Uni-direction Orienting and Size Effect Automatic Alignment Using Capillary Based in Fluidic Self-Assembly Process

Advances of miniaturization and microfluidics lead to novel technologies in assembling micro-scale electronic components in thousands and in parallel. Present study proposes a fluidic self-assembly (FSA) approach for fast, economic, and precise handling of micro-scale parts in asymmetric shapes. The micro parts, fabricated from silicon-oxide wafers and ranged in size from 350 x 350 x 170 mum to 1000 x 1000 x 440 mum , are aligned and filled to designated sites in the substrate under water using a pipette. The adhesion force of square-patterned micropart immobilized at the bigger binding sites was estimated at 117 +15 mu N, resulting in highter assembly yield of up to 73% for these sample. Furthermore, the novel designs of two dimensional tear-drop/rocking-chair like shapes are employed to improve the recovery angle and reduce the energy barrier for micropart alignment in uni-direction. Filling ratio of 90% is achieved with uni-direction if five hundred parts are filled to all of 64 binding sites with the agitation by an orbital shaker.