(19)
(11)EP 1 146 148 A3

(12)EUROPEAN PATENT APPLICATION

(88)Date of publication A3:
04.02.2004 Bulletin 2004/06

(43)Date of publication A2:
17.10.2001 Bulletin 2001/42

(21)Application number: 00305825.2

(22)Date of filing:  10.07.2000
(51)Int. Cl.7C25D 3/58, C25D 3/60, C25D 3/56
(84)Designated Contracting States:
AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE
Designated Extension States:
AL LT LV MK RO SI

(30)Priority: 14.04.2000 JP 2000114282

(71)Applicant: Nihon New Chrome Co. Ltd.
Tokyo 179-0081 (JP)

(72)Inventors:
  • Kaneko, Mitsuru, c/o Nihon New Chrome Co. Ltd.
    Tokyo 179-0081 (JP)
  • Hatta, Asao, c/o Sakado Factory
    Sakado-City, Saitama 350-0206 (JP)
  • Kunii, Mitsuharu, c/o Sakado Factory
    Sakado-City, Saitama 350-0206 (JP)

(74)Representative: Horner, Martin Grenville et al
Cruikshank & Fairweather 19 Royal Exchange Square
Glasgow G1 3AE Scotland
Glasgow G1 3AE Scotland (GB)

  


(54)Cyanide-free pyrophosphoric acid bath for use in copper-tin alloy plating


(57) The present invention provides a pyrophosphoric acid bath for use in Cu-Sn alloy plating without containing a cyanic ion comprising a reaction product (A) of an amine derivative and an epihalohydrin in a 1:1 mole ratio and a cationic surfactant (B) and, when necessary, further comprising a surface tension adjusting agent (C), a bath stabilizer (D) and an N-benzylpyridinium derivative (E) as additives. According to the bath of the present invention, by changing a bath composition of copper and tin or by employing a characteristic additive, a stable film with a silver-white, gold, copper or light black color can be obtained. By increasing tin contents in the bath, the bath can be used for lead-free solder plating. The bath is safe in handling and hygienic and, moreover, has no sewage process and environmental problems since it contains neither cyanic compound nor formaldehyde derivative.