Single-Oriented Growth of (111) Cu Film on Thin ZrN/Zr Bilayered Film for ULSI Metallization

Abstract

We investigated the influence of ZrN/Zr bilayered film thickness on the (111) Cu orientation and the thermal stability of the Cu/ZrN/Zr/Si contact system by X-ray diffraction and Auger electron spectroscopy analyses. We confirmed that the single-oriented growth of (111) Cu can be realized by interposing the ZrN (400 Å)/Zr (200 Å) bilayered film between Cu and Si. It was revealed that the (111) Cu/(111) ZrN/(002) Zr/(001) Si contact system is satisfactorily stable up to 600°C without undesirable interfacial reaction and interdiffusion, maintaining the low contact resistivity of the ZrSi2 adhesion layer at the Si interface and the single-oriented state of the (111) Cu overlayer.

Evaluation of the thermal stability of reactively sputtered (Ti, Zr)Nx nano-thin films as diffusion barriers between Cu and Silicon

“…Only one FCC phase was observed with the sputtering conditions used, and the crystal lattice constant was found to be in a good agreement with a (Ti, Zr)N solid solution, showing a ratio of Zr / (Ti + Zr) = 0.30. J. Probst et al [15] also observed the peak shift of (111) lattice plane AOhm-cm) for ZrN as compared to TiN (DH F 298 = À 80.5 kcal/mol, q = 21.7 AOhm-cm) suggest better thermochemical stability of ZrN [16]. Consequently, the properties of (Ti, Zr)N x films are extremely sensitive to the filmsT microstructures and chemical composition.…”

Effects of substrate bias and nitrogen flow ratio on the surface morphology and binding state of reactively sputtered ZrNx films before and after annealing

“…Zirconium nitride (ZrN), like all nitrides of the transition metals, is a promising alternative material in many domains because of its excellent properties such as superior mechanical properties, high melting temperature (2980 8C) [1], high thermal stability [2,3], good electrical conductivity [4], which was widely used as diffusion barrier [5,6], hard coating [7,8], corrosion-resistant layer [9,10], and abrasion-resistant [11,12]. Considering the difference in heats of formation, ZrN can be formed more easily than TiN and TaN (DH f 298 = À365.2 kJ mol À1 for ZrN, DH f 298 = À337.8 kJ mol À1 for TiN, and DH f 298 = À252.3 kJ mol À1 for TaN) [13,14].…”

“…Various techniques have been applied to synthesize ZrN x films, such as chemical vapor deposition (CVD) [16], plasma nitridation [17], ion-beam-assisted evaporation [18,19], vacuum-arc deposition [20], and reactive magnetron sputtering [2,3,9,14,21,22]. Among these various techniques, reactive sputtering is the most common technique and is widely used in industry.…”

Realization of Cu(111) Single-Oriented State on SiO2 by Annealing Cu–Zr Film and the Thermal Stability of Cu–Zr/ZrN/Zr/Si Contact System

“…Therefore, it is very important to realize the Cu(111) single-oriented state as a Cu seed layer on the diffusion barrier/SiO 2 system, as pointed out by Hara. 6) In a previous paper, 7) we reported that the sequential single-oriented growth of (111)Cu/(111)ZrN/(002)Zr trilayered films on (001)Si can be realized by interposing the ZrN(400Å)/Zr(200Å) bilayered film between Cu and Si. Because it has been known that the contact resistivity of the Zr/n + -Si system with the ZrSi 2 silicide is lower than those of conventional contact systems such as Ti/n + -Si and Ta/n + -Si which have been generally used, 8) we expect that Zr films will play a role as a good adhesion layer to Si.…”

“…Furthermore, the thermal stability of the Cu-Zr/ZrN/Zr/Si contact system was evaluated for comparison with that of the Cu/ZrN/Zr/Si system reported in a previous paper. 7) …”