AVS 52nd International Symposium
    Plasma Science and Technology Monday Sessions
       Session PS-MoP

Paper PS-MoP14
A Comparative Study on Dry Etching of TaN/HfO@sub 2@ Gate Stack Structure in Inductively Coupled Plasmas using Cl@sub 2@, BCl@sub 3@, and HBr Chemistries

Monday, October 31, 2005, 5:00 pm, Room Exhibit Hall C&D

Session: Plasma Science and Technology Poster Session
Presenter: M.H. Shin, Sungkyunkwan University, Korea
Authors: M.H. Shin, Sungkyunkwan University, Korea
M.S. Park, Sungkyunkwan University, Korea
N.-E. Lee, Sungkyunkwan University, Korea
J.Y. Kim, Kookmin University, Korea
Correspondent: Click to Email
Development of advanced high-k gate dielectrics and its integration into advanced nano-scale CMOS devices below 50-nm technology node has gained considerable attention recently because of the need for the replacement of ultrathin SiO@sub 2@ or nitrided SiO@sub 2@ gate dielectrics. For the integration of the high-k gate dielectric materials in the nano-scale CMOS devices, metal gate electrodes are expected to be used in the future. Currently, the metal gate electrode materials including TaN, TiN, HfN, WN, TaSiN and metal silicides are being widely studied for next generation devices with high-k gate dielectrics. Among many integration issues, selective etching of metal gate electrodes and the high-k gate dielectrics over the Si substrate is expected to be one of critical steps in the process integration of the front-end of the line (FEOL). In this work, as a model system for studying the etching characteristics of the metal gate electrode/high-k dielectric stack structures and etch rate selectivity of the metal gate electrode over the high-k dielectric layer, TaN/HfO@sub 2@ gate structure, was chosen. ICP etching characteristics of TaN(150nm)/HfO@sub 2@(80nm) gate stack structures on Si substrate were investigated by varying the process parameters such as etch gas mixing ratios (Cl@sub 2@/Ar/O@sub 2@, BCl@sub 3@/Ar/O@sub 2@, and HBr/Ar/O@sub 2@), the top electrode power, the DC self-bias voltage (V@sub dc@), and working pressure in an ICP etcher. To understand the role of etch gas chemistry in ICP etching, the relative change in the densities of ion radical and chemical binding states of etched TaN and HfO@sub 2@ surfaces were measured by optical spectroscopy (OES) and X-ray photoelectron spectroscopy (XPS), respectively. The results of the etch rate and etch selectivity of SiO@sub 2@ to HfO@sub 2@ measured as a function of the various process parameters will be discussed in detail in conjunction with the OES and XPS analysis data.