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

Paper PS-MoP4
Boron Effects on SBT Etching with Ar/Cl@sub 2@/BCl@sub 3@ Plasma

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

Session: Poster Session
Presenter: J.W. Seo, Chung Ang University, Korea
Authors: J.W. Seo, Chung Ang University, Korea
W.J. Lee, ETRI, Korea
B.G. Yu, ETRI, Korea
K.H. Kwon, Hanseo University, Korea
G.Y. Yeom, Sung-Kyun-Kwan University, Korea
C.I. Kim, Chung-Ang University, Korea
E.G. Chang, Chung-Ang University, Korea
Correspondent: Click to Email
Among the ferroelectric thin films that have been widely investigated for FRAM(ferroelectric random access memory) applications, SrBi@sub 2@Ta@sub 2@O@sub 9@ thin film is appropriate to memory capacitor materials for its excellent fatigue endurance. However, very few studies on etch properties of SBT thin film have been reported although dry etching is an area that demands a great deal of attention in the very large scale integration of ferroelectric thin film capacitors for FRAM applications. In this study, inductively coupled plasma(ICP) etcher was used for high density plasma etching of SrBi@sub 2@Ta@sub 2@O@sub 9@/Pt/Ti/SiO@sub 2@/Si with Ar/Cl@sub 2@/BCl@sub 3@ gas chemistries. SBT thin film was prepared with sol-gel method. Etch properties, such as etch rate, selectivity and profile, were measured according to split process parameters including RF power, bias voltage, chamber pressure and gas mixing ratio. Chemical reaction and residue of etched surface was analyzed with XPS(X-ray photoelectron spectroscopy) and SIMS(Secondary ion mass spectrometry). Changes of chemical composition in the chamber was analyzed with OES(Optical emission spectroscopy). As mole fraction of BCl@sub 3@ varied, boron effects with respect to residue, selectivity and etched profile was investigated. SBT was dominantly etched by Ar bombardment. Selectivity to photoresist(PR) or SiO@sub 2@ increased as decreasing mole fraction of Ar gas. Additive BCl@sub 3@ enhanced selectivity, profile and relative etch rate. SEM(Scanning electron microscopy) was used for examination of patterned SBT thin film. Change of stoichiometry on the film surface is discussed by comparing with OES analysis.