Evaluation of Contact and Via Step Coverage Using a Novel Two-Step Titanium Nitride Barrier Deposition Process

Abstract

AbstractAluminum plug technologies are still used for many different semiconductor device applications and are cost-effective processes. However, there are some disadvantages associated with them. The key disadvantage is aluminum junction spiking caused by aluminum diffusing down into the silicon substrate and silicon diffusing up into the aluminum plug due to a poor titanium nitride (TiN) barrier [1]. The tungsten plug process is primarily used for 0.5mm and smaller technologies. Titanium nitride barrier material plays an important role as an underlayer for tungsten plugs to prevent tungsten hexafluoride (WF6) from attacking the titanium (Ti) film [2]. The role of the TiN barrier is to retard or prevent diffusion of the materials that the TiN layer separates [3]. In this work, the authors investigated the TiN barrier film properties with respect to nitrogen flows at two different power set points and argon gas flows. Different experiments were performed to understand the properties of the TiN film with respect to process variables. Single-step and dual-step TiN barrier processes were studied for contact and via step coverage profiles used for aluminum and tungsten plug technologies.