Chemical mechanical planarization (CMP) occurs at an atomic level at the slurry/wafer interface and hence slurries and the interaction of the films and polishing pads play a critical role in the successful implementation of this process. Understanding the tribological properties of a dielectric layer in the CMP process is critical for successful evaluation and implementation of the materials. In this paper, we present the effect of tribological properties of undoped and florine doped silicon dioxide films on their CMP process. A micro-CMP tester was used to study the fundamental aspects of CMP process. We have studied the CMP process of oxides on polyurethane pads (IC1000-B4/SubaIV) with colloidal silica slurry at different conditions. The coefficient of friction (COF) and acoustic emission signal was monitored during process. The COF was measured during the process and was found to varies differently for different samples and with down force and platen roatation. The effects of machine's parameters on the polishing performance and correlation of physical phenomena with the process has been discussed.

The mechanical response of materials can be dramatically altered by the presence of absorbed species on the surface. An electrochemical environment enables discrete control of the surface, keeping it clean (comparable to ultra-high vacuum) and inducing stable stress states. Applying a potential to the surface alters surface charge, which changes the surface free energy. Oxides are easily added or removed. Utilizing the phenomenon of underpotential deposition (UPD), one monolayer of metal can be added to a surface. The degree of lattice mismatch between the metal and the deposited monolayer will also vary the stress state of the surface. The changes in the mechanical properties of these highly controlled surfaces are measured by in-situ nanoindentation at various potentials. Nanoindentation of single crystals with very low dislocation densities allows careful observation of dislocation behavior with applied load. This enables the identification of dislocation mechanisms by quantifying the changes in mechanical properties under specific environments. Au has been extensively studied in electrochemistry literature; it is well behaved and well characterized. It is a model system that has demonstrated variation in mechanical properties in different electrochemical states. Lessons learned on Gold have also been applied to Zn and Ni systems.

An elasto-plastic spherical indentation study on materials with a yield strength gradient, like steels which have undergone thermal hardening such as nitriding, is carried out using both experimental and finite element methods. A theory based on the evolution of hardness, is proposed to determine the yield stress and hardness profiles for materials with a decreasing yield stress with depth.

Results for carbo-nitriding steels obtained by the standard Vickers micro hardness technique are compared with those obtained by the proposed method.

Chromium aluminum oxynitride (Cr-Al-N-O) thin films have been successfully prepared by pulsed laser deposition (PLD). Experiments were carried out by changing surface area ratio of the targets (SR = SAlN / (S +SAlN)) from 0 to 100 %. The composition of the thin film prepared at SR = 75 % was determined to be Cr0.11Al0.39N0.25O0.25 by Rutherford backscattering spectroscopy (RBS). The hardness of the Cr-Al-N-O thin film was found to be above HV 4000 when the aluminum content in cations (x) was 25 at. %. The high hardness can be explained by solid solution hardening and/or increasing bulk modulus. The oxidation of the Cr-Al-N-O thin film occurred above 900°C. From the result of grazing angle X-ray diffractometry (GXRD), the oxidation resistance of the Cr-Al-N-O thin film was found to be improved due to the fact that Cr2O3 and -Al2O3 grains are formed at the outermost surface of the thin film.

To investigate phase evolution of β-(Ni,Pt)Al/γ-(Ni3Al) in thermal barrier coating bond coat systems, specimens were subjected to 1200°C cyclic and isothermal heating. By removing the thermally grown oxide (TGO) after every 10 hours of heating, aluminum (Al) depletion from the bond coat was accelerated. Non-accelerated and accelerated Al-depletion samples were examined with scanning electron microscopy after every 10 hours of cyclic and isothermal heating. Observations from after the first 10 hours of thermal exposure show distinct microstructural differences. After 50 hours of heating, cyclic accelerated Al-depletion samples show more distinct grain boundaries and a higher proportion of-(Ni3Al) phase than isothermalaccelerated Al-depletion samples. Through instrumented micro-indentation, trends in elastic modulus were determined for isothermal and cyclic accelerated Al-depletion specimens.

Life time limiting effects in roller bearings and gear wheel applications are wear, sizing, and fatigue damages like micro pitting. These mechanisms are related to a number of parameters: lubrication conditions, surface roughness, and the hardness of the bulk material. Nowadays, Me-DLC coatings like MAXITÓ W-C:H offer surface protection under dry, mixed, and hydrodynamic conditions. This allows the increase of load capacities, respectively the decrease of gearing size. Moreover, a reduction of toxic lubrication additives can be achieved. The performance of the MAXITÓ W-C:H coatings in roller bearings was investigated on the FE8 test rig under mixed friction conditions. The W-C:H was deposited via the PVD technique of magnetron sputtering onto case hardened steel. The coating thickness was varied from 1.5 to 5 m m with respect to optimised wear resistance. The wear was drastically reduced by powers of ten as compared to uncoated roller bearings.

High-quality Ta2O5/SiO2 were deposited with oxygen gas cluster ion assisted deposition at low-temperature for advanced optical filters. With gas cluster ion assisted deposition, high refractive index and very smooth surface of Ta2O5 films were realized. The optimum cluster ion energy and cluster ion current density for Ta2O5 films were found to be 7keV and 0.5μA/cm2, respectively. The structure of film was very uniform and no porous or columnar structures were observed. The surface or interfaces of Ta2O5/SiO2 films were also very flat by surface smoothing effect of cluster ion beams. Very smooth surface can be realized even though the bottom surface was rough. There was no significant wavelength shift after an environmental test, which indicates that dense oxide films were formed at low-temperature with O2 cluster ion assisted deposition.

Multilayers of tungsten carbide/carbon (WC/C) with an amorphous structure and multilayers of titanium nitride/titanium-aluminum nitride (TiN/(Ti,Al)N) with a polycrystalline structure, prepared by physical vapor deposition, have been subjected to nanoindentation testing. The investigation has been aimed at establishing whether the load-displacement responses provides accurate information on the fracture mechanisms and whether such mechanisms can be characterized using a new technique for cross-sectional electron microscopy of the nanoindentations. Analysis of the load-displacement curves showed that they can be used to identify the cracking mechanisms occurring in the multilayers and that cross-sectioning of the nanoindentations is necessary if a more complete understanding of the multilayer coatings behavior is required.

Tantalum has mainly two phases: alpha phase (bcc structure) and beta phase (tetragonal structure). The meta-stable beta phase is usually obtained in sputtered films. Alpha phase is preferred over the beta for some applications as beta phase is very brittle. One of such application is to protect steel from the erosive and the corrosive wear. It was found that with the intermediate layer of tantalum nitride the preferred alpha phase was grown on steel by DC magnetron sputtering technique. Electrical and structural properties of these films were studied by four-point probe measurement and x-ray diffraction (XRD). Stoichiometry of the interfacial tantalum nitride layer was investigated by nuclear reaction analysis (NRA). Influence of the interfacial film thickness and the ratio of argon and nitrogen gas during reactive deposition of tantalum nitride on the tantalum phase were investigated. This work also reports on the dependence of tantalum phase on the substrate temperature (100-400°C) during sputtering in Ar and Kr gases.

Thin films of titanium iron (TiFe) were prepared by a pulsed ion-beam evaporation (IBE) method. A pulsed ion beam of proton accelerated at 1 MV (peak) with a pulse width of 50 ns and a current of 70 kA was focused on TiFe alloy targets. Soda lime glass substrates were placed in front of the targets. Phases in the thin films were identified by X-ray diffraction (XRD). XRD results revealed that the thin films deposited on the glass substrates consist of a TiFe phase. Crystallized Ti-Fe thin films without oxides were successfully obtained. Surface roughness of the thin film was 0.16 m m.

Nanograins were introduced into the surface layers of an Al-alloy during surface vibrational mechanical attrition. Transmission electron microscopy revealed that microstructures developed with an increase in strain, in the following sequence, i.e., lamellar microbands of elongated subgrains, equiaxed submicro-, and nano-grains respectively. The grain subdivision into the subgrains was found to be the main mechanism responsible for grain refinement. The simultaneous evolution of high boundary misorientations was ascribed to the boundary rotation for accommodating further strains. Results showed that the grains could refine remarkably into the nanometer regime (<100 nm) within the outer surface of the layer. The depth of the nanocrystal layers increased and the grain size decreased with the extension of processing time. The nanocrystal layers evidenced an increase in hardness.

The purpose of this research was to probe nanotube-polymer composites for evidences of radiation induced chemistry at the interface of the host polymer and the nanotube structures. Single wall carbon nanotube (SWNT) / poly (methyl methacrylate) (PMMA) composites were fabricated and exposed to gamma radiation with a Co60 source at a dose rate of 1.28 X 106 rad/hour in an air environment for a total dose of 5.9 Mrads. Neat nanotube paper and neat PMMA were also exposed. Spun coat films of SWNT/PMMA were exposed to gamma radiation with a Ce157at a dose rate of 4.46 x 103 rad/hr for a total dose of 3.86 Mrads. Both irradiated and non-irradiated samples were compared. Glass transition temperatures were characterized by differential scanning calorimetry. Dynamic mechanical analysis and dielectric analysis evidenced changes in relaxations induced by irradiation. Irradiated composites exhibited radiation induced chemistry distinct from degradation effects noted in the pure polymer. Scanning electron microscopy provided images of the SWNTs and SWNT/PMMA interface before and after irradiation. This investigation imparts insight into the nature of radiation induced events in nanotubes and nanocomposites.

Electrophoretic deposition was effective for the synthesis of the film type CVD diamond on the WC cutting tool without removing cobalt on the surface, although the adhesion force of CVD diamond was insufficient for the application to a cutting tool. Heat treatment after electrophoretic deposition improved the adhesion force.

The wear resistance of metal carbide-metal nacreous nanostructures is compared to that of a solid metal carbide hard coating. A reciprocating nanoscratch method has been developed which allows the assessment of wear resistance of the film independent of substrate type or film-substrate adhesion. A series of nominally 1 micron thick TiC-based multilayer films on Si substrates were produced using RF magnetron sputtering. A scratch protocol consisting of 70 reciprocal scratches each 9.5 m m in length was applied. Data reduction techniques were used to remove the effects of sample tilt and drift. The resulting normal displacement as a function of scratch cycles is used to compare the wear of different films on Si <111> substrates. Specific wear characteristics related to film morphology are examined. This investigation showed that this nanoscratch technique holds promise as a thin film wear characterization technique.

With a well-controlled laser melt injection (LMI) process, for the first time the feasibility is demonstrated to produce SiC particles (SiCp) reinforced Ti6Al4V functionally graded materials (FGMs). SiCp are injected just behind the laser beam into the extended part of the laser melt pool that is formed at relatively high beam scanning velocities. The process allows for the minimization of the decomposition reaction between SiCp and Ti6Al4V melt, and also leads to FGMs of SiCp/Ti6Al4V instead of a homogeneous composite layer on Ti6Al4V substrates. An injection model is designed based on the temperature/viscosity field of the laser pool for a deeper understanding the mechanism of formation of the FGMs with LMI. The model is based on finite element calculations of the temperature field in the melt pool, physical considerations of the LMI process and it is supported by experimental observations. Three types of reaction layers are observed around SiCp, namely a thin monocrystalline TiC layer, a cellular polycrystalline TiC layer and a thick mixed layer of TiC with Ti5Si3. Among them, only the monocrystalline TiC layer exhibits particular orientation relationships to the SiCp lattice, i.e. (111)TiC//(0001)SiC and <110>TiC//<1100>SiC or (111)TiC // (1012)SiC and <110>TiC//<1210>SiC. These two kinds of TiC reaction layers act as a barrier against the interfacial reaction and its swift formation during rapid cooling hinders the dissolution of SiCp in the Ti-melt.

This paper describes the effects of porosity and thermal ageing at 950°C for 4000 hr. in air on in-plane cracking behavior of plasma-sprayed thermal barrier coating (TBC) made up of 8 % yittria-stabilized zirconia. The in-plane TBC cracking was analyzed by a protruded TBC bend testing technique together with finite element stress analysis. As-deposited and aged TBC protruded specimens showed a large variation of porosity depending on the location of specimen extraction. The critical local tensile stress (s) necessary for the initiation of in-plane cracks for each specimen with different porosity was determined using elastic moduli (E) estimated from the porosity dependence of E. The s for in-plane cracking of the as-deposited TBC initially increased with increasing porosity and showed a peak when the porosity reached 0.23. It was shown that in-plane cracking at the interface of TBC and thermally grown oxides required much higher s than that at the interface of TBC and bond coatings. The thermal ageing led to a slight increase in s for away-from-interfacial TBC cracking. The dependence of in-plane TBC cracking behavior on the porosity is discussed in terms of effective critical stress via the Griffith criterion for porous materials.

Metal matrix composites (MMCs) combine the properties of metal and ceramic or intermetallic materials. Common examples of metal matrix composites are Cu-Al2O3, SiCw-Al, Al-Al2O3, Al-B4C, and Ni-NiAl3. Mechanical or thermal properties, such as strain-stress behavior, or thermal expansion coefficient can be tailored by changing the content of the reinforcing phase. The most common techniques of measuring mechanical properties of composite materials rely on macroscopic approach. During the past fifteen years, a significant effort has been made to develop various techniques of measuring mechanical properties on a microscopic level. These techniques include atomic force microscope (AFM) and depth sensing indentation techniques, based on Hertzian contact mechanics. However, it is still a challenge to measure reliably and quantitatively the Young's modulus and Poisson's ratio of individual phases as well as properties at the interfaces. This presentation will focus on fundamental aspects of measuring of mechanical properties of metal matrix composites at nano-scale using Interfacial Force Microscopy (IFM). The IFM is a scanning probe microscope, which utilizes a unique self-balancing capacitance force sensor. Force-displacement curves obtained with the IFM are analyzed using Hertzian contact mechanics to extract the Young's moduli of the individual phases and interface region with high spatial resolution. The properties of Cu-Al2O3, Al-SiCp composites will be discussed in detail. Furthermore, a comparison of experimental data with mechanical properties calculated from first principles will be discussed.

The optical properties of organosilicate glass (OSG) samples were investigated with spectroscopic ellipsometry. We found that samples with dramatically higher hardness had higher indices of refraction (RI) and thus higher electron densities and lower relative porosities than films with lower hardnesses. The reverse was true for films with low hardnesses. As well, these films did not have the same optical properties as porous SiO2 across the spectral range measured, which we show has significant implications for the in-line optical metrology of these materials.

Nitride and carbide are superhard material with a high potential for applications in different fields. A new group of coatings are the multilayered/microlaminate coatings, which have shown very interesting properties. Single and microlaminate films were coated on Silicon (Si) substrates using pulsed laser deposition (PLD) technique. Films were deposited at different substrate temperatures in order to study the microstructure evolution and their effect on the mechanical properties of these microlaminate films. Structure of the films was characterized by x-ray diffraction (XRD) technique. Surface morphology and roughness of the films were investigated using atomic force microscopy (AFM). Hardness and modulus of the films were investigated using nanoindentation technique. It has been demonstrated that using boron carbide as a bottom layer increases the hardness and Young's modulus values of carbide composite coatings. Microlaminates of boron carbide/titanium carbides have shown higher hardness and modulus as compared to the microlaminates of nitride coatings.

The tribology of material contacts under cyclic compression in the direction perpendicular to the plane of the contact was studied by measurement of the contact electrical resistivity of the contact during the dynamic loading. The real-time monitoring allowed observation of both reversible and irreversible effects. The material contacts studied were those involving steel, carbon fiber polymer-matrix composite, cement mortar and graphite, due to their relevance to fastening, concrete structures, electric brushes and electrical pressure contacts. Correlation was made between the contact resistivity and the occurrence of elastic/plastic deformation at asperities. The interfacial structure was found to depend on the stress and the loading history.