Barrier layer deposition using HDP-CVD

In conventional integrated circuit fabrication, circuit elements are formed by etching a pattern of gaps in a layer of metal such as aluminum. The gaps are then filled with a dielectric such as silicon dioxide. Copper is poised to take over as the main on-chip conductor for all types of integrated circuits due to its lower resistance as compared to conventional aluminum alloys. Unfortunately it is difficult to etch copper and therefore, damascene processes have developed for fabrication of copper-based integrated circuits. In damascene processes, dielectric layers are deposited to form an integrated stack and then etched to form gaps that are subsequently filled with copper. A method is provided for depositing a barrier layer on a substrate using a gaseous mixture that includes a hydrocarbon-containing gas and a silicon-containing gas. The gaseous mixture is provided to a process chamber and is used to form a plasma for depositing the barrier layer. The barrier layer is deposited with a thickness less than 500 . Suitable hydrocarbon-containing gases include alkanes and suitable silicon-containing gases include silanes.