Masatoshi Kanamaru

Fabrication of a 35-channel optical scanner integrated by passive-self alignment using through-holes precisely formed by DRIE

A 35-channel optical scanner integrating a mirror array and a collimator-lens array was fabricated. The mirror array consists of a mirror substrate with 35 single-axis-rotational mirrors and an electrode substrate for actuating the corresponding mirror by electrostatic force. Each substrate includes two kinds of through-holes: one for passing a collimated-optical beam through, the other for inserting a precise pin for passive-self alignment of the mirror array and the collimator-lens array. To precisely form the through-holes suitable for passive-self alignment, deep reactive ion etching (DRIE) conditions were optimized. DRIE from both surfaces of a substrate under the optimized conditions - a C/sub 4/F/sub 8//SF/sub 6/ gas-flow ratio of 90% and a bias power in SF/sub 6/ gas of 110 W - can form through-holes with an average undercut of 3.4 /spl mu/m and an average sidewall angle of 89.9 degrees. By passive-self alignment, namely, inserting a pin into the fabricated through-hole and stacking the mirror array on the collimator-lens array, the measured assembly deviation of each substrate was less than 17.5 /spl mu/m.

MEMS Gyroscope With Less Than 1-deg/h Bias Instability Variation in Temperature Range From −40 °C to 125 °C

We developed a gyroscope with less than 1-deg/h bias instability variation in a temperature range from −40 °C to 125 °C while performing around 4-deg/h bias instability. This stability was achieved by using the stable frequency separation between the drive and sense modes of a Coriolis vibratory gyroscope. To achieve this stability, the mechanical part was designed with a one-sided open frame to mitigate the variation of resonant frequencies caused by thermal stress. At the circuit level, we implemented a self-clocking architecture with a bandpass

Development of wafer-level-packaging technology for simultaneous sealing of accelerometer and gyroscope under different pressures

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Fabrication of an optical beam scanning array integrating mirror and lens arrays by passive self-alignment using precisely formed through-holes

analog-to-digital converter to maintain low quantization noise level over the operational temperature range. The fabricated gyroscope demonstrated a 2-Hz variation of frequency separation for an operational frequency of 18.5 kHz in the operational temperature range. At a system level, a bias instability variation of 0.9 deg/h in the temperature range while performing bias instability less than 4.21 deg/h was demonstrated. This low-noise variation is potentially beneficial for applications requiring a Kalman filter, such as GPS-denied navigation systems, that demands a precise and predetermined noise property.

Study of Production Technique for Metallic Ultra Fine Particles Using Arc Energy

This research demonstrates a newly developed anodic bonding-based wafer-level-packaging technique to simultaneously seal an accelerometer in the atmosphere and a gyroscope in a vacuum with a glass cap for micro-electromechanical systems sensors. It is necessary for the accelerometer, with a damping oscillator, to be sealed in the atmosphere to achieve a high-speed response. As the gyroscope can achieve high sensitivity with a large displacement at the resonant frequency without air-damping, the gyroscope must be sealed in a vacuum. The technique consists of three processing steps: the first bonding step in the atmosphere for the accelerometer, the pressure control step and the second bonding step in a vacuum for the gyroscope. The process conditions were experimentally determined to achieve higher shear strength at the interface of the packaging. The packaging performance of the accelerometer and gyroscope after wafer-level packaging was also investigated using a laser Doppler velocimeter at room temperature. The amplitude at the resonant frequency of the accelerometer was reduced by air damping, and the quality factor of the gyroscope showed a value higher than 1000. The reliability of the gyroscope was also confirmed by a thermal cyclic test and an endurance test at high humidity and high temperature.

Method of manufacturing semiconductor apparatus

An optical beam scanning array (OBSA) integrating two mirror arrays and a collimator-lens array was fabricated. The passive self-alignment inserting a pin into a through-hole was carried out for integration of the mirror arrays and the collimator-lens array. The mirror arrays consist of a mirror substrate with 35 single-axis-rotational mirrors and an electrode substrate for actuating the corresponding mirror by electrostatic force. Each substrate includes two kinds of through-holes: one for passing a collimated-optical beam through, the other for inserting a pin. The conditions for deep-reactive-ion etching (DRIE) of silicon were optimized to form through-holes suitable for passive self-alignment. DRIE from both surfaces of a silicon wafer under the optimized DRIE conditions—a C4F8/SF6 gas-flow ratio of 90% and a bias power in SF6 gas of 110 W—formed precision through-holes with an average undercut of 3.4 µm and an average sidewall angle of 89.9°. The passive self-alignment then yielded an assembly deviation of less than 17.5 µm, which meets the specification of less than 50 µm. This means that passive self-alignment using a through-hole formed under the optimized DRIE conditions can be exploited to make OBSAs without requiring optical alignment of mirrors and lenses.

Slider unit controllably actuated at a surface of a moving information recording medium

Ultra fine particles (referred to as UFP here) have drawn considerable attention in recent years as possible new function materials. As such, they have been the subject of intensive research in various fields.1 The authors have studied the UFP production technique using arc energy looking closely at the electromagnetic force resulting from arc current. Through this study a method for producing UFP with higher efficiency was developed. The results of that investigation are covered in this report.