Research On Si₃N₄ Hillock Defect In Damascene Technology Of Copper Interconnect

With the IC development toward the direction of the high density and high performance, the size of semiconductor device continues to shrink and interconnect layers are on the rise. Because copper have too many Advantage such as the low resistivity, the anti electro migration and anti stress migration ability, its'mosaic manufacturing process compatibility and the low cost, copper interconnect has replaced aluminum interconnect and become a new type of dominant interconnect technology. The new interconnection structure, the new process technology (such as electro copper plating and chemical mechanical polishing) and the new interconnect materials (such as low k dielectric, barrier layer and passivation material) have been developed and applied to integrated circuit interconnect technology, which greatly improves the performance of integrated circuits. But it also triggered a series of interconnect reliability. In the copper interconnect process, hillock defect occurs due to copper solicitations and stress migration It was a important phenomenon in the failure model of copper interconnect that copper solicitations induced current leakage and the void was caused by stress migration.The study analyzed the formation mechanism and the failure mechanism of hillock defect, focusing on current leakage and void. Secondly the influence of"NH3 treatment"step and"Pre Dep"step on hillock defect was focused during the desperation of Si3H4. Based on the design analysis, the process parameters such as gas flow, heater spacing and RF power etc were optimized. Thirdly, the stress sources was identified by the actual production process data. Then the anneal time was focused to solve the void issue. At last the production yield and reliability was enhanced by solving hillock defect.