COPPER LPCVD FOR ADVANCED TECHNOLOGY

Copper thin films have been deposited by low pressure chemical vapor d eposition (LPCVD) from the inorganic precursor compound [Cu3Cl3] synth esised by the reaction between chlorine and copper foil. Thermodynamic calculations following a typical a priori procedure have been carried out previously with the MELANGE software to simulate both copper chlo rination and copper formation by reduction of [Cu,CI,] by hydrogen. Th ese simulations have shown that the chlorination and the reduction eff iciency can be controlled by the temperature during the process and th e total pressure into the reactor. The depositions were performed ''in -situ'' on 4'' Si wafers covered by a refractory metal film (W, Cr, Ti ), heated by halogen lamps up to 600 degrees C. The morphology, compos ition and properties of the deposited layers have been characterized. The characteristics of the deposited films are strongly influenced by the substrate nature, the substrate temperature and the reactor total pressure. High deposition rates up to 200 nm/min and low resistivity ( 1.8 to 2.2 mu Omega cm) have been obtained. Very good conformity (> 90 %) with a high aspect ratio up to 3 has been achieved.