US Patent 7874474 Self-assembly of elements using microfluidic traps

A self-assembly process is disclosed for integrating free standing microcomponents onto a template having a plurality of binding sites, an interconnect network, and trapping structures disposed downstream of the binding sites. The self-assembly is accomplished by flowing a fluid medium containing the microcomponents over the template such that some of the microcomponents are trapped at binding sites. The template may be simultaneously (or subsequently) heated to melt a binder such as a solder spot at each of the binding sites, and then cooled to connect the trapped microcomponents to the interconnect network. In one embodiment, removable blocking elements are disposed upstream of some of the binding sites, for example formed from photoresist. After assembling a first set of microcomponents, the blocking elements are removed, and a second set of microcomponents in a fluid medium are flowed over the template for assembly into the newly unblocked binding sites.