The mechanical properties of a series of titanium nitride films on stainless steel substrates have been evaluated using an indentation technique with a mechanical properties microprobe (MPM). The MPM makes possible measurement of film properties without contribution by the substrate material. The titanium nitride films were deposited with a PVD technique known as sputter ion plating (SIP). Deposition substrate bias was varied from 0 to −120 V, while keeping other deposition parameters constant. With increasing negative substrate bias, dramatic increases in hardness and elastic modulus have been observed.

Substrate curvature measurements were used to monitor viscous flow in Pd79Si21 films at temperatures between 100 and 250°C. To determine the viscosity and the change in viscosity the elastic constants of the film were measured by depositing films on pre-bent substrates: E = 10 ± 1 1010 Pa and ν = 0.43 ± 0.04 The activation enthalpy for η is 13 ± 1 kJ/mole.

Stresses in thin narrow textured metal lines were measured using x-ray diffraction techniques. Arrays of 1.5μm wide, 0.32μm thick aluminum lines, both with and without a 0.32μm thick SiNx passivation layer, were heat-treated at 400°C in a hydrogen/nitrogen atmosphere. After heat treatment the lines were examined periodically using chromium radiation to monitor the relaxation of the stress developed during heat treatment. The apparent stress in both the passivated and unpassivated lines relaxed significantly over the measurement period of three days. The higher stresses present in the passivated lines may be partially responsible for the voids which were found after aging at room temperature.

Thin aluminum films deposited on silicon substrates are representative of materials systems used in integrated circuit technology. Large stresses in such systems usually arise from thermal expansion mismatch between the thin film and the substrate, and constitute an important reliability concern.

X-ray and continuous indentation testing were used to measure post-heat treatment stresses in a 0.3 μm thick aluminum film on a silicon substrate. The sample was heat treated at 450°C for one hour in an inert atmosphere, after which the stress relaxation was followed as a function of time. The stress data gathered by the two techniques agree very closely during a time span of about 100 hours.

Indentation load relaxation (ILR) experiments with indentation depths in the submicron range are described. The observed flow behavior of a 1μm thick A1-2%Si film deposited on a silicon substrate depended on the depth of penetration. For shallow penetration depths, the shape of the flow curves obtained from this sample are similar to those obtained from a conventional load relaxation test of a bulk specimen. For penetration depths close to the film/substrate interface, the influence of the substrate on the film's deformation behavior was observed.

Tin films were deposited on silicon substrates by RF diode sputtering and the growth behavior of these films were characterized by scanning electron microscopy. The time dependent plastic flow behavior in these films were examined by performing indentation tests using a dcpth-scnsing hardness testing machine. Individual indentation experiments with different constant load segments were conducted and the creep characteristics of both sputtered films and bulk Sn were examined. The stress exponents determined from these tests were compared with those determined for bulk Sn from conventional creep tests. The influence of the substrate material on the creep properties of the film are described.

Thin film aluminum fibers with grain sizes of 35 and 100 nm were pulled in a microtensile tester. The larger grains led to greater yield and tensile strengths but smaller strains to failure. Both samples had mechanical strengths 3–6 times greater than bulk aluminum. In addition, the small grained fibers had a strain rate sensitivity exponent of 0.26 suggesting diffusion controlled plastic deformation mechanisms.

Work-hardening curves of aluminum foils and of stacks of O.1μm thick 22 ct. gold foils, deformed between rotating Bridgman anvils, have been obtained for pressures up to 1533 MPa and shear strains to 400,000%. No sample thickness effect has been found between 5μm and 3μm, nor any significant difference between homogeneous foils and multi-layer foils, but heat-treatments do affect the results, as apparently does the introduction of 50nm thick sputtered copper layers between stacks of gold foils. Increases of strength with pressure appear to be due to corresponding increases of the Peierls-Nabarro stress. X-ray evidence indicates the reorientation of the foils from an initial (001) recrystallization texture after rolling to the (111) texture that was to be expected. Ordinary deformation behavior is indicated throughout, except for a tendency for slight negative work-hardening in the lower pressure range. At the extreme, assuming homogeneous deformation, the foils thinned to 60nm.

In a microscratch test performed by using an upgraded microindenter, the normal load, tangential load, scratch length and acoustic emission, are monitored simultaneously during an entire scratch process for the purposes of measuring the critical load and studying the ffilure mechanisms of the deposited films. The adhesion strength, scratch hardness, fracture toughness and friction are the mechanical properties which are possible to obtain by using this technique. Results from aluminum, carbon and zirconia coatings will be discussed.

The capabilities to monitor tangential force and acoustic emission have been added to the microscratch mode of the IBM microindenter. These two new monitoring devices combined with the existing normal loadcell enhance the ability of the microscratch test to measure mechanical properties of thin film materials. As a demonstration of the upgraded microindenter, scratch tests were performed on 11 0nm and 20nm thick carbon films deposited on Si <100> substrates. The scratch morphology was examined by scanning electron microscopy to correlate the mechanical data to corresponding failure mechanisms.

In the case of the 110nm film, a brittle type fracture was taking place as the applied normal load exceeded a critical value. All three monitored outputs detected the first occurrence of the spallation ofthe film. In contrast to the thicker film, large scale spallation was not observed for thle 20nm film, and the acoustic emission detector did not show any significant output. An apparent friction coefficient(FR) is defined as the ratio ofthe tangential force to the normal load. FR is determined to be a useful parameter for monitoring the indenter's transition through the coating into the substrate, particularly in the case of small scale fracturing or simple ploughing through types of failure.

Carbon overcoat films are used extensively in thin film disk applications to provide wear resistance. A nano-indentation technique and wafer curvature measurements have been used to study the mechanical properties of carbon films sputtered under various processing conditions. Specifically, the effects of substrate/target spacing, power, pressure, and substrate bias have been studied for films sputtered in an argon plasma. The relationship of these properties to contact start-stop performance of hydrocarbon lubricated disks is further described. The frictional performance during the test can be related to film hardness, while the durability can be affected by the residual film stress.

An atomic force microscope, operated in ultra-high vacuum has been employed to study the tribological properties of diamond films under small loads (< 10−6 N) on a nanometer scale. The incidence of intermittent motion, “stick-slip”, while sliding a diamond tip across the diamond film, is detected under certain experimental conditions and is discussed with respect to the difference between static and kinetic friction, sample topography and a varying sample condition.

The effects of ion implantation on microtexture of vapordeposited carbon film were studied by Raman, XRD, TEM and sheet resistivity measurements. Growth of graphitemicrocrystals in the film was found when the film was implanted at the temperature above about 500 K. while graphite-sheet in the as-deposited film was distorted when it was implanted at the temperature below 300 K. The critical temperature for the ion beam annealing was estimated to be about 350 K. Ion implantation also caused the increase of the adhesion strength of the carbon film to a substrate.

Films of amorphous carbon (a-C) and hydrogenated amorphous carbon (a-C:H) are deposited by R.F. Magnetron Sputtering and Sputter Assisted Plasma CVD respectively and their properties are compared. It is found that high optical gap, high resistivity a-C can be obtained, so indicating a large amount of sp 3 bonded C atoms. For this reason attention was mainly focused on a-C and possible application were considered.

By means of the hoop apparatus, contact resistance and coefficient of friction of fiber bundles on a solid substrate have been determined in air at different humidities. The results can be explained by a two-component model, comprising (i) a double molecular layer of adsorbed water at contact spots and (ii) a zone about each contact spot within which excess adsorbed moisture which has been squeezed out from the load-bearing area bypasses the spot.

The strength of planar interfaces between a substrate and a thin coating (1–2 µm) can be measured quite effectively by a laser spallation technique. In this technique a laser pulse of a high energy and a predetermined length is converted into a pressure pulse of a critical amplitude and width that is sent through the substrate toward the free surface with the coating. The compressive pressure pulse is reflected into a tension pulse from the free surface of the coating and loads the coating/substrate interface in tension. The laser flux is tuned to a threshold level at which the interface comes apart. The critical stress amplitude that accomplishes the removal of the coating is determined from a computer simulation process. The simulation itself is verified by means of a piezoelectric crystal probe which is capable of mapping out the profile of the stress pulse generated by the laser pulse.

Very large compressive stresses have been measured in thin LPD tungsten films. These stresses are responsible for the extensive buckling of the films. Buckling occurs over a wide range of radii and is accompanied by random spalling over the same range. The large compressive stresses are thought to be oxidation induced. The pattern of random buckle spalling does not fit the specific spalling criteria proposed by other workers. These criteria are examined and a further explanation for the spalling behaviour of these films proposed

Tantalum films begin to crack and spall during vapour deposition on glass at a thickness of 180 nm. Islands and ribbons, 10 – 30 µm in size, delaminate by crack growth along the Ta/glass interface for several gIm after which the crack penetrates into the glass to a depth of 0.5–1 µm and complete spalling occurs. X-ray diffraction showed that about 50 % of the original bct, β-tantalum, phase had transformed to the bcc α-Ta phase. When Ta was deposited on glass that was first covered with 52 nm of copper, spalling was observed to begin at a thickness of 105 nm. In this case, the film first cracks and then peels along the Cu/glass interface and curls into scrolls indicating the presence of a small stress gradient. X-ray diffraction of the asdeposited film, and electron diffraction of ion-milled flakes, showed that Ta films deposited on Cu-coated glass almost completely transform to bcc α-Ta. The critical thickness for delamination along the Cu/glass interface is about 1/2 that for cracking in the glass substrate when an intermediate layer of Cu is not present. All of the above findings are in good agreement with previous observations on Cr films.

The response of four transparent materials, soda-lime glass, fused silica, single crystal (0001) A12O3, and Y2O3-ZrO2, to contact by a sharp indenter has been studied. Insitu observation and continuous monitoring of the load and displacement throughout the test allowed the indentation fracture sequence of the transparent materials to be characterized and also permitted the effects of these fracture events on the corresponding load displacement curves to be noted. It was found that if the cracks produced during indentation grew discontinuously, they manifested themselves in discontinuities in displacement on the corresponding load-displacement curve.

We have conducted a molecular dynamics computer simulation of the rupture of a small, two-dimensional film. The film was composed of two hundred atoms arranged on a close-packed triangular lattice and was thermally equilibrated at a reduced temperature of 0.05. Following equilibration, the rupture characteristics of the film were investigated under tensile loading, and the atomistic dynamical response was followed throughout the rupture process. An estimate of the internal stress field was made by performing a time average over the random forces. In tensile failure, the system undergoes an initial elastic deformation followed by plastic flow. The fundamental mechanisms of defect nucleation are briefly discussed.