the present invention provides a micro sensor for monitoring the cleaning and drying processes of surfaces of dielectric films , micro features in porous dielectric films and biologic or other cells common in microelectronics fabrication , mems fabrication or microbiology test system fabrication . by embedding electrodes in the surface of a supporting dielectric , the sensor can probe the surface and pores of a covering dielectric or a cell on the covering dielectric . the addition of a guard reduces the effects of any parasitic capacitance , which extends the measurement bandwidth of the sensor and allows it to be manufactured at the scale of a single cell , a feature that is particularly important for applications in microbiology .