Cobalt disilicide interconnects for micromechanical devices

A focused ion beam system working with 35 keV Co+ ions has been used to produce CoSi2 interconnects by means of ion beam synthesis. The capability of maskless patterning of the focused ion beam, its large depth of focus and the possibility of a dynamic focus control allow the fabrication of interconnects in three-dimensional devices with this method. investigations have been performed using polycrystalline, amorphous and single-crystalline silicon substrates. The influence of implantation dose has been studied, the electrical resistance and thermal stability of the interconnects has been measured. For room temperature implantation and annealing at 600 degrees C for 1 h resistivities between 34 and 60 mu delta cm have been obtained for the various substrate materials. The CoSi2 interconnects have been found to be thermally stable up to 700 degrees C. In order to demonstrate this method interconnection lines have been fabricated on the sloped walls of deep anisotropically etched grooves 280 mu m.