Resistivity Of Cu Film Research Articles

Deformation mechanism of powder-spray-coated Cu particle at room temperature

The deposition behavior of copper particles during the aerosol deposition (AD) process was predicted according to the particle velocity via a numerical model. Plastic deformation of Cu particles was predicted by a cumulative effect among the injected carrier gas consumption, particle velocity, internal energy, compressive strain, and heat-induced thermal softening of the particle. Besides, there is possibility on oxidation of copper, which is influence on increase of electrical resistivity, caused by the induced heat. To compare the simulation results and understand the actual deposition behavior of Cu particles, Cu films were fabricated through AD using subdivided gas consumptions. The microstructure was confirmed by both the plastic strain through the Williamson–Hall plot and the strain results by the simulation. From the simulation and X-ray analysis, the characteristic of induced heat was analyzed to demonstrate the influence on oxidation, and to obtain suitable AD condition for low resistivity of Cu film.

Effect of Halides on Cu Electrodeposit Film: Potential-Dependent Impurity Incorporation

In this study, the effect of halides (X = Cl−, Br−, and I−) on the electrodeposited Cu film properties such as film resistivity, crystal structure, and impurity were evaluated. The resistivity of the Cu film electrodeposited with iodide in the plating electrolyte increased significantly, whereas the resistivity of the Cu film electrodeposited with chloride and bromide remained unchanged. Scanning electron microscopy, X-ray diffractometry, atomic force microscopy, and X-ray photoelectron spectroscopy analyses of the Cu electrodeposit films indicated that the increase in the resistivity with the addition of iodide originated from its incorporation into the film. CuX precipitate as a plausible impurity species, would be simultaneously removed via the reductive dissolution during Cu electroplating. Therefore, high impurity level for iodide would be associated with more negative reduction potential for CuI compared to those of CuCl and CuBr. It was supported by the potential-dependency of the impurity level and the resistivity of Cu film electrodeposited with iodide where the more negative deposition potential resulted in the less resistivity. The impurity level of CuI in Cu film was estimated via Mathiessen's rule in the range of a few μM in the electrolyte.

The properties of Cu metallization based on CuMgAl alloy buffer layer

The properties of Cu metallization based on CuMgAl alloy thin film as buffer layer were investigated in view of adhesion, diffusion and electronic properties in order to develop the applications of Cu metallization. The perfect adhesion of Cu film was obtained for the deposited CuMgAl buffer layer at 2.5sccm oxygen flux and 250°C substrate temperature. The resistivity of Cu film decreases with the increased substrate temperature and has a maximum for 2.5sccm oxygen flux in the deposition of CuMgAl film. A much-desired taper angle and a little critical dimension bias for the Cu/CuMgAl interconnect line were obtained in one wet etching step. Auger electron spectroscopy (AES) shows that the CuMgAl alloy barrier layer deposited at 2.5sccm oxygen flux and 250°C substrate temperature has good anti-diffusion between Cu film and substrate due to the formation of Mg and Al oxides in the interface of CuMgAl /substrate.

The Microstructure and Electrical Property of Porous Cu Film on Soft PVDF Substrate

The porous Cu film was deposited on soft PVDF substrate by magnetron sputtering at different sputtering pressure. The microstructure and electrical properties of Cu films were investigated as a function of sputtering pressure by X-ray diffraction XRD and Hall effect method. The results show that the surface morphology of Cu film is porous, and the XRD revealed that there are Cu diffraction peaks with highly textured having a Cu-(220) or a mixture of Cu-(111) and Cu-(220) at sputtering pressure 0.5 Pa. The electrical properties are also severely influenced by sputtering pressure, the resistivity of the porous Cu film is much larger than that fabricated on Si substrate. Furthermore, the resistivity increases simultaneously with the increasing of Cu film surface aperture, but the resistivity of Cu film still decreases with the increasing grain size. It can be concluded that the crystal structure is still the most important factor for the porous Cu film resistivity.

Low-resistivity Cu film electrodeposited with 3- N,N-dimethylaminodithiocarbamoyl-1-propanesulfonate for the application to the interconnection of electronic devices

In this study, we analyzed the properties of Cu films electrodeposited with 3- N,N-dimethylaminodithiocarbamoyl-1-propanesulfonate (DPS) as an organic additive in damascene Cu electrodeposition, in comparison with bis(sulfopropyl) disulfide (SPS). It was observed that the resistivity of Cu film electrodeposited with DPS was lower than that with SPS. Spectroscopic analyses showed that the impurity level and crystallinity of Cu films are almost the same, but the difference was found in the film roughness. Low roughness of Cu film electrodeposited with DPS led to the low resistivity, and it was speculated that the low roughness is related to the strong adsorption through the nitrogen atom in the DPS molecule.

Influence of Carbon Nanotubes on the Electrodeposition of Copper Interconnects

The electrochemistry of the co-deposition of Cu with carbon nanotube, CNTs is studied by voltammetry and chronoamperometry experiments. Electrochemical data shows CNTs have a slightly accelerating influence on the Cu electrodeposition when nafion was added in the bath as a surfactant of CNTs. The amount of CNTs in the deposit is up to 2% by weight. Kinetic data confirms that the addition of CNTs to the Cu baths increases the Cu exchange current density and decreases the equilibrium potential value. The electrical resistivity results show that at room temperature the resistivity of Cu/CNT composites film (2.47 μΩ-cm) is close to the resistivity of Cu film (2.15 μΩ-cm). A clear decrease of sample resistivity is observed with increasing anneal temperature upto 315ºC. The resistivity also increases when the concentration of CNTs is increased from 10 mg/l to 100 mg/l in the bath.

Influence of surface additives iodine and indium on the initial growth in copper chemical vapor deposition

The influence of surface additives, iodine and indium, on copper chemical vapor deposition (CVD) in its initial growth period is studied. The Cu CVD has been carried out on TaN/SiO2 and Cu(sputtered)/TaN/SiO2 substrates using Cu–hexafluoroacetylacetonate–vinyltrimethylsilane (Cu(hfac)(vtms)) precursor. Addition of iodine enhances the horizontal growth and reduces the vertical growth of Cu nuclei on the TaN surface. Addition of indium increases the number density of copper nuclei significantly on TaN. Both effects accelerate the initial growth rate and shorten the initial period. The X-ray photoelectron spectra confirm that iodine floats out to the growing copper surface, but indium does not. Since iodine is floating on the copper surface, it is a surfactant and its influences persist throughout the deposition. On the other hand, the influences of extranucleation sites provided by indium cease at the end of initial growth. Hence, Cu CVD on the In-added TaN surface develops a continuous film quickly, but its growth afterwards is similar to that without indium. On the Cu(sputtered)/TaN/SiO2 substrate, the surface is featured with faceted and protruded Cu grains in the initial growth. The iodine adsorption on sputtered copper worsens the initial morphology and leads to a porous and less conductive film. After 1-h deposition at 145°C, the sheet resistivity of Cu film on iodine-adsorbed TaN/SiO2 substrate is 1.8 ± 0.1μΩ-cm.

Effect of hydrogen remote plasma annealing on the characteristics of copper film

The effect of hydrogen remote plasma annealing on the characteristics of copper film such as resistivity, chemical composition and morphology was investigated. The hydrogen remote plasma enhanced the reflow of Cu and the preferential growth of Cu (111). With the increase of H 2 gas flow rate ratio {[H 2]/([H 2]+[N 2])}, plasma treatment time, and RF power, the resistivity of Cu film decreased due to the removal of impurity inside the film. The surface roughness decreased due to the smoothing of the surface, as the annealing time was increased up to 5 min but above that, the surface roughness increased because of agglomeration. The profile of Cu film in the trench opening became more conformal due to the enhanced reflow.