Externally resonated linear microvibromotor for microassembly

A new method for on-substrate fine positioning of microscale/mesoscale discrete components is presented [1]-[3], where component positions are finely adjusted using microlinear sliders and fixtures on the substrate. Each microlinear slider is actuated by vibratory impacts exerted by two pairs of microcantilever impacters. These microcantilever impacters are selectively resonated by shaking the entire substrate with a piezoelectric vibrator, requiring no need for built-in driving mechanisms such as electrostatic comb actuators, as reported previously [4], [5]. This selective resonance of the microcantilever impacters via an external vibration energy field [6] provides with a very simple means of controlling forward and backward motion of the microlinear slider, facilitating assembly and disassembly of a microcomponent on a substrate. An analytical model of the device is derived in order to obtain, through the simulated annealing algorithm, an optimal design, which maximizes translation speed of the linear slider at desired external input frequencies. Prototypes of the externally resonated linear microvibromotor are fabricated using the three-layer polysilicon surface micromachining process provided by the Microelectronics Center of North Carolina, Research Triangle Park, NC, multiuser microelectromechanical processes service, These prototypes are tested for forward and backward motion via external vibration applied by an piezoelectric flexure vibrator, as well as the horizontal positioning and release of 500-mu m-square polysilicon chips against a reference fixture element anchored to the substrate.