A sensor with a movable microstructure including a sensitive element, formed in a first chip of semiconductor material for producing an electrical signal dependent on a movement of at least one movable microstructure relative to a surface of the first chip. The sensitive element is enclosed in a hollow hermetic structure, and circuitry for processing the electrical signal is formed in a second chip of semiconductor material. The hollow hermetic structure includes a metal wall disposed on the surface of the first chip around the sensitive element, and the second chip is fixed to the metal wall.