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The increasing usage of electronic devices and the progressive trend of miniaturisation in automotive applications require different installation locations. According to varying locations, different climate conditions will occur. In this article, the influence of condensation on the reliability of electronic devices is examined. For the detection of failures or the loss of functionality it is essential to determine the occurrence of condensation. A new microsensor based on the CCCprinciple (condensate controlled capacitance) allows the measurement of the condensed water mass directly. Depending on the gaps of special designed stray field capacity in combination with a water drop sensitive detection system, a change of the capacity with increasing water mass is shown. It is necessary to analyse failure mechanisms like corrosion induced leakage currents and electrochemical migration. For the research of these failure mechanisms special test patterns were designed and assembled. These samples were exposed to a certain climate profile, which produces a reproducible and defined amount of condensation, this can occur in certain locations in automotives. On the bases of these test patterns, which consist of both combs with different spaces and chip capacities with variable sizes, diverse influences were examined. Beside field strength also the surface metallisation and the cleanliness of the samples were investigated and quantified.

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Energy-autarkic sensor systems use energy from their environment for operation and data transfer. This needs both an efficient energy harvesting strategy and an appropriate energy storage management but also ultralow-power technologies for sensors, signal processing, and wireless signal transfer. Binary Zero-Power Sensors are threshold switches which take the switching energy directly from the quantity to be measured. For this purpose stimuli-responsive polymers-in particular hydrogels-are used which swell upon the influence of particular quantities like humidity, temperature or pH value. The swelling causes the deflection of a flexure element closing or opening the contacts of a switch. In this manner they deliver the switching states ''ON'' and ''OFF'' without any additional electrical energy.

We present recent results on a binary threshold sensor based on the binary zero-power sensor (BIZEPS) platform which is able to use the energy provided directly from the measured relative humidity of the ambient air to mechanically switch an electrical micro contact. This zero-power switch behavior is realized by using the humidity-sensitive volume swelling of a polymer layer as the detection element deflecting a mechanically deformable silicon boss structure, thus closing the electrical contacts of the switch. For the humidity-sensitive sensor switch considered here, a humidity-sensitive hydrogel blend of poly(vinyl alcohol) and poly(acryl acid) was used. The sensitive part affected by the measurand is completely separated from the electrical part, thus providing long-term stability. By using an inverse silicone stamping technique the polymer layer with a thickness of about 15 µm was patterned on test structures possessing a thin silicon flexure plate of 5 mm x 5 mm in size and 20 µm in thickness. Reproducible deformations of up to 15 … 24 µm has been measured. Investigations of the swelling kinetics showed for several discrete relative humidity values a saturation of the water load. The time to reach this saturation state is reduced from 5 hours down to approx. 20 min by increasing the relative humidity beyond the threshold value of 70% r.H. A significant influence of the temperature to the humidity load could not be observed.