Multi Material Micro Manufacture Network of Excellence - Micro-sensors & actuators

Wafer-scale manufacturing of robust trimorph bulk SMA microactuators

Tue, 29 Jul 2008 12:01:00 +0000

N. Sandström (a), S. Braun (a), T. Grund (b), G. Stemme (a), M. Kohl (b), W. van der Wijngaart (a)
a Microsystem Technology Lab, KTH - Royal Institute of Technology, Stockholm, SWEDEN
b Institut für Mikrostrukturtechnik, Forschungszentrum Karlsruhe GmbH, Karlsruhe, GERMANY

Abstract

This paper demonstrates the concept of wafer-level fabrication and integration of robust bulk SMA microactuators based on adhesive bonding of cold-rolled SMA sheets to silicon wafers. Contact printing of an adhesive polymer ensures a selective bonding when transferring full SMA sheets to silicon structures on a patterned wafer. The induced stress of a thin dielectric film deposited on top of the SMA sheet ensures a stable and built-in reset mechanism of the actuators. The trimorph microactuators can be actuated by indirect resistive heating through a thin metal film. We report on the successful wafer-scale fabrication of actuator cantilevers and their characteristics. First test cantilevers show a cold-state deflection of 300 μm which, however, is limited by the silicon substrate. Upon heating, the cantilever shows a stroke of approx. 80 μm.

Mixed technologies for gas sensors microfabrication

Tue, 20 May 2008 09:22:26 +0000

Carmen Moldovan (a), Sebastian Sosin (a), Oana Nedelcu (a), Ulrike Kaufmann (b), Hans-Joachim Ritzhaupt-Kleissl (b),
Stefan Dimov (c), Petko Petkov (c), Robert Dorey (d), Katrin Persson (e), David Gomez (f), Per Johander(g)
a National Institute for R&D in Microtechnologies, Erou Iancu Nicolae 32 B, Bucharest 077190, Romania
b Forschungszentrum Karlsruhe, Institut für Materialforschung III, P.O. Box 3640, 76021 Karlsruhe, Germany ;
c Manufacturing Engineering and Multidisciplinary Technology Centre, Cardiff University;
d Nanotechnology Group, Cranfield University, Cranfield, Bedfordshire, UK;
e IMEGO, Arvid Hedvalls Backe 4, SE 411 33 Goteborg, Sweden;
f Fundacion Tekniker
g IVF - Industrial Research and Development Corporation; Argongatan 30, S431 53 Molndal, Sweden

Abstract

The paper presents the development of a novel suspended membrane resistive gas sensor on a ceramic substrate. The sensor is designed and simulated to be fabricated by combining laser milling techniques, conductive ceramic technology, thin film technology, and semiconductor metal oxides. Trenches are created in the alumina substrate in order to define the geometry of the heater using laser processing of the substrate. The heater is completed by filling the trenches with conductive ceramic paste and then baking to remove the solvent from the paste. The next step consists of polishing the surface to obtain a surface roughness small enough for thin film technology. A dielectric (SiO2 or ceramic) material is then deposited, acting as hot plate and also as electrical isolation between the heater and sensing electrode. The sensing electrode consists of an interdigitated resistor made of Au or Pt with thickness in the range of 2000 -3000 Å. The gas sensitive layer (SnO2) is deposited by screen printing or spinning. When heated it react with gas molecules and changes its resistivity, thereby acting as a sensor. The final step involves releasing the sensor, enabling it to be suspended on four bridges, to minimise the dissipation of the heat in the substrate.

The ceramics substrates microprocessing by high precision laser technologies for microsystems, microsensors and actuators applications

Tue, 20 May 2008 08:26:06 +0000

Dr. Dumitru Ulieru (a), Dr. Ileana Cernica (b)
(a) ROMES S.A., 126 A, Iancu Nicolae Str, 77190, Voluntari (Bucharest), Romania,
(b) IMT – Bucharest, 32B, Erou Iancu Nicolae Str., 77190, Voluntari (Bucharest), Romania

Abstract

Microsystems (MST) as MEMS, MOEMS, MCMs, microsensors and actuators uses the same techniques as microelectronics processing to create structural components that are essentially micronic or submicronic mechanical parts. These parts usually require high precision fabrication unless post-fabrication finishing. For various types of materials of which a great used for obtaining microsystems, micro and nanodevices the laser micro and nanoprocessing is the best solution for accuracy and roughness surface quality high precision technologies suitable for batch processing of ceramics and other MSN substrate materials.

High precision microdrilling of microvias and different microholes configurations.
Technical features of microprocessing for microsystems application with RF MCM detailed presented in the paper as
shown on more tables with analyze of answers of more kind of support materials at laser radiation. The authors present also the detailed results of microprocessing of microholes realized by different lasers radiation as UV, Nd:YAG and CO2 for microvias of higher layers count for high density circuits ( HDI ) connection microholes as blind, through tapered holes, circular a/o squared areas etc.
Microcutting and contouring processing by high precision laser technologies.
On the paper are presented the experiments and results studies obtained by the authors on the basis of high precision laser for chips separation and / or singulation on ceramics wafer processed including as individual extraction possibility.
Surface patterning generation by laser microprocessing
The fine pattern generation of metal or alloy films on ceramic substrates can be structured directly with the laser direct patterning process. Our novel technology applications unless chemicals can resolve this problem by offering structuring processing of sensors and sensors systems able to fulfill these requirements.

Thin Film Polymer Actuators for Micro-Fluid Applications

Mon, 12 Nov 2007 16:23:32 +0000

A. Boersma, R. de Zwart, R. Boot, P.J. Bolt
TNO Science and Industry, Eindhoven, The Netherlands

Abstract

Thin film actuators have been manufactured for application in small devices, such as valves and (micro)pump. These actuators are based on new materials especially suited to be used as electro-active dielectric elastomers. The properties of these elastomers are tuned to the specific requirements. It was found that the electric voltage required for operating could be lowered by a factor of three to five. The thin film actuators were processed into small valves and pumps for the manipulation of gasses and liquids. It was shown that the actuators could be operated when immersed in a liquid (e.g. water) and can be used as valves in microfluidic sensor array devices. The next step in the development is fine-tuning of the valve setting in order to minimize leakage and optimize performance and durability.

Simulation of Micropart Motion under 2D Force Fields Implemented on a Cilia Microactuator Array

Mon, 12 Nov 2007 16:23:32 +0000

P. Lazarou, N. A. Aspragathos
Robotics Group, Department of Mechanical Engineering and Aeronautics, University of Patras, Patras T.K. 26500, Greece

Abstract

Micromanipulation is a hot topic in the manufacturing of MEMS products. Alternatives to established manipulation techniques that have been proposed in the recent years include manipulation with force fields and microcilia actuator arrays. In this paper, a simulator for the positioning and alignment of microparts on a microcilia array under two dimensional force fields is presented. A description of its design and motion dynamics is given and the simulation results are presented and discussed.

Method for Overcoming the Unwanted Displacements of an Electro-Thermally Actuated Microgripper

Mon, 12 Nov 2007 16:23:32 +0000

R. Voicu, D. Esinenco, R. Müller, L. Eftime, C. Tibeica
National Institute for Research and Development in Microtechnologies – IMT Bucharest, 126A, Erou Iancu Nicolae Street, Bucharest, Romania

Abstract

Thermal microactuators are based on the principle of material deformation due to heat generated by Joule effect. As a class of microactuators, the microgrippers are promising tools for manipulation of micro and nano - scaled objects. The designs of two models of SU-8 microgrippers electro-thermally actuated are described. A simple design for an electro-thermaly actuated polymeric microgripper is compared with an improved design using a pair of heaters on both sides of the microgripper. We demonstrated that it is possible to reduce the unwanted out of plane displacement, the second model capable of being more stable to the out of plane deflection, generated by the stress, when a voltage is applied. Electro-thermo-mechanical simulations based on finite element method were performed for each of the model in order to make a comparison between the results. Preliminary results on the fabrication of the last model, using a surface micromachining technique and an SU-8 polymer as functional material are presented.

Novel Piezoresistive e-NOSE Sensor Array Cell

Mon, 12 Nov 2007 16:23:32 +0000

V.Stavrov(a), P.Vitanov(b), E.Tomerov(a), E.Goranova(b), G.Stavreva(a)
a: Nano ToolShop Ltd., Microelectronica Industrial Zone, 2140 Botevgrad, Bulgaria
b: Central Laboratory of Solar Energy and New Energy Sources, Bulgarian Academy of Sciences, 72”Tzarigradsko chaussee”, blvd, 1784 Sofia, Bulgaria

Abstract

Future of analytical and manufacturing methods based on micro-mechanical cantilevers, depends critically on the ability to implement parallel operation and fast signal processing [1]. There are two mean reasons: high throughput requirement and complexity (multidimensionality) of analyzed value. In order to get parallel function, any single device should be simultaneously: recognizable, autonomously actuated and independently accessible for readout. Devices, fulfilling these requirements, are suffering from a substantial increase in complexity of both layout and manufacturing technology. In present paper, we demonstrate a novel design of a MEMS (Micro-Electro-Mechanical Systems) cell designed for e-NOSE applications, using results of previous works [2,3], which solves above mentioned problems.

The cell consists of four integrated cantilevers, each having a separate piezoresistor. Additionally, the cantilevers are designed to be different in length and thus having different resonance frequencies. Thus, individual cantilevers are frequency recognizable/addressable. Samples of self-actuated piezoresistive cantilever sensor have been fabricated on n-type, silicon, applying combined surface and bulk micromachining techniques. The cantilever dimensions were chosen to provide approx. 1.8 kHz resonance frequency gap between neighbor individual sensors. The new micro-machined cell is suitable for chemical and biological recognition as a micro-balance.

Bimaterial Actuators and Sensor with Built-in Compensation of the Ambient Temperature Interference

Mon, 12 Nov 2007 16:23:32 +0000

J. Matović(a), Z. Jakšić(b)
a: ISAS, Technical University, 1040, Vienna, Austria
b: IHTM, University of Belgrade, 11000, Belgrade, Serbia

Abstract

We present a novel simple and efficient method for the full removal of the influence of ambient temperature variations to the operation of bimaterial-based MEMS actuators and sensors. The removal of the undesired interference is achieved through the very structure of the bimaterial cantilever, by reversing the order of bimaterial constituent materials at a certain length. Thus an extremely simple geometry is obtained for full self-compensation of the structures. We performed the full simulation of our devices by the finite element method. The structures require standard surface micromachining and utilize only Si-technology compatible materials like polyimides or SU-8. A simple rule for the determination of the zero-deflection condition is presented. The described compensation method enables a significantly reduced bimaterial device area and a much higher packaging density in element arrays, as well as an improved signal-to-noise ratio. The method is especially convenient for photodetector arrays for direct conversion of infrared radiation spatial distribution into a visible image.

A New Concept for an Absolutely Encoded Angular Resolver

Mon, 12 Nov 2007 16:23:32 +0000

V. Mayer, T. Botzelmann, K.-P. Fritz, J. Seybold, H. Kück
Hahn-Schickard-Gesellschaft, Institute of Micro Assembly Technology, Allmandring 9b, 70569 Stuttgart, Germany

Abstract

At HSG-IMAT a new concept for an absolutely encoded optical angular resolver has been developed. The key element of the sensor concept is a disc with a high precision solid measure which is fabricated using the well known manufacturing process for compact discs (CD-Technology). Using this process, it is possible to fabricate a high precision solid measure in high quantities and at low manufacturing costs. To detect the absolute angular position, a laser beam is focused onto the solid measure. The beam is deflected by the diffractive gratings of the solid measure, whereupon the different first orders fall onto separated elements of a photo diode array. To verify the principle of operation an experimental setup assembled under a microscope, with a CCD-chip instead of a photodiode array, was used to demonstrate the signal modulation. Based on these experiments, a small size demonstrator device was designed and assembled. The successful experimental results with this demonstrator device show the large potential of this new sensor concept for different applications.

Design and Optimization of Flat Solenoid MEMS Actuator by Selection of Proper Material Properties

Mon, 12 Nov 2007 16:23:32 +0000

G. Todorov, K. Kamberov, and L. Dimitrov
CAD/CAM/CAE Laboratory, Technical University of Sofia, Sofia 1000, Bulgaria

Abstract

MEMS actuators are widely used in modern industry. Their main advantage is the concentration of desired mechanical characteristics in a limited space. This paper presents a design and optimization of a flat solid MEMS actuator. The optimization is based of the selection of material properties needed for the achievement of the actuator mechanical characteristics required for good performance. The main goal is to reach necessary output mechanical force with minimal side force effects. The output mechanical force is evaluated by modeling and simulation of the magnetic field and its parameters by the use of FE Analyses. In order to make proper simulations, a finite element model of the complete actuator structure is made up suggested).

Another problem that has been solved in the paper is checking of actuator’s geometry and its dimensions in order to evaluate the effective use of the material. As a result of the study, the optimal output function of the mechanical force versus the stage position has been determined. This has been done on the basis of updated material specifications. The optimal design of a flat solenoid MEMS actuator is proposed.

A New Approach to Qualitiy Assurance in Resistance Welding for Microsensors Packaging

Mon, 12 Nov 2007 16:23:32 +0000

D. Ulieru(a), Alina Matei(b), Elena Ulieru(c), A. Tantau(c)
a: ROMES S.A., 126A, Iancu Nicolae Str., Bucharest, 72996, Romania
b: National Institute for Research and Development in Microtechnologies, 32B, Erou Iancu Nicolae Str., Bucharest, 077190, Romania
c: SITEX 45 SRL, 114, Ghica Tei Blvd., bl. 40, ap. 2, Dept. 2, Bucharest 72235, Romania

Abstract

The permanent development of microelectronics technologies provide new challenges for miniaturization and complexity increasing for new packaging technologies. So the exciting applications for microsystems, sensors and actuators production are looking for the best quality hermetic sealing of metal packages. The paper showed our researches and experiments results for a new approach to quality assurance in resistance welding. These will analyze the main causes of weld failures and also our methods of determining its value. On the basis of this requirement have monitored through the weld sequence, integrated concept of power monitor. The technical features developed a modern concept applicable to a wider range of fields. Our monitor could be used to wide range of welding technologies like distributed spot and focused spot, projection, roller spot and mash welding machines, working with single or three phase, ac. or dc. The experiments with our equipment have proven its advantage for fast production assembly line.

Photosensor of CDSSE for Fiber Optics Applications

Mon, 12 Nov 2007 16:23:32 +0000

Peter Shindov(a), Nasko Elektronov(b),Valery Serbezov(c), Franz Herbst(c)
a: Technical College-"John Atanasoff"
b: JN-Corp.
c: Multicoats Ltd.

Abstract

The development of new generations of laser source for fiber optic’s applications require more fast new photosensors with spectral characteristics in visible range. The idea of this work is development of technology and device – fast photosensor with spectral range adapted to modern lasers for the quickly increasing needs of optoelectronics and fiber optics communications. By pulsed laser deposition (PLD) usage UV N2 Laser for ablation λ=337.1 nm, energy per pulse 8 mJ and CW 60 W CO2 Laser for heating are produced thin CdSxSe1-x films on quartz substrate. Polycrystalline thin films with thickness from 0.5 to 2.0 μm and dominant orientation – (002) are formed by energy density 4.5 J/cm2 and repetition rate 20 Hz .The thin films are investigated by EDAX and SEM. The films are additional thermo treatment for increasing ratio photocurrent – dark current. This ratio reaches 107. By means of TEA UV N2 Laser with energy per pulse-0.3 mJ, pulse duration 2 ns are formed planar Ohm contacts from CdO directly onto thin film. The contacts are investigated by XRD. By means of coordinate table the contacts are formed on the backside of the structure. The dimension of photosensitive structure is 250x250 μm. The distance between contacts areas is 10 μm. The spectral response of devices is measured. The maximum spectral sensitive is at λ=575 nm. Lux ampere characteristics are measured. The increasable fronts and decreаsаble fronts at the structure are measured. They are 2 ns, at ratio 1000.

Feasibility study for microfluidic separation device for biological fluids

Mon, 02 Apr 2007 14:10:43 +0000

4M Partner:
Imego AB

4M Partner No:
18

Collaborator Name:
Denator AB

Proposal for extended project to RAS:
Yes

Technology enquiry/solution sought:

The study requested is a preparation for a possible research and development project of a product that can perform fast separation and inactivation of biological fluids. Proteins, peptides and metabolites are rapidly degraded after extraction, which causes large problems for both academic and industrial protein research. In this study, Imego will investigate the feasibility of fabricating low-cost glass and polymer chips that combine microfluidic separation with Denator’s proprietary preservation technology.

USTUTT

Tue, 30 Jan 2007 13:05:53 +0000

Facilities/Hardware:

Sensors and actuators based on metallized polymers, precision micro injection moulding, environmental testing
website: www.uni-stuttgart.de/izfm

RAS contact:
kueck

University of Bath

Thu, 18 Jan 2007 10:20:05 +0000

Facilities/Hardware:

Plating & thermoforming equipment
Digitisation and scanning machine
Electron optic and analysis and associated preparation equipment
Netzch Dilatometer
Take Control Piezometer
HP494B Impedance analyser
Solatron 1260 and dielectric interface
Non-contact suface profiler (Proscan)

RAS contact:
Alan Bramley