SUMMARY
The investigation of the electroless deposition of Sn on Cu (immersion type process) from acid baths contained tin(II) chloride, thiourea and HCl, was described in the paper. Modifications of tin coating thickness and deposition rate were determined as a function of changes in bath components concentration - SnCl2 (0,1-0,2 M), thiourea (0,6-0,8 M), HCl (0,2-0,5 M) and other process parameters – deposition time (15-210 min), temperature (60-80°C), diameter of Cu-substrate wire. The Sn deposition rate increased with increasing concentration of SnCl2, thiourea, HCl and with temperature. The deposition rate decreased with increasing deposition time, wire diameter and for higher concentrations of HCl and thiourea. The observed dependencies for deposition of coatings (thickness up to 3 μm), could be explained as multi-reaction process - exchange of Cu by Sn and dissolution of Sn in HCl.
Key words
Electroless immersion deposition, Sn on Cu, thiourea baths.
1 Politechnika Warszawska
2 Instytut Mechaniki Precyzyjnej, Warszawa
