Does Integrated-Circuit Fabrication Show the Path for the Future of Mechanical Manufacturing?

tion (VLSI), to domains other than mere logic devices. The feasibility of building small sensory devices, actuators, and motors was demonstrated by a number of microelectromechanical systems (MEMS) researchers. MEMS technology is not associated with one particular process, but rather encompasses a rich variety of process flows. Devices are fabricated by a sequence of conventional VLSI unit processes, including oxidation, diffusion, photolithography, etching, sputtering, and CVD. Augmenting these are new processes developed especially for MEMS, such as wafer bonding and deep reactive-ion etching. The feature size of MEMS devices is one or two orders of magnitude below the size scale where the Swiss watchmaking industry left off, but one or two orders of magnitude bigger than the resolution that is easily achievable in current VLSI fabrication plants. Another important characteristic is that most artifacts built with VLSI fabrication techniques have rather flat geometries. Incremental layer-building inherently facilitates the construction of devices with high eccentricities normal to the building direction. Independently from but parallel to the developments in MEMS, another research community started to generate threedimensional (3D) mechanical structures by decomposing computer-aided design (CAD) models into thin cross-sectional slices and then embedding one cross section on top of the other in complementarily shaped sacrificial supports. Various embodiments of this method, called layered manufacturing, or solid freeform fabrication (SFF), are commercially available and well publicized.1 The majority of SFF processes employ material-deposition strategies ranging from laser-induced curing of monomers, to selective deposition of metal and polymeric powders, to laser fusion of streams of metal powders. Some SFF technologies combine material addition with material-removal strategies such as computer numerical control (CNC) Does Integrated-Circuit Fabrication Show the Path for the Future of Mechanical Manufacturing?