A micro-impact tester has been designed and built by using a piezoelectric impact hammer as an impactor driver. During the course of an impact process, force interactions between the impactor and target surfaces were monitored continuously by a miniaturized piezoelectric loadcell embedded in the flying head assembly. After having fully characterized an impact system, the trajectory of the impactor can be calculated by using the corresponding pre-recorded impact force interaction in the simulation program. The contact and returning velocities, kinetic energy loss of the impactor and the impact penetration curve are the key information obtained from the simulation. Furthermore, the impact morphology can reveal failure mechanisms of materials by providing details such as indent shapes, coating fragments, chipping, crack type and size, and other such information which are useful in assessing the fracture toughness of testing materials. The micro-impact testing was carried out in the contact velocity ranging from 0.3 to 2.0 m/sec. Three types of materials such as metal, glass and amorphous carbon were used in studying their distinct mechanical behavior under high rate indentations. The correlations between the impact conditions, energy losses, impact morphologies and material responses are illustrated and discussed.

The effect of residual stress on the scratch adhesion critical load has been measured for sputtered tantalum films. In this single metallurgical system, six different failure modes could be observed, ranging from ductile ploughing to extensive spallation. For tantalum films deposited on silicon substrates, a 15% decrease in critical load was observed as the film residual stress increased from -1.1 GPa to +1.0 GPa. A larger percentage decrease (50%) was observed for films deposited on softer AIMg/NiP substrates. Film spallation was more extensive for films deposited over a thin carbon layer and for these films critical loads increased slightly with film stress. These results are substantially in contradiction with existing quantitative models for the scratch adhesion test and indicate that failure by shear at the film-substrate interface can be more important than failure by compressive buckling.

A nickel micromechanical device was resonated and the natural frequency of the structure was monitored over time. Any structural rearrangement or damage initiation in the material was expected to cause a corresponding change in the resonant frequency of the device. The resonant frequency of the device was initially about 31.8 kHz and the frequency was found to decline over time at a rate of 0.17 Hz/s.

The realization of structures with silicon surface micromachining requires very low stresses of the structural elements. When low tensile film strains have been difficult to measure as no double-beam type structures susceptible for buckling at low tensile strains have been in use, a new “diamond beam” structure is proposed for the tensile-to-compressive strain conversion. The device performance is analysed as a strain gauge.

The micromachined structures can also be used as substrates for deposited films. The formulation is presented for double beam as substrate for deposited film compressive strain gauging. The structures were applied for strained sputter-deposited Molybdenum, and it was found that large undercut of the double beam edge must be avoided as well as the spacer film thickness must be large enough for beam buckling to be noticeable.

In this paper we address possible causes for inconsistencies in bulge test results and describe methods by which the bulge test technique can be made to produce accurate and reliable results. Experiments have been conducted on a variety of materials: polyimide (PIQ13) and polycarbonate (Lexan), silver and silver-palladium multilayers, and silicon nitride. All the materials tested yield biaxial moduli that are in the range of expected values for the bulk material. In addition, the tests show that the technique can be used to differentiate between the elastic properties of materials throughout the range of elastic stiffnesses, with even crystallo-graphic texture having a notable impact on the measured modulus. These results will be presented along with the methods used for preparing bulge test samples.

The adhesion of chemical vapor deposited (CVD) diamond thin films to substrates is a major limitation to using this new and exciting material. It is important to have a quantitative and absolute measurement of adhesive strength to understand and identify remedies. There are many methods to measure adhesion, but most rely on comparison to a standard instead of being an absolute measurement. The blister test is potentially able to measure adhesion both quantitatively and absolutely, but the existing analysis is not sufficient. This paper presents a fracture mechanics approach to analyze the blister test for a circular plate in order to obtain the appropriate quantitative information, i.e., the crack extension force, G. Several shape models exist. We consider several models to predict the behavior of this plate and then derive an equation that expresses G in terms of the critical pressure and critical volume at which de-bonding occurs. As a result of this analysis, we identify the key experimental parameters and show that this equation is insensitive to the model used.

In order to model and design micromechanical sensors and actuators, it is of crucial importance that thin film mechanical parameters, such as the Young's modulus and the residual stress, are known. In this paper, the parameter extraction method using resonant structures has been used to obtain these data and has been compared with the bulge test. Circular aluminum diaphragms have been used as samples.

High precision force displacement indenting instruments are now widely used for the determination of the mechanical properties of materials. However, for thin films attached to a substrate, the basis of any analysis of such high precision data is still limited. In this study the force displacement data has been generated using spherically tipped indenters of radii from 5 to 150 μm loaded onto a 2.74 μm thick TiN film on a silicon substrate as well as onto the substrate directly. Data have been generated using two loading procedures, continuous and load partial-unloading, almost entirely within the elastic contact regime. The results are analysed to determine the modulus of the TiN film.

Three-dimensional finite element simulation is employed to investigate the general indentation behaviour of bulk materials and corresponding film-substrate systems in Vickers hardness test. MARC™, a routine finite element software package was used on the following samples: bulk aluminium, bulk steel and their respective film-substrate systems, i.e., aluminium on steel as soft film on hard substrate and steel on aluminium as reverse situation. The results are given in two different cross-sectional planes, i.e., through opposite pyramidal edges and perpendicular to pyramidal side faces. In all cases the calculation provides a general view of the deformation characteristics, but also values for material displacement and the extension and shape of the stress fields as well as the plastically deformed zone under load or after load release. The indenter load versus indentation depth relation during loading and unloading are also calculated for all the examples.

A continuous microindentation apparatus was constructed with a maximum load capacity of 45 N (resolution of 0.1 N) and with a maximum displacement of 500 μm (resolution of 2.0 μm) and used to test bulk materials (brass, aluminum, steel, soda-lime glass and PMMA) and epoxy coatings on substrates of aluminum, steel, soda-lime glass and PMMA. The hardness (H) was determined with a Vickers indenter and compared to that obtained with a Tukon hardness tester. The elastic modulus of the coated systems was also estimated from the unloading curves. In general, we found that the indentation behavior of the epoxy coated system was influenced by the substrate with softer substrates (as with PMMA) being deformed before the indenter penetrates the coating. With all coated systems, the on-load value of H was independent of the penetration depth until the indenter penetrated the substrate. For the aluminum, steel and soda-lime glass substrates, the value of H after penetration increased slowly due to the pile up of the epoxy coating underneath the indenter supporting more of the load. For the PMMA substrate, hardness decreased after penetration because the hardness of PMMA was less than the epoxy coating.

The nanoindenter has a tremendous potential for the measurement of mechanical properties of thin films and coatings. Information can be obtained about plastic, elastic and time dependent deformation behaviour. In some cases fracture behaviour of the coatings and the adhesion of the coating to the substrate can also be investigated.

Before accurate and reproducible measurements can be made the nanoindenter needs to be suitably calibrated. The magnitude of the uncertainties associated with calibration and their relevance to measurements are also required. Additionally it is important that a thorough understanding of the effect of thermal drift on the measurement process is developed. Traceability of calibration is also an important consideration.

The primary areas where calibration is essential are displacement, load and shape of the indenter.

A model has been developed to determine the hardness of thin films from the measured change in hardness with indenter displacement using a depth-sensing indentation instrument. The model is developed by dividing the measured hardness into film and substrate contributions based on the projected areas of both the film and substrate under the indenter. The model incorporates constraints on the deformation of the film by the surrounding material in the film, the substrate, and friction at the indenter/film and film/substrate interfaces. These constraints increase the pressure that the film can withstand and account for the increase in measured hardness as the indenter approaches the substrate.

The model is evaluated by fitting the predicted hardness versus depth curves to data obtained from titanium and Ta2O5 films of varying thicknesses on sapphire substrates. The model predicts a lower interfacial strength for Ta2O5 films on sapphire with a carbon layer between the film and the substrate than that obtained for a film without an interfacial carbon layer.

Common methods for analyzing depth-sensing indentation data are briefly reviewed and an overview of the principal factors limiting the accuracy and precision of results obtained using these methods is presented. The largest deviations from the elastic contact models used to interpret depth-sensing indentation data arise from time-dependent displacements and uncertainties in the shape of the indenter tip, the elastic/plastic nature of the contact and the compliance of the testing machine.

In light of recent advances in the analysis of depth-sensing indentation data and of the importance of this technique in the study of the mechanical properties of thin films, a special discussion session was held in order to explore the state of the art and to provide an informal forum for discussion. This is a brief review of that discussion. The discussion was focused by the four main sources of deviation from model behavior described in the previous paper.

A micro-wear testing technique has been developed by incorporating a piezoelectric pusher into an existing micro-indenter system. The pusher and its associated servo-control circuitry were designed to generate a precise reciprocating horizontal motion at the indenter tip for implementing micro-scaled wear test. The information acquired from the test includes the wear loading curve, i.e., the normal applied load versus wear penetration depth, the friction force and in turn, the apparent wear friction coefficient. Acquiring the electrical resistance across the coating thickness is also possible if an electrical conducting indenter is utilized. Furthermore, in collaboration with the surface characterization tools, the wear morphology revealed useful information regarding the coating failure mechanism(s) and shed some light towards understanding coating tribology. The tester design concepts, operating procedure, data acquisition and analysis will be examined. Experimental results on ultra thin carbon coatings with various thicknesses will be employed to illustrate the capabilities of the microwear tester.

The validity of Lc of film failure is studied with friction — detected scratch test . The specimens used in the experiment are ion-plated TiN and Ti films,Chemical-Plated NiPCu films on steel of various hardness,ion beam mixed plated TiN films on optical glass,The morphology of failed films was studied under optical microscope and scanning electronmicroscope,The composition of starting failure of films was analyzed with electro — probe. It is found that in the curves of scratch tests of ion-plated TiN and Ti films on high-speed steel,the load corresponding the sudden change of the horizontal force is the same as the critical load of film failure,however,the critical load obtained in the scratch test of the ion-plated TiN and Ti films on soft steel is the some deference compared with optical microscope analyzed, that is principally due to the property of films and substrates (hardness and coefficient).

The morphology and mechanism of ion — plated TiN and Ti films on high —speed steel are also studied in the paper.

The adhesion between film and substrate is an effective method in evaluating the films property. After apprasing the effectiveness of acoustic emission monitoring scratch test, someone think that no matter coated with hard or soft film it is effective on the brittle hard substrate. However,there exist errors to different extent on other film-substrate system,and the scratch test is inapplicable for soft film-soft substrate system[1]. P. A. Steinmann pointed out while studying the factors influnceing the critical load Lc,that friction coefficient is a key factor on Lc,it provided valuable information in measuring Lc,but it think it is imporsible to measure Lc totally dependent on sudden change friction or friction coefficient, howeveer, for a specific coating substrate system,it is acceptable to say that Lc is dependent on friction coefficient[2]. This paper study experimentally on the friction detected scratch test and found out that effectiveness of Lc varies substantially in different film-substrate system. The author studiied the regularity of various system and discuse the season. The failure morphology and principles of ion-plated TiN and Ti film on highspeed steel are also analyzed in this paper.

Stress-induced voiding in microelectronics chips has been reported to exhibit a variety of dependencies on temperature and on passivation stress. The dependence of line failure is reported here at four different temperatures (150, 225, 285, and 315 ºC) for AI-0.5%Cu and, AI-0.5%Cu and AI-1%Si lines with passivation thicknesses (silicon oxide or silicon nitride) ranging from 0.1 to 2.5 times the metal thickness. Failure distributions change in a complex manner with changing passivation thickness, and with temperature for a specific passivation thickness, raising questions on the validity of using the conventional median time to failure (t50) and lognormal slope (σ) to project field failure rates from data generated by accelerated life testing.

Strain relaxation in passivated Al-0.5% Cu lines was measured using X-ray diffraction coupled with in-situ observation of the formation and growth of stress induced voids. Samples of 1 μm thick Al-0.5% Cu lines passivated with Si3N4 were heated to 380ºC, then cooled and held at 150ºC. During the test, principal strains along the length, width, and height of the line were determined using a grazing incidence x-ray geometry. From these measurements the hydrostatic strain in the metal was calculated and strain relaxation was observed. The thermal cycle was duplicated in a high voltage scanning transmission electron microscope equipped with a backscattered electron detector. The 1.25 μm wide lines were seen to have initial stress voids. Upon heating these voids reduced in size until no longer observable. Once the samples were cooled to 150ºC, voids reappeared and grew. The measured strain relaxation is discussed in terms of void and θ-phase (Al2Cu) formation.

Stress and current induced degradation of the interconnects may well define the ultimate limits on device density and total on-chip power in microelectronic circuits. The two damage mechanisms are found to be mutually interdependent in a fashion determined by the line microstructure, as well as by design features such as W-studs and refractory metal back up layers. We have developed a comprehensive model for the synergistic effects of stress migration and electromigration, taking such factors into account. The present work reviews the modelling of the statistical failure distributions, with emphasis on the temperature and current density dependencies, for the case of 'near-bamboo' sub-micron lines.

Accelerated electromigation tests on unpassivated, pure aluminum interconnects were performed. The failure mechanisms were observed by interrupting the tests and examining the conductor lines using an SEM. Because the metal thin film was subjected to a so-called laser reflow process before patterning, grain boundaries were visible in the SEM as thermal grooves. Voids were observed to move along the line and to grow in a transgranular manner, and a characteristic asymmetric void shape was identified which seems to be related to the failure mechanism. It is argued that substantial progress in modelling and understanding of electromigration failure can be made by consideration of such void shape effects.