AVS 46th International Symposium
    Plasma Science and Technology Division Monday Sessions
       Session PS-MoP

Paper PS-MoP20
Etching Mechanism of (Ba,Sr)TiO@sub 3@ Films in High Density Cl@sub 2@/BCl@sub 3@/Ar Plasma

Monday, October 25, 1999, 5:30 pm, Room 4C

Session: Poster Session
Presenter: S.B. Kim, Chung-Ang University, Korea
Authors: S.B. Kim, Chung-Ang University, Korea
Y.H. Lee, Sung-Kyun-Kwan University, S.Korea
G.Y. Yeom, Sung-Kyun-Kwan University, Korea
T.H. Kim, Yeojoo Institute Technology, Korea
K.H. Kwon, Hanseo University, Korea
C.I. Kim, Chung-Ang University, Korea
Correspondent: Click to Email
(Ba,Sr)TiO@sub 3@ thin films have attracted great interest as new dielectric materials of capacitors for ultra-large-scale integrated dynamic random access memories (ULSI-DRAMs) such as 256 Mbit or 1 Gbit. In this study, Cl@sub 2@/BCl@sub 3@/Ar inductively coupled plasmas was used to etch (Ba,Sr)TiO@sub 3@ and the effect of etch parameter such as gas mixing ratio, coil rf power, dc bias voltage and chamber pressure. The characteristics of the plasmas were estimated using a Langmuir probe and optical emission spectroscopy (OES). (Ba,Sr)TiO@sub 3@ was etched under (Cl@sub 2@+BCl@sub 3@)/((Cl@sub 2@+BCl@sub 3@)+Ar) of 0.2. The maximum etch rate of the BST films was 56 nm/min under Cl@sub 2@/(Cl@sub 2@+Ar) of 0.2@super 1@, therefore Ar gas was constant at 0.2 and the ratio of Cl@sub 2@/BCl@sub 3@ was changed. The change of Cl, B radical density measured by OES as a function of BCl@sub 3@ percentage in Cl@sub 2@/BCl@sub 3@. The profile of (Ba,Sr)TiO@sub 3@ and residue remaining after the etch was investigated by scanning electron microscopy (SEM). To study on chemical reaction between BST and CF@sub 4@ and analysis composition of surface residue remaining after the etch, films etched with different Cl@sub 2@/BCl@sub 3@ gas mixing ratio were investigated using x-ray photoelectron spectroscopy (XPS) and secondary ion mass spectrometer (SIMS). @FootnoteText@ ACKNOWLEDGMENTS This work was supported by GRANT No. KOSEF 981-0908-032-2 from the Korea Science and Engineering Foundation. 1. S. B. Kim, C. I. Kim, E. G. Chang, G. Y. Yeom, "Study on surface reaction of (Ba,Sr)TiO@sub 3@ thin Films by high density plasma etching", J. Vac. Sci. Technol. A Jul/Aug. (1999) will be published.