AVS 51st International Symposium
    Plasma Science and Technology Monday Sessions
       Session PS1-MoM

Paper PS1-MoM1
Etching of SiC and SiCN with Tetrafluoroethane/Oxygen Reactive Plasma

Monday, November 15, 2004, 8:20 am, Room 213A

Session: Low-k Dielectric Etching
Presenter: H.C. Galloway, Texas State University
Authors: H.C. Galloway, Texas State University
K.P. Radican, Trinity College Dublin, Ireland
J.M. McDonald, Texas State University
C. Martinez, Texas State University
D. Donnelly, Texas State University
D.C. Koeck, Texas State University
Correspondent: Click to Email
Two materials, SiC and SiCN, are being increasingly considered as barriers for low dielectric constant materials in integrated circuit systems. It is important for researchers to be able to effectively remove these barrier layers to provide ohmic contact to the silicon substrate. The etch rate as a function of oxygen concentration was investigated in the RF magnetron plasma etching of SiC and SiCN with tetrafluoroethane gas. The etch rate and surface roughness were measured with atomic force microscopy, while evidence of polymer deposition or other surface contamination was analyzed with FTIR. Etch rates of > 10 nm/sec can be achieved with high selectivity with respect to an aluminum mask, and near infinite selectivity with respect to silicon. This process has been demonstrated to be compatible with producing test structures of aluminum contacts to measure the electrical properties of some low-k materials. Tetrafluoroethane is of interest due to its high fluorine content. It is also a nontoxic, ozone friendly gas with a short atmospheric lifetime. The role of oxygen in the etching process will be discussed and this etching process will be compared to other similar etches that have been previously reported.