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ABSTRACT: Fine size Ni/Sn bumps were formed by electroless Ni/Sn plating and hydrogen plasma reflow, and then electrical characteristics of nMOSFETs and pMOSFETs were evaluated on the bumped chips. After the hydrogen plasma reflow, threshold voltages and carrier mobilities were not changed from those of the nMOSFETs and pMOSFETs as fabricated, before Ni/Sn plating. Also, gate leak currents were not increased by the plasma reflow for both the nMOSFETs and pMOSFETs. Off leak currents of the nMOSFETs were slightly decreased after the plasma reflow. In contrast, off leak currents of the pMOSFETs were slightly increased up to several tens of pA after the plasma reflow. However, the changes of the off leak currents by the plasma reflow were very small for both the nMOSFETs and pMOSFETs. Electrical damages induced by the plasma reflow were negligible for both the nMOSFETs and pMOSFETs.
Electronics Packaging Technology Conference, 2007. EPTC 2007. 9th; 01/2008
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ABSTRACT: We investigated electroless Ni uniformity on Al metal pads connected to different size pads or a pn junction for under bump metallurgy in flip-chip assemblies. In an electrically isolated pad, Ni thickness decreased as the pad size decreased. Because of nonlinear diffusion of Pb<sup>2+</sup> stabilizer in the plating solution, fewer electrons were supplied to the smaller pad than to the larger pad by an anodic oxidation reaction on the pad surface. In pads smaller than 50 mum square, the Ni thickness increased when connected to a 100 mum square pad. This increase might be caused by electrons flowing from the 100 mum square pad to the smaller pad to produce an equipotential for the connected pads. In addition, the Ni thickness was increased by electrical connection to an n-type Si in the presence of fluorescent light illumination for a pn junction area larger than 100 mum<sup>2</sup>. For a pad connected to a p-type Si, however, Ni thickness decreased in comparison to that of an electrically-isolated pad, regardless of the light illumination or pn junction area. The change of Ni height on pads connected to the pn junction is attributable to photoelectrons injected into the n-type Si, or to electron-hole recombination in the p-type Si. These results indicate that the pads should be of the same size within a chip for better Ni uniformity. Moreover, blocking light during Ni electroless plating can eliminate Ni thickness differences due to an n-type Si connection.
IEEE Transactions on Components and Packaging Technologies 10/2007; · 0.94 Impact Factor
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A. Ikeda,
Y. Sugimoto,
T. Kuwada,
S. Kajiwara,
T. Fujimura,
K. Iwasaki,
H. Ogi,
K. Hamaguchi,
H. Kuriyaki,
R. Hattori, Y. Kuroki
Reliability Physics Symposium, 2005. Proceedings. 43rd Annual. 2005 IEEE International; 02/2005
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ABSTRACT: We designed and measured test element group wafers thinned to 10 μm for 3D system in package. The n-well p-Si diodes in 10 μm thick wafer showed increasing of the reverse saturation current in comparison to the currents in 20 μm, 30 μm or 640 μm thick wafer. While the pMOSFETs and nMOSFETs in 10 μm thick wafer showed no degradation of mobility, sub-threshold swing and threshold voltage. Defects might be induced by mechanical stress during wafer back grinding process near wafer back side, within a few micron-meters from the wafer back surface.
Microelectronic Test Structures, 2004. Proceedings. ICMTS '04. The International Conference on; 04/2004
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ABSTRACT: In this paper we study about the fabrication of absorber-embedded in membrane type deep X-ray exposure mask with wide exposure area made with Si substrate.
Microprocesses and Nanotechnology Conference, 2003. Digest of Papers. 2003 International; 11/2003
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ABSTRACT: The on-chip microcapillary applying for electrophoresis analysis device has been fabricated on photosensitive glass. This process can make a high aspect-ratio channel structure. The channel-depth can be controlled by varying wet-etching time without widening the channel width because the substrate material has vertical high etch rate selectivity. This high aspect-ratio structure obtains a long optical path and appropriate sample volume resulting in high-sensitivity for various analyses. The fabrication process is simpler than a usual glass micromachining process because of photo-resistless lithography process. In order to smooth the channel surface and to attach a cover glass onto the substrate, a polysilazane coating process is proposed and revealed to be effective.
Microsystem Technologies 09/2003; 9(8):541-545. · 0.93 Impact Factor
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ABSTRACT: Silicon oxynitride (SiON) has emerged as a better gate dielectric material to replace ultra-thin gate SiO<sub>2</sub> in scaled down metal-oxide-semiconductor (MOS) devices. The present study investigates the leakage current in SiON grown by a plasma-based process. Thin films of SiON (6 nm) were grown on Si substrates by nitriding rapid thermally grown SiO<sub>2</sub> layers in a low-energy, microwave excited nitrogen plasma and by subsequent re-oxidation; and the resulting films were characterized in Al/SiON/p-Si MOS structures under atmospheric, vacuum and low temperature conditions. The analysis of the current-voltage (I-V) characteristics obtained under atmospheric conditions shows an enhanced leakage current in the pre-Fowler-Nordheim region of 4∼8 MV/cm oxide field range. However, I-V characterization in vacuum showed the complete removal of this additional current component. This current was found to be not due to a charging/capacitive effect. It is speculated that this additional mid-ox ide-field leakage current could possibly be due to a conducting pathway given rise to by interaction of atmospheric gases/water molecules with the plasma induced defects on the oxynitride film.
Properties and Applications of Dielectric Materials, 2003. Proceedings of the 7th International Conference on; 07/2003
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ABSTRACT: Human genome project has now been completed. At the next stage, the analysis of the DNA diversity originated from each individual is a very important aspect. It requires a method that can determine the base-pair sequence quickly and easily for fast and effective analysis. Separating the biochemical samples by electrophoresis is one of the analysis processes. Recently, electrophoresis has been performed in the fine channel formed on various substrates. By utilizing a microchannel chip for electrophoresis, the dead volume of the reagent and detection apparatus, and energy are reduced. To improve the separation performance of microchannel chip, the width of the channel should be narrower. On the other hand, the volume of the sample that can be introduced is restricted. Then, the channel is filled with ionic solution, and the top of the substrate is covered with a plate for shallow channel, so as not to cause current leakage induced by applying high voltage during electrophoresis. But, it requires a high quality substrate-cover adhesion. technique. We propose a high-aspect-ratio open-top microchannel plate. The high-aspect-ratio structure increases the sample and reagent volume inside the channel without increasing the channel width, which results in an enhancement of the detection sensitivity. And the buffer solution is introduced only before the measurement and sequential supply from an external source is not needed. The chip is standalone. The deep channel leads to another advantage. Its deep depth prevents overflow of the solution to the uncovered channel. By avoiding the difficult sealing process, the fabrication process become easy and high-throughput is realized.
Microprocesses and Nanotechnology Conference, 2002. Digest of Papers. Microprocesses and Nanotechnology 2002. 2002 International; 12/2002
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ABSTRACT: In a capillary electrophoresis separation performance is affected by various factors, for example, an electroosmotic flow, dispersion of sample plug and sample adsorption to capillary wall. In order to miniaturize the microcapillary onto a chip we have to understand them in detail and investigate their influence. Confocal Laser Scanning Microscopy (CLSM) in fluorescence mode (FV300 Fluoview OLYMPUS JAPAN CO., LTD, Japan) was used to observe the motion of the samples in microcapillary fabricated on a chip. The CLSM is a powerful tool to understand their influence since it can capture the fluorescence images sliced in the plane perpendicular to the optical axis and can scan the plane position along the optical axis. Therefore it makes possible to observe the sample behavior inside the channel. This study also contributes the investigation of the microfluidic manipulation which includes a micropump, a microvalve and other microfluidic actuator devices under electrokinetic driven conditions.
Microprocesses and Nanotechnology Conference, 2002. Digest of Papers. Microprocesses and Nanotechnology 2002. 2002 International; 12/2002
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ABSTRACT: To analyze DNA fragments rapidly and easily will be a most important process in a future DNA industry. This paper reports a new fabrication process and a new device structure for microchip-based capillary electrophoresis (CE) using chemically machinable photosensitive glass substrate. The fabrication process of our device has an advantage in mass production as an inexpensive device. In addition we can easily obtain the high aspect-ratio structure of the channel, which presents high performance in separation characteristics
Microprocesses and Nanotechnology Conference, 2000 International; 08/2000
