Nanowelding in Whole-Lifetime Bottom-Up Manufacturing: From Assembly to Service.

The continuous miniaturization of microelectronics is pushing the transformation of nanomanufacturing modes from top-down to bottom-up. Bottom-up manufacturing is essentially the way of assembling nanostructures from atoms, clusters, quantum dots, etc. The assembly process relies on nanowelding which also existed in the synthesis process of nanostructures, construction and repair of nanonetworks, interconnects, integrated circuits, and nanodevices. First, many kinds of novel nanomaterials and nanostructures from 0D to 1D, and even 2D are synthesized by nanowelding. Second, the connection of nanostructures and interfaces between metal/semiconductor-metal/semiconductor is realized through low-temperature heat-assisted nanowelding, mechanical-assisted nanowelding, or cold welding. Finally, 2D and 3D interconnects, flexible transparent electrodes, integrated circuits, and nanodevices are constructed, functioned, or self-healed by nanowelding. All of the three nanomanufacturing stages follow the rule of "oriented attachment" mechanisms. Thus, the whole-lifetime bottom-up manufacturing process from the synthesis and connection of nanostructures to the construction and service of nanodevices can be organically integrated by nanowelding. The authors hope this review can bring some new perspective in future semiconductor industrialization development in the expansion of multi-material systems, technology pathway for the refined design, controlled synthesis and in situ characterization of complex nanostructures, and the strategies to develop and repair novel nanodevices in service.