Tsukuba Research Laboratory

Tsukuba, Japan

Tsukuba Research Laboratory

Tsukuba, Japan
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Iwashita K.,Tsukuba Research Laboratory | Katoh T.,Tsukuba Research Laboratory | Nakamura A.,Tsukuba Research Laboratory | Murakami Y.,Tsukuba Research Laboratory | Iwasaki T.,Hitachi Ltd.
Journal of Photopolymer Science and Technology | Year: 2016

As there is an increasing demand for advanced electronic devices, high-density and fine circuit is required more than ever before. However, it is difficult to fabricate fine Cu wiring below 5 μm on an organic substrate using current processes such as semi-additive process (SAP). In this paper, the trench wiring formation process with photosensitive organic materials was studied to make fine Cu wiring below 5 μm. Photosensitive organic materials were mainly used as protection and insulation layers of very large scale integrated circuit because they simplify via formation processing by photolithography. We newly developed film-type photosensitive insulation material for high-density interposer. The photosensitive insulation film (PIF) showed high resolution (L/S = 3/3μm for 10 μm-thick film) and suitability to novel trench Cu wiring formation process. Cu embedded wiring (L/S = 3/3 μm for 10 μm-thick Cu) was enabled by trench Cu wiring formation process. © 2016SPST.


Mitsukura K.,Tsukuba Research Laboratory | Saisyo R.,Tsukuba Research Laboratory | Makino T.,Tsukuba Research Laboratory | Hatakeyama K.,Hitachi Ltd. | And 7 more authors.
Journal of Photopolymer Science and Technology | Year: 2015

Photodefinable wafer level underfill has been developed and its design concept has been verified, that is, the removal of underfill on the top of bumps enables the excellent quality of bump connection without underfill entrapment. The photodefinable composition using carboxylic type polyimide shows poor resolution, whereas the phenol type polyimide based Photo WLUF, CD3000B, has good patterning properties. CD3000B could form underfill patterns having 15 μm diameter holes on 25 μm Cu bumps through conventional photolithography processes. The bonded samples showed the seamless bump junction and passed moisture sensitivity level 2 and thermal cycling reliability test. © 2015SPST.


Horikawa Y.,Kyoto University | Imai T.,Kyoto University | Takada R.,Kyoto University | Watanabe T.,Kyoto University | And 3 more authors.
Applied Biochemistry and Biotechnology | Year: 2012

In this paper, we report the combination of a near-infrared (NIR) spectroscopic method with multivariate analysis in order to develop a calibration model of the saccharification ratio of chemically pretreated Erianthus. The regression models clearly depend on the NIR spectral regions, and the information of CH and aromatic framework vibrations contributed most effectively to the alkaline dataset. From interpretations of the regression coefficient, lignin and cellulose were negatively and positively correlated with the saccharification ratio, respectively, and this result was supported by the data from wet chemical analysis. A more complex dataset was obtained from varied chemical pretreatments; here, the saccharification ratio was either small or had no linear correlation with each structural monocomponent. These results enabled the successful construction of the PLS regression model. NIR spectroscopy can be a rapid screening method for the saccharification ratio, and furthermore, can provide information of the key factors influencing the realization of more efficient enzymatic accessibility. © Springer Science+Business Media, LLC 2011.


Horikawa Y.,Kyoto University | Imai T.,Kyoto University | Takada R.,Kyoto University | Watanabe T.,Kyoto University | And 3 more authors.
Applied Biochemistry and Biotechnology | Year: 2011

We report a simple analytical procedure combining near-infrared (NIR) spectroscopy with multivariate analysis to detect the saccharification efficiency of pretreated rice straw. Three types of sample preparation methods were tested to develop a powerful calibration model, with the disk sample used as the standard protocol. From the spectra dataset of NaOH-treated biomass, we obtained a good calibration for the saccharification ratio and some major structural components by partial least-squares regression. Adding dataset from hot water and dilute sulfuric acid pretreatments to NaOH sample dataset, an acceptable calibration model to predict the saccharification ratio as well as the glucose, xylose, and lignin contents was generated. NIR has a great potential for rapid screening of saccharification efficiency of pretreated biomass, which would allows us to control the quality of processing toward better bioethanol production. © Springer Science+Business Media, LLC 2010.


Horikawa Y.,Kyoto University | Konakahara N.,Kyoto University | Imai T.,Kyoto University | Kentaro A.,Kyoto University | And 2 more authors.
Polymer Degradation and Stability | Year: 2013

The enzymatic hydrolysis of cellulose I achieves almost complete digestion when sufficient enzyme loading as much as 20 mg/g-substrate is applied. However, the yield of digestion reaches the limit when the enzyme dosage is decreased to 2 mg/g-substrate. Therefore, we have performed three pretreatments such as mercerization, dissolution into phosphoric acid and EDA treatment. Transformation into cellulose II hydrate by mercerization and dissolution into phosphoric acid were not sufficient because substrate changed to highly crystalline structure during saccharification. On the other hand, in the case of crystalline conversion of cellulose I to IIII by EDA, almost perfect digestion was achieved even in enzyme loading as small as 0.5 mg/g-substrate, furthermore, hydrolyzed residue was typical cellulose I. The structural analysis of substrate after saccharification provides an insight into relationships between cellulose crystalline property and cellulase toward better enzymatic digestion. © 2013 Elsevier Ltd. All rights reserved.


Horikawa Y.,Tokyo University of Agriculture and Technology | Horikawa Y.,Kyoto University | Imai T.,Kyoto University | Abe K.,Kyoto University | And 5 more authors.
Cellulose | Year: 2016

We developed a novel and practical assessment technique for endoglucanase (EG) activity by measuring the degree of polymerization (DP) of cellulose from Eucalyptus globulus. This evaluation method demonstrated that EG II from Trichoderma reesei had higher endoglucanase activity than EG I, which has not been detected in conventional experiments using carboxymethyl cellulose as a model substrate. In addition, a high-throughput protocol for DP measurement was developed by using near-infrared spectroscopy combined with a multivariate analysis. Interpreting the regression coefficient, a reciprocal correlation was observed between the relative crystallinity of the cellulosic residue after enzymatic hydrolysis and the DP. © 2016 Springer Science+Business Media Dordrecht


Suzuki J.,Tsukuba Research Laboratory | Arima Y.,Tsukuba Research Laboratory | Yamaji M.,Tsukuba Research Laboratory | Kawashima H.,Tsukuba Research Laboratory | Tanaka S.,Tsukuba Research Laboratory
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2010

We report on a curved waveguide fabrication using femtosecond laser processing with a glass hologram. We design and produce a glass hologram that transforms femtosecond laser beam into a half-ring beam. The half-ring beam generated by the glass hologram is patterned inside fused silica with one laser shot. The guided light whose bending radius is larger than 1mm is observed at wavelength of 635nm. As a simple application, a directional coupler consisting of a straight-line waveguide and a half-ring waveguide is fabricated by two laser shots. Its basic functionality as a coupler is confirmed. We also develop a hologram that simultaneously produces a straight-line and a half-ring. Using it, we demonstrate a directional coupler fabrication inside crown glass with one laser shot. © 2010 Copyright SPIE - The International Society for Optical Engineering.


Suzuki J.,Tsukuba Research Laboratory | Arima Y.,Tsukuba Research Laboratory | Tanaka S.,Tsukuba Research Laboratory
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2011

Using femtosecond laser processing with glass-hologram, fabrication of 1cm-long straight waveguide and X-coupler is reported in this paper. We design and fabricate 4-level glass-hologram which generates 1cm-long straight line intensity. We fabricate 1cm-long waveguides inside fused silica at one shot exposure with the glass-hologram. We investigate the waveguide performance of near field pattern and propagation loss at wavelength of 1550nm. The near field pattern is almost circular shape. The propagation loss at 1550nm is estimated to be < 1.0 dB/cm. As an example of an optical device consisting of straight waveguides, we fabricate X-coupler or 2x2 coupler using straight line waveguides, and observe the output power ratio depending on crossing angle. © 2011 Copyright Society of Photo-Optical Instrumentation Engineers (SPIE).


Sai H.,Japan National Institute of Advanced Industrial Science and Technology | Matsui T.,Japan National Institute of Advanced Industrial Science and Technology | Bidiville A.,Japan National Institute of Advanced Industrial Science and Technology | Koida T.,Japan National Institute of Advanced Industrial Science and Technology | And 3 more authors.
Materials Research Society Symposium Proceedings | Year: 2013

Periodically textured back reflectors with hexagonal dimple arrays are applied to thin-film microcrystalline silicon (μc-Si:H) solar cells for enhancing light trapping. The period and aspect ratio of the honeycomb textures have a big impact on the photovoltaic performance. When the textures have a moderate aspect ratio, the optimum period for obtaining a high short circuit current density (JSC) is found to be equal to or slightly larger than the cell thickness. If the cell thickness exceeds the texture period, the cell surface tends to be flattened and texture-induced defects are generated, which constrain the improvement in JSC. Based on these findings, we have fabricated optimized μc-Si:H cells achieving a high active-area efficiency exceeding 11% and a JSC of 30 mA/cm2. © 2013 Materials Research Society.


Horikawa Y.,Kyoto University | Imai M.,Kyoto University | Kanai K.,Kyoto University | Imai T.,Kyoto University | And 4 more authors.
Biochemical Engineering Journal | Year: 2015

This study reports a method that combines near-infrared (NIR) measurements with multivariate analysis to predict the saccharification efficiency of hydrothermally pretreated Eucalyptus globulus during ethanol conversion. Optimization of the NIR data with or without spectral treatment determined the best calibration model in the region 10000-4000cm-1 of the original spectra, with an RMSEP of 2.08% and Rp 2 of 0.99. By investigating the regression coefficient to understand the key regions and chemical components, for original and multiplicative scatter correction (MSC)-treated spectra, the water absorption and higher wavenumber regions were important. For the second derivative spectra, the regression model was constructed based on the CH overtone vibrations (6050-5500cm-1). The regression coefficient demonstrated that the removal of hemicellulose resulted in higher lignin content, which might affect the biomass properties in terms of water absorption and enhanced enzymatic hydrolysis evaluated by dinitrosalicylic acid (DNS) method. For a higher throughput system, aqueous sample analysis was performed using an immersion probe equipped with an InGaAs detector, which generated an acceptable calibration model having RMSEP of 4.25% and Rp 2 of 0.94. These results show the great potential of NIR spectroscopy for achieving fast, accurate, and nondestructive analysis, and its highly adaptability for maintaining an ethanol bioconversion system.TGS, triglycine sulfate. © 2015 Elsevier B.V.

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