The microflown, from die to product

This article reports on various steps to transform a concept to a product. A sound intensity probe based on a micro-machined acoustic sensor "the Microflown" is used as an example. Requirements for the micromachined part are simplicity and uncomplicated processing to reach a high throughput. For monitoring the quality, simple and reliable characterisation tools should be designed as well. To gain credibility independent labs should test the product. The product should offer a complete solution that competes in overall costs and performance, and it must be possible to connect it into existing systems

Long-time data storage: relevant time scales

Dynamic processes relevant for long-time storage of information about human kind are discussed, ranging from biological and geological processes to the lifecycle of stars and the expansion of the universe. Major results are that life will end ultimately and the remaining time that the earth is habitable for complex life is about half a billion years. A system retrieved within the next million years will be read by beings very closely related to Homo sapiens. During this time the surface of the earth will change making it risky to place a small number of large memory systems on earth; the option to place it on the moon might be more favorable. For much longer timescales both options do not seem feasible because of geological processes on the earth and the flux of small meteorites to the moon.\u

The black silicon method V: a study of the fabrication of movable structure for micro electromechanical systems

This paper presents a study of various well-known release techniques (bulk- and surface-micromachining) for the fabrication of movable silicon micromechanical structures. Their pro's and con's will be discussed. Further, a detailed study of a new self-aligned plasma technique is presented which uses silicon on insulator wafers (SOI). It has the ability to etch, release, and passivate MEMS in one ME run. Therefore, MEMS can be fabricated quickly, accurate, and at low costs

A microsieve for leukocyte depletion of erythrocyte concentrates

A new ultra thin filtration membrane has been used for leukocyte removal from erythrocyte concentrates. This filtration membrane, an Aquamarijn Microsieve(R), has a high pore density and a narrow pore size distribution and shows good separation behaviour. The low surface roughness of the microsieve will contribute to the biocompatibility and will reduce cell rupture, in particular hemolysis, during filtration. In this paper a brief overview of the effects that occur during filtration will be given. Also the results of the experiments of leukocyte removal from erythrocyte concentrates will be discusse

Buckled membranes for microstructures

Based on energy variation methods we calculated the deflection of membranes under the combined load of an external pressure and an internal lateral stress. A lateral load gives rise to buckling once a critical load is exceeded. The combination of transversal loads and lateral loads changes the properties of the membrane (and other structures) in the vicinity of the buckling load: The membrane deflects at all lateral loads and the critical load, above which two states are possible shifts. A result important for the design of microsystems, which are based on the buckling phenomenon, is the pressure required to switch the membrane from one state to the other. The theory is tested successfully with micromachined silicon/silicon-dioxide membrane

Quasi-buckling of micromachined beams

Buckling of structures with imperfections, quasi-buckling (QB), is studied. At the bifurcation load, these structures show a smooth transition into one of the stable postbuckling equilibrium states, instead of the traditional sudden change in deflection characteristics. QB structures can show the classical snap-through buckling behaviour, i.e., a sudden change of postbuckling equilibrium state. The QB is described with a generalized temperature, Tg, representing the compression of the structure. Imperfections and distributed deflection loads are represented by a generalized pressure, pg. Experiments on micromachined beams, exposed to heating (Tg) and to a Lorentz force (pg), verify that the QB phenomena can efficiently transfer a longitudinal stress into a transversal deflection, with a scale-factor depending on both Tg and pg

Self assembled three-dimensional nonvolatile memories

A promising strategy for for the realisation of three-dimensional memories could be the self assembly of articial sub-micron elements (smarticles). Such elements can be realised by combining edge-lithography techniques and anisotropic etching. The first experiments into this direction are encouraging