Classifications

• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D3/00—Electroplating: Baths therefor
  • C25D3/02—Electroplating: Baths therefor from solutions
• • 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
• • 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
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D3/00—Electroplating: Baths therefor
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D3/00—Electroplating: Baths therefor
  • C25D3/02—Electroplating: Baths therefor from solutions
  • C25D3/30—Electroplating: Baths therefor from solutions of tin
  • C25D3/32—Electroplating: Baths therefor from solutions of tin characterised by the organic bath constituents used

Definitions

• the present invention relates to a plating bath additive containing a hydroxyalkanesulfonic acid as a main component, as well as a plating bath using the said additive.
• Hydroxyalkanesulfonic acids have heretofore been used as a component of various plating baths.
• a hydroxyalkanesulfonic acid is used as a plating bath component for the formation of tin-lead alloy electroplating so as to serve as a film for improving solderability or as an etching resist film.
• JP 11-1792A it is disclosed that a hydroxyalkanesulfonic acid is used as a plating bath component for plating to an electronic part or for forming Pb-Sn alloy salient electrodes onto a surface of a semiconductor wafer.
• JP 11-279787A it is disclosed that a hydroxyalkanesulfonic acid is used as a plating bath component for silver or silver alloy plating.
• JP 2000-87252A it is disclosed that a hydroxyalkanesulfonic acid is used as a plating bath component for an electroless tin-bismuth alloy plating bath.
• isethionic acid as a conventional hydroxyalkanesulfonic acid is obtained as sodium salt by subjecting ethylene oxide to the action of sodium hydrogen sulfite (see Encyclopaedia Chimica, Vol. 1, page 581), which is then ion-exchanged to remove the alkali metal for use as an acid.
• the present inventors found out that if an alkali metal was present within a plating bath, the alkali metal remained even if the surface of a plated article after plating was subjected to cleaning having such an economical characteristic as falling under an industrially allowable range, thus sometimes resulting in circuit-to-circuit insulation in the electronic part becoming defective. In this way we accomplished the present invention.
• the present invention resides in a plating bath additive containing a hydroxyalkanesulfonic acid as a main component, characterized in that the content of an alkali metal relative to the hydroxyalkanesulfonic acid is less than 0.05 mass%.
• the present invention also resides in the above plating bath additive wherein the hydroxyalkanesulfonic acid is isethionic acid.
• the present invention further resides in the above plating bath additive wherein the hydroxyalkanesulfonic acid is obtained by a method involving oxidizing a hydroxyalkylmercaptan with use of hydrogen peroxide.
• the present invention further resides in a plating bath using the above additive.
• a plating bath additive and a plating bath using the said additive, which plating bath contains a hydroxyalkanesulfonic acid and which even when applied to an electronic part such as a semiconductor device does not give rise to such a problem as circuit-to-circuit insulation in the electronic part becoming defective.
• the plating bath additive according to the present invention contains a hydroxyalkanesulfonic acid as a main component, with the content of an alkali metal relative to the hydroxyalkanesulfonic acid being less than 0.05 mass%.
• the hydroxyalkanesulfonic acid component is not Specially limited.
• Compounds represented by the general formula HO-R-SO 3 H are preferred wherein R is a hydrocarbon group having 1 to 12 carbon atoms and the hydroxyl group may be located at any position of R.
• 2-hydroxyethane-1-sulfonic acid isethionic acid
• 2-hydroxypropane-1-sulfonic acid 1-hydroxypropane-2-sulfonic acid
• 3-hydroxypropane-1-sulfonic acid 2-hydroxybutane-1-sulfonic acid
• 4-hydroxybutane-1-sulfonic acid 2-hydroxypentane-1-sulfonic acid
• 2-hydroxyhexane-1-sulfonic acid 2-hydroxydecane-1-sulfonic acid.
• 2-hydroxydecane-1-sulfonic acid is preferred as the plating bath additive.
• Isethionic acid can be obtained by a conventional method involving subjecting ethylene oxide to the action of sodium hydrogensulfite to afford sodium salt and subsequent ion exchange to remove an alkali metal component. In this case, the ion exchanging operation is repeated until the alkali metal content becomes less than 0.05 mass% relative to the hydroxyalkanesulfonic acid.
• JP 10-204052A which involves oxidizing a hydroxyalkylmercaptan with use of hydrogen peroxide, is preferred because an alkali metal is not used and therefore a hydroxyalkanesulfonic acid with an alkali metal content of less than 0.05 mass% can be obtained more effectively.
• the plating bath additive according to the present invention is useful as a hydroxyalkanesulfonic acid component added to the plating bath and the hydroxyalkanesulfonic acid content in the plating bath additive is arbitrary. Any other desired components than the hydroxyalkanesulfonic acid may be added into the plating bath of the present invention, provided it is necessary to make a control so that the alkali metal content relative to the hydroxyalkanesulfonic acid does not become 0.05 mass% or more.
• antioxidants e.g., catechol, hydroquinone, ascorbic acid
• brighteners or brightening aids e.g., benzaldehyde, formalin, glyoxal
• complexing agents e.g., EDTA, ethylenediamine, citric acid
• nonionic surfactants as homogenizers (e.g., polyethylene glycol, oxyethylene-oxypropylene block copolymer, alkylphenol ethylene oxide adducts, polyhydric alcohol fatty acid esters, fatty acid alkanol amides), and antioxidation aids or smoothing agents (e.g., thiourea, ethylene thiourea, thioglycolic acid).
• the plating bath according to the present invention contains the plating bath additive described above.
• components so far known as components of a plating path containing a hydroxyalkanesulfonic acid may be used in respective known ranges.
• arbitrary components may be selected for the plating bath of the invention as desired by a user, with no special limitation being placed thereon.
• Such components mention may be made of compounds (e.g., copper, tin, silver, and their salts and oxides, each alone or in combination of two or more) which supplies ions of a metal to be plated, inorganic acids, organic acids, oxidizing agents, reducing agents, surfactants, pH adjustors, pH controllers, buffer agents, smoothing agents, stress relaxation agents, stabilizers, complexing agents (chelating agents), brighteners, semibrighteners, antioxidants, dispersants, homogenizers, and other additives known to be incorporated in plating baths.
• Arbitrary components which may be incorporated in the plating bath additive of the present invention are also capable of being incorporated in the plating bath of the invention.
• reaction solution was then passed through a 35 mm dia. tower charged with 200 mL of an ion exchange resin (Duolite A-561, a product of Sumitomo Chemical Co.), from the top of the tower and is thereby purified to afford 54.0 mass% of an isethionic acid solution (yield 241.6 g : percent yield 95.9%). No alkali metal was detected from this aqueous isethionic acid solution (detection limit 10 ppb).
• an ion exchange resin Duolite A-561, a product of Sumitomo Chemical Co.
• the aqueous isethionic acid solution was used as a plating bath additive (1).
• a 43 mass% aqueous solution of commercially available sodium isethionate (a product of Aoki Yushi Kogyo Co.) was prepared and was then passed through a 30 mm dia. tower charged with 82 mL of an ion exchange resin (MONOSPHIA 630C_H, a product of The Dow Chemical Co.), at a (downflow) SV1.0, from the top of the tower; and was thereby purified to afford 10 mass% of an aqueous isethionic acid solution having a sodium content of 5 mass% relative to isethionic acid. The aqueous isethionic acid solution was then concentrated to an isethionic acid concentration of 40 mass% and the thus-concentrated.aqueous solution was used as a comparative plating bath additive (1).
• a 49.2 mass% aqueous 2-hydroxypropane-1-sulfonic acid solution was prepared in the same way as in Example 1 except that 2-mercaptoethanol was substituted by 2-mercaptopropanol. No alkali metal was detected from the aqueous 2-hydroxypropane-1-sulfonic acid solution.
• the aqueous 2-hydroxypropane-1-sulfonic acid solution thus prepared was used as a plating bath additive (3) according to the present invention.
• aqueous solutions of the composition shown in Table 1 were prepared as plating baths (Sn plating baths).

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Electrochemistry (AREA)
• General Chemical & Material Sciences (AREA)
• Mechanical Engineering (AREA)
• Electroplating And Plating Baths Therefor (AREA)
• Chemically Coating (AREA)
• Electroplating Methods And Accessories (AREA)

Applications Claiming Priority (2)

Publications (3)

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• 2004
  • 2004-01-16 JP JP2004009284A patent/JP2005200714A/ja active Pending
• 2005
  • 2005-01-05 KR KR1020050000663A patent/KR20050075692A/ko not_active Withdrawn
  • 2005-01-10 TW TW094100656A patent/TW200536955A/zh unknown
  • 2005-01-14 CN CNA2005100039750A patent/CN1670259A/zh active Pending
  • 2005-01-14 EP EP05250172A patent/EP1555335B1/fr not_active Expired - Lifetime
  • 2005-01-14 US US11/035,847 patent/US20050155514A1/en not_active Abandoned
  • 2005-01-14 DE DE602005019930T patent/DE602005019930D1/de not_active Expired - Lifetime

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