This paper describes the mechanical behavior of the evaporated layers between the thick gold electrode and the substrate in LiNbO3/Pt/Ti/Au/Au lithium niobate integrated optical waveguide modulator, using depth sensing diamond nanoindentation technique. In spite of its limitation in testing ultra thin films, this technique showed its usefulness in characterizing the recent application as well as integrated optical (IO), and MEMS devices. The mechanical properties of the evaporated layers such as hardness, elastic modulus, yield strength, and plastic deformation have been investigated by nanoindentation using a Berkovich indenter at a penetration depth of dequals100nm, and average values are given. It was found that the effect of the substrate on the film properties is negligible at penetration depth less tahn 20% of the film thickness, thus, the values of hardness and modulus are Eapproximately equals 20GPa, Happroximately equals 1GPa for the 20nm thin titanium film, Eapproximately equals 10GPa, Happroximately equals 0.5GPa for the 10nm thin platinum layer, Eapproximately equals 130GPa, Happroximately equals GPa for a 100nm thin gold layer, and Eapproximately equals 230GPa, Happroximately equals 13GPa for the LiNbO3 substrate. Moreover, platinum delaminates from titanium at critical normal load L_c1approximately equals 15$mnN, and its presence decreases the critical load L_c2, required to detach titanium from LiNbO3 substrate from L_c2approximately equals 50(mu) N to L_c2approximately equals 45(mu) N. The practical adhesion in the interface at the substrate and Pt-Ti layers has been also studied by scratching technique, using cube corner diamond tip. The scratch test was combined wiht examination of the scratch track morphology and the interface between Ti/Pt thin fils and substrate by scanning electron microscopy (SEM) together with energy dispersive spectroscopy (EDS), and the correlation of the films failure with the adhesion strength was investigated. Scratch tests reveal also, a decrease of the value of adhesion strength at titanium and substrate interface from L_c2approximately equals 4mN to L₂approximately equals 3.5mN when Pt is evaporated on the Ti layer.

Many MEMS applications require multi-level microstructures in which two or more levels have to be aligned to each other in the processing. In this paper a passive alignment system based on a mechanical registration method utilizing reference posts is described. A detailed analysis of the test results was conducted to reveal main error sources and estimate the accuracy of this alignment method. An alignment accuracy of +/- 5(mu) m between 2 layers has been achieved. The further work on improving the alignment accuracy and expending in this alignment method to graphite masks for multi-level X-ray or combined optical/x-ray lithography is proposed.

Full metal probes have proven their suitability for electrical atomic force microscopy (AFM) in the last few years. Such probes could be fabricated cheaper if one reduces the number of steps and processing time. Therefore we have developed a procedure which allows to manufacture full metal probes with only two lithography steps. The etching of thin membranes is dropped which reduces the processing time by 25% compared to our previous procedure. It requires only topside processing. The probes can be peeled off from the wafer due to a special metallization procedure. This paper discusses the process scheme and presents measurements on semiconductor devices.

Electrical probes consisting of cantilever beams with integrated pyramidal metal or diamond tips have to be mounted to small holder chips before they can be used in electrical atomic force microscopy (AFM). Gluing procedures have been developed for this step but such a connection suffers mainly from low electrical conductivity and often also from low mechanical stability. Furthermore, it is not very suitable for massfabrication. Soldering is a well-established mounting method in microelectronics (e.g. surface mounted devices (SMD)) and could overcome these problems. Therefore, we have developed a soldering procedure for moulded AFM probes. This paper presents the optimized soldering procedure and demonstartes its use for probe mounting. Excellent results were obtained using a metallization system of Ti:W+Ni+Au and a SnBi58 solder paste in combination with a hotplate for the soldering step. The soldered probes are highly conductive and the mechanical connection between probe and holder chip is very rigid. They show clear resonance peaks in tapping mode AFM which we could not obtain with our glued probes before.

The advent of microfluidic systems demands compact models for the description of flow in the constituent system components. The situation is analogous to the evolution of compact models for electron flows in MOSFETs, which were essential for the development of integrated microelectronic systems. We develop here a compact gas flow model for microvalves, which relates valve flow to a limited but meaningful set of parameters. Specifically, these are the gas type; inlet and outlet pressures; ambient temperature; valve inlet diameter; the gap between the membrane and the valve inlet; and the coefficient of discharge of the valve inlet. The result is a simple, accurate model, appropriate for the design and analysis of microfluidic systems. We also demonstrate a characterization methodology for extracting the required model parameters from measurements of flow versus pressure and gap. This characterization has produced values for the coefficient of discharge, which match expectations based on previous theory and measurement. It has also produced a single parameter describing the effect of the gap in controlling the flow, across broad ranges of valve inlet diameter, membrane-to-inlet gap, and pressure.

We have produced an automatic method with which to simulate the structural response of prestressed multi-layer plate and beam micro- structures accurately and reliably. The method relives the microsystem designer of the burden of finite element mesh design by performing local mesh refinement. A coarse mesh is iteratively refined according to an error that is computed directly from the finite element solution. The refinement strategy covers locally prestressed regions, plate composition inhomogeneities, and singular loads, yielding an optimized mesh and a highly accurate computed deformation.

Mechanical tests of thin films require novel and sophisticated methods that can address the geometry and microstructure of the films. A new method of micro-tensile testing of MicroElectroMechanical Systems (MEMS) films has been demonstrated. An improved apparatus has been designed and implemented to measure the elastic tensile properties. (Young's modulus, Poisson's ration and tensile strength) of surface micromachined polysilicon specimans. The tensile specimans are dog-bone shaped ending in a large paddle for convenient electrostatic or, in the improved apparatus, UV adhesive gripping. The test section of the specimens is 400(mu) m long with 2(mu) mx50(mu) m cross section. The method employs Atomic Force Microscope (AFM) acquired surface topologies of deforming specimans to determine (fields of) strain by way of the Digital Image Correlation method (DIC). With this method, high strength of non- linearly behaving materials under different environmental conditions can be tested by measuring the strains directly on the surface of the film with nanometer resolution in in-place and out-of-plane measurements.

Although a lot of work has been done on understanding auto-adhesion (stiction) in MEMS, the effect of surface roughness has never been extensively addressed. In this paper, a model is presented, which describes the auto-adhesion interaction energy of micromachined surfaces in contact. Included in the model is the capillary force, in such a way that it can be readily extended to accommodate electrostatic and van de Waals forces as well, in combination with the roughness of the contacting surfaces. By investigating the effect of the height distribution of the surfaces, a term is derived for the surface interaction energy in different environment conditions as a function of the mean separation between the rough surfaces. To obtain an equilibrium distance between the surfaces, the repulsive part of the interaction is also modeled. The combination of these terms gives us the equilibrium distance between the surfaces and the corresponding surface interaction energy, thereby quantifying the effect environmental conditions have on auto-adhesion. The results of the model agree well with surface interaction energies in MEMS known from literature for different environmental conditions.

It is well recognized that controlling surface forces is one of the key issues in the design, fabrication, and operation of microelectromechanical systems (MEMS). Since the majority of MEMS devices are made of silicon from surface micromaching, an attractive approach is to use the well-know alkytrichlorsilane self-assembled monolayers (SAM) on oxidized silicon surfaces to control surface enery. While this approach has enjoyed some success in reducing adhesion in model MEMS structures, a major impediment to its implementation in a manufacturing setting is that it is highly irrreproducible and very sensitive to a number of experimental parameters. In this report we present a novel strategy for the efficient assembly of organic monolayers directly onto the silicon surface via Si-O linkages. This is achieved by the reaction between an alcohol functional group and a chlorinated Si surface. The resulting molecular monolayers are thermally and chemically stable and are successfully demonstrated in adhesion reduction in a model MEMS structure, namely, a cantilever beam array (CMA). Polycrystalline beams with length up to 1.5 mm can be released. Major advantages of this new approach for surface control in MEMS include simplicity, reproducibility, and reliability.

Masks made from graphite stock material have been demonstrated as a cost-effective and reliable method of fabricating X-ray masks for deep and ultra-deep x-ray lithography (DXRL and UDXRL, respectively). The focus on this research effort was to fabricate masks that were compatible with the requirements for deep and ultra deep X-ray lithography by using UV optical lithography and gold electroforming. The major focus was on the uniform application of a thick resist on a porous graphite substrate. After patterning the resist, gold deposition was performed to build up the absorber structures using pulsed- electroplating. In this paper we will report on the current status of the mask fabrication process and present some preliminary exposure results.

In this paper, the capabilities and problems if micro-Raman spectroscopy are discussed for measuring local mechanical stress, both in mono- crystalline and poly-crystalline silicon microstructures. The possibilities of this technique are demonstrated for two different MEMS: the crystalline Si membrane of a pressure sensor and a poly-crystalline Si beam. For both MEMS, an auto-focus Raman system was used. The stress in the membrane of the pressure sensor was investigated before and after bonding of the Si wafer containing the sensors to a glass substrate. This bonding resulted in an under-pressure in the sensor, deflecting the membrane inwardly. Raman spectra were measured from the top surface and the bottom surface of the membrane. This resulted in a map of the stress distribution. It indicates, for the top surface, tensile stress near the edges, compressive stress in the center, and hardly any stress at the corners. The stress in the poly-crystalline Si beam was measured using two different wavelengths of the laser beam. The results show a local tensile stress distribution along the length of the beam.

Both electrical and mechanical models, exemplified with a micromachined capacitive switch with simple bridge structure, accurately describing its electrical and mechanical characteristics are described in this paper. The electrical model is represented as a RLC circuit, while the mechanical model is represented as a fixed-fixed beam. The advantage of these models is that it is possible to pre-determine various characteristics, such as the switching time of micromachined capacitive switches, during the design stage. These models can be used to accurately design micromachined capacitive switches for microwave applications. An illustrated fabrication process is also discussed.

This paper presents the work performed in MUMPs on RF MEMS micro-switch. Concepts, design and characterization of switches are studied. The study particularly focuses on the electrical resistance characterization and modelization. The switches developed uses two different principle: overflowed gold and hinged beam. The realized contacts exhibited high on resistance (~20(Omega) ) due to nanoscopics asperities of contacts and insulating interfacial films. Results of a typical contact cleaning method are also presented.

Although vibrating microgyroscopes has been an active area of research in the last few years, the resolution requirements for high performance applications have not yet been met. This paper reports the development of a high performance comb-driven vibratory angular rate gyroscope. The gyroscope uses a rotary electrostatic actuation and differential capacitive sensing. The calculations show a resolution of about 8 deg/hr. The gyroscope is fabricated using SOI wafer with a 40 (mu) m thick layer of single-crystal silicon. The overall size of the gyroscope is about 2.8 mm diameter. The high sensitivity of the present design is achieved by employing a large sensing area couled with a higher layer thickness. Simply increasing the sensor area without increasing the layer thickness may yield a higher sensitivity, but lead to problems such as stiction and lower pull-in voltages. Increasing the suspension stiffness increases the pull-in voltage. However, an increase in suspension stiffness may also also increase the natural frequencies which will lower the sensitivity and resolution. The design of the gyroscope involves complex and often conflicting requirements, and some of these important aspects are discussed in this paper.

A new study of characterizing the mechanical properties of the most used CMOS (Complementary Metal Oxide Semiconductor) materials and how to optimize design variables has revealed a convenient method that could be easily applied for many other micro-electro-mechanical device design and fabrication processes. In general thin film material properties are highly process dependent and are strictly connected to the final performance of some devices. While most micro-device designers do perform calculation to some extent before submitting their design to real fabrication process in order to have the accuracy and precision of the calculation is the input set of constituent material parameters. Mechanical properties of thin films are sometimes unavailable from regular CMOS fabrication foundries where many CMOS compatible micro- devices are fabricated in batches. This paper proposed a design and analysis flow to extract the needed material properties by making simple structures using pilot processes at desired foundry service. As the pilot process results come out, varied material properties can be verified by comparing the experimental data and simulation of data of specially designed test keys. Some test key designs have been widely reported [1,2]. As many of the existing test key designs are only concentrating on one layer or two of thin film materials in the test structures, the proposed method could work out for multi-layers of thin film materials at the same time, which comes even closer to the practical needs of CMOS compatible MEMS.

In previous works, we have developed silicon-based, bimorph resonators, using a uniaxial giant magnetostrictive thin film. Such material has the unique feature to produce both bending and torsional vibration with a single magnetic field excitation. We have used these resonators to build a 2D-Micro-Optical scanner, which has shown actuation capabilities high enough for most applications. Even with non-optimized magnetostrictive material and mechanical design, it has shown comparable performances with those of its piezoelectric or electrostatic counterparts. In this paper, we present new characterizations, which have been made when applying a magnetic DC bias field in addition for the AC field needed for the excitation. Though this DC field is not essential for the operation of the device, it can be used for instance to tune the ratio of bending/torsional vibration amplitudes. In addition to this behavior, it was found that the bias field has also a strong effect on the resonance frequencies of the mechanical structure. This dependence was also found to be dependent on the AC excitation field amplitude. These experimental results are discussed and analyzed in both a qualitative and a quantitative way using a theoretical model. On one hand, the dependence on the AC field amplitude is ascribed to the so-called Hard- spring effect, due to the nonlinear term of the elastic restoring force in large deflection amplitude regime. On the other hand, the dependence on DC field is ascribed to the so-called Delta-E effect, which is a variation of the effective Young's modulus due to the magneto-mechanical coupling.

The contribution of this paper is to improve the analytical model of the dynamic system for an electrostatically driven device. Therefore, the material properties such as Young's modulus will be determined more accurately; furthermore, the dynamic behavior of electrostatically actuated devices can be predicted more precisely.

Silicon micromechanics in an emerging field which is beginning to impact almost every area of science and technology. In areas as diverse as the chemical, automotive, aeronautical, cellular and optical communication industries, Silicon micromachines are becoming the solution of choice for many problems. In this paper we will describe what they are, how they are built, and show how they have the potential to revolutionize lightwave systems. Devices such as optical switches, variable attenuators, active equalizers, add/drop multiplexers, optical crossconnects, gain tilt equalizers, data transmitters and many others are beginning to find ubiquitous application in advanced lightwave systems. We will show examples of these devices and describe some of the challenges in attacking the billions of dollars in addressable markets for this technology.

Silicon bulk micromachining which is based on a silicon etching and a glass-silicon anodic bonding plays important roles to make micro sensors and micro actuators. Three dimensional microfabrication of other functional materials as piezoelectric materials are also important to develop high performance microactuators, micro energy source and so on. Vacuum sealing is required to prevent a viscous dumping for packages micromechanical sensors. Extremely small structures as microprobe are required for high resolution, high sensitivity and quick response. As sophisticated microsystems which are made of many sensors, circuits and actuators are required for example for maintenance tools used in a narrow space. Developments for those required will be described.

The continuous progress in micro- and nano-system technologies has allowed the successful development of many innovative products in process control, environmental monitoring, healthcare, automotive and aerospace as well as information processing systems. In this paper on overview will be given of current progress in micro- and nanofabrication process technologies, such as deep reactive ion etching, micro-electro discharge machining, thick photoresistant processing and plating. The availibility of these micro- and nanofabrication processes will be illustrated with examples of new generations of silicon-based sensors, actuators and Microsystems with a particular emphasis on real applications of these components and systems.