AVS 51st International Symposium
    Plasma Science and Technology Monday Sessions
       Session PS-MoP

Paper PS-MoP23
Effect of BCl3 Addition on Etching Characteristics of TaN in BCl3/Cl2/Ar Inductively Coupled Plasma

Monday, November 15, 2004, 5:00 pm, Room Exhibit Hall B

Session: Poster Session
Presenter: M.H Shin, Sungkyunkwan University, South Korea
Authors: M.H Shin, Sungkyunkwan University, South Korea
S.W. Na, Sungkyunkwan University, South Korea
N.-E. Lee, Sungkyunkwan University, South Korea
J.H. Ahn, Hanyang University, South Korea
Correspondent: Click to Email
Patterning of absorbers is a crucial step in the manufacturing of EUVL (Extreme ultra-violet lithography) masks due to the stringent CD and reflectance requirements. So, patterning characteristics of new absorber materials for EUVL masks have to be evaluated [1]. Tantalum nitride (TaN) is one of the candidates for absorber layers in the mask used for the next generation EUVL and X-ray lithography because of the relative ease of patterning and its durability in cleaning processes. In this work, etching characteristics of 500-nm-thick TaN layers were investigated in a modified 8 inch commercial ICP (inductively coupled plasma ) etcher having a 3.5 turn spiral copper coil on the top of chamber separated by a 1-cm-thick quartz window. RF powers of 13.56MHz were applied to the top electrode coil and the substrate holder to induce ICP and self-bias voltage to the wafer, respectively. In order to investigate the effect of BCl@sub 3@ addition to Ar/Cl@sub 2@ chemistry on the TaN etch characteristics, TaN etch rates were measured by changing the added BCl@sub3@ flow rate and the bottom electrode power while the Cl@sub 2@ and Ar gas flows are fixed at 80sccm and 20sccm, respectively. To understand the role of BCl@sub 3@ gas in BCl@sub 3@/Cl@sub 2@/Ar ICP etching, the relative change in the densities of Cl and Ar radicals and the chemical binding states of etched TaN surfaces were measured by optical spectroscopy (OES) and X-ray photoelectron spectroscopy (XPS), respectively. The results showed the relative density of the Cl radicals was higher in the BCl@sub 3@/Cl@sub 2@/Ar chemistry than in Cl@sub 2@/Ar chemistry at the same total gas flow rate. The effects of BCl@sub 3@ addition to Cl@sub 2@/Ar chemistry on the etch characteristics of TaN (etch rate, selectivity over SiO@sub 2@ buffer layer, etc) will be discussed in detail. [1] F. Letzkus, J Butschke, M. Irmscher, F. M. Kamn, C. Koepernik, J. Mathuni, J. Rau, G. Ruhl: Microelectronic Engineering 2004.