Fabrication metal microstructures, assembling

A shift toward utilizing physicochemical processes, newer materials, and techniques is inevitable [23]. Processes such as wafer bonding [24], stereolithography [25], and self-assembly [2 can enable complex 3D structure fabrication. Smart composite microstructures [27] of carbon, silicon, polymer, etc., can provide for robust structures with flexible joints. For tools, metals such as stainless steel, platinum-tantalum, and nickel-titanium or natural materials such as gelatin and collagen can be used. 

The ability to coat polymer microstructures with different materials is an attractive method for creating devices in other areas of research than photonics. When these materials are conductive, electrical components with intricate geometries can be fabricated by TPP such as the micro-inductor in Figure 7.10c [100]. By using wet-chemistry processes such as self-assembly and electroless plating, several metals (Ag, Au, and Cu) were grown to form conductive skins on the surfaces of 3D microstructures [101-103]. Particularly interesting is the process developed by Fourkas and coworkers because of its selectivity. They have shown for example that metallization can occur on microstructures composed of an acrylate backbone polymer while it is ineffective on microstructures composed of the methacrylate counterpart [100]. 

---