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The fabrication and characterization of a thermal flow sensor based on porous silicon technology is reported. The sensor, developed for gas metering applications, was designed in order to maintain compatibility with a gaseous environment and to exhibit a low power consumption. The different steps of the fabrication process are described with emphasis on the porous silicon technology and packaging techniques. Thermal characterizations of the sensors and measurements in continuous flows were performed.

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Smart card integrated circuits are never completely immune against any invasive attack (chemical, physical or energetic), and a hardware protection of the chip could be necessary. One solution consists in shielding the devices at the wafer level with a silicon structured cap (Sishell™). In order to increase security, this cap can also comport active functions. In this case electrical connections between the two wafers are necessary. This paper presents a new solution to interconnect two wafers, compatible with smart cards integration requirements. Starting from a previous technology on 'Anisotropic Conductive Film, hard localised Z axis micro-bumps are grown directly on wafer pads. Electrical contact and bonding are obtained simultaneously by thermo-compression at wafer level (top wafer on base wafer supporting the micro-bumps and glue). During this step, hard micro-bumps brake native oxide and create intimate contact with the top wafer Al pads. Two kinds of glue were implemented to obtain wafer bonding: epoxy and polyimide.

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