Abstract:
The electronic device (15) is formed in a die including a body (2) of semiconductor material having a first face (9) covered by a covering structure (7, 10) and a second face (12). An integral spreader of metal is grown galvanically on the second face during the manufacture of a wafer, prior to cutting into dice. The covering structure (7, 10) comprises a passivation region (7) and a protective region (10) of opaque polyimide; the protective region (10) and the passivation region (7) are opened (11) above the contact pads (6) for the passage of leads (22).
Abstract:
The manufacture process comprises: forming a first wafer (20) of semiconductor material housing integrated electronic components forming a microactuator control circuit and a signal preamplification circuit (22); forming microactuators (10), each comprising a rotor (52) and a stator (51), in a surface portion of a second wafer (28) of semiconductor material; attaching the second wafer (28) to the first wafer (20), with the surface portion of the second wafer facing the first wafer; thinning the second wafer (28); attaching the second wafer (28) to a third wafer (75) to obtain a composite wafer (78); thinning the first wafer (20); cutting the composite wafer (78) into a plurality of dice (77) connected to a protection chip (75'); removing the protection chip (75'); attaching read/write transducers (6) to the dice (77); and attaching the dice to supporting blocks (3) for hard-disk drivers (1).
Abstract:
The microactuator (9') comprises a stator element (17') and a rotor element (11') which are capacitively coupled. The rotor element (11') comprises a suspended mass (12) and a plurality of movable drive arms (13') extending radially from the suspended mass (12) and biased at a reference potential. The stator element (17') comprises a plurality of first and second fixed drive arms (18a', 18b') associated with respective movable drive arms (13') and biased at a first drive potential. A mechanical damping structure (32) is formed by at least one movable damping arm (13'') extending radially from the suspended mass (12) and by at least one first and one second fixed damping arm (18a'', 18b'') associated with the movable damping arm (13'') and biased at said reference potential, to dampen settling oscillations of the rotor element (11').