| Co-Investigator(Kenkyū-buntansha) |
AKABOSHI Hruo Hitachi Ltd., Hitachi Research Laboratory, Senior Researcher, 日立研究所, 主担研究員
NISHINA Tatsuo Tohoku Univ., Dept. Mol. Chem. and Eng., Research Associate, 工学部, 助手 (60172673)
OSAWA Masatoshi Tohoku Univ., Dept. Mol. Chem. and Eng., Associate Professor, 工学部, 助教授 (00108466)
MATSUE Tomokazu Tohoku Univ., Dept., Dept. Mol. Chem. and Eng., Associate Professor, 工学部, 助教授 (70173797)
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| Research Abstract |
This research project aimed at developing the electrochemical microfabrication technology in electrolytic and electroless deposition of conducting layers and at applying it to electrochemical molecular devices. One of the most important technology in electrochemical metal deposition at present is PC board manufacturing and strong demands driving technology are miniaturization, higher aspect ratio through hole plating and high quality deposits with good mechanical properties. In this connection a part of work was devoted to collaborate with an industry to study laser-assisted electroplating and organic additive effects to improve the mechanical properties.
1. Studies on laser-assisted metal deposition and electrochemical microfabrication by plating techiques
(1) Laser-assisted electroplating seems to be useful for maskless high speed plating, but the quality of deposits was not good.
(2) In industrial electroless Cu plating, the addition of 2, 2' bipyridyl is quite effective in production
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of high quality Cu film. We applied various techniques such as surface enhanced Raman spectroscopy, in situ IR spectroscopy and electrochemical impedance spectroscopy to reveal the structure of adsorbed molecules and obtained interesting results. In addition to the above microscopic studies, a new technique, low angle incident insitu X ray diffraction, has been introduced to determine the crystal size of deposits growing with and without the additive. Results of correlation between the crystal size and the concentration of additive, and of the formation of Cu_2O as impurity in the presence of 2, 2' bipyridyl and its decomposition by aeration will provide useful information to refine the existing plating processes.
2. Fabrication of microelectrodes and its application to electrochemical molecular devices
(1) Fabrication techniques for various types of microarray electrodes of Pt, Au and ITO, i. e., interdigitated array and independent electrode array electrodes, has been developed, of which dimension are 4-20 mum in gap and electrode widths. Sub-micron size disk type ultra-microelectrodes were also fabricated. As to the disk type electrode concentrated effort has been done to reduce the tip diameter to few microns including an insulator sheath, and ultra-micro ring electrodes were developed using electroless deposition of Ag. Platinum coated Ag ring electrodes were used for amperometric intercelluar voltammetry in a single protoplast cell.
(2) Using microarray electrode systems, we have tried to construct electrochemical devices such as HPLC detectors provided with electrochemical amplification by redox cycling and with a multi-functional display of effluent time and electrode potential. Another interesting application noticed in this work is development of electrochemical digital devices responding chemical signals. We found that the electrode array interconnected with thin polypyrrole films deposited by electropolymerization shows a sensitive response to pH change, giving large conductivity change between adjacent band arrays, similar behavior to FFT device. Based on this finding, pH switchs and enzyme switches which are integrated systems of polypyrrole and enzymes have been developed. Less
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