Ultra thin platinum films were grown by dc magnetron sputtering on thermally oxidized Si (100) substrates. The electrical resistance of the films was monitored in-situ during growth. The coalescence thickness was determined for various growth temperatures and found to increase from 1.3 nm for films grown at room temperature to 1.8 nm for films grown at 250 degrees C, while a continuous film was formed at a thickness of 3.9 nm at room temperature and 3.5 nm at 250 degrees C. The electrical resistivity increases with increased growth temperature, as well as the morphological grain size, and the surface roughness, measured with a scanning tunneling microscope (STM).

Ultra thin platinum films were grown by dc magnetron sputtering on thermally oxidized Si (100) substrates. The electrical resistance of the films was monitored in situ during growth. The coalescence thickness was determined for various growth temperatures and found to increase from 1.1 nm for films grown at room temperature to 3.3 nm for films grown at 400 degrees C. A continuous film was formed at a thickness of 2.9 nm at room temperature and 7.5 nm at 400 degrees C. The room temperature electrical resistivity decreases with increased growth temperature, while the in-plain grain size and the surface roughness, measured with a scanning tunneling microscope (STM), increase. Furthermore, the temperature dependence of the film electrical resistance was explored at various stages during growth.

This paper describes the main results of the EU FP7 project TUMESA - MEMS tuneable metamaterials for smart wireless applications. In this project, we studied several reconfigurable antenna approaches that combine the new technology of MEMS with the new concept of artificial electromagnetic materials and surfaces (metamaterials and metasurfaces) for realisation of millimetre wave phase shifters and beam-steering devices. MEMS technology allows to miniaturise electronic components, reduce their cost in batch production, and effectively compete with semiconductor and ferroelectric based technologies in terms of losses at millimetre wavelengths. Novel tuneable materials and components proposed in this project perform as smart beam steering devices. Fabricated with MEMS technology in batch and on a single chip, proposed tuneable devices allow substituting of larger and more complex sub-system of, e.g., a radar sensor. This substitution provides a dramatic cost reduction on a system level.

This paper reports a novel room-temperature hermetic liquid sealing process where the access ports of liquid-filled cavities are sealed with wire-bonded stud bumps. This process enables liquids to be integrated at the fabrication stage. Evaluation cavities were manufactured and used to investigate the mechanical and hermetic properties of the seals. Measurements on the successfully sealed structures show a helium leak rate of better than 10 (10) mbarL s (1), in addition to a zero liquid loss over two months during storage near boiling temperature. The bond strength of the plugs was similar to standard wire bonds on flat surfaces.

This paper reports a novel room temperature hermetic liquid sealing process based on wire bonded "plugs" over the access ports of liquid-filled cavities. The method enables liquids to be integrated already at the fabrication stage. Test vehicles were manufactured and used to investigate the mechanical and hermetic properties of the seals. A helium leak rate of better than 1E-10 mbarL/s was measured on the successfully sealed structures. The bond strength of the "plugs" were similar to standard wire bonds on flat surfaces.

This paper reports experimental results of a novel room temperature vacuum sealing process based on compressing wire bonded gold “bumps”, causing a material flow into the access ports of vacuum-cavities. The leak rate out of manufactured cavities was measured over 5 days and evaluated to less than the detection limit, 6×10^-12 mbarL/s, per sealed port. The cavities have been sealed at a vacuum level below 10 mbar. The method enables sealing of vacuum cavities at room temperature using standard commercial tools and processes.

We present the design, fabrication, and characterization of a grating for coupling between a single mode silica fiber and the TE mode in a silicon photonic waveguide on a silicon on insulator (SOI) substrate. The grating is etched completely through the silicon device layer, thus permitting the fabrication of through-etched surface coupled silicon nanophotonic circuits in a single lithography step. Furthermore, the grating is apodized to match the diffracted wave to the mode profile of the fiber. We experimentally demonstrate a coupling efficiency of 35% with a 1 dB bandwidth of 47 nm at 1536 nm on a standard SOI substrate. Furthermore, we show by simulation that with an optimized buried oxide thickness, a coupling efficiency of 72% and a 1 dB bandwidth of 38 nm at 1550 nm is achievable. This is, to our knowledge, the highest simulated coupling efficiency for single-etch TE-mode grating couplers. In particular, simulations show that apodizing a conventional periodic through-etched grating decreases the back-reflection into the waveguide from 21% to 0.1%.

A novel low-temperature wafer-level vacuum packaging process is presented. The process uses plastically deformed gold rings as sealing structures in combination with flux-free soldering to provide the bond force for a sealing wafer. This process enables the separation of the sealing and the bonding functions both spatially on the wafer and temporally in different process steps, which results in reduced areas for the sealing rings and prevents outgassing from the solder process in the cavity. This enables space savings and yields improvements. We show the experimental result of the hermetic sealing. The leak rate into the packages is determined, by measuring the package lid deformation over 10 months, to be lower than 3.5 x 10(-13) mbar l s(-1), which is suitable for most MEMS packages. The pressure inside the produced packages is measured to be lower than 10 mbar.

Dye molecules embedded in different matrices in the form of thin films are the basis of specific materials used for laser cavities, optical filters, optical gas sensors, etc. In the present communication we discuss a new methodology based on the remote microwave plasma assisted deposition of dye containing thin films that circumvent the above mentioned problems. It permits a tailored synthesis of optically active nanometric thin films containing dye molecules which are active as fluorescence emitters (i.e., coloured and fluorescent films). The principle of this new procedure is the partial polymerization of dye molecules that are evaporated over a substrate while exposed to a remote microwave Ar plasma. As a result of this process a polymeric thin film is produced in one step where some dye molecules keep intact their optical activity (although eventually, their optical response can be slightly modified by matrix effects). This methodology has been recently used for the deposition of novel plasma nanocomposites containing non-aggregated laser dyes to maximize the fluorescent emission of the materials and for the fabrication of optical NO2 sensing nanocomposites. To illustrate the possibilities of the technique we present here results for different fluorescent dye molecules, as perylene dyes, and several xanthene and oxazine derivative cationic dyes which are typically used as gain media in tuneable laser dyes. The luminescent, optical and sensing properties of these dye containing nanocomposites will be presented. These active optical layers are being developed for the fabrication of photonic sensor devices, optical filters and photonic chips (PHODYE EU Project). This is due to the full compatibility of the synthetic methodology with the present integrated microelectronic and optoelectronic technology. The possibilities for the fabrication of photonic devices integrating these active optical layers will be demonstrated. Especial attention will be paid to recent results about the incorporation of the luminescent films in photonic crystals and about the conformal growth of luminescent planar defects within artificial opals.

A new kind of visible-blind organic thin-film material, consisting of a polymeric matrix with a high concentration of embedded 3-hydroxyflavone (3HF) dye molecules, that absorbs UV light and emits green light is presented. The thin films can be grown on sensitive substrates, including flexible polymers and paper. Their suitability as photonic active components in photonic devices is demonstrated.

We describe a versatile three gun magnetron sputtering system with a custom made sample holder for in situ electrical resistance measurements, both during film growth and ambient changes on film electrical properties. The sample holder allows for the preparation of patterned thin film structures, using up to five different shadow masks without breaking vacuum. We show how the system is used to monitor the electrical resistance of thin metallic films during growth and to study the thermodynamics of hydrogen uptake in metallic thin films. Furthermore, we demonstrate the growth of thin film capacitors, where patterned films are created using shadow masks.

This paper presents for the first time a novel concept of a MEMS waveguide switch based on a reconfigurable surface, whose working principle is to short-circuit or to allow for free propagation of the electrical field lines of the TE10 mode of a WR-12 rectangular waveguide. This transmissive surface is only 30μm thick and consists of up to 1260 reconfiguring cantilevers in the waveguide cross-section, which are moved simultaneously by integrated MEMS comb-drive actuators. For the first fabrication run, the yield of these reconfigurable elements on the chips was 80-86%, which still was good enough for resulting in a measured insertion loss in the open state of better than 1dB and an isolation of better than 20dB for the best designs, very wideband from 62 to 75GHz. For 100% fabrication yield, HFSS simulations predict that an insertion loss in the open state of better than 0.1dB and an isolation of better than 30dB in the closed state are possible for designs with 800 and more contact points for this novel waveguide switch concept.

This paper presents for the first time a novel concept of a MEMS waveguide switch based on a reconfigurable surface, whose working principle is to short-circuit or to allow for free propagation of the electrical field lines of the TE10 mode of a WR-12 rectangular waveguide. This transmissive surface is only 30μm thick and consists of up to 1260 reconfiguring cantilevers in the waveguide cross-section, which are moved simultaneously by integrated MEMS comb-drive actuators. For the first fabrication run, the yield of these reconfigurable elements on the chips was 80-86%, which still was good enough for resulting in a measured insertion loss in the open state of better than 1dB and an isolation of better than 20dB for the best designs, very wideband from 62 to 75GHz. For 100% fabrication yield, HFSS simulations predict that an insertion loss in the open state of better than 0.1dB and an isolation of better than 30dB in the closed state are possible for designs with 800 and more contact points for this novel waveguide switch concept.

We present a compact system consisting of a miniaturized fluid dispenser, delivering liquid laser dye to a micro-chip dye laser. This demonstrates the elimination of bulk fluid pumps for a microfluidic system by using a miniaturized, electrically and chemically inert dispenser, capable of delivering very low flow for extended periods of time.

We present a procedure to reconfigure microring resonators based on liquid surface adhesion. Droplets of organic solvents were deposited over Si3N4/SiO2 strip- and slot-waveguide ring resonators, and the transmission spectra were measured several hours after the evaporation of the droplets at room temperature. Our measurements show that the optical properties of the microrings are significantly modified by liquid adhered to the waveguides, persisting even 96 h after bulk evaporation. Liquid-solid interfacial forces slow down liquid evaporation at the nanoscale, enabling permanent photonic configurations. Rewriteability is achieved by removing the adhered liquid with heat.

We demonstrate label-free molecule detection by using an integrated biosensor based on a Si3N4/SiO2 Slot-waveguide microring resonator. Bovine serum albumin (BSA) and anti-BSA molecular binding events on the sensor surface are monitored through the measurement of resonant wavelength shifts with varying biomolecule concentrations. The biosensor exhibited sensitivities of 1.8 and 3.2 nm/(ng/mm(2)) for the detection of anti-BSA and BSA, respectively. The estimated detection limits are 28 and 16 pg/mm(2) for anti-BSA and BSA, respectively, limited by wavelength resolution.

We report an experimental demonstration of an integrated biochemical sensor based on a slot-waveguidemicroring resonator. The microresonator is fabricated on a Si3N4-SiO2 platform and operates at a wavelength of 1.3 mu m. The transmission spectrum of the sensor is measured with different ambient refractive indices ranging from n = 1. 33 to 1.42. A linear shift of the resonant wavelength with increasing ambient refractive index of 212 nm/refractive index units (RIU) is observed. The sensor detects a minimal refractive index variation of 2 X 10(-4) RIU.

We report on the first demonstration of guiding light in vertical slot-waveguides on silicon nitride/silicon oxide material system. Integrated ring resonators and Fabry-Perot cavities have been fabricated and characterized in order to determine optical features of the slot-waveguides. Group index behavior evidences guiding and confinement in the low-index slot region at O-band (1260-1370nm) telecommunication wavelengths. Propagation losses of < 20 dB/cm have been measured for the transverse-electric mode of the slot-waveguides.

We demonstrate slot-waveguide microring resonators and Fabry-Perot microcavities on Si3N4/SiO2. Characterization indicates guiding and confinement in the waveguide nanometric-size low-index slot region at O-band (1260-1370nm) wavelengths. We measured propagation losses <20 dB/cm.

Transfer bonding is a reliable cost-efficient and low-temperature CMOS compatible technique which allows batchintegration of materials whose incompatibility with Si makes them unsuitable for monolithic integration. In thisheterogeneous device integration method the material and process incompatibilities inherent in Si IC technology areovercome by fabricating devices on separate substrates and then transferring them onto target (e.g. CMOS) wafers.Transfer bonding has great potential for integrating RF-MEMS devices incorporating, for example, high thermal budgetmaterials such as PZT and PST or non-ferroelectric piezoelectrics such as AlN and ZnO into microwave ICs forenhanced systems performance. This paper presents an overview of technology developments within the EUsponsored project Q2M for the realization of transfer bonded piezoelectrically actuated RF MEMS switches and othercomponents focusing in particular on material factors relating to growth of the piezoelectric films, in this case sol-geldeposited PZT, that restricts the choice of device layers and impact on PZT properties such as microstructure, filmorientation and piezoelectric coefficients. New process developments such as hard masking of PZT pattern during RIEetching and its compatibility with polymer transfer bonding are discussed.

Within this master thesis work, a novel TSV technology with RF capabilities is presented. A major focus was laid on the design and the construction of a fully automated fabrication tool for the assembly of Ni TSV cores. The utilisation of the ferromagnetic properties of nickel allowed for a highly parallelised self-assembly process which was implemented in the automated fabrication. Furthermore, a special eort was made to improve the RF capabilities of this type of TSVs. In order to increase the RF conductibility, a novel type of metal conductor was devised and fabricated. The deposition of a thin gold layer on the perimeter of the conductor allowed for an optimal utilisation of the skin eect to enhance the RF performance. The above-mentioned newly developed assembly tool was then used to build RF transmission lines test structures.

This thesis presents methods for the wafer-level integration of shape memory alloy (SMA) and electrostatic actuators to functionalize MEMS devices. The integration methods are based on heterogeneous integration, which is the integration of different materials and technologies. Background information about the actuators and the integration method is provided.

SMA microactuators offer the highest work density of all MEMS actuators, however, they are not yet a standard MEMS material, partially due to the lack of proper wafer-level integration methods. This thesis presents methods for the wafer-level heterogeneous integration of bulk SMA sheets and wires with silicon microstructures. First concepts and experiments are presented for integrating SMA actuators with knife gate microvalves, which are introduced in this thesis. These microvalves feature a gate moving out-of-plane to regulate a gas flow and first measurements indicate outstanding pneumatic performance in relation to the consumed silicon footprint area. This part of the work also includes a novel technique for the footprint and thickness independent selective release of Au-Si eutectically bonded microstructures based on localized electrochemical etching.

Electrostatic actuators are presented to functionalize MEMS crossbar switches, which are intended for the automated reconfiguration of copper-wire telecommunication networks and must allow to interconnect a number of input lines to a number of output lines in any combination desired. Following the concepts of heterogeneous integration, the device is divided into two parts which are fabricated separately and then assembled. One part contains an array of double-pole single-throw S-shaped actuator MEMS switches. The other part contains a signal line routing network which is interconnected by the switches after assembly of the two parts. The assembly is based on patterned adhesive wafer bonding and results in wafer-level encapsulation of the switch array. During operation, the switches in these arrays must be individually addressable. Instead of controlling each element with individual control lines, this thesis investigates a row/column addressing scheme to individually pull in or pull out single electrostatic actuators in the array with maximum operational reliability, determined by the statistical parameters of the pull-in and pull-out characteristics of the actuators.

This paper introduces the concept of batch micrufabrication and electrical contacting of bulk SMA nticroactuators. This concept addresses technical solutions for the main challenges related to using SMA actuators such as the necessary mechanical bias force, the difficult electrical contacting and the high power needed for actuation. We report on initial SMA-dielectric-metal trimorph test structures and their characteristics. The bias force is provided by a dielectric layer and the electrical contacting of the bulk SMA is avoided using indirect electrical heating via an additional metal layer. Three nun long beams can provide several hundreds of mu N and deflect several hundreds of mu m. The actuation power is reduced approx. 2.5 times compared to direct heating schemes.

This paper introduces the first area-optimized micromachined knife gate microvalve. In comparison to recent microvalves the pressure-flow performance is increased using out-of-plane actuators and an out-of-plane orifice. Three different actuator-gate designs and their fabrication are described. The valve features integrated therinal silicon/aluminum bimorph actuators where the aluminum layer forins the resistive heater as well as the bimorph material. The characterization of the actuators and of the pressure-flow perfon-nance is presented. The valve allows a flow change of Delta Q=3.4 1/min at 100 kPa on an active chip area of only 2.3 x 3.7 mm(2).

This paper reports on a microelectromechanical switch array with up to 20x20 double switches and packaged on a single chip and utilized for main distribution frames in copper-wire networks. The device includes 5x5 or 20x20 allowing for an any-to-any interconnection of the input line to the specific output line. The switches are on an electrostatic S-shaped film actuator with the contact moving between a top and a bottom electrode. device is fabricated in two parts and is designed to assembled using selective adhesive wafer bonding in a wafer-scale package of the switch array. The 5x5 switch arrays have a size of 6.7x6.4mm(2) and the arrays are 14x10 mm(2) large. The switch actuation for closing/opening the switches averaged over an array measured to be 21.2 V / 15.3 V for the 5x5 array 93.2 V / 37.3 V for the 20x20 array. The total impedance varies on the 5x5 array between 0.126 Omega 0.564 Omega at a measurement current of 1 mA. The resistance of the switch contacts within the 5x5 array determined to be 0.216 Omega with a standard deviation 0. 155 Omega.

This paper reports on a micro-electromechanical (MEMS) switch array embedded and packaged on a single chip. The switch array is utilized for the automated re-configuration of the physical layer of copper-wire telecommunication networks. A total of 25 individually controllable double-switches are arranged in a 6.7 x 6.4 mm(2) large 5x5 switch matrix allowing for any configuration of independently connecting the line-pairs of the five input channels to any line-pair of the five output channels. The metal-contact switch array is embedded in a single chip package, together with 4 metal layers for routing the signal and control lines and with a total of 35 I/O contact pads. The MEMS switches are based on an electrostatic S-shaped thin membrane actuator with the switching contact bar rolling between a top and a bottom electrode. This special switch design allows for low actuation voltage (21.23 V) to close the switches and for high isolation. The total signal line resistances of the routing network vary from 0.57 Omega to 0.98 Omega. The contact resistance of the gold contacts is 0.216 Omega.

This paper investigates the design and optimization of a row/column addressing scheme to individually pull in or pull out single electrostatic actuators in an N(2) array, utilizing the electromechanical hysteresis behavior of electrostatic actuators and efficiently reducing the number of necessary control lines from N(2) complexity to 2N. This paper illustrates the principle of the row/column addressing scheme. Furthermore, it investigates the optimal addressing voltages to individually pull in or pull out single actuators with maximum operational reliability, determined by the statistical parameters of the pull-in and pull-out characteristics of the actuators. The investigated addressing scheme is implemented for the individual addressing of cross-connect switches in a microelectromechanical systems 20 x 20 switch array, which is utilized for the automated any-to-any interconnection of 20 input signal line pairs to 20 output signal line pairs. The investigated addressing scheme and the presented calculations were successfully tested on electrostatic actuators in a fabricated 20 x 20 array. The actuation voltages and their statistical variations were characterized for different subarray cluster sizes. Finally, the addressing voltages were calculated and verified by tests, resulting in an operational reliability of 99.9498% (502 parts per million (ppm) failure rate) for a 20 x 20 switch array and of 99.99982% (1.75 ppm failure rate) for a 3 x 3 subarray cluster. The array operates by ac-actuation voltage to minimize the disturbing effects by dielectric charging of the actuator isolation layers, as observed in this paper for dc-actuation voltages.

This paper reports on microelectromechanical (MEMS) switch arrays with 5 × 5 and 20 × 20 double-pole single-throw (DPST) switches embedded and packaged on a single chip, which are intended for automating main distribution frames in copper-wire telecommunication networks. Whenever a customer requests a change in his telecommunication services, the copper-wire network has to be reconfigured which is currently done manually by a costly physical re-routing of the connections in the main distribution frames. To reduce the costs, new methods for automating the network reconfiguration are sought after by the network providers. The presented devices comprise 5 × 5 or 20 × 20 double switches, which allow us to interconnect any of the 5 or 20 input lines to any of the 5 or 20 output lines. The switches are based on an electrostatic S-shaped film actuator with the switch contact on a flexible membrane, moving between a top and a bottom electrode. The devices are fabricated in two parts which are designed to be assembled using selective adhesive wafer bonding, resulting in a wafer-scale package of the switch array. The on-chip routing network consists of thick metal lines for low resistance and is embedded in bencocyclobutene (BCB) polymer layers. The packaged 5 × 5 switch arrays have a size of 6.7 × 6.4 mm² and the 20 × 20 arrays are 14 × 10 mm² large. The switch actuation voltages for closing/opening the switches averaged over an array were measured to be 21.2 V/15.3 V for the 5 × 5 array and 93.2 V/37.3 V for the 20 × 20 array, respectively. The total signal line resistances vary depending on the switch position within the array between 0.13 Ω and 0.56 Ω for the 5 × 5 array and between 0.08 Ω to 2.33 Ω for the 20 × 20 array, respectively. The average resistance of the switch contacts was determined to be 0.22 Ω with a standard deviation of 0.05 Ω.

This paper presents a smart row / column addressing scheme for large MEMS rnicroswitch arrays, utilizing the pull-in / pull-out hysteresis of their electrostatic actuators to efficiently reduce the number of control lines. Single-chip 20 x 20 double-switch switch arrays with individually programmable 400 switch elements have been fabricated and the smart addressing scheme was successfully evaluated. The reproducibility of the actuation voltages within the array is very important for this addressing scheme and therefore the influence of effects such as isolation layer charging on the pull-in voltages has also been investigated.

This paper presents a concept for the wafer-scale manufacturing of microactuators based on the adhesive bonding of bulk shape-memory-alloy (SMA) sheets to silicon microstructures. Wafer-scale integration of a cold-state deformation mechanism is provided by the deposition of stressed films onto the SMA sheet. A concept for heating of the SMA by Joule heating through a resistive heater layer is presented. Critical fabrication issues were investigated, including the cold-state deformation, the bonding scheme and related stresses, and the titanium-nickel (TiNi) sheet patterning. Novel methods for the transfer stamping of adhesive and for the handling of the thin TiNi sheets were developed, based on the use of standard dicing blue tape. First demonstrator TiNi cantilevers, wafer-level adhesively bonded on a microstructured silicon substrate, were successfully fabricated and evaluated. Intrinsically stressed silicon dioxide and silicon nitride were deposited using plasma-enhanced chemical vapor deposition to deform the cantilevers in the cold state. Tip deflections for 2.5-mm-long cantilevers in cold/hot state of 250/70 and 125/28 mu m were obtained using silicon dioxide and silicon nitride, respectively. The bond strength proved to be stronger than the force created by the 2.5-mm-long TiNi cantilever and showed no degradation after more than 700 temperature cycles. The shape-memory behavior of the TiNi is maintained during the integration process.

The objective of this research work was to investigate the low temperature gold silicon eutectic bonding of SMA with silicon wafers. The research work was carried out to optimize a bond process with better yield and higher bond strength. The gold layer thickness, processing temperature, diffusion barrier, adhesive layer, and the removal of silicon oxide are the important parameters in determining a reliable and uniform bond. Based on the previous work on Au-Si eutectic bonding, 7 different Si substrates were prepared to investigate the effect of above mentioned parameters. Cantilevers with different bond sizes were prepared from SMA and steel sheets. Afterwards, these cantilevers were bonded to the prepared substrates. The bond yield and bond strength are the two parameters which establish the bond quality. Quantitative analysis was carried out by shear tests. Scanning Electron Microscopy (SEM) and Mapping were used for the analysis of the bond interface and diffusion of elements across the bond. The research has resulted in bonding of SMA cantilevers onto silicon wafers with high yield and bond strength. Steel cantilever can also be bonded by Au-Si eutectic alloy but the processing of the steel sheet is critical. Further research is needed for the fabrication of steel cantilevers and to investigate the stresses across the bond interface. It was found that the amount of gold is the key factor for reliable bonding.

This thesis presents technological advancements in microfluidics. The overall goals of the work are to develop new miniaturized tests for point-of-care diagnostics and robust super-lubricating surfaces for friction reduction. To achieve these goals, novel materials, surfaces and manufacturing methods in microfluidics have been developed.

Point-of-care diagnostic tests are portable miniaturized instruments that downscale and automate medical tests previously performed in the central laboratories of hospitals. The instruments are used in the doctor’s office, in the emergency room or at home as self-tests. By bringing the analysis closer to the patient, the likelihood of an accurate diagnosis, or a quick therapy adjustment is increased. Already today, there are point-of-care tests available on the market, for example blood glucose tests, rapid streptococcus tests and pregnancy tests. However, for more advanced diagnostic tests, such as DNA-tests or antibody analysis, integration of microfluidic functions for mass transport and sample preparation is required. The problem is that the polymer materials used in academic development are not always suited for prototyping microfluidic components for sensitive biosensors. Despite the enormous work that has gone into the field, very few technical solutions have been implemented commercially.

The first part of the work deals with the development of prototype point of-care tests. The research has focused on two major areas: developing new manufacturing methods to leverage the performance of existing materials and developing a novel polymer material platform, adapted for the extreme demands on surfaces and materials in miniaturized laboratories. The novel manufacturing methods allow complex 3D channel networks and the integration of materials with different surface properties. The novel material platform is based on a novel off-stoichiometry formulation of thiol-enes (OSTE) and has very attractive material and manufacturing properties from a lab-on-chip perspective, such as, chemically stable surfaces, low absorption of small molecules, facile and inexpensive manufacturing process and a biocompatible bonding method. As the OSTE-platform can mirror many of the properties of commercially used polymers, while at the same time having an inexpensive and facile manufacturing method, it has potential to bridge the gap between research and commercial production.

Friction in liquid flows is a critical limiting factor in microfluidics, where friction is the dominant force, but also in marine applications where frictional losses are responsible for a large part of the total energy consumption of sea vessels. Microstructured surfaces can drastically reduce the frictional losses by trapping a layer of air bubbles on the surface that can act as an air bearing for the liquid flow. The problem is that these trapped air bubbles collapse at the liquid pressures encountered in practical applications.

The last part of the thesis is devoted to the development of novel low fluidfriction surfaces with increased robustness but also with active control of the surface friction. The results show that the novel surfaces can resist up to three times higher liquid pressure than previous designs, while keeping the same friction reducing capacity. The novel designs represent the first step towards practical implementation of micro-structured surfaces for friction reduction.

We present a one-step, reversible, and biocompatible bonding method of a stiff patterned microfluidic "Biosticker", based on off-stoichiometry thiol-ene (OSTE) polymers [1], to state-of-the-art spotted microarray surfaces. The method aims at improving and simplifying the batch back-end processing of microarrays. We illustrate its ease of use in two applications: a high sensitivity flow-through protein assay; and a DNA-hybridization test. Read-out was performed in a standard highvolume array scanner, and showed excellent spot homogeneity and intensity. The Biosticker is aimed to be a plug-in for existing microarray platforms to enable faster protein assays and DNA hybridizations through mass transport optimization.

This paper introduces and experimentally verifies a method for robust, active control of friction reduction in microchannels, enabling new flow control applications and overcoming previous limitations with regard to sustainable liquid pressure. The air pockets trapped at a

superhydrophobic micrograting during liquid priming are coupled to an actively controlled pressure source, allowing the pressure difference over the air/liquid interface to be dynamically adjusted. This allows for manipulating the friction reduction properties of the surface, enabling active control of liquid mass flow through the channel. It also permits for sustainable air lubrication at theoretically unlimited liquid pressures, without loss of superhydrophobic properties. With the non-optimized grating used in the experiment, a difference in liquid mass flow of 4.8 % is obtained by alternatively collapsing and recreating the air pockets using the coupled pressure source, which is in line with a FE analysis of the same geometry. A FE analysis of a more optimized geometry predicts a mass flow change of over 30%, which would make possible new microfluidic devices based on local friction control. It is also experimentally shown that our method allows for sustainable liquid pressure 3 times higher than the Laplace pressure of a passive device.

We present the design, fabrication, and characterisation of an array of optical slot-waveguide ring resonator sensors, integrated with microfluidic sample handling in a compact cartridge, for multiplexed real-time label-free biosensing. Multiplexing not only enables high throughput, but also provides reference channels for drift compensation and control experiments. Our use of alignment tolerant surface gratings to couple light into the optical chip enables quick replacement of cartridges in the read-out instrument. Furthermore, our novel use of a dual surface-energy adhesive film to bond a hard plastic shell directly to the PDMS microfluidic network allows for fast and leak-tight assembly of compact cartridges with tightly spaced fluidic interconnects. The high sensitivity of the slot-waveguide resonators, combined with on-chip referencing and physical modelling, yields a volume refractive index detection limit of 5 x 10(-6) refractive index units (RIUs) and a surface mass density detection limit of 0.9 pg mm(-2), to our knowledge the best reported values for integrated planar ring resonators.

This paper introduces a robust, high yield, single-step fabrication method for creating densely spaced, miniaturized out-of-plane fluidic interconnecting channels (=vias) in standard poly(dimethylsiloxane) PDMS. Unblocked vias are essential for creating 3D microfluidic networks. Previously reported methods either had low yield, because of residual membranes covering the vias after polymerization, or required complicated extra steps to remove the blocking membranes.

In contrast, our method prevents the formation of residual membranes by inhibition of the polymerization on top of the protuding mold features defining the vias locations. In addition to providing unblocked vias, the inhibition also leaves a flat partially cured, sticky top surface that adheres well to other surfaces and allows self-sealing stacking of several PDMS layers. We demonstrate the new method by manufacturing a densely perforated PDMS membrane and a large scale integrated (LSI) 3D PDMS microfluidic channel network. Our method enables batch manufacturing of complex fluidic devices by speeding up and simplifying the fabrication of complex microfluidic components in standard PDMS.

This paper presents an uncomplicated high-yield fabrication process for creating large-scale integrated (LSI) 3-D microfluidic networks in poly(dimethylsiloxane) (PDMS). The key innovation lays in the robust definition of miniaturized out-of-plane fluidic interconnecting channels (=vias) between stacked layers of microfluidic channels in standard PDMS. Unblocked vias are essential for creating 3-D microfluidic networks. Previous methods either suffered from limited yield in achieving unblocked vias due to residual membranes obstructing the vias after polymerization, or required complicated and/or manual procedures to remove the blocking membranes. In contrast, our method prevents the formation of residual membranes by inhibiting the PDMS polymerization on top of the mold features that define the vias. In addition to providing unblocked vias, the inhibition process also leaves a partially cured, sticky flat-top surface that adheres well to other surfaces and that allows self-sealing stacking of several PDMS layers. We demonstrate the new method by manufacturing a densely perforated PDMS membrane and an LSI 3-D PDMS microfluidic channel network. We also characterize the inhibition mechanism and study the critical process parameters. We demonstrate that the method is suitable for structuring PDMS layers with a thickness down to 10 mu m.

We introduce and have successfully tested an uncomplicated polydimethylsiloxane (PDMS) compatible method for batch manufacturing vertical microfluidic interconnects via a surface inhibition of cationic photopolymerization. The yield of the maskless method is 100%. Moreover, the method enhances bond strength with subsequently laminated polymer layers.

We present an easy to use, rapid fabrication platform for microfluidic systems, based on micro-molding of novel thiolene based polymer formulations. The novel fabrication platform addresses major drawbacks of PDMS by allowing large freedom in material and surface properties, including: (photo)patterning of stable surface modifications, bonding without plasma treatment, rapid UV or thermal curing, variable E-modulus, minimized leaching of uncured components [1] and suppressed non-specific binding of biomolecules [2]. This process is potentially suited for both rapid prototyping in the laboratory and medium-scale commercial production, bridging the “development gap”.

In this article we introduce a novel polymer platform based on off-stoichiometry thiol–enes (OSTEs), aiming to bridge the gap between research prototyping and commercial production of microfluidic devices. The polymers are based on the versatile UV-curable thiol–ene chemistry but takes advantage of off-stoichiometry ratios to enable important features for a prototyping system, such as one-step surface modifications, tuneable mechanical properties and leakage free sealing through direct UV-bonding. The platform exhibits many similarities with PDMS, such as rapid prototyping and uncomplicated processing but can at the same time mirror the mechanical and chemical properties of both PDMS as well as commercial grade thermoplastics. The OSTE-prepolymer can be cast using standard SU-8 on silicon masters and a table-top UV-lamp, the surface modifications are precisely grafted using a stencil mask and the bonding requires only a single UV-exposure. To illustrate the potential of the material we demonstrate key concepts important in microfluidic chip fabrication such as patterned surface modifications for hydrophobic stops, pneumatic valves using UV-lamination of stiff and rubbery materials as well as micromachining of chip-to-world connectors in the OSTE-materials.

We present a low temperature (< 37°C) wafer-scale microfluidic batch packaging process using covalent, dry bonding of offstoichiometry thiol-ene polymers (OSTE), enabling rapid, bio-compatible integration of fluidics on wafer-scale in combination with excellent polymer properties.