Autocatalytic Deposition of Tin

Electroless tin can be deposited by means of a disproportionation reaction in alkaline solution. The initiation of the reaction has been studied and the optimum concentrations of the bath compounds were determined. Hydroxy compounds were shown to be applicable as stabilizers. From 119Sn NMR measurements on tin(II) compounds of hydroxystannite and stabilizers in combination with deposition rate measurements information about the disproportionation reaction at the tin surface has been derived. Whisker growth of the electroless tin layer was prevented by a lead top layer, prepared by an electrochemical exchange reaction.