Self-assembly of three-dimensional microstructures using rotation by surface tension forces

The authors propose that automatic, parallel and self-limiting operations can be performed to reconfigure microstructures into full three-dimensional geometries, using the surface tension forces provided by molten solder to perform out-of-plane rotation of flexible hinges. Analysis is presented which indicates that the final angle of rotation can be controlled through initial solder volume, and that the forces are easily sufficient for the particular example of silicon micro-mechanical devices. However, the principle is general and could be applied to other materials.