Physical vapor deposited AlN as scalable and reliable interconnect etch-stop ≤ 10nm node

Physical vapor deposited (PVD) AlN is introduced as a novel interconnect etch-stop layer. Superior dielectric etch selectivity is demonstrated over conventional silicon-based etch-stops, due to minimized impurity and high film density provided by PVD. This enables reduction of etch stop thickness, resulting in 5% capacitance reduction at 10nm node dimensions. Interface control and film treatments are optimized to improve reliability. PVD AlN is compatible with selective Co capping layer for electro-migration improvements. Control of film doping extends the film beyond 10nm technology node.