SH) group.
- Here, as described above, the plating bath has improved stability by blending the organic compound containing divalent sulfur, but has the problem of lower deposition properties of palladium onto the nickel plating film. In particular, there is a problem of significantly lower deposition properties of palladium onto a nickel plating film having a low phosphorus content.
- The present inventors have studied the above problem and found the following: Using a stabilizer made of an organic compound in which a divalent sulfur compound is bonded to a compound with a heterocyclic structure (i. e., R1-R2 described above) reduces a reduction in the deposition properties of palladium on the nickel plating film and improves the stability of the plating bath.
- The present inventors also have found the following: Using an organic compound having a thiol group or a disulfide bond, among organic compounds in which a divalent sulfur compound is bonded to a compound with a heterocyclic structure, alters the thiol group or the disulfide bond due to an oxidation-reduction reaction in the plating bath (i.e., a disulfide bond is generated by an oxidation reaction of the thiol group, and a thiol group is generated by a reduction reaction of the disulfide bond), which changes the deposition properties of palladium and reduces the stability of the plating bath.
- That is, it is possible to achieve both of the deposition properties of palladium and the stability of the plating bath by using, as the stabilizer, an organic compound in which a divalent sulfur compound is bonded to a compound with a heterocyclic structure and which contains neither a thiol group nor a disulfide bond.
- It is also possible to deposit palladium even on a tiny region on the nickel plating film with a low phosphorus content.
- The content of the stabilizer in the electroless palladium plating bath (i.e., the single amount where the agent is used alone, and the total amount where two or more kinds are used in a mixture) may be adjusted as appropriate in consideration of the deposition properties of palladium in the plating processing and the stability of the plating bath. The lower limit is preferably 0.01 mg/L or more, more preferably 0.03 mg/L or more, and still more preferably 0.05 mg/L or more. The upper limit of the content of the stabilizer is preferably 10 mg/L or less, more preferably 5 mg/L or less, and still more preferably 1 mg/L or less.
- In the electroless palladium plating bath according to the present disclosure, various additives usually used in the field of plating bath can be added in addition to the components described above. Examples of such additives include a pH adjuster, a buffer, and a surfactant.
- The pH adjuster is an additive that having the function of adjusting the pH of the plating bath. Examples of the pH adjuster include: acids such as hydrochloric acid, sulfuric acid, nitric acid, citric acid, malonic acid, malic acid, tartaric acid, and phosphoric acid; and alkalis such as sodium hydroxide, potassium hydroxide, and ammonia water. Note that these pH adjusters may be used alone or two or more kinds may be used in a mixture.
- A too low pH tends to lower the rate of depositing palladium, whereas a too high pH may reduce the stability of the electroless palladium plating bath. The electroless palladium plating bath according to the present disclosure may have a pH preferably ranging from 4 to 10, and more preferably from 5 to 8.
- A buffer with a buffering function may be added. Examples of the buffer include: carboxylic acids such as citric acids (e.g., trisodium citrate dihydrate), tartaric acid, malic acid, and phthalic acid; phosphoric acids such as orthophosphoric acid, phosphorous acid, hypophosphorous acid, and pyrophosphoric acid; phosphates thereof such as potassium salts, sodium salts (e.g., trisodium phosphate dodecahydrate), and ammonium salts; boric acid; and tetraboric acid. These buffers may be used alone or two or more kinds may be used in a mixture.
- A surfactant is added as necessary to improve the stability, avoid pits, improve the appearance of the plate, and for other purposes. The surfactant is not particularly limited. Various kinds such as nonionic, cationic, anionic, and amphoteric surfactants can be used.
- The electroless palladium plating bath according to the present disclosure is applicable to, for example, a multilayer plating film including a palladium plating film and a gold plating film. The underlayer on which the palladium plating film is formed is not particularly limited. Examples of the underlayer include: various known base materials such as aluminum (Al), aluminum-based alloys, copper (Cu), and copper-based alloys; and plating films obtained by coating base materials with metal, such as iron (Fe), cobalt (Co), nickel (Ni), copper, zinc (Zn), silver (Ag), gold, platinum (Pt), and alloys thereof, having catalytic properties for reductive deposition of a palladium plating film. Even metal with no catalytic properties can be used as an object to be plated by various methods.
- In addition, the electroless palladium plating bath according to the present disclosure is applicable to an ENEPIG process. In the ENEPIG process, for example, a multilayer plating film (i.e., the electroless nickel/palladium/gold plating film) is obtained which includes a nickel plating film, the palladium plating film described above, and a gold plating film, in this order on aluminum, an aluminum-based alloy, copper, or a copper-based alloy constituting electrodes. Each of the plating films may be formed by a commonly used method.
- Next, a method of producing a multilayer plating film including the palladium plating film formed in the electroless palladium plating bath according to the present disclosure will be described based on the ENEPIG process described above. The conditions for forming the palladium plating film are not limited to those described in the following description and changeable as appropriate based on known techniques.
- The plating conditions and plating equipment for electroless nickel plating using an electroless nickel plating bath are not particularly limited. Various known methods can be selected as appropriate. For example, an object to be plated may be brought into contact with an electroless nickel plating bath at a temperature ranging from 50°C to 95°C for about 15 to 60 minutes. The thickness of the nickel plating film may be set as appropriate in accordance with required characteristics, and usually ranges from about 3 µm to about 7 µm. Various known compositions such as the nickel-phosphorus alloy and the nickel-boron (B) alloy can be used for the electroless nickel plating bath.
- The plating conditions and plating equipment for electroless palladium plating using an electroless palladium plating bath according to the present disclosure are not particularly limited. Various known methods can be selected as appropriate. For example, an object to be plated including a nickel plating film may be brought into contact with an electroless palladium plating bath at a temperature ranging from 50°C to 95°C for about 15 to 60 minutes. The thickness of the palladium plating film may be set as appropriate in accordance with required characteristics, and usually ranges from about 0.001 µm to about 1.0 µm.
- The plating conditions and plating equipment for electroless gold plating using an electroless gold plating bath are not particularly limited. Various known methods can be selected as appropriate. For example, an object to be plated including a palladium plating film may be brought into contact with an electroless gold plating bath at a temperature ranging from 40°C to 90°C for about 3 to 20 minutes. The thickness of the gold plating film may be set as appropriate in accordance with required characteristics, and usually ranges from about 0.001 µm to about 2 µm.
- The electroless palladium plating bath according to the present disclosure is also useful for electronic device components having a plating film. Examples of the electronic device components include components, such as a chip component, a crystal oscillator, a bump, a connector, a lead frame, a hoop material, a semiconductor package, and a printed board, that constitute an electronic device.
- The palladium plating film according to the present disclosure is obtained using the electroless palladium plating bath according to the present disclosure described above. The palladium plating film includes both of a pure palladium film and a palladium alloy plating film containing an alloy component. This is because elements other than palladium may be contained in the palladium plating film depending on the type of the reducing agent to be used. In some cases, components derived from the various additives may also be contained. The rest of the palladium plating film includes palladium and inevitable impurities.
- For example, if formic acid or a salt thereof or hydrazine or a salt thereof is used as the reducing agent, a pure palladium film is obtained. On the other hand, if a phosphoric acid compound such as hypophosphite or phosphite is used as the reducing agent other than the formic acid or the salt thereof, a palladium plating film containing phosphorus is obtained. If a boron compound such as an amine borane compound or a hydroboration compound is used, a palladium plating film containing boron is obtained. If both of a phosphoric acid compound and a boron compound are used, a palladium plating film containing both of phosphorus and boron is obtained.
- The following describes the invention related to the present application more specifically based on examples and comparative examples. However, the present disclosure is not limited to the following examples at all.
- The plating bath of each of Examples 1 to 18, Comparative Examples 1 to 8, and Reference Example 1 (i.e., an example containing no stabilizer) was prepared by mixing and stirring a palladium compound (i.e., palladium salt), ethylenediamine as the complexing agent, trisodium citrate dihydrate as the buffer, sodium formate as the reducing agent, and a stabilizer at concentrations shown in Tables 2 to 4. The plating bath was set to a temperature (i.e., temperature of the plating processing) of 60°C, and the pH was set to 6.0.
-
- Before forming the electroless plating film, the substrate was subjected sequentially to Pretreatment Steps 1 to 5 shown in Table 1.
- Step 1: Using MCL-16 (trade name: EPITHAS MCL-16 manufactured by C. Uyemura & Co., Ltd.), the substrate (a Si or TEG wafer) was subjected to cleaner treatment.
- Step 2: Then, acid rinse treatment was performed using 30 mass% of a nitric acid solution to form an oxide film on the surface of the substrate.
- Step 3: After that, using MCT-51 (trade name: EPITHAS MCT-51 manufactured by C. Uyemura & Co., Ltd.), the substrate was subjected to primary zincate treatment.
- Step 4: Next, the substrate was subjected to acid rinse treatment using 30 mass% of a nitric acid solution to remove a Zn substitution film, thereby forming an oxide film on the surface of the substrate.
- Step 5: Then, using MCT-51 (trade name: EPITHAS MCT-51 manufactured by C. Uyemura & Co., Ltd.), the substrate was subjected to secondary zincate treatment.
- Next, the substrate subjected to the pretreatment described above was subjected to Plating Processing Step 6 shown in Table 1 to form an electroless nickel plating film on the substrate. More specifically, using a nickel plating bath (trade name: NIMUDEN NPR-18 manufactured by C. Uyemura & Co., Ltd.), electroless plating processing was performed to form an electroless nickel plating film containing phosphorus (a nickel plating film having a concentration of phosphorus in the film ranging from 4% to 8%) on the substrate. Similarly, using a nickel plating bath (trade name: NIMUDEN NLL-1 manufactured by C. Uyemura & Co., Ltd.), electroless plating processing was performed to form a nickel plating film with a low phosphorus content (a nickel plating film having a concentration of phosphorus in the film being less than 4%) on the substrate.
- Next, the substrate having the above-described nickel plating film thereon was subjected to Plating Processing Step 7 shown in Table 1 (i.e., the electroless plating processing using the palladium plating baths of Examples 1 to 18, Comparative Examples 1 to 8, and Reference Example 1) to form a palladium plating film on the surface of the nickel plating film (a pad of 100 µm × 100 µm and a pad of 2 mm × 3 mm) on the substrate.
[Table 1] Processing Solution Processing Temperature Processing Time (sec) Pretreatment Step 1 Cleaner MCL-16 50°C 300 2 Acid rinse 30 mass% Nitric Acid 21°C 60 3 Primary Zincate Treatment MCT-51 21°C 20 4 Acid rinse 30 mass% Nitric Acid 21°C 60 5 Secondary Zincate Treatment MCT-51 21°C 40 Plating Processing Step 6 Electroless Ni (MP-Ni) NPR-18 80°C 1200 Electroless Ni (LP-Ni) NLL-1 90°C 7 Electroless Pd Examples 1-18 Comparative Examples 1-8 Reference Example 1 240 - Next, using an X-ray fluorescence spectrometer (trade name: XDV-µ manufactured by FISCHER INSTRUMENTS K.K.), the thickness of the palladium plating film formed on each of the pads was measured. The results are shown in Tables 2 to 4.
- Whether or not palladium particles are deposited in the palladium plating bath after the electroless palladium plating processing was visually observed and evaluated under the following criteria. The results are shown in Tables 2 to 4.
- ○: Even after one week from the plating processing, no deposition of palladium particles was observed.
- ×: Deposition of palladium particles was observed within one week after the plating processing.
- The following is found from Tables 2 and 3: In each of Examples 1 to 18 using, as the stabilizer, an organic compound in which a divalent sulfur compound was bonded to a compound with a heterocyclic structure and which contained neither a thiol group nor a disulfide bond, the thickness of the palladium plating film on the nickel plating film (i.e., the pad of 100 µm × 100 µm and the pad of 2 mm × 3 mm) is maintained as in Reference Example 1 containing no stabilizer. This means that even if a stabilizer is used, a reduction in the deposition properties of palladium is reduced In particular, it is found that even on a nickel plating film having a low phosphorus content (a nickel plating film having a concentration of phosphorus in the film being less than 4%), palladium is sufficiently deposited as on an electroless nickel plating film containing phosphorus (a nickel plating film having a concentration of phosphorus in the film ranging from 4% to 8%).
- In addition, even after one week from the plating processing, no deposition of palladium particles was observed in the plating bath, which shows excellent stability of the plating bath.
- On the other hand, as shown in Table 4, no palladium was deposited at all on the nickel plating film (the pad of 100 µm × 100 µm) having a lower phosphorus content in each of Comparative Examples 1 to 3 using, as a stabilizer, a compound with a heterocyclic structure to which no divalent sulfur compound was bonded, Comparative Examples 4, 6, and 8 using, as a stabilizer, an organic compound in which a divalent sulfur compound was bonded to a compound with a heterocyclic structure and which contained a thiol group, and Comparative Examples 5 and 7 using, as a stabilizer, an organic compound in which a divalent sulfur compound was bonded to a compound with a heterocyclic structure and which contained a disulfide bond. It is also found that deposition of palladium particles was observed in the plating bath within one week after the plating processing, which shows poor stability of the plating bath.
- The present disclosure is particularly advantageously used for a multilayer plating film including a palladium plating film and a gold plating film, and an electroless palladium plating bath used in an ENEPIG process or other processing.
Plating Bath Composition | |||||||||||
Example | |||||||||||
1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | |||
Pd Salt | Tetraamminepalladium Sulfate (as Pd) | g/L | 1.5 | 1.5 | 1.5 | 1.5 | 1.5 | ||||
Tetraamminepalladium Hydrochloride (as Pd) | g/L | 1.5 | 1.5 | ||||||||
Palladium Sulfate (as Pd) | g/L | 1.5 | |||||||||
Palladium Chloride (as Pd) | g/L | 1.5 | |||||||||
Complexing Agent | Ethylenediamine | g/L | 4 | 4 | 4 | 4 | 4 | 4 | 4 | 4 | 4 |
Buffer | Trisodium Citrate Dihydrate | g/L | 10 | 10 | 10 | 10 | 10 | 10 | 10 | 10 | |
Reducing Agent | Formic Acid Na | g/L | 25 | 25 | 25 | 25 | 25 | 25 | 25 | 25 | 25 |
Stabilizer | 2-4-thiazolyl)benzimidazole | mg/L | 0.1 | 1 | |||||||
2-methylthio)benzimidazole | mg/L | 0.1 | 0.3 | ||||||||
2-methylthio)benzothiazole | mg/L | 0.2 | |||||||||
(2-benzothiazolylthio)acetic acid | mg/L | 0.2 | |||||||||
3-2-benzothiazolylthio)propionic acid | mg/L | 0.2 | |||||||||
2-methylthio)pyridine | mg/L | 0.2 | |||||||||
(4-pyridylthio)acetic acid | mg/L | 0.2 | |||||||||
pH | 6.0 | 6.0 | 6.0 | 6.0 | 6.0 | 6.0 | 6.0 | 6.0 | 6.0 | ||
Processing Temperature | 60 | 60 | 60 | 60 | 60 | 60 | 60 | 60 | 60 | ||
Palladium Plating Film Thickness (µm) | Underlayer: Nickel Plating Film with Phosphorus Concentration in Film of 4% to 8% | Pad of 2 mm × 3 mm | 0.13 | 0.11 | 0.13 | 0.12 | 0.13 | 0.14 | 0.15 | 0.14 | 0.12 |
Pad of 100 µm × 100 µm | 0.11 | 0.11 | 0.12 | 0.11 | 0.12 | 0.12 | 0.13 | 0.13 | 0.09 | ||
Underlayer: Nickel Plating Film with Phosphorus Concentration in Film of Less Than 4% | Pad of 2 mm × 3 mm | 0.13 | 0.10 | 0.11 | 0.10 | 0.14 | 0.13 | 0.15 | 0.13 | 0.11 | |
Pad of 100 µm × 100 µm | 0.10 | 0.09 | 0.09 | 0.09 | 0.12 | 0.11 | 0.12 | 0.12 | 0.07 | ||
Stability of Plating Solution | ○ | ○ | ○ | ○ | ○ | ○ | ○ | ○ | ○ |
Plating Bath Composition | |||||||||||
Example | |||||||||||
10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | |||
Pd Salt | Tetraamminepalladium Sulfate (as Pd) | g/L | 1.5 | 1.5 | 1.5 | 1.5 | 1.5 | 1.5 | 1.5 | 1.5 | 1.5 |
Tetraamminepalladium Hydrochloride (as Pd) | g/L | ||||||||||
Palladium Sulfate (as Pd) | g/L | ||||||||||
Palladium Chloride (as Pd) | g/L | ||||||||||
Complexing Agent | Ethylenediamine | g/L | 4 | 4 | 4 | 4 | 4 | 4 | 4 | 4 | 4 |
Buffer | Trisodium Citrate Dihydrate | g/L | 10 | 10 | 10 | 10 | 10 | 10 | 10 | 10 | 10 |
Reducing Agent | Formic Acid Na | g/L | 25 | 25 | 25 | 25 | 25 | 25 | 25 | 25 | 25 |
Stabilizer | 4,4'-dipyridyl sulfide | mg/L | 0.4 | ||||||||
2-methylthio-4-pyrimidinol | mg/L | 0.2 | |||||||||
S-methylthiobarbituric acid | mg/L | 0.2 | |||||||||
4-amino-6-chloro-2-(methylthio)pyrimidine | mg/L | 0.2 | |||||||||
5-(methylthio)-1H-tetrazole | mg/L | 0.2 | |||||||||
5-(ethylthio)-1H-tetrazole | mg/L | 0.2 | |||||||||
5-(benzylthio)-1H-tetrazole | mg/L | 0.2 | |||||||||
N-(phenylthio)phthalimide | mg/L | 0.3 | |||||||||
5-(methylthio)thiophene-2-carboxaldehyde | mg/L | 0.4 | |||||||||
pH | 6.0 | 6.0 | 6.0 | 6.0 | 6.0 | 6.0 | 6.0 | 6.0 | 6.0 | ||
Processing Temperature | 60 | 60 | 60 | 60 | 60 | 60 | 60 | 60 | 60 | ||
Palladium Plating Film Thickness (µm) | Underlayer: Nickel Plating Film with Phosphorus Concentration in Film of 4% to 8% | Pad of 2 mm × 3 mm | 0.11 | 0.13 | 0.12 | 0.14 | 0.16 | 0.12 | 0.13 | 0.12 | 0.12 |
Pad of 100 µm × 100 µm | 0.10 | 0.12 | 0.11 | 0.13 | 0.14 | 0.12 | 0.12 | 0.11 | 0.08 | ||
Underlayer: Nickel Plating Film with Phosphorus Concentration in Film of Less Than 4% | Pad of 2 mm × 3 mm | 0.11 | 0.12 | 0.10 | 0.13 | 0.16 | 0.13 | 0.11 | 0.13 | 0.11 | |
Pad of 100 µm × 100 µm | 0.10 | 0.12 | 0.08 | 0.11 | 0.14 | 0.11 | 0.10 | 0.12 | 0.08 | ||
Stability of Plating Solution | ○ | ○ | ○ | ○ | ○ | ○ | ○ | ○ | ○ |
Plating Bath Composition | |||||||||||
Comparative Example | Reference Example | ||||||||||
1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 1 | |||
Pd Salt | Tetraamminepalladium Sulfate (as Pd) | g/L | 1.5 | 1.5 | 1.5 | 1.5 | 1.5 | 1.5 | 1.5 | 1.5 | 1.5 |
Tetraamminepalladium Hydrochloride (as Pd) | g/L | ||||||||||
Palladium Sulfate (as Pd) | g/L | ||||||||||
Palladium Chloride (as Pd) | g/L | ||||||||||
Complexing Agent | Ethylenediamine | g/L | 4 | 4 | 4 | 4 | 4 | 4 | 4 | 4 | 4 |
Buffer | Trisodium Citrate Dihydrate | g/L | 10 | 10 | 10 | 10 | 10 | 10 | 10 | 10 | 10 |
Reducing Agent | Formic Acid Na | g/L | 25 | 25 | 25 | 25 | 25 | 25 | 25 | 25 | 25 |
Stabilizer | Pyridine-2-Carboxylic Acid | mg/L | 10 | ||||||||
Benzothiazole | mg/L | 1.0 | |||||||||
Piperazine | mg/L | 300 | |||||||||
2-mercaptobenzothiazole | mg/L | 0.5 | |||||||||
2,2'-dithiodipyridine | mg/L | 0.5 | |||||||||
4-mercaptotoluene | mg/L | 0.5 | |||||||||
2,2'-dibenzothiazolyl disulfide | mg/L | 0.2 | |||||||||
2-mercaptobenzimidazole | mg/L | 0.2 | |||||||||
pH | 6.0 | 6.0 | 6.0 | 6.0 | 6.0 | 6.0 | 6.0 | 6.0 | 6.0 | ||
Processing Temperature | 60 | 60 | 60 | 60 | 60 | 60 | 60 | 60 | 60 | ||
Palladium Plating Film Thickness (µm) | Underlayer: Nickel Plating Film with Phosphorus Concentration in Film of 4% to 8% | Pad of 2 mm × 3 mm | 0.03 | 0.14 | 0.10 | 0.15 | 0.10 | 0.13 | 0.11 | 0.12 | 0.16 |
Pad of 100 µm × 100 µm | 0.02 | 0.12 | 0.06 | 0.13 | 0 | 0.12 | 0.12 | 0.11 | 0.14 | ||
Underlayer: Nickel Plating Film with Phosphorus Concentration in Film of Less Than 4% | Pad of 2 mm × 3 mm | 0.03 | 0.11 | 0.10 | 0.12 | 0.09 | 0.11 | 0.12 | 0.12 | 0.15 | |
Pad of 100 µm × 100 µm | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0.13 | ||
Stability of Plating Solution | × | × | × | × | × | × | × | × | × |
Claims (5)
- An electroless palladium plating bath at least comprising:a palladium compound; a reducing agent; a complexing agent; and a stabilizer,the stabilizer being an organic compound in which a divalent sulfur compound is bonded to a compound with a heterocyclic structure, the organic compound containing neither a thiol group nor a disulfide bond.
- The bath of claim 1, wherein
the stabilizer has a concentration ranging from 0.01 mg/L to 10 mg/L. - The bath of claim 1 or 2, wherein
the heterocyclic structure is a nitrogen-containing heterocyclic structure or a sulfur-containing heterocyclic structure. - The bath of claim 3, wherein
the compound with the heterocyclic structure is at least one selected from the group consisting of imidazole, imidazolidine, imidazoline, oxadiazole, oxazine, thiadiazole, thiazole, thiazolidine, tetrazole, triazine, triazole, piperazine, piperidine, pyrazine, pyrazole, pyrazolidine, pyridine, pyridazine, pyrimidine, pyrrole, pyrrolidine, benzothiazole, benzimidazole, isoquinoline, thiophene, tetrahydrothiophene, pentamethylene sulfide, and a derivative thereof. - The bath of any one of claims 1 to 4, wherein
the divalent sulfur compound is at least one selected from the group consisting of: thiadiazole, thiazole, thiazolidine, benzothiazole, thiophene, tetrahydrothiophene, methanethiol, benzenethiol, pentamethylene sulfide, dimethyl sulfide, methyl mercaptan, ethyl mercaptan, allyl mercaptan, thiopropionic acid, thioacetic acid, ethyl methyl sulfide, 1-propanethiol, 2-propanethiol, 2-aminoethanethiol, 2-mercaptoethanol, 4-mercaptopyridine, dimethyl sulfoxide, thiazolidine, S-methyl thioacetate, ethyl sulfide, methylpropyl sulfide, 1-butanethiol, thioglycolic acid, 2-(methylthio)ethanol, 3-mercapto-1-propanol, 2-methylthiazoline, cyclopentanethiol, 2-methyltetrahydrothiophene, pentamethylene sulfide, thiomorpholine, S-methyl thiopropionate, 3-mercaptopropionic acid, and a derivative thereof.
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JPH11269658A (en) * | 1998-03-24 | 1999-10-05 | Ishihara Chem Co Ltd | Electroless palladium plating liquid |
JP5622678B2 (en) * | 2011-07-14 | 2014-11-12 | 石原ケミカル株式会社 | Plating bath containing imidazole ring-bonded oxyalkylene compound |
CN106191825A (en) * | 2016-07-04 | 2016-12-07 | 长沙理工大学 | A kind of based on SO42the displacement reduction chemical palladium plating solution of system |
EP3452635A1 (en) * | 2016-05-04 | 2019-03-13 | ATOTECH Deutschland GmbH | Process for depositing a metal or metal alloy on a surface of a substrate including its activation |
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US20080147495A1 (en) * | 2006-12-19 | 2008-06-19 | General Electric Company | System and method for providing promotions |
JP2011249511A (en) * | 2010-05-26 | 2011-12-08 | Sumitomo Bakelite Co Ltd | Method of manufacturing substrate with gold-plating metal fine pattern, substrate with gold-plating metal fine pattern, printed wiring board, interposer, and semiconductor device |
US11732157B2 (en) * | 2019-10-15 | 2023-08-22 | Fujifilm Electronic Materials U.S.A., Inc. | Polishing compositions and methods of use thereof |
TW202138505A (en) * | 2020-03-31 | 2021-10-16 | 美商富士軟片電子材料美國股份有限公司 | Polishing compositions and methods of use thereof |
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Publication number | Priority date | Publication date | Assignee | Title |
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JPH11269658A (en) * | 1998-03-24 | 1999-10-05 | Ishihara Chem Co Ltd | Electroless palladium plating liquid |
JP3972158B2 (en) | 1998-03-24 | 2007-09-05 | 石原薬品株式会社 | Electroless palladium plating solution |
JP5622678B2 (en) * | 2011-07-14 | 2014-11-12 | 石原ケミカル株式会社 | Plating bath containing imidazole ring-bonded oxyalkylene compound |
EP3452635A1 (en) * | 2016-05-04 | 2019-03-13 | ATOTECH Deutschland GmbH | Process for depositing a metal or metal alloy on a surface of a substrate including its activation |
CN106191825A (en) * | 2016-07-04 | 2016-12-07 | 长沙理工大学 | A kind of based on SO42the displacement reduction chemical palladium plating solution of system |
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