Search

Thin strips of electrochemically deposited nanocrystalline nickel-iron with thicknesses of 320 or 330 µm are modified by defined grinding. Small changes in the cutting depth and the variation of the grinding process, up cut or down cut, result in different surface states. X-ray diffraction provides the analyses of the microstructures and residual stresses on the surfaces. In the initial state, the grain sizes have an average value of 9.3 nm, the micro strains 0.74% and the residual stresses predominantly values in the low-pressure range. Up grinding with the smallest depth of cut 1 µm causes the lowest compressive residual stresses at workpiece surface due to cold plastic deformation. Larger cutting depths and surface temperatures reduce the mechanical effects. Then prevailing thermal effects cause tensile residual stresses through thermoplastic deformation and through changes in the microstructure, which can be observed by grain enlargements and decreases in micro strains. However, the recovery and recrystallization processes are only partial. Down grinding with a cutting depth of 3 µm thus leads to a maximum grain size increase to 23.4 nm and a maximum decrease in micro strain to 0.41% as well as to maximum residual stresses of 880 MPa.

A new, scalable process chain for the fabrication of curved micro-structured metallic tools is developed and evaluated. Arrays of arrows, circles, semicircles and rings with final lateral dimensions of 124 to 819 µm are realised on the tools and successfully transmitted in one process step to stainless steel workpieces with a functional area of 6.5 cm2 using pulsed electrochemical machining. Photolithography-etching or micromilling are applied as initial micro-structuring processes, resulting in micro-structured master forms. These forms are copied into reusable silicon forms. This is followed by epoxy casting and electroforming to obtain the final tools. The tools are made of Nickel and have a diameter of 34 mm. Whilst micromilling, photolithography, silicon casting, epoxy casting and electroforming copy the structures very precisely, the wet etching process induces a widening of the dimensions due to the isotropic character of the process. The advantage of the process chain is the reusability of the master as well as of the silicone forms, which can be copied very precisely and easily with scalable processes to get precision tools with relatively large micro-structured areas. The reusability of the forms makes the fabrication of micro-structured tools relatively cost-efficient. The use of photolithography as the initial structuring process enables the generation of arbitrary, user-defined geometries for the micro-structures on the tool surface. The process chain described has the potential to fabricate lateral structure sizes on tools down to one micrometre.

Nanocrystalline nickel-iron layers are produced electrochemically on copper discs by varying the current density and then annealed in a vacuum furnace at a temperature range between 200 and 800 °C. Grain size, iron content, texture and microstrain of the microstructure are primarily characterized by X-ray diffraction (XRD). Instrumented indentation tests and microbending tests for mechanical characterization are carried out. The iron contents of the investigated layers are 5.7, 8.8, 13.5 and 17.7 wt.-%. By varying the annealing temperature, the reduction of the microstrains is initiated at 200 °C and ends at a temperature of about 280 °C. Primary recrystallization starts slightly higher at 220 °C and is completed at 300 °C. With higher iron content, the indicated temperatures shift to slightly higher values. Indentation modulus, Young's modulus, indentation hardness and strength change considerably after the annealing treatment. Fracture strain at the edge, as a measure of ductility, decreases immediately after annealing at 200 °C to 0 %. Low annealing temperatures occurring before the beginning of primary recrystallization lead to an increase in indentation hardness and 0.01-% offset bending yield strength Rp0.01∗ as compared to the electrochemically deposited initial state. After annealing at high temperatures, the mechanical parameters are mostly below the initial values for electrochemical deposition. Hall-Petch (HP) behavior is observed for Rp0.01∗, both for the electrochemically deposited specimens down to almost 6 nm and for the specimens annealed at high temperatures. Specimens annealed at low temperatures deviate from the HP straight line to higher values. In this case, an increase in strength is assumed to be due to the very small nanocrystalline (nc) grain sizes, segregation at the grain boundaries and a decrease in dislocation density. Indentation hardness measurements show almost no dependence on D−0.5 for the electrochemically deposited specimens and also for annealed specimens below 30nm grain size. Above 30nm, the indentation hardness values are considerably higher than for the HP straight line. Overall, the hardness and strength values of the nc specimens, electrochemically deposited or additionally annealed, are significantly higher than those of the microcrystalline (mc) specimens.

Nanostructuring is a promising and successful approach to tailor functional layers and to improve the characteristics of biosensors such as signal transmission and tighter cell-surface coupling. One of the major objectives in biosensing and tissue engineering is the development of interfaces that mimic the natural environment of biosystems composed of extracellular matrix biomolecules. Nevertheless, effective techniques to reconstruct the random distribution of these biomolecules are still not well established. For this reason, the presented work demonstrates different methods based on nanoimprint lithography to replicate randomly distributed natural nanostructures with complex geometries into different polymers and metals. The fidelity of the replicated nanostructures has been evaluated by atomic force microscopy and the attributes of the fabrication processes have been discussed. Finally, different replication techniques have been combined for the biomimetic nanostructuring of the dielectric passivation layer as well the metal electrode surface to develop novel whole-surface-nanostructured microelectrode arrays.

A bacterial cellulose (BC) nanofibril network is modified with an electrically conductive polyvinylaniline/polyaniline (PVAN/PANI) bilayer for construction of potential electrochemical biosensors. This is accomplished through surface-initiated atom transfer radical polymerization of 4-vinylaniline, followed by in situ chemical oxidative polymerization of aniline. A uniform coverage of the BC nanofiber with 1D supramolecular PANI nanostructures is confirmed by Fourier transform infrared, X-ray diffractogram, and CHN elemental analysis. Cyclic voltammograms evince the switching in the electrochemical behavior of BC/PVAN/PANI nanocomposites from the redox peaks at 0.74 V, in the positive scan and at -0.70 V, in the reverse scan, (at 100 mV·s-1 scan rate). From these redox peaks, PANI is the emeraldine form with the maximal electrical performance recorded, showing charge-transfer resistance as low as 21 Ω and capacitance as high as 39 μF. The voltage-sensible nanocomposites can interact with neural stem cells isolated from the subventricular zone (SVZ) of the brain, through stimulation and characterization of differentiated SVZ cells into specialized and mature neurons with long neurites measuring up to 115 ± 24 μm length after 7 days of culture without visible signs of cytotoxic effects. The findings pave the path to the new effective nanobiosensor technologies for nerve regenerative medicine, which demands both electroactivity and biocompatibility.

Microbial cellulose paper treated with polyaniline and carbon nanotubes (PANI/CNTs) can be attractive as potential flexible capacitors in terms of further improvements to the conductivity and thermal resistance. The interactions between PANI and CNTs exhibit new electrochemical features with increased electrical conductivity and enhanced capacity. In this study, PANI/CNTs was incorporated into a flexible poly(4-vinylaniline)-grafted bacterial cellulose (BC/PVAN) nanocomposite substrate for further functionalization and processability. PANI/CNTs coatings with a nanorod-like structure can promote an efficient ion diffusion and charge transfer, with a significant enhancement of the electrical conductivity after CNTs reinforcement of 1 order of magnitude up to (1.0 ± 0.3) × 10–1 S·cm–1. An escalating improvement of the double charge capacity (∼54 mF) of the grafted BC nanocomposites was also detected through electrochemical analysis. The multilayered electrical coatings also reinforce the thermal resistance, ...

Nanocrystalline nickel-iron microstructures, manufactured by means of an electrochemical deposition process via electrolyte solutions, were investigated to collect relevant information for the use of nickel-iron for micro-components. By varying the current density, nickel-iron coatings can be set to show specific grain sizes, iron content, lattice strains and textures. Uniform microstructures exist in each of the deposited nickel-iron coatings. The grain sizes determined using x-ray analysis (XRD) cover a range of 6 to 17 nm. XRD texture analyses parallel to the deposition plane resulted in {111} and {200} orientations. To characterize the material's mechanical properties indentation hardness measurements and micro-bending tests were performed. For a 0.01 %-offset bending yield strength (Rp0.01*), grain sizes of 6 to 17 nm clearly demonstrate Hall-Petch behavior. In addition, the investigations show lower work hardening and lower values for remaining edge strain at fracture for decreasing grain size. In contrast to Rp0.01*, the Young's modulus, indentation modulus, indentation hardness values and the bending strength, within their scatter bands, all remain largely unaffected by the different microstructures. Overall, all measured strength and hardness values of the considered nanocrystalline microstructures are very high in comparison to microcrystalline microstructures.

As a first step towards the production of functional cell sheets applicable for the regeneration of gut muscle layer, microstructured bacterial cellulose (mBC) was assessed for its ability to support the growth of enteric nervous system (ENS) and gut smooth muscle cells (SMCs). To improve the cellular response, mBC was modified with silk sericin (SS) which has renowned abilities in supporting tissue regeneration. While SS did not impair the line structures imparted to BC by PDMS templates, similarly to the patterns, it affected its physical properties, ultimately leading to variations in the behavior of cells cultured onto these substrates. Enabled by the stripes on mBC, both SMCs and ENS cells were aligned in vitro, presenting the in vivo-like morphology essential for peristalsis and gut function. Interestingly, cell growth and differentiation remarkably enhanced upon SS addition to the samples, indicating the promise of the mBC-SS constructs as biomaterial not only for gut engineering, but also for tissues where cellular alignment is required for function, namely the heart, blood vessels, and similars.

Purpose The purpose of this paper is to fabricate a new Cu-Sn-Ni-Cu interconnection microstructure for electromigration studies in 3D integration. Design/methodology/approach The Cu-Sn-Ni-Cu interconnection microstructure is fabricated by a three-mask photolithography process with different electroplating processes. This microstructure consists of pads and conductive lines as the bottom layer, Cu-Sn-Ni-Cu pillars with the diameter of 10-40 μm as the middle layer and Cu conductive lines as the top layer. A lift-off process is adopted for the bottom layer. The Cu-Sn-Ni-Cu pillars are fabricated by photolithography with sequential electroplating processes. To fabricate the top layer, a sputtered Cu layer is introduced to prevent the middle-layer photoresist from being developed. With the final Cu electroplating processes, the Cu-Sn-Ni-Cu interconnection microstructure is successfully achieved. Findings The surface morphology of Cu-Sn pillars consists of densely packed clusters which are formed by an ordered arrangement of tetragonal Sn grains. The diffusion of Cu atoms into the Sn phases is observed at the Cu/Sn interface. Furthermore, the obtained Cu-Sn-Ni-Cu pillars have a flat surface with an average roughness of 13.9 nm. In addition, the introduction of Ni layer between the Sn and the top Cu layers in the Cu-Sn-Ni-Cu pillars can mitigate the diffusion of Cu atoms into Sn phases. The process is verified by checking the electrical performance using four-point probe measurements. Originality/value The method described in this paper which combined a three-mask photolithography process with sequential Cu, Sn, Ni and Cu electroplating processes provides a new way to fabricate the interconnection microstructure for future electromigration studies.

Magnetic position sensors with highest accuracy of 700 nm and a bidirectional repeatability of 110 nm were fabricated based on a new architecture and process technology. The sensor concept relies on tunnel magneto resistive (TMR) sensing elements which are deposited and structured on silicon wafers. The TMR elements are arranged to segmented chains with connections in between to form one incremental sensor and one absolute sensor per die. The TMR structures sense the magnetic poles of up to 25.6 mm long absolute and incremental tracks on the scale bar which moves in parallel along the surface in front of the sensor die. Key for the high precision of the sensor is the extreme shrink of the TMR sensing structures as well as the usage of very small magnetic poles on the scale bar with a pole width of 50 $\mu$m and a pole pitch of 100 $\mu$m. Due to the low magnetic field strength of the miniaturized magnetic poles the scale bar has to move very close with a distance of < 30 $\mu$m to the surface of the sensor. Based on that, a conventional chip connection by flip chip or wire bonding cannot be used here. Instead of this all interconnects are routed vertically by using though silicon vias (TSVs) to the back side of the sensor dices and are redistributed there to an area array pattern. In order to simplify the overall process and to avoid impacts of the TSV implementation to the TMR process the TSVs were first fabricated as blind plugs into the blank wafers before the TMR structures were generated.The final sensor dices have a thickness of 100 $\mu$m and are mounted by flip chip bonding with their back side to ceramic interposers. Due to a special arrangement of the magnetic poles on the absolute track of the scale bar a true power on position determination is possible without reference check.

Bacterial cellulose (BC) fibers are chemically functionalized with poly(4-vinylaniline) (PVAN) interlayer for further enhancement of electrical conductivity and cell viability of polyaniline (PANI) coated BC nanocomposites. PVAN is found to have promoted the formation of a uniform PANI layer with nanofiber- and nanorod-like supramolecular structures, as an overall augmentation of PANI yield. Compositional and microstructural analysis indicates a PVAN/PANI bilayer of approximately 2 μm formed on BC. The solid-state electrical conductivity of such synthesized BC nanocomposites can be as high as (4.5 ± 1.7) × 10−2 S cm−1 subject to the amounts of PVAN chemically embraced. BC/PVAN/PANI nanocomposites are confirmed to be thermally stable up to 225 °C, and no signs of cytotoxicity for SVZ neural stem cells are detected, with cell viability up to 90% on BC/PVAN/PANI membranes. We envisage these new electrically conductive BC/PVAN/PANI nanocomposites can potentially enable various biomedical applications, such as for the fabrication of bioelectronic interfaces and biosensors.

This paper presents the conception, the fabrication, first characterization results as well as application scenarios for a new position sensor system architecture based on tunnelmagnetoresistive (TMR) technology. The new concept aims for improving the precision of magnetic position sensing by miniaturization of both magnetic scale and magnetic field sensing circuitry. The concept is enabled by though silicon vias (TSVs) which allow to route the signals from the sensing elements though the chip directly to its back side. Since interconnection structures like wire bond loops are avoided at the front side of the sensors the here located sensing elements can be brought into very close distance to the magnetic stimulus. The TSV based chip architecture enables a successful sensor implementation based on hard magnetic CoP poles with a width of 50 µm and a periodic length of 100 µm as well as a corresponding magnetic readout circuitry utilizing TMR junctions with a diameter of 3 µm. The fabricated sensor chips support the readout of two adjacent magnetic scales which are used as incremental and absolute track. Based on that, high precision position measurements with better than 700 nm accuracy and less than 110 nm bidirectional repeatability could be shown on a scale with 25 mm travel length. The system supports true power on functionality, meaning that the absolute position on the full scale is given immediately after power on without any reference check.

Multielectrode array (MEA) technology is used as an extracellular recording method to investigate the electrical activity of complex excitable cell networks and tissue slices. In this context, an array of single-contactable, sensing electrodes record the electrical field potentials induced by the ion flux across the cell membranes. Therefore, MEAs are an ideal tool to investigate network activities for prolonged periods. Still, MEA technology suffers from low-signal-to-noise ratios caused by a dissatisfied cell-electrode contact, thus revealing only limited measurements. To improve cell recording, a tight cell-electrode contact is inalienable. This can be achieved by three-dimensional micro- or nanostructures on top of the sensing electrodes. Beside the fact of increasing the electrochemically active surface area, thus leading to a decrease in the overall chip impedance, the nano-sized structures can also trigger an engulfment process of the cells. By minimizing the gap between cell and electrode, a high seal resistance can be achieved which in return results in recording of higher signal amplitudes. In this work, electrochemical concepts are used for fabrication as well as for characterizing the chips and to investigate the cell-electrode interaction. The developed process allows the fabrication of half-structured MEAs with different three-dimensional nanostructure shapes, geometries and pitch lengths and is mainly based on thermal nanoimprint lithography (NIL), gold electroplating and microstructuring techniques. During thermal NIL a customized, nanostructured master mold is pressed into a polymer resist of a wafer substrate, thus creating a negative copy of the master´s nanostructures. The subsequent electroplating step can be adjusted in a way, that it fills or overgrows the NIL templates, thereby creating different shapes. Photolithography, chemical vapor deposition and etching steps are used to fabricate the overall MEA geometry. Cyclic voltammetry as well as electrochemical impedance spectroscopy have been applied to characterize the effect of different nanostructure geometries on charge transfer, double-layer capacitance and impedance of the MEA electrodes. Compared to unstructured electrodes, charge transfer and double-layer capacitance of the nanostructured electrodes are increased, whereas the impedance of the nanostructured electrodes are decreased. These results can directly be related to an increase of the electrochemically active surface area and vary with the investigated nanostructure layout. To examine the effect of the nanostructures on cell-electrode coupling in detail and to quantify cell adhesion, impedance sensing at a fixed frequency of 1 kHz has been performed using the impedance-stable human embryonic kidney cell line HEK 293. Impedance values have been measured with and without cells. Due to the chip layout where non- and nanostructured electrodes have been included on the chip, the relative change of the impedance values could directly be correlated with cell-electrode adhesion. By this, a significant increase or decrease of cell-electrode coupling depending on the nanostructure layout could be demonstrated. For verification, action potential recordings with neural stem cells of the subventricular zone of postnatal mice have been performed, showing a distinct increase of the recorded signal amplitudes of the nanostructured electrodes compared to unstructured electrodes of the same chip. The latter might be correlated to an engulfment process of the cells. Figure: Left: Impedance measurement to quantify cell-electrode adhesion. Right: SEM picture of attached SVZ cells on top of overgrown pillar structures (Inset: Magnification, scale bar: 2 µm). Figure 1

In biomedical approaches cell culture models do often not fully represent their biological counterparts. Often the methods used do not completely mimic the in-vivo situation, either by using only single-cell-type culture approaches, or by using inadequate culture conditions. We therefore developed a variable system based on individual modules to simulate in vitro equivalent cell-barriers (e.g. for mucous layers). This system allows the growth of different communicating cell types in micro channels. Hot embossing is used to fabricate the micro structured polymer sheets. The stamp for hot embossing is fabricated by UV-lithography/electroforming or by micro milling. The system consists of a container with micro fluidic modules and a pump-system for a continuous medium-supply. An individual module is made of two micro-structured polycarbonate-sheets separated by a transmissible polycarbonate membrane. The two sheets are arranged orthogonally to induce a cross flow. The system is highly variable by channel-geometry (height and width), capacity (number of micro fluidic modules), and pore sizes of the transmissible membranes. In a first approach we simulated the intestinal mucosa. Epithelial cells and primary neurons of the enteric nervous system were cultured on both sides of the transmissible membrane within the two different compartments. So the cells could be supplied with two different media. We kept a mono-culture of primary neurons or epithelial cells for 5 days and a co-culture between these two cell-types was established for 4 days. The proposed system delivers a sophisticated model for the simulation of various epithelial layers which takes the specific biological properties into account.

Surface quality and biocompatibility were critical properties of bone scaffolds. Fabrication and biological properties of porous hydroxyapatite (HA) scaffolds made by extrusion deposition method (EDM) and microwave sintering were investigated in this paper. The scaffolds with side length of 3.61 mm, height of 0.51 mm, pore size of 139 µm, Ra of 1.67 µm, and Rmax of 10.5 µm were used as substrates for osteosarcoma cells (SAOS 2) culturing to investigate the scaffolds' biological properties. Surface metrology and morphology before and after cell culture were measured to approach the interaction of cell culture with the scaffolds. The results showed that the HA scaffolds made by EDM had good biocompatibility and the surface metrology of scaffolds does not have an obvious change under cell culture even for 21 days. SAOS-2 could attach to and grew well on scaffolds even after culturing for 21 days. And Ra and Rmax of scaffolds surfaces were 1.67 ± 0.59 µm and 10.5 ± 3.9 µm before cell culture and 1.64 ± 0.62 µm and 10.6 ± 4.5 µm after cell culture. EDTA have significant influences upon the HA grains, and the cells themselves also seem to lead to subtle scaffold degradation.

The effect of pulse plating (PF) and direct current (DC) plating on the magnetic properties and grain size of electroplated NiFe films for the application in magnetic microsensors, i.e., as integrated magnetic concentrator, has been studied. In order to further improve magnetic properties additional subsequent thermal annealing experiments were carried out with chosen films. A sulphate-based NiFe electrolyte containing various additives operated at a pH of 3.5 and a temperature of 50 °C was used. The softmagnetic NiFe films were deposited at a thickness of >10 µm on silicon substrates with a sputtered 200 nm thick Cu seed layer and a 50 µm high photoresist mould. The composition and magnetic properties were measured by energy dispersive X-ray spectroscopy (EDX) and vibrating sample magnetometer (VSM), respectively. The morphology was investigated by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The composition of the fabricated fcc NiFe films ranged from 3 to 42 wt% Fe with a good adhesion. The as-plated NiFe exhibited nanocrystalline grain sizes ranging from 12 to 18 nm with a coercivity as low as 16 A m−1. It was found that the grain size is generally higher at a lower iron content. However, pulse forward (PF) plating favours a refined grain size over DC plating which can be attributed to an increased nucleation rate caused by the high pulse current densities (high overpotential). By applying a thermal annealing for 2 h at 300 °C in a vacuum oven the coercivity of NiFe samples with ∼18.5 wt% Fe could be further reduced to 6 A m−1.

Repeated photolithographic and etching processes allow the production of multileveled polymer microstructures that can be used as templates to produce bacterial cellulose with defined surfaces on demand. By applying this approach, the bacterial cellulose surface obtains new properties and its use for culturing neural stem cells cellulose substrate topography influences the cell growth in a defined manner.

Several electroplating conditions have been investigated systematically using a rotating hull cell to find appropriate process conditions for the electroplating of soft magnetic NiFeMo. NiFeMo discs with a diameter of 5 mm were electroplated on prestructured 4″ Si wafers with sputtered 10 nm of Cr and 200 nm of Cu acting as adhesion and seed layers, respectively. It was possible to fabricate 10 micrometer thick, as-plated NiFeMo structured layers with good adhesion and a Mo content ranging from 1 to 16 wt%. XRD measurements of NiFeMo revealed an estimated grain size well below NiFe along with a lattice expansion exceeding the common limits of NiFe. So far compact NiFeMo discs with a slight anisotropic, as-plated coercivity of 14.4 A/m have been fabricated. This low coercivity allows additional magnetic applications using electroplated material in an integrated process.

The objective of this research was to study the influence of electroplating parameters on electrodeposit characteristics for the production of nickel (Ni) and nickel–iron (Ni–Fe) microparts by photoelectroforming. The research focused on the most relevant parameter for industry, which is the current density, because it determines the process time and the consumed energy. The results of the Ni and Ni–Fe characterisations can be divided into two aspects closely linked with each other: the morphology and the hardness.

The renaissance of the traditional contactless conductivity detec-tion (CCD) for ion analysis by transferring its principle to microchips for modern lab-on-a-chip applications is calling for further improvements to make use of all its inherent advantages. This contribution summarizes some progress in basic understanding, technological development and extended application.

Permalloy (Ni 81 Fe 19 ) films and foils were fabricated by means of electroplating. Two different types of samples were produced, (i) a patterned permalloy film on a Si wafer (type 1) and (ii) a NiFe foil (type 2), which was separated from the substrate after deposition. The samples were characterized employing magnetic force microscopy (MFM), transmission electron microscopy (TEM) and electron-backscatter diffraction (EBSD). On the foil type sample, MFM reveals a maze domain pattern, and on the structured samples (type 1), a Landau domain pattern is obtained. EBSD enables the identification of the permalloy Kikuchi pattern without the effect of a substrate. The analysis reveals randomly oriented grains with a narrow size distribution.

Direct- and pulse-reverse current electrodeposition processes and their influence on the spatial nickel-iron alloy composition are described. High-aspect ratio gear wheel structures are electroplated from a nickel sulphate/iron sulphate bath. Subsequent determination of the iron content at the gear-wheels cross section using scanning electron microscopy demonstrates that pulse reverse plating results in an uniform alloy composition across different structure dimensions. By contrast, local variations in iron content were observed in case of direct current plating.

Several specific electroplating parameters are varied to develop a manufacturing process for nickel-iron coatings with low residual stresses and favourable structures and hardness values. Here, the produced coating conditions on the surface are characterised according to alloy compositions, microstructures, residual stresses, texture and microhardness as well as the elastic indentation modulus. The manufacture of the coatings was carried out in a laboratory electroplating plant. The process parameters are: electroplating in electrolytic baths with and without saccharin as an additive, with different iron content as well as with various current parameters. The results show significant influences of saccharin, as a bath additive, and of the pulse frequency during the reverse current pulse procedure on the coating conditions. Supplementary investigations are scheduled for determining the distributions of the conditions through the coating thickness. Similarly, micromechanical tests are planned. Process parameters with optimal conditions can then be selected from the determined process-condition property relation. This is to subsequently serve as the basis for improving the manufacture of micro gear-wheels. The micro gear-wheels are produced by electroforming using the direct LIGA process. Einfluss von Galvanikprozessparametern auf die Zustande abgeschiedener Nickel-Eisen-Schichten Zur Entwicklung eines Herstellungsprozesses fur eigenspannungsarme Nickel-Eisen-Schichten mit gunstigen Gefugen und Hartezustanden werden gezielt einige Galvanikprozessparameter variiert. Dabei erzeugte Schichtzustande werden an der Oberflache nach Legierungszusammensetzungen, Gefugen, Eigenspannungs-, Textur- und Mikrohartezustanden sowie elastischen Eindringmoduln charakterisiert. Das Herstellen der Schichten findet in einer Laborgalvanikanlage statt. Prozessparameter sind das Galvanisieren in Elektrolytbadern mit und ohne Saccharin als Badzusatz, mit unterschiedlichen Eisengehalten sowie mit verschiedenen Stromparametern. An den Schichten ermittelte Ergebnisse zeigen signifikante Einflusse von Saccharin als Badzusatz und von der Pulsfrequenz beim bipolaren Pulsstromverfahren auf die Schichtzustande. Erganzende Untersuchungen zur Ermittlung der Verteilungen der Zustande uber der Schichthohe sind vorgesehen. Ebenso sind mikromechanische Prufungen geplant. Aus dem ermittelten Prozess-Zustands-Eigenschaftszusammenhang lassen sich dann Prozessparameter mit optimalen Zustanden auswahlen. Diese sollen spater als Grundlage zur verbesserten Herstellung von Mikrozahnradern dienen. Gefertigt werden die Mikrozahnrader durch Galvanoformung nach dem Direkt-LIGA-Verfahren.

Metals are vital building blocks for MEMS. Pure metals and metal alloys are employed in microsystem design to achieve a wide array of functionality. Common examples include electrical conductors, mechanical structures, magnetic elements, thermal conductors, optical reflectors, and more. In this chapter, additive processes for metals are discussed in the context of their application in MEMS. Particular attention is paid to MEMS-centric processing technologies, where thick metal layers are often required. Basic guidelines are given for material selection, and fabrication recipes are provided as a starting point for process development.

A novel method to manufacture two-dimensional bundles of single mode optical fibres at sub-micron pitch accuracy is presented. An array of holes, each surrounded by four electrodes has been produced using the UV-LIGA process. Electrostatic fields between the electrodes and a metal coated optical single mode fibre inserted into such a hole, are used to position the fibre. The position of the fibre core can be monitored and moved to its ideal position. Using thermal or UV activation a cement filling the hole around the fibre is cured to fix the fibre in place.