***PLEASE NOTE YOU MUST IDENTIFY A DIFFERENT PRESENTER FOR THIS ABSTRACT.  YOU MAY PRESENT ONE PAPER ONLY (ORAL OR POSTER) AT THE CONFERENCE. J. WOO IS CURRENTLY LISTED AS PRESENTER FOR ABSTRACT #1295***Recently, to overcome these problems, conventional poly-Si gates on ultrathin SiO2 dielectric layers could be replaced by metal gates on high-k dielectric materials. Metal electrode/high-k gate stacks have already been implemented, but require continuous improvement with scaling. Currently, to integrate Hf-based high-k dielectric materials including HfO2, HfAlO, HfON, and HfSiO, the use of various metal gate electrode materials including TaN and TiN is being widely studied. Among these materials, TaN/HfAlO are promising candidates for replacing ploly-Si/SiO2. TaN is very attractive due to its high thermal stability, good adhesion, high melting point, and low resistivity (25 to 250 µΩ/cm). To pattern the metal electrode/high-k gate stack structure, etching of the metal electrode against a high-k dielectric layer using etching processes can be employed. In this approach, a very high etch selectivity of the metal gate electrode to the high-k dielectric is required because of the very thin nature of high-k dielectric materials. Therefore, a very high etch selectivity of the metal gate electrode to the high-k dielectric is also needed to minimize Si damage loss at ultrashallow source/drain regions.

In this work, the TaN thin films were etched in Cl2/BCl3/Ar and O2/Cl2/BCl3/Ar plasma. The effects of adding O2 to the Cl2/BCl3/Ar chemistry were investigated for the purpose of improving the etch selectivity of the TaN to SiO2 layer. The etching characteristics of TaN thin films were investigated in terms of etch rates and selectivity as a function of the gas mixing ratio. X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES) was used for elemental analysis of the etched surfaces.