A Novel MO Precursor for Metal Tantalum and Tantalum Nitride Film
- PDF / 84,197 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 23 Downloads / 246 Views
0914-F09-03
A Novel MO Precursor for Metal Tantalum and Tantalum Nitride Film Kenichi Sekimoto1,2, Taishi Furukawa1,2, Noriaki Oshima1,2, Ken-ichi Tada1, and Tetsu Yamakawa1 1 Intelligent Material Group, Sagami Chemical Research Center, 2743-1,Hayakawa, Ayase, Kanagawa, 252-1193, Japan 2 Tokyo Research Center, TOSOH Corporation, 2743-1,Hayakawa, Ayase, Kanagawa, 252-1123, Japan
ABSTRACT A novel tantalum precursor, bis(ethylcyclopentadienyl)hydridocarbonyltantalum (Ta(EtCp)2(CO)H EtCp:ethylcyclopentadienyl), for chemical vapor deposition (CVD) and atomic layer deposition (ALD) was synthesized. The molecular structure of this precursor was determined by 1H and 13C NMR, IR, ICP-AES and elemental analysis. This precursor is liquid at room temperature, and its vapor pressure and decomposition temperature indicates that this precursor is suitable for CVD and ALD process. The composition analysis of metal tantalum films deposited by thermal CVD revealed that the concentration of carbon was larger than tantalum. On the other hand, an argon plasma CVD technique reduced the carbon concentration drastically. INTRODUCTION Tantalum nitride (TaN) is used for a diffusion barrier film in a copper (Cu) interconnect. Since TaN has poor adhesion to Cu, an adhesive layer is put between TaN and Cu film. A metal tantalum (Ta) film is one of the candidates for the adhesive layer. In the current process, the Ta/TaN laminated film is deposited by physical vapor deposition (PVD). Whereas the barrier film is required to be thiner and more conformal with shrinkage of the interconnect dimensions. Thus, CVD and ALD processes have been investigated as a new deposition method. Several tantalum compounds have been investigated for the precursors of CVD and ALD processes. Tantalum amide complexes such as pentakis(dimethylamido)tantalum (PDMAT) [1] and tris(tert-butylimido)(diethylamido)tantalum (TBTDET) [2,3] contain nitrogen atoms in the molecules. Therefore, it is difficult to make a metal tantalum film. Halogen atoms in tantalum halides (TaCl5 and TaBr5) [4] are cause of corrosion or poor adhesion. In this study, the novel tantalum compound, bis(ethylcyclopentadienyl)hydridocarbonyltantalum (Ta(EtCp)2(CO)H, Figure 1), which have neither nitrogen nor halogen atom, was synthesized and examined for the CVD precursor.
Et CO Ta H Et
Figure 1. Molecular structure of Ta(EtCp)2(CO)H. EXPERIMENT Ta(EtCp)2(CO)H was synthesized from bis(ethylcyclopentadienyl)trihydridotantalum (Ta(EtCp)2H3) and CO. The former trihydride complex was prepared following the literature method [5]. Ta(EtCp)2(CO)H was purified by distillation under a reduced pressure. The molecular structure was confirmed by 1H and 13C-NMR, IR, ICP-AES and elemental analysis. The vaporizing and decomposition characteristic were investigated with thermo gravimetric (TG) and differential scanning calorimetric (DSC) curves obtained under an argon atmosphere. The vapor pressure was determined by a static method. Film depositions on Si/SiO2 or Si substrates were performed using cold wall type the
Data Loading...
