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This paper presents the development of a new microgripper actuated by means of rotary-comb drives equipped with two cooperating fingers arrays. The microsystem presents eight CSFH flexures (Conjugate Surface Flexure Hinge) that allow the designer to assign a prescribed motion to the gripping tips. In fact, the adoption of multiple CSFHs gives rise to the possibility of embedding quite a complex mechanical structure and, therefore, increasing the number of design parameters. For the case under study, a double four-bar linkage in a mirroring configuration was adopted. The presented microgripper has been fabricated by using a hard metal mask on a Silicon-on-Insulator (SOI) wafer, subject to DRIE (Deep Reactive Ion Etching) process, with a vapor releasing final stage. Some prototypes have been obtained and then tested in a lab. Finally, the experimental results have been used in order to assess simulation tools that can be used to minimize the amount of expensive equipment in operational environments.

High energy, ultra-short multimode soliton pulse fission is observed and numerically studied in multimode GRIN fibers, showing complex dynamics bringing to multiple fundamental solitons that do not entirely follow standard single mode soliton perturbation theory predictions.

Beam self-imaging in nonlinear graded-index multimode optical fibers is of interest for many applications, such as implementing a fast saturable absorber mechanism in fiber lasers via multimode interference. We obtain a new exact solution for the nonlinear evolution of first and second order moments of a laser beam of arbitrary transverse shape carried by a graded-index multimode fiber. We have experimentally directly visualized the longitudinal evolution of beam self-imaging by means of femtosecond laser pulse propagation in both the anomalous and the normal dispersion regime of a standard telecom graded-index multimode optical fiber. Light scattering out of the fiber core via visible photo-luminescence emission permits us to directly measure the self-imaging period and the beam dynamics. Spatial shift and splitting of the self-imaging process under the action of self-focusing are also revealed. Funding Agencies|European Research Council (740355); Agence Nationale de la Recherche (ANR-18-CE080016-01); CILAS Company (ArianeGroup); Vetenskapsrådet (2017-05309); Russian Ministry of Science and Education (14.Y26.31.0017)

Gyroscopes are one of the next killer applications for the MEMS (Micro-Electro-Mechanical-Systems) sensors industry. Many mature applications have already been developed and produced in limited volumes for the automotive, consumer, industrial, medical, and military markets. Plenty of high-volume applications, over 100 million per year, have been calling for low-cost gyroscopes. Bulk silicon is a promising candidate for low-cost gyroscopes due to its large scale availability and maturity of its manufacturing industry. Nevertheless, it is not suitable for a real monolithic IC integration and requires a dedicated packaging. New designs are supposed to eliminate the need for magnets and metal case package, and allow for a real monolithic MEMS-IC (Integrated Circuit) electronic system. In addition, a drastic cost reduction could be achieved by utilizing off-the-shelf plastic packaging with lead frames for the final assembly. The present paper puts forward the design of a novel tri-axial gyroscope based on rotating comb-drives acting as both capacitive sensors and actuators. The comb-drives are comprised of a single monolithic moving component (rotor) and fixed parts (stators). The former is made out of different concentrated masses connected by curved silicon beams in order to decouple the motion signals. The sensor was devised to be fabricated through the PolyMUMPs&reg, process and it is intended for working in air in order to semplify the MEMS-IC monolithic integration.

We study nonlinear self-imaging dynamics in graded-index multimode optical fibers. Side-scattering of light that accompanies the propagation of intense femtosecond pulses permits us to directly measure the self-imaging period.

Micro Electro Mechanical Systems (MEMS)-Technology based micro mechanisms usually operate within a protected or encapsulated space and, before that, they are fabricated and analyzed within one Scanning Electron Microscope (SEM) vacuum specimen chamber. However, a surgical scenario is much more aggressive and requires several higher abilities in the microsystem, such as the capability of operating within a liquid or wet environment, accuracy, reliability and sophisticated packaging. Unfortunately, testing and characterizing MEMS experimentally without fundamental support of a SEM is rather challenging. This paper shows that in spite of large difficulties due to well-known physical limits, the optical microscope is still able to play an important role in MEMS characterization at room conditions. This outcome is supported by the statistical analysis of two series of measurements, obtained by a light trinocular microscope and a profilometer, respectively.

Although tissue and cell manipulation nowadays is a common task in biomedical analysis, there are still many different ways to accomplish it, most of which are still not sufficiently general, inexpensive, accurate, efficient or effective. Several problems arise both for in vivo or in vitro analysis, such as the maximum overall size of the device and the gripper jaws (like in minimally-invasive open biopsy) or very limited manipulating capability, degrees of freedom or dexterity (like in tissues or cell-handling operations). This paper presents a new approach to tissue and cell manipulation, which employs a conceptually new conjugate surfaces flexure hinge (CSFH) silicon MEMS-based technology micro-gripper that solves most of the above-mentioned problems. The article describes all of the phases of the development, including topology conception, structural design, simulation, construction, actuation testing and in vitro observation. The latter phase deals with the assessment of the function capability, which consists of taking a series of in vitro images by optical microscopy. They offer a direct morphological comparison between the gripper and a variety of tissues.

This paper presents the first prototype of a new concept nanogripper whose overall size has been reduced as much as permitted by a new fabrication process based on Nano Technology. The jaws lumen size is adequate to the mechanical manipulation of microorganisms colonies.

Progress in MEMS Technology continuously stimulates new developments in the mechanical structure of micro systems, such as, for example, the new concept so-called CSFH (Conjugate Surfaces Flexural Hinge), which makes it possible, simultaneously, to minimize the internal stresses and to increase motion range and robustness. Such hinge may be actuated by means of a rotary comb-drive, provided that a proper set of simulations and tests are capable to assess its feasibility. In this paper, a CSFH has been analyzed with both theoretical and Finite Element (FEM) methods, in order to obtain the relation between voltage and generated torque. The FEM model, realized with an APDL code (ANSYS Parametric Design Language), considers also the fringe effect on the comb drive finger. Electromechanical couple field analysis is performed by means of both Direct and Load Transfer Methods. Experimental tests have been also performed on a CSFH embedded in a MEMS prototype, which has been fabricated starting from a SOI wafer and using D-RIE(Deep Reactive Ion Etching). Results showed that CSFH performs better than linear fexure hinges in terms of larger rotations and less stress for given applied voltage.

This paper presents a new concept flexure hinge for MEMS applications and reveals how to design, construct, and experimentally test. This hinge combines a curved beam, as a flexible element, and a pair of conjugate surfaces, whose contact depends on load conditions. The geometry is conceived in such a way that minimum stress conditions are maintained within the flexible beam. A comparison of the new design with the other kind of revolute and flexible joints is presented. Then, the static behavior of the hinge is analyzed by means of a theoretical approach, based on continuum mechanics, and the results are compared to those obtained by means of finite element analysis (FEA) simulation. A silicon hinge prototype is also presented and the construction process, based on single step lithography and reactive ion etching (RIE) technology, is discussed. Finally, a crucial in–SEM experiment is performed and the experimental results are interpreted through the theoretical models.

Although a certain amount of work has been presented in literature which concerns micro and nano tribology, few contributions have been dedicated to the development of experimental set up for friction assessment in MEMS. The present paper offers a contribution which attempts to fill this gap: the proposal of a new concept design of a micro-tribometer for testing silicon-silicon sliding in MEMS devices, particularly in those obtained via D-RIE process. Since the general contact conditions at the macro scale are very different from those which characterize MEMS, the proposed tribometer is very different from the classic pin-on-disk or block-on-ring. For this reason, a dedicated MEMS has been built, whose only purpose is recreating silicon-silicon sliding under prescribed loads and, then, assessing friction and wear. Since most of MEMS have planar relative motion, the tribometer presented in this article is able study only planar relative motions, and so it has been essentially based on a the creation of a pair of conjugate profiles, whose relative motion has been obtained by using Finite Element Analysis (FEA) simulations, rather than by the classical centrodes theory.Copyright © 2014 by ASME

In this work we report the application of the selective wet processing technique based on dynamic liquid meniscus for copper pillar bumps (CPB) plating. The industrial plating of copper for CPB process is typically carried out at 2 μm/min. A much higher copper deposition rate is necessary to improve throughput for this process. To achieve higher deposition rates of copper the hydrodynamic issue that is natural for all conventional plating baths processes must be solved. A number of solutions is proposed towards realization of high speed and high throughput CPB plating process. Uniformity of copper pillar over a 6-inches silicon wafer is presented and the morphology and shapes of pillars are investigated by scanning electron microscopy (SEM). Copper pillar height and dimension are investigated within different topology over the wafer showing the robustness of the process for the thickness uniformity. Preliminary investigation of the CPB plating shows the uniformity of better than 2 % within 6” silicon wafer.

This paper describes the design, simulation, construction process and experimental analysis of a microgripper, which makes use of a new concept hinge, called CSFH (Conjugate Surfaces Flexure Hinge). The new hinge combines a curved cantilever beam, as flexible element, and a pair of conjugate surfaces, whose contacts depend on load conditions. CSFH hinges improve accuracy and guarantee that minimum stress conditions hold within the flexible beam. This microgripper is designed for Deep Reactive-Ion Etching (D-RIE) construction process and comb-drive actuation. Theoretical basis and Finite Element Analysis (FEA) simulations have been employed in order to predict the feasibility of the device under construction. Finally, some experimental evidence of the construction process has been provided.

A new selective processing technique based on a confined dynamic liquid drop\meniscus is presented. This approach is represented by the localized wet treatment of silicon wafers using dynamic liquid drop that while is in contact with the wafer forms a dynamic liquid meniscus. The main scientific innovation and relevance introduced by this work have been applied to industrial solar cell production and on silicon wafer metal bumps formation for the IC interconnection (i.e. copper pillars). Such new technique allows to touch in specific defined positions the silicon wafer in order to perform any kind of wet processing (e.g. etching, cleaning and/or plating) without the need of any protective resist. To investigate on pendant dynamic liquid drops and dynamic liquid meniscus use of computational fluid dynamic technique (i.e. numerical techniques to accurately predict fluid flows) was followed and is presented. An experimental setup has been built to validate the calculations. Numerical results showed a good agreement with experimental ones. Prototypes heads, using stereo-lithography systems, were developed and localized selective plating without the need of lithography step was performed on silicon.

A new plane parallel micro-manipulator is presented in this paper, together with the numerical procedure that has been used in order to optimize some kinetostatic performance indices, among which the kinematic condition number and the mechanical advantage. The approach is based on a refined simplification of the direct kinematic problem and it is applied to the pseudo-rigid body model of the original compliant mechanism, with an acceptable approximation. The method has been iterated several times to evaluate a fitness function that has been used by an Evolutionary Method of computation for the search of global optimum, namely, a Genetic Algorithm. The results will be used for refining the geometric design of the parallel micro-manipulator, which will be built by means of MEMS-Based technologies in silicon.

Electroporation is an effective method to deliver drugs into tumor cells to kill them, by applying a pulsed electric field to the cellular membrane. Existing electrodes consist of clamping claws or arrays of needles and can be effectively applied only to small areas. New electrodes that can treat large areas are sought; flexibility is needed to adapt to irregular tumor shape and, to be folded to enter from small surgical opening. In this work we present the design and test of a 16 cm2 flexible electrode for electroporation with biosensing capabilities, built with standard flexible circuit technologies enclosed in a biocompatible package. The electrode contains electronics to provide cryptography-based identification to the electroporation machine to avoid setup errors and protection against use of counterfeited electrodes. In-vitro tests of the electrode show that electroporation occurs up to a depth of 8 mm with 100% electroporation efficiency over the 30% of electrode area. Temperature rise on the electrode during treatment does not exceed 6 degrees celsius, a value that not causes damage to the cells.

The need of micromanipulation devices has been growing rapidly during the last decades, specially in the fields of Biology and Micro-Assembly, and many solutions have been proposed to cope with the increasing demand. The present paper suggests a possible way to micromanipulating objects in various conditions, adopting MEMS technologies to develop a microgripper based on a new flexural hinge, recently patented by the Authors. The micromechanism has been modified considering results obtained through FEA. Finally, a brief description of the construction process is provided, together with some experimental activities.

A new selective processing technique based on a confined dynamic liquid drop\meniscus is presented. This approach is based on localized wet treatment of silicon wafers using confined and dynamic liquid drop that while in contact with the wafer forms a dynamic liquid meniscus. Such new technique allows to touch in specific defined positions the silicon wafer (front and/or back) in order to perform any kind of wet processing without the need of protective photo-resist. The new selective processing technique allows the metallizations (front and back) of mono and multi crystalline silicon solar cells. The front grid contacts are obtained by locally etching the silicon nitride, forming in a thin layer of meso-porous silicon and totally filling the meso-porous layer by pulse reverse plating a Nickel film. Copper and Tin are then electroplated using the same selective processing. This technology provides an effective solution to avoid silver pastes for front contact grid, as it guarantees low specific contact resistivity (550 μΩcm2 on a 75 Ω/□ n-type doped emitter) and good adhesion to the silicon substrate (i.e. greater than 550 g/mm). The Al back side of the solar cell are also treated by the new selective process. Tin is directly deposited on Aluminum back contact showing adhesion higher than silver on silicon (i.e. > 1N/mm). © 2013 The Authors.

In this work it is described an high-density contacting technology that can replace wire bonding in power electronic applications, to overcome known limitation of bond wires liftoff occurring after several power cycles due to the difference in the coefficient of thermal expansion of silicon and aluminum. In the presented technology, MEMS (micro-electro-mechanics systems) micro-fabrication processes are used to realize contact structures that, pressed against the silicon dice, provide a reliable compliant contact. One advantage of this technology is that the contacts can be hosted on a printed circuit board that integrates the control circuitry for the power devices. This will reduce the footprint of power systems, like Integrated High Power Modules (IHPM). Reduced footprints are beneficial in applications where space is a concern, like the automotive industry. The description of the technological steps for building the contacting assembly is reported together with process conditions and electrical performances of two test structures.

In this paper, the performance of compliant parallel manipulators, in a given working position, is evaluated in terms of the MA (mechanical advantage) and k(J) (kinematic condition number). Such evaluation is done by means of a new and fast method for direct kinematic analysis of parallel manipulators. The method, which is useful to enhance both the design synthesis and the control strategy, is applied on the so called pseudo-rigid body mechanism, which represents a simplification of its corresponding compliant mechanism. Computer codes have been developed in MatLab programming language. The case under study consists of a MEMS (Micro Electro Mechanical System) compliant robot that has been built by the research group in silicon for micromanipulation. Such MEMS robot could be designed thanks to a new flexural hinge concept. Some experimental tests have been carried out on sample prototypes in order to inquire about the real feasibility of the micro-robot.Copyright © 2012 by ASME

A novel topology for a micromachined acoustic speaker suitable for cellular phones is proposed in this paper. The membrane is composed of two materials, each of them with different function: a silicon moving part acting as a rigid piston, and polymer annulus acting only as suspension. The high ratio between Young moduli and masses of membrane and suspension leads to a simpler design of the mass-spring-damper system. This new topology can be obtained thanks to a new micromachining technology, that leads to an higher adhesion between polymer and silicon. Simulations presenting the main micro-loudspeaker parameters (e.g. SPL, frequency response) are presented in details as also the principal technological steps.

The electrochemotherapy is an effective treatment that requires the application of an intense electric field to the tumoral tissue to open the cellular membrane and deliver drugs. This work will present the results of the ongoing research project, showing a new technology and design geometry that allows to realize flexible electrodes able to wrap biological tissues bringing the necessary electric field intensity for the electroporation of cells to reach a unique penetration depth to the centimeter range. The flexible electrode is realized by conversion of porous silicon into nano-porous metals (copper and/or gold) filled by a biocompatible thermoplastic polymer.

Most power electronic modules are specifically designed for the customer and this entails intense labour during the production phase. The monolithic integration for power electronic devices in the form of power IC has not proven to be efficient, neither from a technical, nor from an economic point of view. In a typical high power module the power devices are assembled on a heatsink and, driver, sensor and protection circuits are mounted on separate PCBs assembled to the power devices. This results in low performance and high cost. Higher integrated power modules are produced assembling power devices in die format onto a DCB (Direct Copper Bonding) substrate and interconnect them by wire bonding technique [1]. The relative driver, sensor and protection circuits are surface mounted on a separate PCB assembled with the former.

In this work we present a composite nanostructure based on PS-Cu and obtained by a corrosive deposition of Cu from an aqueous solution containing copper ions. PS samples of different porosities ranging from 15% to 75% were immersed in a 0.025 M CuSO4-5H(2)O + 0.005 M HF solution for different times. Scanning electron microscopy analysis was carried out to study the structural form of the PS-Cu nano-composite samples. It was clearly observed that Cu was deposited into and onto PS as nanosized granular film. Characteristic of Cu distribution, structural features of Cu film and factors that influence Cu film structure are described. It is shown that variation of PS porosity and corrosive deposition time provides formation of new composite PS-Cu structures. (C) 2007 Elsevier Ltd. All rights reserved.

Microrobots are used nowadays in several fields of application, specially in mini invasive surgery. However, they are rather difficult to be constructed, and the traditional micro machining tools are not adequate yet to built the smaller parts. The construction of the microrobots is even harder if more than one D.O.F. are required for the mechanism, because these systems are more complicated. This paper deals with the development of a 3 D.O.F. planar micro platform with remote system of actuation. The new approach of design and manufacturing is based on two innovative solutions: a) the adoption of the technologies used to built MEMS, Micro Electro Mechanical Systems; b) the introduction of new flexural hinge to develop compliant micro mechanisms. The new concept of flexural hinge is described in the paper, also from a theoretical point of view. Several example of possible structures are proposed and analyzed, together with their remote wire actuation systems. Finite Element Analysis (FEA) has been also adopted to analyze the system performance under small deformations. The principle of fabrication is, then, described. The process consists of a sequence of single steps which have allowed to achieved an overall maximum size down to 3–4 mm and the minimum thickness of the smaller components down to 50µm.