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The invention relates to a method for making a 3D nanostructure having a nanosubstructure, comprising the steps of:i) providing a mold comprising at least one sharp concave corner;ii) conformational depositing at least one structural material in the sharp concave corneriii) isotropically removing structural material;iv) depositing at least one other structural material;v) removing earlier deposited structural material;vi) forming a nanosubstructure; andvii) removing the mold thereby providing the 3D nanostructure having the nanosubstructure.

A method of manufacturing a plurality of through-holes (132) in a layer of material by subjecting the layer to directional dry etching to provide through-holes (132) in the layer of material; For batch-wise production, the method comprises - after a step of providing a layer of first material (220) on base material and before the step of directional dry etching, providing a plurality of holes at the central locations of pits (210), - etching base material at the central locations of the pits (210) so as to form a cavity (280) with an aperture (281), - depositing a second layer of material (240) on the base material in the cavity (280), and - subjecting the second layer of material (240) in the cavity (280) to said step of directional dry etching using the aperture (281) as the opening (141) of a shadow mask.

We present results from a robust numerical model that predicts the deformation in electrokinetically operated micro- and nanofluidic channels with a step change in conductivity. This model accounts for the coupling between pressure and the change in hydraulic resistance from deformation. Using this model we unearth a relationship between the final deformation and the initial pressure and use it to predict deformation in typical micro- and nanofluidic systems and reveal that significant deformation orCha even channel collapse can occur under ordinary operating conditions.

The experimental results show that these novel batch fabricated scanning Hall probe can be used in tapping mode AFM, and have the capability of measuring the absolute value of the magnetic field distribution. Further reduction of resolution can be achieved by improvement of the instrumentation, and is ultimately limited only by the dimensions of the Hall cross. Since with corner lithography sub-100 nm linewidths are possible, these new probes are promising candidates for routine quantitative analysis of magnetic stray fields, such as above permanent magnets and magnetic recording heads.

The shuffle motor is a linear electrostatic stepper motor employing a mechanical transformation to obtain large forces and small steps. A model has been made to calculate the step size and the driving voltage as a function of the load force and the motor geometry. The motor consists of three polysilicon layers and has been fabricated using surface micromachining. Tests show an effective step size of about 85 nm and a produced force of 43 μN at 40 V driving voltage.

A novel method has been developed to cavitate aqueous solutions, which is called electrocavitation. An axial voltage is applied in a nanochannel containing an aqueous solution with a stepwise conductivity gradient. A combination of electrical and viscous forces then generates a tension in the solution which, at sufficiently low pressures, causes it to cavitate. Measurement of the current during the experiment as well as optical observation provides knowledge on the time and axial position of cavitation, after which the pressure at the cavitation position can be calculated from a theoretical model in which also the ζ-potential is inserted, which is separately determined from electroosmotic flow experiments. It is found that generally the cavitation position coincides with the position of the conductivity step. In several experiments the cavitation pressure in successive experiments on the same channel became increasingly lower, suggesting a gradual removal of cavitation nuclei from the system. We calculated that pressures as low as −1630 bar ±10 % have been reached, close to theoretically predicted pressures for homogeneous cavitation. The platform performs reliably and can be easily controlled.

Due to the smoothness of the surfaces in surface micromachining, large adhesion forces between fabricated structures and the substrate are encountered. Four major adhesion mechanisms have been analysed: capillary forces, hydrogen bridging, electrostatic forces and van der Waals forces. Once contact is made adhesion forces can be stronger than the restoring elastic forces and even short, thick beams will continue to stick to the substrate. Contact, resulting from drying liquid after release etching, has been successfully reduced. In order to make a fail-safe device stiction during its operational life-time should be anticipated. Electrostatic forces and acceleration forces caused by shocks encountered by the device can be large enough to bring structures into contact with the substrate. In order to avoid in-use stiction adhesion forces should therefore be minimized. This is possible by coating the device with weakly adhesive materials, by using bumps and side-wall spacers and by increasing the surface roughness at the interface. Capillary condensation should also be taken into account as this can lead to large increases in the contact area of roughened surfaces.

This paper presents the realization of micrometer sized silicon nitride tetrahedra with well-defined angles that are folded out of a planar geometry using capillary forces. The required specific three-dimensional shape is achieved by a well-defined folding sequence. Using the favorable properties of the recently developed corner lithography technique, a programmable stop hinge is micro-machined by etching specifically defined intersection planes of the silicon mold. Tetrahedra were successfully folded by capillarity validating this new technique. The demand for such a microstructure has become very large since it can form the essential basic element for future three-dimensional data storage systems.

Since the early 1970s there is a notion that water near polar or charged surfaces is somehow ordered or structured, leading to a so called structural component of the disjoining pressure.

The invention relates to a method for making a 3D nanostructure having a nanosubstructure, comprising the steps of : i) providing a mold comprising at least one sharp concave corner; ii) conformational depositing at least one structural material in the sharp concave corner; iii) isotropically removing structural material; iv) depositing at least one other structural material; v) removing earlier deposited structural material; vi) forming a nanosubstructure; and vii) removing the mold thereby providing the 3D nanostructure having the nanosubstructure.

The present invention provides a microneedle, comprising a shaft of a monocrystalline material having at least three walls which are formed by a crystal plane of the monocrystalline material; and a tip connected to an end of the shaft comprising at least three walls which are formed by a crystal plane of the material. The material is preferably silicon. Two of the walls of the tip are formed by the same crystal planes as two walls of the shaft. These two walls are formed by a crystal plane. Preferably, three walls of the tip are formed by a crystal plane.

The invention relates to a method for making a 3D nanostructure having a nanosubstructure, comprising the steps of : i) providing a mold comprising at least one sharp concave corner; ii) conformational depositing at least one structural material in the sharp concave corner; iii) isotropically removing structural material; iv) depositing at least one other structural material; v) removing earlier deposited structural material; vi) forming a nanosubstructure; and vii) removing the mold thereby providing the 3D nanostructure having the nanosubstructure.

Nanowires of vaious lengths and widths have been fabricated using a wafer-scale shadow mask with deposition windows, or nanoslits, created with focused ion beam machining. Metallic nanowires with widths down to 50 nm and lengths up to 100 micrometers have been realized. Measurements of electrical I-V characteristics show linear behavior of nanowires with widths and thickness each around 50 nm

1D nanochannels are fabricated by direct bonding between the silicon wafer containing the nanochannels, microchannels, access holes and the blank thin glass of 170 µm thickness. The thin glass wafers are used as channel covers because of their appropriate thickness for use with coverglass corrected water immersion lenses. As the nanochannel chips are used on an inverted microscope, access holes are created in the silicon wafer so that polyimide is good selection for protection during deep etching of the macro holes. Fabricated nanochannels with 50 nm depth were successfully filled with low concentration of solutions Alexa 488 could be observed through fluorescence microscopy. These nanochannels are promising for mobility studies of single molecules such as quantum dots.

Keywords: Nanochannels, capillarity, viscosity

This paper focuses on the development of highly sensitive calorimetric flow sensors. Both the hydrodynamics of the flow channel, as well as the heat transfer are analyzed in detail. With the expressions for the hydraulic resistance of the flow channel and the hydraulic system requirements for the flow sensor, it is possible to optimize the design of the flow channel. It is theoretically shown why for small ν the calorimetric flow sensor output is linear in ν. Also it follows from theory that for a symmetrical configuration, in this linear regime the heater temperature is independent of ν for constant heating power. This suggests that for low Reynolds Number, King's Law has to be modified. Different configurations and methods are analyzed: absolute, differential, two beam, three beam, CPA, CTA and TBA. The latter is a real thermal balance measurement and allows the use of non-linear sensing elements. From our experience with acoustical measurements it is possible to estimate practical attainable sensitivity. In combination with proper flow channel design, and a fabrication technology for narrow channels, it is shown that pL/s sensitivity is in reach.

The Micro Walker project ,which is reported in this thesis, focuses on the development of linear micro-motors with a large dynamic range (reach : resolution). The key question for this project is if it is possible to implement walking motion in MEMS, and what can be the performance of linear micromotors employing walking motion. From their potential application in data storage guiding specifications are derived: An output acceleration of a mg load larger than 100 m / s2, 10 nm resolution, reach larger than 10 mm, a driving voltage below 30 V and a maximum linear size smaller than 1 mm. The linear micromotors to made in the project, are based on variable capacitance electrostatic actuation and surface micromachining fabrication technology. Electrostatic motors have already been made in the 18th century. The first known variable capacitance motor has been built by Zipernowski in 1889. Different propulsion principles for linear micromotors have been found in literature: Inertial drive, elastic inertial drive, impact drive, traveling field surface drive, scratch drive, zigzag drive, transformation of rotary into linearly motion, and walking motion. The latter principle is implemented in the project. Controlled friction in clamp feet is necessary for walking. Therefore, microtribology is one of the main topics in this thesis. The focus is on shearing friction in elastic adhesive contacts.

MicrochanneIs were created by fusion bonding of a Pyrex cover to a thermally oxidized silicon wafer, which contained anisotropically etched grooves. Such channels are frequently used in microfluidic handling systems, for example, in chemical analysis. Since in some of these labs-on-a-chip, in particular those used in liquid chromatography, the channels are subjected to high pressures of up to a few hundred bar, it is important to have information about the mechanical stability of the channel chip, in particular of the wafer bond involved in it. The latter is the subject of this paper. The maximum pressure that can be applied to several different channel chips was investigated experimentally. In order to find the relation among this maximum pressure, channel geometry, materials elasticity, and bond energy, an energy model was developed that is generally applicable to all types of wafer bonds. It was shown that the model is substantiated by the experimental pressure data, from which it could be calculated that the effective bond energy increased from 0.018 to 0.19 J/m/sup 2/ for an annealing temperature ranging from 310 to 470/spl deg/C.

In ref 1, the erroneous numbers are not discussed in detail, yet we briefly noted, p 349, the observation of an enhanced ﬿lling speed with respect to the Lucas Washburn equation....

PbZr0.53Ti0.47O3 films were deposited on Si-SiO2-Ta-Pt substrates via a conventional sol-gel procedure. Electrical properties of the films were: resistivity ca. 5 × 1011 Ωcm, relative dielectric permittivity 900-1100, remnant polarization ca. 20 μC/cm2, breakdown electric field larger than 50 MV/m. The deflection amplitude of piezoelectrically excited Si cantilevers, covered with SiO2-Ta-Pt-PZT-Al, was determined with the aid of a heterodyne Mach-Zehnder interferometer. The piezoelectric strain constant d31 of the PZT films was determined from the amplitude measured at frequencies far below the first mechanical resonance (quasi-static method). The d31 constant was also determined from the deflection amplitude at the first mechanical resonance and the quality factor of the cantilever. Measured values ranged from -30 pC/N for unpoled films to -160 pC/N for films poled at room temperature and 40 MV/m.

The shuffle motor is a electrostatic stepper motor that employs a mechanical transformation to obtain high forces and small steps. A model has been made to calculate the driving voltage, step size and maximum load to pull as well as the optimal geometry. Tests results are an effective step size of about 85 nm and a maximum produced force of about 40 /spl mu/N at 40 V clamping voltage and 25 V actuator voltage.

A linear electrostatic stepper motor has been designed and fabricated in a single mask surface micromachining process. It consists of two drive units that alternately generate a step to move the shuttle. The friction and adhesion in the clamps has been measured. A friction coefficient of 0.8/spl plusmn/0.3 has been found. The adhesion in the clamp is just low enough to release the clamping shoe. Stepping cycles have been performed successfully to obtain a deflection of 15 /spl mu/m, with steps in the order of 2 /spl mu/m. The deflection is limited by the suspension. The generated force equals 3 /spl mu/N at 40 V driving voltage.

Two new methods have been developed to fabricate nanochannels by conventional micromachining. We succeeded in restricting the width of the channels to the submicrometer scale, while using standard photolithography with a resolution in the order of 1 μm. The first method is based on the sacrificial etching of a nanowire, which was formed on the side wall of a step. The second method is based on the adhesion of the capping layer to the substrate after removal of a sacrificial strip separating the two. The fabricated nanochannels are localized and can be connected to microchannels and reservoirs