A surface micromachined, out-of-plane anemometer

A novel out-of-plane hot-wire anemometer has been developed by combining surface micromachining and efficient three-dimensional assembly. The sensing filament is made of metal instead of doped silicon. It is elevated from the substrate using an efficient three-dimensional assembly process, resulting in greater sensitivity. The overall process temperature is low (<250/spl deg/C), hence the process can be realized on non-silicon, low-cost and flexible substrates. The time constant in constant-current mode is found to be below 50-/spl mu/s with a wire thickness of 1000 /spl Aring/ and wire length of 50-/spl mu/m.