NMEMS Technology Research Organization

Tsukuba, Japan

NMEMS Technology Research Organization

Tsukuba, Japan
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Yamashita T.,Japan National Institute of Advanced Industrial Science and Technology | Okada H.,Japan National Institute of Advanced Industrial Science and Technology | Kobayashi T.,Japan National Institute of Advanced Industrial Science and Technology | Togashi K.,NMEMS Technology Research Organization | And 4 more authors.
Proceedings of IEEE Sensors | Year: 2017

In this paper, we present a novel sensor array manufacturing process that involves transfer printing methods using a chip mounter with a vacuum collet. We have successfully fabricated 5× 5 array of MEMS-based very fragile ultra-thin piezoelectric strain sensors on a polyethylene naphthalate (PEN) flexible printed circuit (FPC) with etched Cu pattern. Twenty five of the piezoelectric strain sensors made of ultra-thin 2-μm-thick Pb(Zr, Ti)O3 (PZT)/3-μm-thick Si plate were transfer printed onto the PEN FPC with adhesive layer by the chip mounter. PZT and Cu pattern were wired with Ag paste by screen printing. Since output voltage corresponding to the magnitude of the strain from the developed 5× 5 sensor array was generated, it was confirmed that ultra-thin sensors could be integrated to the PEN FPC substrate by these transfer and screen printing techniques without damage. We succeeded in strain distribution display by color mapping method using the data from the sensor array. © 2016 IEEE.


Zymelka D.,NMEMS Technology Research Organization | Togashi K.,NMEMS Technology Research Organization | Togashi K.,Dai Nippon Printing | Yamashita T.,Japan National Institute of Advanced Industrial Science and Technology | And 3 more authors.
Proceedings of IEEE Sensors | Year: 2017

The principal goal of this work was to develop and to evaluate the suitability of low-cost carbon-based printed strain sensors array designed for measuring 2D dynamic strain distribution. The studies were focused toward potential application of the sensing sheets in structural health monitoring (SHM) of bridges. In contrast to conventional strain gauges and silicon-based sensors characterized by good reliability, the printed sensors are out of interest, mainly due to the possibility of fast, large area and low-cost manufacturing. The collected results show that by the implementation of appropriate sensors design the printed carbon-based strain sensors, despite high the temperature coefficient of resistance, may be successfully used to build the sensing sheets for measuring dynamic strain distribution in various engineering constructions. © 2016 IEEE.


Yoshimi S.,Dai Nippon Printing | Yoshimi S.,NMEMS Technology Research Organization | Fujimoto K.,Dai Nippon Printing | Fujimoto K.,NMEMS Technology Research Organization | And 9 more authors.
Proceedings - Electronic Components and Technology Conference | Year: 2013

A Silicon interposer with through silicon via (TSV) has become important key components of 3D integration. It is used as an intermediate carrier and a wiring device for IC components like logics, memories, sensors, and so on. Due to wiring with custom design on front and back side, a TSV interposer enables to adapt the fine pitch IO terminals of the mounted ICs to the IO geometries of the package level. However the key problem facing the TSV interposer is a cost issue. In this paper, TSV based interposer fabrication process for 3D packaging has been presented and the process uniformity with 300 mm wafer was evaluated for cost reduction and yield improvement. TSVs of 50 μm in diameter were formed on a 300 mm wafer of 500 μm in thickness by deep reactive ion etching (DRIE) process and the vias were isolated with SiO2 layer, followed by barrier/seed layers of Ti/Cu deposition. The TSVs were filled with solid Copper (Cu) using electroplating of optimized periodic pulse reverse (PPR) and chemical mechanical polishing (CMP) process also developed to remove the Cu overburden. For void free TSV interconnects and uniformity improvement, the Cu electroplating process was simulated with 300 mm wafer and developed with the simulation result. The process uniformity of Cu electroplating was equivalent to the simulation result and void free TSV interconnects were successfully formed. The RDL lines were formed on the TSV by Cu electroplating and the RDL lines were electrically isolated with the dielectric PBO film. The TSV interposer of 500 μm thickness has been fabricated successfully with MEMS processes and the vias were in good conductivity from the top to the bottom. The distribution of via etching process, via filling process and CMP process were evaluated and no significant failures were observed. The uniformity of the via etching process was less than 5 %. The distribution of Cu overburden thickness was less than 100 μm. The dishing amount of Cu via after CMP was less than 10 μm. The electric characteristics of RDL leakage current and via resistance were measured. The leakage current between RDL lines was about 10-9 A so that the RDL lines were electrically isolated. The average value of via resistances was 2.43 ohm and via resistances were normally distributed with tangible electric characteristics. The fabrication process of TSV based silicon interposer with 300 mm wafer by MEMS processes was successfully demonstrated in terms of mass production. © 2013 IEEE.


Zhu Q.S.,NMEMS Technology Research Organization | Zhu Q.S.,Japan National Institute of Advanced Industrial Science and Technology | Toda A.,Meltex Inc. | Zhang Y.,NMEMS Technology Research Organization | And 5 more authors.
International Journal of Electrochemical Science | Year: 2013

In this work, we presented a "bottom-up" and a "two-step" electrodeposition formulas for copper filling within high aspect through polymer holes (TPHs), which are needed for integrating flexible bio-micro-electro-mechanical system (bio-MEMS) sensors with conventional CMOS circuits. By using the "two-step" electrodeposition formula, a void-free copper filling is successfully realized for TPHs with the diameter of 20 μm and height of 125 μm in a common plating solution. The void-free filling effect was attributed to the preformed "V" profile after the first-step deposition. The filling time is reduced by about 80% than that of the "bottom-up" filling formula. The results suggest that the "two-step" deposition mode can be a potential solution to the long time of the through polymer holes filling. © 2013 by ESG.


Zhu Q.S.,NMEMS Technology Research Organization | Zhu Q.S.,Japan National Institute of Advanced Industrial Science and Technology | Toda A.,Meltex Inc. | Zhang Y.,NMEMS Technology Research Organization | And 5 more authors.
Journal of the Electrochemical Society | Year: 2014

In this work, the Cu electrodeposition was carried out for the filling of through silicon via (TSV) using an additive-free Cu electrolyte and periodic pulse reverse (PPR) current. It was attempted to understand the filling mechanism by PPR plating and then to explore a potential solution for void-free filling in easy electrolytes. The filling results showed that the void size was continually reduced as decreasing current density. A void-free filling was obtained at low current density. During the Cu growth process, a "V" shape filling structure occurred at the upper of the via and the ratio of this structure increased with the decrease of current density. The electrochemical analyzes results demonstrated that at low current density, the potential during forward deposition was more uniform along the depth, and during reverse pulse the potential difference between the shallow and deep location was larger than that at high current density. This result implied that at low current density the reverse pulse played a strong suppression effect that contributed to the "V" shape growth. A competitive growth model between the bottom reversed "V" structure and the upper "V" structure was proposed to explain the void-free filling mechanism in PPR plating process. © 2014 The Electrochemical Society. All rights reserved.


Tanaka J.,NMEMS Technology Research Organization | Imamoto H.,NMEMS Technology Research Organization | Seki T.,Omron Corporation | Oba M.,Omron Corporation
Proceedings of IEEE Sensors | Year: 2014

This paper describes the low power consumption wireless human detector which can monitor wide area. We have developed the S-shaped thermopile infrared sensor element by utilizing micro-electro-mechanical-systems (MEMS) technology. The developed thermopile infrared array sensor achieved high temperature resolution and fast response time. Number of human who exists in the detection area is simply detected by the human detection process using temperature outputs from the thermopile infrared array sensor. © 2014 IEEE.


Yamashita T.,NMEMS Technology Research Organization | Yamashita T.,Japan National Institute of Advanced Industrial Science and Technology | Zhang Y.,NMEMS Technology Research Organization | Zhang Y.,Japan National Institute of Advanced Industrial Science and Technology | And 6 more authors.
Proceedings of IEEE Sensors | Year: 2014

This paper presents a novel film based flexible clamp type current sensor for green wireless sensor networks fabricated by printed silver paste coil using the process technology in screen-printing as a low cost, simple, and rapid method. Since developed sensor has high flexibility, it can be used by winding the cable and drastically reduce the installation space. In addition, it can construct wireless sensor networks easily because wireless terminals can drive autonomously without external power supply by utilizing the secondary current generated in the coil of the sensor by electromagnetic induction. The sensor's output voltage changed linearly with variation of the value of primary current in the 0 to 100 A range. When the value of primary current was 100 A, the output voltage was 69 mV per 150 turns in the coil. Although the ambient temperature around the sensor was raised at 80°C due to heat evolved by the electric resistance of the coil, there was no almost variation of the voltage. This result indicates the practical applicability as the current sensor for electrical cables. © 2014 IEEE.


Tomimatsu Y.,NMEMS Technology Research Organization | Takahashi H.,University of Tokyo | Kobayashi T.,Japan National Institute of Advanced Industrial Science and Technology | Matsumoto K.,University of Tokyo | And 3 more authors.
Proceedings of the 2013 IEEE 8th International Conference on Intelligent Sensors, Sensor Networks and Information Processing: Sensing the Future, ISSNIP 2013 | Year: 2013

This paper reports a wake-up switch using a piezoelectric differential pressure sensor in order to reduce the power consumption of a wireless sensor node. Air pressure change surrounding the sensor is detected by using a Pb(Zr, Ti)O3(PZT) thin film cantilever with the dimension of 1500 μm × 1000 μm × 2 μm. The sensor has high sensitivity with low power consumption due to its thin cantilever and low capacitance. The sensitivity was 2.4 mV/Pa from -30 Pa to 30 Pa. It was demonstrated that the fabricated sensor performed as a wake-up switch when pressure varies in 10 Pa with low power consumption. © 2013 IEEE.


Shiraishi N.,NMEMS Technology Research Organization | Shiraishi N.,Tokyo University of Agriculture and Technology | Ikehara T.,NMEMS Technology Research Organization | Ikehara T.,Japan National Institute of Advanced Industrial Science and Technology | And 5 more authors.
Sensors and Actuators, A: Physical | Year: 2013

We investigated the size and mode dependencies of the resonance frequencies and quality factors of PMMA (polymethyl methacrylate) and PC (polycarbonate) cantilevers under atmospheric pressure in order to obtain fundamental data for polymer-based VOC (volatile organic compound) sensors. PMMA cantilevers and PC cantilevers are fabricated by hot embossing, bonding, and polishing techniques. Variations in the vibration mode result in large variations in the resonance frequencies and quality factors of these cantilevers. The measured resonance frequencies correlated well with the theoretical undamped resonance frequency of a flexural-vibrating cantilever. The measured quality factors varied from 10 to more than 100, depending on the vibration mode. A higher mode tended to exhibit a higher quality factor. © 2013 Elsevier B.V.


Lu J.,Japan National Institute of Advanced Industrial Science and Technology | Okada H.,Japan National Institute of Advanced Industrial Science and Technology | Itoh T.,Japan National Institute of Advanced Industrial Science and Technology | Harada T.,NMEMS Technology Research Organization | Maeda R.,Japan National Institute of Advanced Industrial Science and Technology
IEEE Sensors Journal | Year: 2014

Pursuit of the lowest size-limit of wireless sensor nodes may not only reduce power consumption and production cost, but also enables its layout-free ubiquitous applications, i.e., in our green sensor networks to compress energy consumption through visibility and optimization. In this paper, we engaged in developing the world smallest wireless sensor node with ultralow power consumption from both electrical block integration and physical interconnection points-of-view. A customized IC for signal processing and data transmission, which has universal interface to sensors and power management capability, was designed and then fabricated by using 0.18 μm 1.8 V/3.3 V 1P6M logic process. By introducing buried bump interconnection technology, we have successfully obtained one of the world's smallest wireless sensor nodes, as small as 3.9 mm × 3.9 mm × 3.5 mm, for humidity and temperature monitoring. The sensor node also features an general purpose interface, available for analog and digital sensors, and the ultrasmall footprint of above sensor node enables its layout-free distribution or integration inside other remote sensing systems. Although the adopted antenna size was 2 cm × 5 cm, its flexibility enables free attach to any curved surfaces. Experimental results demonstrated that besides preferred ultralow power consumption and data transmission distance, configuration of above sensor nodes enables its easy assembly with stand-alone power source and flexible antenna for wide variety of applications. © 2001-2012 IEEE.

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