The tin or tin alloy electroplate bath which possesses tin or tin alloy electroplate

摘要

PROBLEM TO BE SOLVED: To prevent the erosion of electronic parts by a plating liquid and to avert the deposition of metal on an insulator part even if a current density is increased by using a plating bath which contains a tin (II) salt, or metal salt contg. the same, a complexing salt and a brightening agent consisting of an amine or amide compd. and has pH in a specific range. ;SOLUTION: The plating bath contains the tin (II) salt or the tin (II) salt and at least one kind of the metal salts selected from lead, copper, zinc, cobalt and nickel. The complexing salt is adequately citric acid, etc. The polyoxyethylene alkylamine or polyoxyethylene alkylamide expressed by either of formula I or formula II is used as the brightening agent. In the formulas, R is 6 to 8C alkyl group, m+n is an integer from 2 to 11. The amt. of the brightening agent to be added is wide in its effective range as the brightening agent is hardly decomposed by reduction but if the agent is added too much to the bath, air foamability increases. The amt. is, therefore, specified preferably to 0.5 to 5 g/l. The pH of the plating bath is specified to a range of 3 to 10.;COPYRIGHT: (C)1998,JPO