Multi-batch micro-selfassembly via controlled capillary forces

Recent advances in silicon processing and microelectro-mechanical systems (MEMS) have made possible the production of very large numbers of very small components at very low cost in massively parallel batches. Assembly, in contrast, remains a mostly serial (i.e., non-batch) technique. In this paper, we argue that massively parallel selfassembly of microparts will be a crucial enabling technology for future complex microsystems. As a specific approach, we present a technique for assembly of multiple batches of microparts based on capillary forces and controlled modulation of surface hydrophobicity. We derive a simplified model that gives rise to geometric algorithms for predicting assembly forces and for guiding the design optimization and selfassembling microparts. Promising initial results from theory and experiments and challenging open problems are presented to lay a foundation for general models and algorithms for selfassembly.