Abstract: This paper introduces a new technology to fabricate a micro electromagnetic actuator with high energy density without an enclosed magnetic circuit.This technology includes fabricating multi-turns planar micro coils and fabricating the thick magnetic (NiFe) core on the silicon wafer.The multi-turns planar micro coils are fabricated by the electroplating method from the surface along the line and by dynamically controlling the current density of the copper electrolytes.In order to fabricate thick NiFe plating,the adhesion properties between the NiFe plating and the silicon substrates are improved by changing the surface roughness of the silicon substrates and increasing the thickness of the seed layer.Furthermore,the micro electromagnetic actuator is tested and the energy density of the actuator is evaluated by force testing.The experiments show that the microactuator is efficient in producing high magnetic energy density and high magnetic force.

Key words: micro electromagnetic actuator, high energy density, multi-turns double planar microcoils, thick