IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Dielectrics Monday Sessions
       Session DI1-MoP

Paper DI1-MoP20
Enhancement of Etching Characteristics of (Ba,Sr)TiO@sub 3@ Using Magnetically Enhanced Inductively Coupled CF@sub 4@/Ar Plasma

Monday, October 29, 2001, 5:30 pm, Room 134/135

Session: High K Dielectrics Poster Session
Presenter: T.H. Kim, Yeojoo Institute of Technology, Korea
Authors: D.P. Kim, Chung-Ang University, Korea
C.I. Kim, Chung-Ang University, Korea
T.H. Kim, Yeojoo Institute of Technology, Korea
Y.J. Seo, Daebul University, Korea
E.H. Kim, Cheju National University, Korea
E.G. Chang, Chung-Ang University, Korea
Correspondent: Click to Email
Now, three major trends in IC device fabrication are putting more functions on individual chips, fabricating faster chips, and lowering IC fabrication costs. Smaller memory cell increases its speed with using other materials sets like metal gates and electrodes, and high-k dielectrics. Ferroelectric (Ba,Sr)TiO@sub 3@ (BST) thin film have been attractive for advanced dynamic random access memories (DRAMs) applications due to its high dielectric constant. The smaller features need better plasma-etching processes to ensure etch fidelity and new features. Because the etch rate of BST thin film is low in a reactive ion etcher and an inductively coupled plasma etcher, magnetically enhanced inductively coupled plasma (MEICP) was used. Plasma density of MEICP is higher than that of RIE and ICP. In this study, BST thin films were etched in CF@sub 4@/Ar. The experiments were carried out with measuring etch rates and selectivity as a function of gas mixing ratio, rf power, dc bias voltage and chamber pressure. The maximum etch rate of BST thin film was 1800 Å/min at CF@sub 4@(10)/Ar(90), rf power of 600W, dc voltage of -300V, and chamber pressure of 5 mTorr. The selectivities of BST to Pt and photoresist were 0.6 and 0.7, respectively. The chemical states on the etched surface were investigated with x-ray photoelectron spectroscopy (XPS) and secondary ion mass spectrometry (SIMS). Atomic force microscopy (AFM) and scanning electron microscopy (SEM) were used to investigate the surface morphology of BST thin films exposed in plasma. X-ray diffraction (XRD) was evaluated to investigate physical properties of BST before and after etching process. Electrical property was characterized by measuring leakage current.