Cofabrication: A Strategy for Building Multicomponent Microsystems

This Account describes a strategy for fabricating multi-component microsystems in which the structures of essentially all of the components are formed in a single step of micromolding. This strategy, which we call “cofabrica-tion”, is an alternative to multilayer microfabrication, in which multiple layers of components are sequentially aligned (“registered”) and deposited on a substrate by photolithog-raphy. Cofabrication has several characteristics that make it an especially useful approach for building multicomponent microsystems. It rapidly and inexpensively generates correctly aligned com-ponents (for example, wires, heaters, magnetic field generators, optical waveguides, and microfluidic channels) over very large surface areas. By avoiding registration, the technique does not impose on substrates the size limitations of common registrations tools, such as steppers and contact aligners. We have demonstrated multicomponent microsystems with surface areas exceeding 100 cm2, but in principle, device size is only limited by the requirements of generating the original master. In addition, cofabrication can serve as a low-cost strategy for building microsystems. The technique is amenable to a variety of laboratory settings and uses fabrication tools that are less expensive than those used for multistep microfabrication. More