Three dimensional assembly and actuation of nanopatterned membranes using nanomagnets

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, June 2011.Cataloged from PDF version of thesis.Includes bibliographical references (p. 166-170).A new method for aligning and actuating membranes for 3D nano-assembly based on the interactions of nanomagnets has been developed. Arrays of nanopatterned magnetic material are integrated onto thin-film membranes. It is shown theoretically and experimentally that separate arrays of nanomagnets attract and self-align when brought into close proximity. This provides a useful mechanism for 3D nanofabrication because it allows higher positional tolerances as the nanomagnets provide the fine alignment. The features on the membrane can first be patterned using traditional wafer and thin-film processes with features such as nanophotonics as well as the nanomagnets. The membranes are then folded or stacked bringing the magnets into coarse alignment. The magnets pull-in, align and bond the membrane segments to create a highly aligned structure in 3D space. A theoretical framework was developed for the magnetic and mechanical design elements of the system. A set of experiments based on folding the membrane to bring the arrays into coarse alignment was designed requiring new mechanical hinge elements at the micro-scale. Nanomagnets were shown to provide the folding actuation, as well as alignment. It was shown that the nanomagnet arrays can provide better than 30nm self-alignment over a 100 micron membrane segment. It was also shown that the nanomagnets can provide reconfigurability, in that the systems can controllably be shifted between more than one alignment position. Further steps were taken to improve the alignment, increase the membrane size, integrate other nanofeatures and improve the membrane processing.by Anthony John Nichol.Ph.D