Stress-controlled formation of TiN hard mask

摘要

A method to form a titanium nitride (TiN) hard mask in the Damascene process of forming interconnects during the fabrication of a semiconductor device, while the type and magnitude of stress carried by the TiN hard mask is controlled. The TiN hard mask is formed in a multi-layered structure where each sub-layer is formed successively by repeating a cycle of processes comprising TiN and chlorine PECVD deposition, and N2/H2 plasma gas treatment. During its formation, the stress to be carried by the TiN hard mask is controlled by controlling the number of TiN sub-layers and the plasma gas treatment duration such that the stress may counter-balance predetermined external stress anticipated on a conventionally made TiN hard mask, which causes trench sidewall distortion, trench opening shrinkage, and gap filling problem.

主权项

1. A method comprising:
determining a number of a metal nitride sub-layers and a duration of a treatment process to be performed in the formation of each of the metal nitride sub-layers, wherein the determination is made in such a way that when a hard mask is formed in accordance with the metal nitride sub-layer number and the duration of the treatment process, the hard mask will have an internal stress that counter-balances an external stress to be exerted on the hard mask to be formed over a substrate; and forming the hard mask over the semiconductor substrate, wherein the hard mask is formed of the number of determined metal nitride sub-layers and wherein each of the metal nitride sub-layers is successively formed by a cycle of processes that includes depositing a metal nitride and performing treatment process for the determined duration.