Rocco Crescenzi - Academia.edu (original) (raw)

Papers by Rocco Crescenzi

This paper describes the design, simulation, construction process and experimental analysis of a ... more 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. CSFHs improve accuracy and guarantee that minimum stress conditions hold within the flexible beam. This microgripper is designed for Deep Reactive-Ion Etching (DRIE) 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 industrial selective processing technique based on a confined dynamic liquid drop\meniscus ... more A new industrial 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. The concept of dynamic meniscus is inherited from the static meniscus, i.e. the liquid bridge that is formed when a liquid is confined between two surfaces. The difference between the static meniscus and the dynamic one is that the shape is defined by the surface tension, contact angles and gravity in the former, and by the equilibrium between fluid speed and the confinement vacuum in the latter. 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 (e.g. etching, cleaning and/or plating) without the need of any protective photo-resist. The main scientific innovation and relevance introduced by this work can be easily applied to industrial solar cell production. Due to jet impingement of the liquid, the diffusion layer is reduced and high deposition rate of metal is obtained (i.e. Cu > 2 μm/s) offering high throughput in small equipment footprint.

This paper describes the design and the manufacturing of a 3U Cubesat designed in collaboration b... more This paper describes the design and the manufacturing of a 3U Cubesat designed in collaboration between the II Faculty of Engineering of Bologna University and the Sapienza aerospace research center (CRAS). The cubesat is developed in the framework of the QB50 project and will host the Von Karman Institute sensor set for atmosphere parameters analysis . Despite its small size this cubesat is a complete platform for space experiments, with a system for active attitude control, a redundant telecommunication system and a high efficiency power control system. This allow to perform complex experiments as the test of a micropropulsion system, in order to verify the effectiveness and the efficiency of a MEMS cold gas micro-thruster. This system operated with nitrogen employs COTS components and a noncommercial MEMS valve-nozzle system. The MEMS control system is based upon a proportional valve using a solenoid-like system, where the moving part is composed by a polymeric material charged w...

studenti Pravnog fakulteta Sveučilišta u Zagrebu Intervju: prof. dr. sc. Dubravka Hrabar U ovom b... more studenti Pravnog fakulteta Sveučilišta u Zagrebu Intervju: prof. dr. sc. Dubravka Hrabar U ovom broju donosimo intervju s novoizabranom dekanicom Pravnog fakulteta Sveučilišta u Zagrebu, profesoricom dr.sc. Dubravkom Hrabar, koja nam otkriva kako se odlučila na studij prava, po čemu se razlikuju studenti onda i danas, o funkcijama na kojima se tijekom svoje karijere nalazila te smo dobili odgovore na brojna pitanja o studentskoj proaktivnosti na Fakultetu i poticanju izvrsnosti od strane Fakulteta.

Micromachines

This paper presents the development of a new microgripper actuated by means of rotary-comb drives... more 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 operationa...

Sensors

Gyroscopes are one of the next killer applications for the MEMS (Micro-Electro-Mechanical-Systems... more 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 ...

Optics Express

Beam self-imaging in nonlinear graded-index multimode optical fibers is of interest for many appl... more 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 an exact solution for the nonlinear evolution of first and second order moments of a laser beam carried by a graded-index multimode fiber, predicting that the spatial self-imaging period does not vary with power. Whereas the amplitude of the oscillation of the beam width is power-dependent. We have experimentally studied 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 fluorescence emission and harmonic wave generation permits us to directly confirm that the self-imaging period is invariant with power. Spatial shift and splitting of the self-imaging process under the action of self-focusing are also emphasized.

Mechanisms and Machine Science, Jul 27, 2017

Applied Sciences

Micro Electro Mechanical Systems (MEMS)-Technology based micro mechanisms usually operate within ... more 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.

Actuators

The number of studies on microgrippers has increased consistently in the past decade, among them ... more The number of studies on microgrippers has increased consistently in the past decade, among them the numeric simulations and material characterization are quite common, while the metrological issues related to their performance testing are not well investigated yet. To add some contribution in this field, an image analysis-based method for microgrippers displacement measurement and testing is proposed here: images of a microgripper prototype supplied with different voltages are acquired by an optical system (i.e., a 3D optical profilometer) and processed through in-house software. With the aim to assess the quality of the results a systematic approach is proposed for determining and quantifying the main error sources and applied to the uncertainty estimation in angular displacement measurements of the microgripper comb-drives. A preliminary uncertainty evaluation of the in-house software is provided by a Monte Carlo Simulation and its contribution added to that of the other error so...

Journal of Micromechanics and Microengineering

Progress in MEMS technology continuously stimulates new developments in the mechanical structure ... more Progress in MEMS technology continuously stimulates new developments in the mechanical structure of micro systems, such as, for example, the concept of 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 a 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 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 flexure hinges in terms of larger rotations and less stress for given applied voltage.

Although tissue and cell manipulation nowadays is a common task in biomedical analysis, there are... more 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.

Volume 2: Dynamics, Vibration and Control; Energy; Fluids Engineering; Micro and Nano Manufacturing, 2014

Although a certain amount of work has been presented in literature which concerns micro and nano ... more 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

Volume 3: Advanced Composite Materials and Processing; Robotics; Information Management and PLM; Design Engineering, 2012

In this paper, the performance of compliant parallel manipulators, in a given working position, i... more 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.

2013 IEEE 63rd Electronic Components and Technology Conference, 2013

ABSTRACT Silicon interposer technology offers System-In-Package (SiP) and System-On-Package (SoP)... more ABSTRACT Silicon interposer technology offers System-In-Package (SiP) and System-On-Package (SoP) designers the unique possibility of achieving 3D integration without the need to implement Through-Silicon-Via (TSV) structures in active silicon, contributing to overall cost reduction of the final product. Silicon interposers require both horizontal and vertical interconnections, to redistribute the signals from the hosted chips. Vertical interconnections are achieved by TSV structures realized by Deep Reactive-Ion-Etching (DRIE) or LASER drilling processes. In this work is presented a lower cost alternative for realizing TSV on silicon wafers: electrochemical etching of silicon, forming vertical high aspect ratio macro-pores on the silicon wafer. The interposer itself is a macro-porous silicon layer, consisting of ordered, straight open pores at regular pitch. An optimized TSV fabrication process on low-cost (100)-oriented, p-type 10-20 Ωcm silicon wafers is presented. 100μm deep via with lateral diameter of 1.5μm and 2μm pitch have been achieved. In this work is reported the manufacture process, the achieved results.

2014 IEEE 64th Electronic Components and Technology Conference (ECTC), 2014

In this work we report the application of the selective wet processing technique based on dynamic... more 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.

2013 IEEE 63rd Electronic Components and Technology Conference, 2013

ABSTRACT A new selective processing technique based on a confined dynamic liquid dropmeniscus is ... more ABSTRACT A new selective processing technique based on a confined dynamic liquid dropmeniscus 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.

Electronic Components and Technology Conference, 2011

A novel topology for a micromachined acoustic speaker suitable for cellular phones is proposed in... more 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

This paper describes the design, simulation, construction process and experimental analysis of a ... more 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. CSFHs improve accuracy and guarantee that minimum stress conditions hold within the flexible beam. This microgripper is designed for Deep Reactive-Ion Etching (DRIE) 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 industrial selective processing technique based on a confined dynamic liquid drop\meniscus ... more A new industrial 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. The concept of dynamic meniscus is inherited from the static meniscus, i.e. the liquid bridge that is formed when a liquid is confined between two surfaces. The difference between the static meniscus and the dynamic one is that the shape is defined by the surface tension, contact angles and gravity in the former, and by the equilibrium between fluid speed and the confinement vacuum in the latter. 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 (e.g. etching, cleaning and/or plating) without the need of any protective photo-resist. The main scientific innovation and relevance introduced by this work can be easily applied to industrial solar cell production. Due to jet impingement of the liquid, the diffusion layer is reduced and high deposition rate of metal is obtained (i.e. Cu > 2 μm/s) offering high throughput in small equipment footprint.

This paper describes the design and the manufacturing of a 3U Cubesat designed in collaboration b... more This paper describes the design and the manufacturing of a 3U Cubesat designed in collaboration between the II Faculty of Engineering of Bologna University and the Sapienza aerospace research center (CRAS). The cubesat is developed in the framework of the QB50 project and will host the Von Karman Institute sensor set for atmosphere parameters analysis . Despite its small size this cubesat is a complete platform for space experiments, with a system for active attitude control, a redundant telecommunication system and a high efficiency power control system. This allow to perform complex experiments as the test of a micropropulsion system, in order to verify the effectiveness and the efficiency of a MEMS cold gas micro-thruster. This system operated with nitrogen employs COTS components and a noncommercial MEMS valve-nozzle system. The MEMS control system is based upon a proportional valve using a solenoid-like system, where the moving part is composed by a polymeric material charged w...

studenti Pravnog fakulteta Sveučilišta u Zagrebu Intervju: prof. dr. sc. Dubravka Hrabar U ovom b... more studenti Pravnog fakulteta Sveučilišta u Zagrebu Intervju: prof. dr. sc. Dubravka Hrabar U ovom broju donosimo intervju s novoizabranom dekanicom Pravnog fakulteta Sveučilišta u Zagrebu, profesoricom dr.sc. Dubravkom Hrabar, koja nam otkriva kako se odlučila na studij prava, po čemu se razlikuju studenti onda i danas, o funkcijama na kojima se tijekom svoje karijere nalazila te smo dobili odgovore na brojna pitanja o studentskoj proaktivnosti na Fakultetu i poticanju izvrsnosti od strane Fakulteta.

Micromachines

This paper presents the development of a new microgripper actuated by means of rotary-comb drives... more 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 operationa...

Sensors

Gyroscopes are one of the next killer applications for the MEMS (Micro-Electro-Mechanical-Systems... more 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 ...

Optics Express

Beam self-imaging in nonlinear graded-index multimode optical fibers is of interest for many appl... more 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 an exact solution for the nonlinear evolution of first and second order moments of a laser beam carried by a graded-index multimode fiber, predicting that the spatial self-imaging period does not vary with power. Whereas the amplitude of the oscillation of the beam width is power-dependent. We have experimentally studied 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 fluorescence emission and harmonic wave generation permits us to directly confirm that the self-imaging period is invariant with power. Spatial shift and splitting of the self-imaging process under the action of self-focusing are also emphasized.

Mechanisms and Machine Science, Jul 27, 2017

Applied Sciences

Micro Electro Mechanical Systems (MEMS)-Technology based micro mechanisms usually operate within ... more 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.

Actuators

The number of studies on microgrippers has increased consistently in the past decade, among them ... more The number of studies on microgrippers has increased consistently in the past decade, among them the numeric simulations and material characterization are quite common, while the metrological issues related to their performance testing are not well investigated yet. To add some contribution in this field, an image analysis-based method for microgrippers displacement measurement and testing is proposed here: images of a microgripper prototype supplied with different voltages are acquired by an optical system (i.e., a 3D optical profilometer) and processed through in-house software. With the aim to assess the quality of the results a systematic approach is proposed for determining and quantifying the main error sources and applied to the uncertainty estimation in angular displacement measurements of the microgripper comb-drives. A preliminary uncertainty evaluation of the in-house software is provided by a Monte Carlo Simulation and its contribution added to that of the other error so...

Journal of Micromechanics and Microengineering

Progress in MEMS technology continuously stimulates new developments in the mechanical structure ... more Progress in MEMS technology continuously stimulates new developments in the mechanical structure of micro systems, such as, for example, the concept of 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 a 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 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 flexure hinges in terms of larger rotations and less stress for given applied voltage.

Although tissue and cell manipulation nowadays is a common task in biomedical analysis, there are... more 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.

Volume 2: Dynamics, Vibration and Control; Energy; Fluids Engineering; Micro and Nano Manufacturing, 2014

Although a certain amount of work has been presented in literature which concerns micro and nano ... more 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

Volume 3: Advanced Composite Materials and Processing; Robotics; Information Management and PLM; Design Engineering, 2012

In this paper, the performance of compliant parallel manipulators, in a given working position, i... more 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.

2013 IEEE 63rd Electronic Components and Technology Conference, 2013

ABSTRACT Silicon interposer technology offers System-In-Package (SiP) and System-On-Package (SoP)... more ABSTRACT Silicon interposer technology offers System-In-Package (SiP) and System-On-Package (SoP) designers the unique possibility of achieving 3D integration without the need to implement Through-Silicon-Via (TSV) structures in active silicon, contributing to overall cost reduction of the final product. Silicon interposers require both horizontal and vertical interconnections, to redistribute the signals from the hosted chips. Vertical interconnections are achieved by TSV structures realized by Deep Reactive-Ion-Etching (DRIE) or LASER drilling processes. In this work is presented a lower cost alternative for realizing TSV on silicon wafers: electrochemical etching of silicon, forming vertical high aspect ratio macro-pores on the silicon wafer. The interposer itself is a macro-porous silicon layer, consisting of ordered, straight open pores at regular pitch. An optimized TSV fabrication process on low-cost (100)-oriented, p-type 10-20 Ωcm silicon wafers is presented. 100μm deep via with lateral diameter of 1.5μm and 2μm pitch have been achieved. In this work is reported the manufacture process, the achieved results.

2014 IEEE 64th Electronic Components and Technology Conference (ECTC), 2014

In this work we report the application of the selective wet processing technique based on dynamic... more 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.

2013 IEEE 63rd Electronic Components and Technology Conference, 2013

ABSTRACT A new selective processing technique based on a confined dynamic liquid dropmeniscus is ... more ABSTRACT A new selective processing technique based on a confined dynamic liquid dropmeniscus 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.

Electronic Components and Technology Conference, 2011

A novel topology for a micromachined acoustic speaker suitable for cellular phones is proposed in... more 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