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This paper covers the design, fabrication, and characterization of two-layer microcoils wherein an unannealed plasma-enhanced CVD Si[O.sub.2] functions as the insulator between silicon-and photoresist-molded copper coils. This design overcomes the thermal limitations placed upon coils that are embedded within polymer molds and thereby enables higher current carrying capability. The fabrication process is compatible with deep reactive-ion etching and may be used to integrate coils with flexures/compliant mechanisms. Thermal and mechanical limitations were determined experimentally and used to create design rules that limit the coil design space. The breakdown strength of the unannealed Si[O.sub.2] was measured at 4.6 MV/cm. Experiments show that coils with 40-[micro]m pitch, 30 x 30-[micro][m.sup.2] winding cross section, and Si[O.sub.2] thickness of 1 [micro]m may carry more than 1 A (larger than [10.sup.9] A/[m.sup.2]) with less than 10[degrees]C temperature change. These characteristics make the coils useful in small-scale actuators and power systems. [2008-0170] Index Terms--Copper damascene, electroplating, magnetic microactuator, microcoil, microelectromechanical devices, silicon dioxide.

We report on the accuracy of the pseudo-rigid-body model (PRBM) in predicting the behavior of a nanoscale parallel-guiding mechanism (nPGM) that uses two single-walled (5,5) carbon nanotubes (CNTs) as the flexural guiding elements. The nPGM has two regions of behavior: region 1 is governed by the bulk deformation of the nanotubes, and region 2 is characterized by hingelike flexing of four 'kinks' that occur due to buckling of the nanotube walls. PRBM parameters for (5,5) CNTs are proposed. Molecular simulation results of region 1 behavior match PRBM predictions of (1) kinematic behavior with less than 7.3% error and (2) elastomechanic behavior with less than 5.7% error. Although region 1 is of more interest because of its well-defined and stable nature, region 2 motion is also investigated. We show that the PRBM parameters are dependent on the selection of the effective tube thickness and moment of inertia, the lesson being that designers must take care to consider the thickness and moment of inertia values when deriving PRBM constants. [DOI: 10.1115/1.2885192] Keywords: compliant mechanism, pseudo-rigid-body, flexure, carbon nanotube, molecular simulations, nanomechanical, nanoelectromechanical

In this paper, we disclose how to contour the beams of microscale thermomechanical actuators (TMAs) in order to enhance the actuator's thermal and mechanical performance. In this approach, we vary the cross-section of the heated beams over the length of the beams. Using this approach, the stored strain energy and axial stiffness of the beam may be modified to achieve an optimized force-displacement relationship. Examples are provided to show that in some designs: 1) the maximum achievable thermal strain of a driving beam may be increased by 29%, 2) actuator stroke may be increased by a factor of four, and 3) identical force or displacement characteristics may be achieved with a 90% reduction in power. This paper presents the theory and models used to predict the thermal and mechanical behavior of the actuator. The theory and models were used to create a deterministic link between the actuator's design parameters and the actuator's performance characteristics. The theory and models were combined within a design tool that is posted at http://pcsl.mit.edu. The tool has been used to generate performance plots that enable designers to: 1) understand the quantitative relationships between design parameters and performance and 2) rapidly converge upon first-pass design parameters. [1695] Index Terms--Contoured beam, microactuator, nanopositioner, thermomechanical actuator.

Quasi-kinematic couplings (QKCs) are alignment devices that incorporate elastic-plastic deformations to combine principles of elastic averaging and exact constraint to achieve precision alignment. This paper shows QKCs can be used for low-cost alignment in high-volume assembly applications. This is demonstrated via a case study of the process used to align main journal bearings in an automobile engine. Results of experiments show best case QKC performance of 0.35 microns compared to 4.85 microns for the widely-used dowel pin-hole design. Statistical analyses predict the QKC will meet five micron alignment requirements in 99.999 percent of all assembly cycles. Compared to the dowel pin-hole design, the QKC uses 60 percent fewer piece parts and costs 36 percent less.