Abstract
A micro sensor is composed of a cantilever beam part, a second base spaced apart the cantilever beam, and an upper plate connecting the cantilever beam and the second base. The cantilever beam part includes a first base, a cantilever beam horizontally extended from the first base, an electrode layer deposited on the cantilever beam top and a humidity sensing layer coated on the electrode layer for shrinking or stretching of its length at different humidity. The upper plate is composed of a cavity and a second electrode layer deposited on the cavity. The first and second electrode layers form a capacitance and the capacitance value changes as the distance between the first and second electrode layers changes.