Material and electrical properties of electroless Ag-W thin film

Thin Ag-W films were prepared on Si (100) substrate and on metal (Ag and Co) seed layers by electroless technology for ULSI applications. The thin film electrical and physical parameters were studied as a function of the film composition. The thin film composition depends on the electroless bath formula. The role of the tungsten in silver matrix was studied via measurements of the film microhardness and thermal stability as function of the composition. The Ag-W films, thicker than 200 nm, exhibited a specific electrical resistivity of about 2μΩ* and a reflectivity larger than 90%. These films have not corroded in air at temperatures up to 200°C (thermal stable). Therefore, we assume that silvertungsten films can be used for applications where reliable conducting thin films is required, such as packaging and interconnects for microelectronics.