Properties Of Copper Thin Films Research Articles

Analysis of mechanical properties of copper thin film in ambient, DI water and slurry environment by nanoindentation

ABSTRACT The nanomechanical properties of chemically altered wafer surface are critical for modelling the material removal in the chemical mechanical planarization (CMP). This paper investigates the nanomechanical properties of copper thin film on the silicon wafer and the reacted passivation layer in different environmental conditions by nanoindentation. The environmental conditions are ambient air, DI water and slurry environment at 45°C temperature. Nanoindentation test is performed on Hysitron TI980 triboindenter using standard Berkovich indenter. Experimental results show that the nanohardness and Young’s modulus of the copper thin film in the ambient environment are 1.72 GPa and 118.03 GPa, respectively. The passivation in DI water results in a slight increase in nano-hardness of copper thin film, on the other hand, a significant decrease in nano-hardness is observed after passivation in the slurry environment. The reduced values of hardness and young’s modulus in the slurry environment are in line with the chemical action of slurry in CMP. The estimated nano-hardness and modulus of the wafer contact surface after the chemical action of slurry are critical process parameters for the analysis and modelling of the advanced node (CMP) process.

Experimental and Numerical Simulation Study of the Vibration Properties of Thin Copper Films Bonded to FR4 Composite

Printed circuit boards constitute the basis of most electronic devices and are mainly fabricated of thin copper films bounded to fiber epoxy laminates, such as FR4. Vibrational stress can induce device failure, and hence, studies addressing their modal properties have important applications. In this paper, cantilever samples made of bare copper bounded to FR4 have been studied to analyze, for the first time, the vibration behavior of specimens with different aspect ratios, with and without central holes of different diameters. Natural frequencies and damping ratios were determined experimentally and analytically using a finite element method for four groups of samples with a very good correspondence between both methods. The fundamental resonance frequency of all the specimens was found to be less than 40 Hz and the influence of a central hole was not significant to affect the modal properties.

Исследование влияния подслоя графена на морфологию, оптические и электрические свойства тонких медных пленок.

Исследование влияния подслоя графена на морфологию, оптические и электрические свойства тонких медных пленок.

Graphene-Supported Thin Metal Films for Nanophotonics and Optoelectronics.

Graphene-metal hybrid nanostructures have attracted considerable attention due to their potential applications in nanophotonics and optoelectronics. The output characteristics of devices based on such nanostructures largely depend on the properties of the metals. Here, we study the optical, electrical and structural properties of continuous thin gold and copper films grown by electron beam evaporation on monolayer graphene transferred onto silicon dioxide substrates. We find that the presence of graphene has a significant effect on optical losses and electrical resistance, both for thin gold and copper films. Furthermore, the growth kinetics of gold and copper films vary greatly; in particular, we found here a significant dependence of the properties of thin copper films on the deposition rate, unlike gold films. Our work provides new data on the optical properties of gold and copper, which should be considered in modeling and designing devices with graphene-metal nanolayers.

Morphology and Electrical Properties of Copper Thin Films Electroplated on Ni/n+-Si(100) for Silicon Solar Contact

Cu thin films were electrodeposited on Ni/n+-Si(100) substrate from sulfuric solution with fixed pH at room temperature. The effect of deposition time of Cu coatings was studied by using the chronoamperometry method (CA), the atomic force microscopy (AFM), X-ray diffraction (XRD) and four point probe to investigate surface topography , structure and electrical properties of Cu films. From electrochemical measurements, the Cu film thickness ranging from 63 nm to 8.9 µm was calculated using Faraday’s law. The AFM study showed a rugose surface of the Cu films and the variation of film morphology with deposition time were established. The XRD spectra revealed the formation of thin Cu films with a preferential orientation. Sheet resistance and resistivity showed strong dependence on the deposition time of Cu films. Cu films will be in the future metal contact for silicon solar cells.

Investigation of Structural, Compositional and Anti-Microbial Properties of Copper Thin Film Using Direct Current Magnetron Sputtering for Surgical Instruments

Surgical instruments and other bioimplant devices, owing to their importance in the biomedical industry require high biocompatibility to be used in the human body. Nevertheless, issues of compatibility, bacterial infections are quite common in such devices. Hence development of surface coatings on various substrates for implant applications is a promising technique to combat the issues arising in these implant materials. The present investigation aims at coating copper on stainless steel substrate using DC Magnetron sputtering which is used to achieve film of required thickness (0.5–8[Formula: see text][Formula: see text]m). The deposition pressure, substrate temperature, power supply, distance between the specimen and target are optimized and maintained constant, while the sputtering time (30–110[Formula: see text]min) is varied. The sputtered copper thin film’s morphology, composition are characterized by SEM and EDAX. X-ray diffraction analysis shows copper oriented on (111) and (002) and copper oxide on (111) planes. The contact angle of copper thin film is 92[Formula: see text] while AISI 316L shows 73[Formula: see text]. The antimicrobial studies carried in Staphylococcus aureus, Escherichia Coli, Klebsiella pneumonia and Candida albicans show that the maximum reduction was seen upto 35, 26, 54, 39[Formula: see text]CFU/mL, respectively after 24[Formula: see text]h. The cell viability is studied by MTT assay test on Vero cell line for 24[Formula: see text]h, 48[Formula: see text]h and 72[Formula: see text]h and average cell viability is 43.85%. The copper release from the thin film to the culture medium is 6691[Formula: see text][Formula: see text]g/L (maximum) is estimated from AAS studies. The copper coated substrate does not show much reaction with living Vero cells whereas the bacteria and fungi are found to be destroyed.

Morphology and Electrical Properties of Copper Thin Films Electroplated on Ni/n+-Si(100) for Silicon Solar Contact

Cu thin films were electrodeposited on Ni/n+-Si(100) substrate from sulfuric solution with fixed pH at room temperature. The effect of deposition time of Cu coatings was studied by using the chronoamperometry method (CA), the atomic force microscopy (AFM), X-ray diffraction (XRD) and four- point probe to investigate surface topography , structure and electrical properties of Cu films. From electrochemical measurements, the Cu film thickness ranging from 63 nm to 8.9 µm was calculated using Faraday’s law. The AFM study showed a rugose surface of the Cu films and the variation of film morphology with deposition time were established. The XRD spectra revealed the formation of thin Cu films with a preferential orientation. Sheet resistance and resistivity showed strong dependence on the deposition time of Cu films. Cu films being the future metal contact for silicon solar cells. Keywords: Cu , Electrodeposition , Morphology , Structure , Thin films , resistivity. Figure 1

The Properties of Cu Thin Films on Ru Depending on the ALD Temperature.

The copper thin films were deposited by Atomic layer deposition (ALD) on a ruthenium depending on the substrate temperatures. The substrate deposited Ru and TaN on SiO2 by plasma enhanced ALD (PEALD) before Cu deposition for an adhesion layer between Si and Cu. The copper thin films were deposited 200 cycles. The thickness of Cu was different depending on the substrate temperatures. The properties of copper thin films were investigated by a 4 point probe, SEM, and AFM. TaN and Ru layers were deposited by plasma enhanced ALD (PEALD) for the adhesion layer. Also, TaN and Ru layers were observed as TEM because the thickness was too thin. The thickness and roughness of Cu thin film increased depending on the deposition temperatures but, Cu thin film was not deposited at 110 °C. The best sheet resistance of the copper thin film was obtained at a deposition temperature of 170 °C.

Study of Microhardness and Young's Modulus of Copper Thin Film by Tip-Grit AFM Scratch Technology in Various Environments

This paper is devoted to investigate an estimation methodology of micro hardness and Young’s modulus of reacted passivation layer of deposited copper thin film in dry and wet environment based a tip-grit atomic force microscope (TGAFM) scratch on copper thin film of silicon wafer. The TGAFM is a modification or attachment of a nanoor micron grit on the tip apex or cantilever beam of a closed-loop control AFM instrument. In this study, a diameter 800 nm SiO2 grit glued on the apex of the tip of AFM is used for experiment. Tip force model has been developed based on Hertzian model and Tresca criterion for stress-strain relationship from the geometries of scratch groove, depth and width to evaluate about microhardness and Young's modulus of copper thin film in regular air and DI-water. Experimental results show that the microhardness (H) is 1.62GPa and the Young's modulus (E) is 160.52GPa of copper thin film in DI-water environment. These mechanical properties of copper thin film is larger than the H= 1.52GPa and E= 126.04GPa for dry environment. Results of this study can be further explored to the grit force reaction on the passivation layer of copper film of chemical mechanical planarization (CMP) process development for semiconductor industry.

A study on the dependence of DC electrical properties and nanostructure of Cu thin films on film thickness

This paper reports the correlation between film thickness, nanostructure and DC electrical properties of copper thin films deposited by PVD method on glass substrate. X-ray diffraction (XRD) and atomic force microscopy (AFM) were used for crystallography and morphology investigation, respectively. Resistivity was measured by four point probe instrument, while a Hall effects measurement system was employed for Hall Effect analysis. The grain size calculated from XRD and AFM, roughness, resistivity, hall coefficient, carrier concentration and mobility were plotted as a function of thickness. The result showed amorphous structure for 20 nm thickness, but with increasing the film thickness, Cu(111) preferred orientation was observed. The grain size, roughness and concentration of carriers increased and resistivity, hall coefficient and mobility decreased with increasing the film thickness. The result of copper thin films electrical investigation showed the value of resistivity and concentrations of carriers come to bulk state value at approximately 160 nm thickness.

Experimental Study on the Nanoindentation of Thin Copper Films from Deep Submicron to Nano-Scale

AbstractThis study uses the nanoindentation technique to evaluate the mechanical properties of thin copper films at indentation depths measured in the order of nanometers. Copper films with various thicknesses are deposited on a single crystal silicon wafer with a (100) orientation and on a polymethylmethacrylate (PMMA) substrate, respectively. The experimental results show that for soft thin films on a hard substrate, the substrate effect is negligible when the indentation depth is less than 20% of the film thickness. However, the results suggest that hard films on a soft substrate should be treated as a composite system in indentation because the substrate effect is significant. Finally, the results reveal that a significant indentation size effect exists for thin films with a thickness of less than 100nm. A number of possible reasons for the depth dependence of the hardness properties at ultra-shallow indentation depths are proposed and discussed.

Oxidation kinetics of nanoscale copper films studied by terahertz transmission spectroscopy

Terahertz (THz) transmission spectroscopy is used to measure the oxidation kinetics of copper thin films evaporated on silicon substrates. The transmission of broadband THz pulses from 1 to 7 THz through the copper film is measured while it gets oxidized at an elevated temperature in ambient air. The change in the transmitted THz electric field is correlated with the growth of the cuprous oxide layer and the decrease in thickness of the copper layer. Oxidation curves were obtained for heating temperatures of 120–150 °C and were found to follow a parabolic rate law. Using the Arrhenius equation, we calculate an activation energy for diffusion of 0.55 eV. By measuring the THz transmission through unoxidized copper layers of several thicknesses, we also measured the optical properties of thin copper films around the percolation threshold thickness of 7 nm. Around the percolation transition, the optical properties of freshly deposited copper thin films are very different from that of copper layers of the same thickness remaining after partial oxidation of thick copper films.

Evaluation of the Mechanical Properties of Copper Thin Film and Copper Bulk at the Nano-Scale by Nanoindenter

This study used the nanoindenter to perform indentation tests on copper bulk and nano copper film in order to discuss the mechanical properties of pure copper at the nano scale. This study tested 7 levels of load, ranging from 20 to 200 μN (load increment at 30 μN) for the indentation tests on copper bulk and nano copper film specimens. Results showed that the load was roughly proportional to the residual depth, in the case of flat nano copper film, while the relationship between the load and the residual depth was not significant in the case of unsmooth copper bulk. Moreover, the hardness of both the copper bulk and the nano copper film would increase along with increasing load, while the Er value change trends of both the copper bulk and the nano copper film specimens differed with increasing load.

A STUDY OF SOME MECHANICAL PROPERTIES OF COPPER-CERAMIC INTERFACE

Element Cu have been deposited on ceramic substrate by use of physical vapor deposition with plasma aided (Ion plating technology ) . The effect of deposition process parameter on mechanical properties of copper thin films were studied ( adhesion and microhardness ) . Also effect of surface nature and temperature annealing have been studied which obtained increase in adhesion and microhardness with increase in applied voltage and annealing . SEM study show that the smooth surface have good uniformity and interface type between the film and substrate .

Influence of the deposition temperature on the properties of copper thin films prepared by alternating injection of Cu(ethylketoiminate) 2 and H 2 on a ruthenium substrate

The copper thin films were deposited by an alternating injection of Cu(ethylketoiminate) 2 and H 2, and the effects of substrate temperature on the atomic layer deposition and the properties of the deposited thin film were investigated. Continuous films with a small sheet resistance were obtained at a deposition temperature of 140 °C. The sheet resistance and the surface roughness increased with increasing deposition temperature due to the agglomeration of copper. The growth rate at 140 °C was 0.12 nm/cycle, with a copper precursor exposure greater than 1.0 × 10 7 L and H 2 exposure greater than 3.0 × 10 8 L.

Thickness Effect on Microstructure and Residual Stress of Annealed Copper Thin Films

In this work, coupled effects of thickness and annealing temperature on both microstructure and residual stress of electroplated copper thin films are studied. Microstructure is investigated by Electron Backscattered Diffraction (EBSD) and residual stress is estimated from samples curvature. All films exhibit highly twinned grains. Except for several microns films, median crystallite size grows with both film thickness and annealing temperature. Concerning residual stress, it decreases, first as the increase of film thickness, and secondly as the decrease of annealing temperature. The comparison between experiments and stress models demonstrates that the root mechanisms of residual stress generation change with annealing temperature. As well as annealing temperature, film thickness determines the level of residual stress through control of microstructure. Furthermore, EBSD investigations confirmed that the relevant microstructural length to define mechanical properties of thin copper films is the median crystallite size.

Mechanical Properties of Copper Thin Films Used in Electronic Devices

This paper presents tensile and low cycle fatigue properties of copper thin films used in electronic devices. Copper films tested were rolled copper, electrolytic copper, direct current plated copper and pulse plated copper films. Tensile tests and strain controlled 4-point bending low cycle fatigue tests were carried out and cycles to crack initiation and those for propagation were obtained. The direct current plated copper showed the largest Young's modulus among the copper films. The electronic copper showed the largest yield stress and ultimate tensile strength, and the pulse plated copper the largest elongation. The strongest resistance to crack initiation was found in the rolled copper but there was no large difference in the cracking resistance among the other copper films. Cracks of the direct current and pulse plated coppers propagated faster than those of the other copper films.

Analysis elastic–plastic behaviour and anisotropy properties of copper film from nanoindentation using numerical computation method

The determination of mechanical properties of nanoscale structures is becoming increasingly important as micro-system and ultra-large-scale integrated circuit technologies continue to mature. Traditional experimental methods cannot avoid the influence on the hardness measurement from the presence of the substrate. Numerical computation method of finite-element modelling with molecular dynamics simulation is used to determine the mechanical properties of copper thin film from indentation, quantifying the difference between load against displacement-into-surface curves obtained from different length scale. The results show that the materials deformation exhibits strong size dependence when the relevant physical length scales fall into the range of microns or below. The P–H graph justifies that the permanent plastic deformation quickly decreased while the elastic deformation gradually increased in the range of nanometre level which means increasing of material microhardness. The different deformation behaviour of crystal layers inside the films may be the potential key factor of its breaking off from the substrate. There is little anisotropy phenomenon in the elastic deformation stage whereas there is obvious anisotropy phenomenon in the plastic deformation process. The anisotropy of thin film has strict preferred orientation distribution and symmetry. The anisotropy deformation gradually minimised accompanying the increasing of plastic deformation illuminates the copper thin film is a nonlinear anisotropy elastic–plastic material.

Texture and Mechanical Properties of Electrodeposited Copper Thin Films

Influence of the electrodepositing parameters e.g. applied electric current as variable on texture formation and on mechanical properties of copper thin films was studied. Experiment was done for copper deposition from sulphate bath under galvanostatic and pulse current. It was found that copper layers exhibits different texture depending on applied current conditions during electrodepositing process. Pulse and direct current conditions leads to different texture of electrodeposited copper. Texture of electrodeposited copper coatings and mechanical properties could be correlated. It was found that, texture indexes although are not complex information about texture could be used for analysis of such correlation in technological process.

The effect of nitrogen plasma on copper thin film deposited by DC magnetron sputtering

The copper nitride (Cu3N) thin films are obtained under the influence of the copper thin films to nitrogen plasma in different conditions. The copper thin films are deposited on Si (100) substrates at a fixed condition by means of the DC magnetron sputtering and then are exposed to low temperature nitrogen plasma. The effects of nitrogen plasma on the structure, morphology, hardness, electrical and optical properties of copper thin films are investigated in various time durations. The X-ray diffraction pattern confirms that by increase of time duration, the copper phase disappears and the copper nitride phases are detected while the roughness of the films reduces.