and a reducing agent. [0049] According to an alternative embodiment of the present invention, a formed passage may be filled with an electroless deposition solution containing a platinum salt such as for example [Pt(NH3)4]Cl2, PtCl4, or (NH4)2PtCl6 at a concentration of preferably 10-20 g/l and a reducing agent such as for example hydrazine or sodium hypophospate.