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The properties of Cu(V) alloy films were investigated to evaluate its potential use as self-forming diffusion barrier in copper metallization. Cu(V) alloy films were deposited on SiO 2 /Si substrates by magnetron sputtering. Cu(V)/SiO 2 /Si systems were subsequently annealed at various temperatures and analyzed by four-point probe measurement (FPP), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). After annealed at 500 °C, the resistivity of the Cu(V) films reduced to 3.1 μΩ cm, there is no obvious increase in resistivity. XRD suggest that Cu alloy film has preferential (111) crystal orientation and no extra peak corresponding to Cu and Si even after annealed at 500 °C. According to TEM results, a self-formed thin layer with the thickness of about 8 nm is observed at the interface between Cu alloy and the SiO 2 /Si substrate in the sample annealed at400 °C. As XPS results, after annealed at 400 °C and 500 °C, V atoms are observed at the surface of the Cu(V) films and the interface of the Cu(V) and SiO 2 /Si. The formation of the self-formed thin layer is probably due to the separation of V at the interface. The sharp declines of the Cu and Si concentrations at the interface indicate a lack of inter-diffusion between Cu and SiO 2 /Si. Adding small amounts of V to Cu film can improve the barrier performance and thermal stability compared with pure Cu contact systems. [ABSTRACT FROM AUTHOR]

Abstract: The properties of Cu–Zr and Cu–Ru alloy films were comparatively studied to evaluate their potential use as alloying elements. Cu alloy films were deposited on SiO2/Si substrates by magnetron sputtering. Samples were subsequently annealed and analyzed by four-point probe measurement, X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy and Auger electron spectroscopy. X-ray diffraction data suggest that Cu film has preferential (111) crystal orientation and no extra peak corresponding to any compound of Cu, Zr, Ru, and Si. According to transmission electron microscopy results, Cu grains grow in size for both systems but the grain sizes of the Cu alloy films are smaller than that of pure Cu films. These results indicate that Cu–Zr film is suitable for advanced barrier-free metallization in terms of interfacial stability and lower resistivity. [Copyright &y& Elsevier]

Abstract: Zr–Ti–N film prepared by sputtering deposition has been employed as a potential diffusion barrier for Cu metallization. It is thought that the existing states of Ti and Zr in the films are Ti–N and Zr–N phase in Zr–Ti–N films. Material analysis by XRD, XPS and sheet resistance measurement reveal that the failure of Zr–N film is mainly due to the formation of Cu3Si precipitates at the Zr–N/Si interface by Cu diffusion through the grain boundaries or local defects of the Zr–N barrier layer into Si substrate. In conjunction with sheet resistance measurement, XRD and XPS analyses, the Cu/Zr–Ti–N/Si contact system has high thermal stability at least up to 700°C. The incorporation of Ti atoms into Zr–N barrier layer was shown to be beneficial in improving the thermal stability of the Cu/barrier/Si contact system. [Copyright &y& Elsevier]

Abstract: Barrier capability of Zr–Si diffusion barriers in Cu metallization has been investigated. Amorphous Zr–Si diffusion barriers were deposited on the Si substrates by RF reactive magnetron sputtering under various substrate temperatures. An increase in substrate temperature results in a slightly decreased deposition rate together with an increase in mass density. An increase in substrate temperature also results in grain growth as deduced from field emission scanning electron microscopy (FE-SEM) micrographs. X-ray diffraction (XRD) spectra and Auger electron spectroscopy (AES) depth profiles for Cu/Zr–Si(RT)/Si and Cu/Zr–Si(300°C)/Si samples subjected to anneal at various temperatures show that the thermal stability was strongly correlated with the deposition temperature (consequently different density and chemical composition etc.) of the Zr–Si barrier layers. ZrSi(300°C) with higher mass density make the Cu/Zr–Si(300°C)/Si sample more stable. The appearance of Cu3Si in the Cu/Zr–Si/Si sample is attributed to the failure mechanism which may be associated with the diffusion of Cu and Si via the grain boundaries of the Zr–Si barriers. [Copyright &y& Elsevier]

Abstract: Zr–N/Zr bilayered film as a diffusion barrier between Cu and Si is evaluated. The thermal stability of the diffusion barrier is investigated by annealing the Cu/Zr–N/Zr/Si samples in N2 for an hour. XRD, SEM and AES results for the above contact systems after annealing at 700°C show that Cu film has preferential (111) crystal orientation and no diffraction peaks of Cu3Si and a Cu–Zr–Si ternary compound are observed for all Cu/Zr–N/Zr/Si contact systems. In addition, the atomic distribution of Zr and Si is evident and grows with increasing temperature up to 700°C, which corresponds to the Zr–Si phase having low contact resistivity. Low contact resistivity and high thermal stability diffusion barrier can be expected by the application of the Zr–N/Zr bilayered film as a diffusion barrier between Cu and Si. [Copyright &y& Elsevier]

The effectiveness of ZrSiN/Zr bilayered films to serve as diffusion barriers in Cu/Si contacts has been investigated. Annealing studies for Cu/ZrSiN/Zr/Si contact systems were carried out in N2/H2(10%) ambient. X-ray diffraction data suggest that Cu film has preferential (111) crystal orientation and Cu silicide cannot be observed up to 700 °C. Scanning electron microscopy micrographs show that the Cu film was integrated and free from agglomeration after annealing at 700 °C. Auger electron spectroscopy depth profiles of the Cu/ZrSiN(10 nm)/Zr(20 nm)/Si samples have no noticeable change except Zr silicide grows with annealing temperature up to 700 °C. The results indicate excellent barrier property for ZrSiN(10 nm)/Zr(20 nm) bilayer structure for Cu metallization. [ABSTRACT FROM AUTHOR]

Abstract: Films of Cu/Cu(Ru) and Cu(Ru) were deposited on Si substrates by magnetron sputtering. Samples were subsequently annealed and analyzed by four-point probe (FPP) measurement, X-ray diffraction (XRD), transmission electron microscopy (TEM) and Auger electron spectroscopy (AES). After annealing at 500°C, resistivity values of both systems decrease, but the reduction is more significant for Cu(Ru). Moreover, the resistivity values of annealed Cu(Ru) film are still greater than those of annealed Cu/Cu(Ru) film. XRD data suggest that Cu/Cu(Ru) film has higher thermal stability and Cu silicide cannot be observed up to 500°C. According to TEM results, after annealing at 500°C, the grain size of the Cu(Ru) film is smaller than that of Cu/Cu(Ru) film. In conjunction with AES, XRD, TEM analyses and sheet resistance measurement, it indicates that Cu/Cu(Ru) seed layers are potentially good for advanced Cu interconnects from the views of interfacial stability and low resistivity. [Copyright &y& Elsevier]