Ultrathin TaN/Ta barrier modifications to fullfill next technology node requirements

A physical vapor deposition tool for 300 mm wafers was coupled with an angle resolved photoelectron spectroscopy tool (ARXPS) and used to study the growth of TaN single layer and TaN/Ta double layer diffusion barriers. The nitrogen content of TaN was adjusted by controlling the nitrogen flow and by varying the deposition power. We describe a process recipe that allows us to decrease the TaN thickness while still maintaining the Ta layer in the low resistivity α-phase. The process recipe was developed on blanket wafers and evaluated in a test structure for high performance CMOS products.