| In this thesis, a new technology which successfully combines silicon bulk micromachining with the electroplating of metal conductors and magnetic materials is presented. This technology has enabled the fabrication of the first bulk micromachined electromagnetic flap actuators. The demonstrated characteristics of these actuators are large size ({dollar}>{dollar}16 mm{dollar}sp2{dollar}) large forces ({dollar}>{dollar}100 {dollar}mu{dollar}N), and large ({dollar}>{dollar}60 degrees) deflections. In this technology, silicon bulk micromachining is used to form the mechanical structures of the actuators, and the electroplating of copper and ferromagnetic permalloy provides the electromagnetic actuating components.; The actuators are configured in the shape of a flap, consisting of a single crystal silicon plate and on-plate electromagnetic components. The silicon plate, 4 mm {dollar}times{dollar} 4 mm {dollar}times{dollar} 40 {dollar}mu{dollar}m, is connected to a substrate via several silicon springs. When the electromagnetic components are activated the silicon plate flaps up and down. Three types of actuators have been examined and they differ in electromagnetic components. Type-1 actuators have a permalloy layer, the type-2 actuators have copper coils, and the type-3 actuators have both the permalloy and copper coils. The actuators are operated in the presence of an externally applied magnetic field, and the deflections of the flap actuators can be controlled either by varying the external magnetic field strength or by changing the current to the copper coils.; The electromagnetically induced deflections of the actuators are measured and agree well with the design using a combined electromagnetic/mechanical model. Achieved deflection angles of the type-1 actuators exceed 60{dollar}spcirc{dollar} at an applied field of around 80 KA/m (1000 gauss). Additional deflection angles of about {dollar}pm{dollar}20 degrees (type-3 actuator) can also be obtained by coil currents of {dollar}pm{dollar}100 mA. As a result, large deflections up to 80{dollar}spcirc{dollar}, together with a large force exceeding 100 {dollar}mu{dollar}N, have been achieved in the micro devices. Moreover, we have successfully demonstrated these actuators in two applications for scanning mirrors for holographic data storage systems and fiber optic bypass switches. |
