Characteristics of tungsten coating on silicon particles prepared by sol-gel method

Cu/Sip composite is an ideal material for electronic packaging due to its excellent properties. However, the Cu–Si intermetallics formed by Cu and Si interfacial reaction seriously deteriorate the ductility and thermal conductivity of the composite. In this paper, Si particles were coated with W layer by sol-gel method to inhibit the formation of intermetallics, and the deposition details of the W layer were investigated. The Si particles need to be pre-treated first, such as decontaminating and roughening, to facilitate subsequent deposition. A uniform WO3·nH2O layer forms on the Si particles, which transforms into W particles or particle aggregates after reduction at 900 °C for 30 min. After re-coating for three times, a complete W coating forms on the Si particles with a theoretical thickness of 0.91 μm. With the increase of the integrity of W coating, the content of Cu–Si intermetallics decreases and ductility of Cu/Sip composites increases. In addition, the W coating on Si particles remains stable at 700 °C, which is an effective route to prepare Cu/Sip composites for electronic packaging.