Naoto Usami

We demonstrated a self-bending flexible tweezer capable of simultaneous mechanical handling and electrical measurement. A soft cantilever of 2mm × 8mm × 75 bent by itself, and electrical signal observation through touched surface was successful. The working voltage (1.5 V) was the lowest, and normalized strain was one of the highest values as compared to world's similar devices, to our best knowledge. Unique fabrication process of flexible cantilever with novel ionic polymer-metal composites (IPMCs) was developed. The material was poly (vinylidene fluoride-co-trifluoroethylene) (PVDF-TrFE) and ionic liquid (IL) by use of acetone solvent, and silver nanowire for electrodes. The IL of 50 wt% gave the largest 7 mm bending displacement at + 1.5 VDC. The cantilever with the above actuator touched on a gold test surface, then electrical observation of alternating voltage of 700 mV (1 kHz and 4 kHz) was confirmed.

We propose a micro-scale electrostatic attach detach actuator device as an enabling component of micro self reconfigurable modular robotic system (SMR), or programmable matter. The system is composed of a number of identical tiny agents that can adhere each other to form arbitral shapes. The actuator is composed of Au electrodes sandwiched by Parylene-C flexible substrate films. The film is made planar, and the SMR agent is realized by wrapping the actuator film around a shell of a unit robot, made by precise 3-D printing. We have measured the adhesive strength to be 99.3 μN at 50 V, that is sufficient to perform attach demonstration.

We assessed potential degradation of MOSFET characteristics induced by post-processing of extra bond pads. The pads are used as stable electrical connections in repairing and test. The test structure consists of 16×16 arrayed PMOSFETs designed with 0.6 μm CMOS technology. An aluminum pad is deposited on the arrayed structure using a silicon shadow mask, and wire bonding is performed subsequently. The characteristics of Id-Vg were compared before and after the post-process. The result indicates that the post-processing does not affect the characteristics of MOSFETs, and therefore it can be used to place post-processed bond pads over an LSI chip.

Imaging devices for near-infrared wavelengths on silicon large scale integration (LSI) are very attractive for secure applications. We here demonstrate an LSI-compatible hybrid IR detector by integrating PbS quantum dots the surface of silicon.

Imaging devices for near-infrared wavelengths on silicon large scale integration (LSI) are very attractive for secure applications. We here demonstrate an LSI-compatible hybrid IR detector by integrating PbS quantum dots the surface of silicon.

We propose an arrayed test structure to assess the damages of metal-oxide-semiconductor field-effect transistors (MOSFETs) exposed under back-side LSI processes, such as by Focused Ion Beam (FIB). Back-side process with FIB is becoming essential to analyze and repair modern LSI chips, to avoid processing through many metal layers with dense wiring and dummy patterns. To access transistors from back-side, however, FET active region must be cropped out and that may cause damage to transistor characteristics. Our test structure consists of 2-D-arrayed MOSFETs. The impact by the back-side process on various conditions can be visualized as I-V characteristics change. The test structure was used with several FIB back-side processes and visualized the damages as threshold shift. The measurement indicated the importance of mixture of fast-and-isotropic etching and slow-and-anistoropic etching to miminimize electrical damage.