Integrated - Structures on Silicon Chips

Some basic issues of integrated micromachinery --microassembly, material, and actuation, have been studied. This manuscript describes four new techniques in surface micromachining: (1) in situ assembly and the use of multiple sacrificial layers, (2) self-constraining and the exploitation of conformal deposition, (3) the introduction of hemispherical bushings to handle adhesion problem in released structures, and (4) thin-film, three-dimensional helical springs formed by strain gradients in the films. We also introduce four methods for mechanical-property characterization of thin films: (1) x-ray analysis to determine the orientation -distribution function (ODF) and thereby to interpret film properties, (2) spring-constrained pin joints for characterization of ultimate strength, (3) self-destructing bridges for fracture-strength characterization, and (4) spiral structures for strain-gradient characterization. Finally, this research also demonstrates for the first time the feasibility of rotational electrostatic micromotors.