Analiza uticaja strukture na mehanička svojstva višeslojnih tankih filmova Ni/Cu za primenu u mikroelektronskim tehnologijama

Multilayer Ni/Cu thin films were produced by dual-bath electrodeposition technique (DBT) on polycrystalline cold-rolled Cu substrate. Different Ni/Cu multilayer structures were realized by changing of process parameters such as total film thickness, sublayer thickness and Ni/Cu sublayer thickness ratio. The mechanical properties of Vickers microhardness and interfacial adhesion in the films were investigated. Decreasing of sublayer thickness down to 300 nm and increasing of Ni:Cu sublayer thickness ratio to 1:4, lead to higher values of Vickers microhardness compared to monolayer metal films. Thin films with sublayer thicknesses from 75 nm to 5 μm show strong interfacial adhesion. A weak adhesion and sublayer exfoliation for the films with sublayer thickness greater than 5μm were found. Three-dimensional Ni microstructures can be fabricated using multilayer Ni/Cu film by selective etching of Cu layers in an acidic thiourea solution ('surface micromachining' technique).Tehnikom elektrohemijske depozicije iz dva kupatila (dual-bath technique, DBT), dobijeni su višeslojni filmovi Ni i Cu, naizmeničnim deponovanjem na polikristalni, hladno-valjani bakarni supstrat. Različite strukture Ni/Cu višeslojnih filmova su ostvarene promenom procesnih parametara kao što su ukupna debljina filma, debljina pojedinačnog sloja u filmu i odnos debljina pojedinačnih slojeva Ni i Cu u filmu. Ispitana su mehanička svojstva mikrotvrdoće po Vikersu i adhezije filma na supstratu i kontaktnim površinama slojeva u filmu. Smanjenjem debljine pojedinačnog sloja do 300 nm i povećanjem odnosa debljina slojeva Ni:Cu na 1:4, došlo se do višestrukog povećanja vrednosti Vikersove mikrotvrdoće u odnosu na jednoslojne metalne filmove. Tanki slojevi Ni i Cu sa debljinom od 75 nm do 5 μm pokazuju dobru međuslojnu adheziju. Filmovi sa debljinom slojeva većom od 5 μm, nemaju dobru međuslojnu adheziju i uočava se delaminacija (razdvajanje) slojeva. Sve strukture višeslojnih filmova Ni i Cu se mogu primeniti za izradu trodimenzionalnih MEMS struktura od Ni, metodom selektivnog nagrizanja slojeva Cu u kiselom rastvoru tiouree tehnikom 'površinskog mikromašinstva'

Photothermal elastic vibration spectra of SiO2 film on Si

The silicon-dioxide film on the silicon substrate (SiO2/Si) samples were investigated by the photothermal elastic vibration method. The photothermal elastic vibrations in two-layer rectangular plates were optically excited by the focused laser beam and the generated vibrations were measured with a sensitive optical probe (the double-heterodyne interferometer). The photothermal elastic vibrations spectra were measured and analyzed for different types of Si substrate (with and without the SiO2 films) vs the frequency of modulation of the excitation laser. This investigation is important for analysis of the influence of the different technological processes to the vibrations of the optically driven micromechanical structures, i.e. how the technological processes change the characteristics of micromechanical structures

Investigation of N-H center dot center dot center dot O interactions in N-monosubstituted caproamide - Ether systems: FT-IR and FT-NIR spectroscopic study

This paper reports FT-IR and FT-NIR spectroscopic study of hydrogen bonding between N-mono-substituted caproamides and different ethers (diethyl ether and tetrahydrofuran) in carbon tetrachloride. With increase in ether concentration increase in intensity of red-shifted band, and decrease of intensity of monomer band has been observed. The MIR and NIR spectroscopic characteristics for N-H center dot center dot center dot O hydrogen bonded complexes and also the equilibrium constants for 1:1 complex formation are given. Further, influence of structural differences of ethers on hydrogen bonding was investigated using Taft equation. Good correlation between logarithm of formation constants and Taft steric and inductive factors has been obtained only for tetrahydrofuran in MIR range

Characterization of electrodeposited powders of the system Ni-Mo-O

The electrodeposition of the Ni-Mo-O alloy powders from ammonium chloride containing electrolytes for different Ni/Mo ions concentration ratios was investigated by the polarization measurements. The morphology, chemical composition and phase composition of the electrodeposited Ni-Mo-O alloy powders were investigated using DSC, TGA, SEM, EDS and XRD analysis. According to the EDS results, the powder composition depends on the Ni/Mo ions concentration ratio. However, some deviations in the composition of the as-deposited powders, as the result of the position of the EDS analysis, revealed that the composition of such powders is not homogeneous. The as-deposited alloy powders were nanocrystalline showing only one broad XRD peak around 44 degrees. Their morphology was found to depend on the Ni/Mo ions concentration ratio. After annealing of the Ni-Mo-O powders for 2 h in N-2 atmosphere at 600 degrees C, well-defined crystals for all powders were detected by SEM. The presence of the NiMoO4 phase only or NiMoO4 and MoO3 phases in these powders (XRD), depending on the Ni/Mo ions concentration ratio, was identified. The additional EDS analysis on different recrystallized grains revealed the influence of the annealing on a composition of the alloy powders

Attachment of MEM piezoresistive silicon pressure sensor dies using different adhesives

This paper gives comparison and discussion of adhesives used for attachment of silicon piezoresistive pressure sensor dies. Special attention is paid on low pressure sensor dies because of their extreme sensitivity on stresses, which can arise from packaging procedure and applied materials. Commercially available adhesives “Scotch Weld 2214 Hi-Temp” from “3M Co.” and “DM2700P/H848” from “DIEMAT”, USA, were compared. First of them is aluminum filled epoxy adhesive and second is low melting temperature (LMT) glass paste. Comparing test results for low pressure sensor chips we found that LMT glass (glass frit) is better adhesive for this application. Applying LMT glass paste minimizes internal stresses caused by disagreement of coefficients of thermal expansions between sensor die and housing material. Also, it minimizes stresses introduced during applying external loads in the process of pressure measuring. Regarding the measurements, for the sensors installed with filled epoxy paste, resistor for compensation of temperature offset change had negative values in all cases, which means that linear temperature compensation, of sensors installed this way, would be impossible. In the sensors installed with LMT glass paste, all results, without exception, were in their common limits (values), which give the possibility of passive temperature compensation. Furthermore, LMT glass attachment can broaden temperature operating range of MEM silicon pressure sensors towards higher values, up to 120 ºC

Far infrared properties of sintered Pb0.9Sn0.1Te doped with palladium

Far infrared reflectivity spectra of sintered Pb0.9Sn0.1Te doped with 0.2 and 2 at.% Pd are measured. The experimental results are analyzed using a fitting procedure based on a modified plasmon-phonon interaction model. The values of calculated parameters are compared with literature data for PbTe and PbSnTe single crystal samples doped with palladium and nickel, with the purpose of determining whether the sintered samples can be used in different devices instead of single crystals

Application of Water Falling Film Dbd for Degradation of Nicotine in Water Solutions

In this paper we present plasma-based degradation of nicotine in water solutions. Water falling film dielectric barrier discharge (DBD) was used as plasma source operating in air at atmospheric pressure. Solutions containing 50 ppm and 300 ppm of nicotine in distilled or tape water were treated directly and indirectly by plasma. Influence of homogeneous catalysts Fe2+ and H2O2 was also tested. Artemia Salina organisms were used for toxicity tests of treated solutions. Degradation efficiency was the highest in direct plasma treatment of nicotine with Fe2+ as a catalyst and in this case the toxicity test showed the lowest mortality.HAKONE XV: INTERNATIONAL SYMPOSIUM ON HIGH PRESSURE LOW TEMPERATURE PLASMA CHEMISTRY: WITH JOINT CO

Mitochondrial Molecular Basis of Sevoflurane and Propofol Cardioprotection in Patients Undergoing Aortic Valve Replacement with Cardiopulmonary Bypass

Background/Aims: Study elucidates and compares the mitochondrial bioenergetic-related molecular basis of sevoflurane and propofol cardioprotection during aortic valve replacement surgery due to aortic valve stenosis. Methods: Twenty-two patients were prospectively randomized in two groups regarding the anesthetic regime: sevoflurane and propofol. Hemodynamic parameters, biomarkers of cardiac injury and brain natriuretic peptide (BNP) were measured preoperatively and postoperatively. In tissue samples, taken from the interventricular septum, key mitochondrial molecules were determined by Western blot, real time PCR, as well as confocal microscopy and immunohisto- and immunocyto-chemical analysis. Results: The protein levels of cytochrome c oxidase and ATP synthase were higher in sevoflurane than in propofol group. Nevertheless, cytochrome c protein content was higher in propofol than sevoflurane receiving patients. Propofol group also showed higher protein level of connexin 43 (Cx43) than sevoflurane group. Besides, immunogold analysis showed its mitochondrial localization. The mRNA level of mtDNA and uncoupling protein (UCP2) were higher in propofol than sevoflurane patients, as well. On the other hand, there were no significant differences between groups in hemodynamic assessment, intensive care unit length of stay, troponin I and BNP level. Conclusions: Our data indicate that sevoflurane and propofol lead to cardiac protection via different mitochondrially related molecular mechanisms. It appears that sevoflurane acts regulating cytochrome c oxidase and ATP synthase, while the effects of propofol occur through regulation of cytochrome c, Cx43, mtDNA transcription and UCP2. Copyright (C) 2012 S. Karger AG, BaselMinistry of Education and Science [173055, 173054