The Experts below are selected from a list of 162 Experts worldwide ranked by ideXlab platform
Tadatomo Suga - One of the best experts on this subject based on the ideXlab platform.
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recycled low temperature direct bonding of si glass and glass glass chips for detachable micro nanofluidic devices
Journal of Materials Science & Technology, 2020Co-Authors: Chenxi Wang, Tadatomo Suga, Hui Fang, Shicheng Zhou, Xiaoyun Qi, Wei Zhang, Yanhong TianAbstract:Abstract Silicon and glass are two of the most ideal materials for micro/nanofluidic devices, which have been widely used for research in multidisciplinary fields. However, many micro/nanofluidic devices enable only single use due to the irreversible bonding between Si/glass or glass/glass chips. If the silicon- and glass-based devices are fabricated to be detachable, the substrates can be reused and bonded again without repeating expensive micro/nanofabrication processes. Herein, we present a recycled direct bonding method for Si/glass and glass/glass chips based on oxygen Plasma Activation and low-temperature annealing processes. Strong bonding strength and void-free bonding interface are obtained after annealing at 150 °C. The surfaces and the bonding interfaces are characterized to elucidate the bonding mechanisms. Moreover, immersion tests are carried out to investigate the interfacial corrosion resistance in various chemical and biological solutions as well as explore a detachable method. The bonding strengths are controlled to meet the demand for micro/nanofluidic devices and the bonding interfaces can be separated in ethanol. As a result, we succeed in the experiment of bonding and detaching of glass substrates without fracturing, which is repeated for three times.
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investigation of fluorine containing Plasma Activation for room temperature bonding of si based materials
Microelectronics Reliability, 2012Co-Authors: Chenxi Wang, Tadatomo SugaAbstract:Abstract Wafer direct bonding of Si based materials, such as silicon, silicon oxide and silicon nitride, is a generic technique enabling realization of innovative structures in semiconductor industry. In this paper, a fluorine containing Plasma activated bonding method is developed to achieve sufficient bonding at room temperature in air ambient with no heating process. The whole process is facile and cost effective without requiring high-vacuum system. It does work well for bonding of Si-based materials except for Si 3 N 4 /Si 3 N 4 bonded pairs. The bonding strengths of specimens prepared by fluorine containing oxygen Plasma are significantly improved at room temperature compared with those by oxygen Plasma. The improved bonding strength is possibly attributed to the formation of fluorinated oxide layers on wafer surfaces after the Plasma treatment.
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room temperature direct bonding using fluorine containing Plasma Activation
Journal of The Electrochemical Society, 2011Co-Authors: Chenxi Wang, Tadatomo SugaAbstract:Room-temperature Si/Si wafer direct bonding has been achieved successfully without wet chemistry treatment as well as no requiring annealing. Very strong bonding strength of Si/Si pairs, close to the bulk-fracture strength of silicon, is demonstrated at room temperature thanks to adding small amount of carbon tetrafluoride (CF 4 ) into oxygen Plasma treatment. The surface energies of bonded Si/Si wafer pairs were influenced by Plasma treatment parameters. Moreover, the wafer surfaces and the bonding interfaces are analyzed to explore the bonding mechanism. Adding small amount of CF 4 into O 2 Plasma does not etch the Si surface in a short time (~60 s), but it renders fluorinated oxide grown on the Si surface, which should be less hydrophilic than the surface treated by O 2 Plasma. Therefore, fewer water molecules at bonding interface may be prone to produce many covalent bonds via polymerization reaction and result in strong bonding at room temperature.
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low temperature bonding of laser diode chips on silicon substrates using Plasma Activation of au films
IEEE Photonics Technology Letters, 2007Co-Authors: Eiji Higurashi, Tadatomo Suga, T Imamura, Renshi SawadaAbstract:A low-temperature bonding of vertical-cavity surface-emitting laser (VCSEL) chips on Si substrates was achieved by using Plasma Activation of Au films. After the surfaces of Au films were cleaned using an Ar radio frequency Plasma, bonding was carried out by contact in ambient air with applied static pressure. The experimental results showed that surface morphological change (the reduction of asperity width) as well as removal of adsorbed organic contaminants by Plasma treatment significantly improved the quality of joints. At a bonding temperature of 100degC, the die-shear strength exceeded the failure criteria of MIL-STD-883.
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room temperature wafer level glass glass bonding
Sensors and Actuators A-physical, 2006Co-Authors: Matiar M. R. Howlader, Satoru Suehara, Tadatomo SugaAbstract:Abstract The findings of this study report the bonding of glass/glass wafers by using the surface activated bonding (SAB) method at room temperature (RT) without heating. In order to bond, the glass wafers were activated by a sequential Plasma Activation process, in which the wafers were cleaned with reactive ion etching (RIE) oxygen radio frequency (rf) Plasma and nitrogen radical microwave (MW) Plasma one after another and then contacted under hand-applied pressure followed by cold rolling under 20 kg load in atmospheric air. High bonding strength for glass/glass was achieved. Paramount influence of N 2 radical MW Plasma on the adhesion enhancement of silicon/silicon bonding motivated the investigation of the N 2 radical MW Plasma relationship with the bonding strength of glass/glass. A considerable influence of N 2 pressure on the bonding strength was not observed except in N 2 gas pressure of 30 Pa, which might be due to the debonding between glue and fixture used for tensile pulling test. No significant effect of OH density of glass wafers on the bonding strength was found below 400 °C. The result was evident from 400 °C and it was about twofold higher at 600 °C than that of RT to 400 °C. This result indicated that the sequential process bonding mechanism was consisting of long bridges of hydrogen bonding by water molecules. Significant environmental influence on the bonding strength was found and which could be correlated with OH molecules of glass wafers.
Shanhui Hsu - One of the best experts on this subject based on the ideXlab platform.
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long term regeneration and functional recovery of a 15 mm critical nerve gap bridged by tremella fuciformis polysaccharide immobilized polylactide conduits
Evidence-based Complementary and Alternative Medicine, 2013Co-Authors: Shu-hui Yang, Shanhui Hsu, Shanho Cha, Chihtsung Weng, Ching-fe JiangAbstract:Novel peripheral nerve conduits containing the negatively charged Tremella fuciformis polysaccharide (TF) were prepared, and their efficacy in bridging a critical nerve gap was evaluated. The conduits were made of poly(D,L-lactide) (PLA) with asymmetric microporous structure. TF was immobilized on the lumen surface of the nerve conduits after open air Plasma Activation. The TF-modified surface was characterized by the attenuated total reflection Fourier-transformed infrared spectroscopy and the scanning electron microscopy. TF modification was found to enhance the neurotrophic gene expression of C6 glioma cells in vitro. TF-modified PLA nerve conduits were tested for their ability to bridge a 15 mm gap of rat sciatic nerve. Nerve regeneration was monitored by the magnetic resonance imaging. Results showed that TF immobilization promoted the nerve connection in 6 weeks. The functional recovery in animals receiving TF-immobilized conduits was greater than in those receiving the bare conduits during an 8-month period. The degree of functional recovery reached ~90% after 8 months in the group of TF-immobilized conduits.
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Long-Term Regeneration and Functional Recovery of a 15 mm Critical Nerve Gap Bridged by Tremella fuciformis Polysaccharide-Immobilized Polylactide Conduits
Hindawi Limited, 2013Co-Authors: Shanhui Hsu, Shu-hui Yang, Shanho Cha, Chihtsung Weng, Ching-fe JiangAbstract:Novel peripheral nerve conduits containing the negatively charged Tremella fuciformis polysaccharide (TF) were prepared, and their efficacy in bridging a critical nerve gap was evaluated. The conduits were made of poly(D,L-lactide) (PLA) with asymmetric microporous structure. TF was immobilized on the lumen surface of the nerve conduits after open air Plasma Activation. The TF-modified surface was characterized by the attenuated total reflection Fourier-transformed infrared spectroscopy and the scanning electron microscopy. TF modification was found to enhance the neurotrophic gene expression of C6 glioma cells in vitro. TF-modified PLA nerve conduits were tested for their ability to bridge a 15 mm gap of rat sciatic nerve. Nerve regeneration was monitored by the magnetic resonance imaging. Results showed that TF immobilization promoted the nerve connection in 6 weeks. The functional recovery in animals receiving TF-immobilized conduits was greater than in those receiving the bare conduits during an 8-month period. The degree of functional recovery reached ~90% after 8 months in the group of TF-immobilized conduits
Ching-fe Jiang - One of the best experts on this subject based on the ideXlab platform.
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Research Article Long-Term Regeneration and Functional Recovery of a 15mm Critical Nerve Gap Bridged by Tremella fuciformis
2016Co-Authors: Polysaccharide-immobilized Polylactide Conduits, Shu-hui Yang, Ching-fe JiangAbstract:Copyright © 2013 Shan-hui Hsu et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Novel peripheral nerve conduits containing the negatively charged Tremella fuciformis polysaccharide (TF) were prepared, and their efficacy in bridging a critical nerve gap was evaluated. The conduits were made of poly(D,L-lactide) (PLA) with asymmetric microporous structure. TF was immobilized on the lumen surface of the nerve conduits after open air Plasma Activation. The TF-modified surface was characterized by the attenuated total reflection Fourier-transformed infrared spectroscopy and the scanning electron microscopy. TF modification was found to enhance the neurotrophic gene expression of C6 glioma cells in vitro. TF-modified PLA nerve conduits were tested for their ability to bridge a 15mm gap of rat sciatic nerve. Nerve regeneration was monitored by the magnetic resonance imaging. Results showed that TF immobilization promoted the nerve connection in 6 weeks
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long term regeneration and functional recovery of a 15 mm critical nerve gap bridged by tremella fuciformis polysaccharide immobilized polylactide conduits
Evidence-based Complementary and Alternative Medicine, 2013Co-Authors: Shu-hui Yang, Shanhui Hsu, Shanho Cha, Chihtsung Weng, Ching-fe JiangAbstract:Novel peripheral nerve conduits containing the negatively charged Tremella fuciformis polysaccharide (TF) were prepared, and their efficacy in bridging a critical nerve gap was evaluated. The conduits were made of poly(D,L-lactide) (PLA) with asymmetric microporous structure. TF was immobilized on the lumen surface of the nerve conduits after open air Plasma Activation. The TF-modified surface was characterized by the attenuated total reflection Fourier-transformed infrared spectroscopy and the scanning electron microscopy. TF modification was found to enhance the neurotrophic gene expression of C6 glioma cells in vitro. TF-modified PLA nerve conduits were tested for their ability to bridge a 15 mm gap of rat sciatic nerve. Nerve regeneration was monitored by the magnetic resonance imaging. Results showed that TF immobilization promoted the nerve connection in 6 weeks. The functional recovery in animals receiving TF-immobilized conduits was greater than in those receiving the bare conduits during an 8-month period. The degree of functional recovery reached ~90% after 8 months in the group of TF-immobilized conduits.
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Long-Term Regeneration and Functional Recovery of a 15 mm Critical Nerve Gap Bridged by Tremella fuciformis Polysaccharide-Immobilized Polylactide Conduits
Hindawi Limited, 2013Co-Authors: Shanhui Hsu, Shu-hui Yang, Shanho Cha, Chihtsung Weng, Ching-fe JiangAbstract:Novel peripheral nerve conduits containing the negatively charged Tremella fuciformis polysaccharide (TF) were prepared, and their efficacy in bridging a critical nerve gap was evaluated. The conduits were made of poly(D,L-lactide) (PLA) with asymmetric microporous structure. TF was immobilized on the lumen surface of the nerve conduits after open air Plasma Activation. The TF-modified surface was characterized by the attenuated total reflection Fourier-transformed infrared spectroscopy and the scanning electron microscopy. TF modification was found to enhance the neurotrophic gene expression of C6 glioma cells in vitro. TF-modified PLA nerve conduits were tested for their ability to bridge a 15 mm gap of rat sciatic nerve. Nerve regeneration was monitored by the magnetic resonance imaging. Results showed that TF immobilization promoted the nerve connection in 6 weeks. The functional recovery in animals receiving TF-immobilized conduits was greater than in those receiving the bare conduits during an 8-month period. The degree of functional recovery reached ~90% after 8 months in the group of TF-immobilized conduits
Martti Toivakka - One of the best experts on this subject based on the ideXlab platform.
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Plasma Activation induced changes in surface chemistry of pigment coating components
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2009Co-Authors: Maiju Pykonen, Hanna Silvaani, J S Preston, Pedro Fardim, Martti ToivakkaAbstract:The influence of Plasma Activation on pigment coating components was investigated. Four model pigment-coated papers were treated with industrial corona, experimental pilot scale argon Plasma, laboratory scale nitrogen Plasma equipment, and finally printed in a pilot scale sheet-fed offset printing press. Surface characterization was performed by contact angle measurements, X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectroscopy (ToF-SIMS). Gallium focused ion beam (FIB) and optical microscope imaging were used to investigate the reason for the decreased print density caused by intensive laboratory scale Plasma. According to the contact angle and XPS results, Plasma Activation increased surface wettability and oxygen/carbon (O/C) ratio. The changes seemed to occur especially in respect to high molecular weight dispersion chemicals of both pigment and latex particles. The used pigment coating components responded differently to the treatments. Water contact angles of kaolin containing papers decreased more than papers containing calcium carbonate or talc. Ground calcium carbonate (GCC) containing paper had the smallest change in O/C ratio. When compared to corona treatment, pilot scale argon Plasma provided higher polarity on the surface and smaller O/C ratio on the reverse side on the paper. The intensive laboratory scale Plasma treatment led a decrease in surface strength and print density. FIB and optical microscope images showed that micro-picking was occurring in the surface layers of the coating leaving some areas unprinted.
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effects of atmospheric Plasma Activation on surface properties of pigment coated and surface sized papers
Applied Surface Science, 2008Co-Authors: Maiju Pykonen, Pedro Fardim, Henna Sundqvist, Joakim Jarnstrom, Ottoville Kaukoniemi, Mikko Tuominen, Johanna Lahti, Jouko Peltonen, Martti ToivakkaAbstract:Abstract Pigment-coated, surface-sized, and surface-sized copy papers were treated with conventional corona, experimental pilot-scale Plasma and laboratory-scale Plasma. All the treatments increased the surface energy and oxidized the surface. The changes in the surface chemistry depended on treatment time and composition of the substrate surface. It seems that Plasma especially oxidizes the long polymer chains, such as surfactants and other paper chemicals, on the surface of the paper. The ToF-SIMS distribution maps indicated that the pilot-scale treatment led to an uneven CO+ group distribution, whereas laboratory scale treatment gave a more even distribution of CO+ groups. In addition to chemical changes, topographical changes due to Plasma treatment were detected. The RMS roughness increased for pigment-coated paper, whereas Plasma treatment induced small nodules between the paper pigment particles with pigmented and surface-sized paper. The increase in roughness was also found to increase the wettability. This serves as a demonstration of roughness-induced increase of surface energy of the samples.
Chenxi Wang - One of the best experts on this subject based on the ideXlab platform.
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recycled low temperature direct bonding of si glass and glass glass chips for detachable micro nanofluidic devices
Journal of Materials Science & Technology, 2020Co-Authors: Chenxi Wang, Tadatomo Suga, Hui Fang, Shicheng Zhou, Xiaoyun Qi, Wei Zhang, Yanhong TianAbstract:Abstract Silicon and glass are two of the most ideal materials for micro/nanofluidic devices, which have been widely used for research in multidisciplinary fields. However, many micro/nanofluidic devices enable only single use due to the irreversible bonding between Si/glass or glass/glass chips. If the silicon- and glass-based devices are fabricated to be detachable, the substrates can be reused and bonded again without repeating expensive micro/nanofabrication processes. Herein, we present a recycled direct bonding method for Si/glass and glass/glass chips based on oxygen Plasma Activation and low-temperature annealing processes. Strong bonding strength and void-free bonding interface are obtained after annealing at 150 °C. The surfaces and the bonding interfaces are characterized to elucidate the bonding mechanisms. Moreover, immersion tests are carried out to investigate the interfacial corrosion resistance in various chemical and biological solutions as well as explore a detachable method. The bonding strengths are controlled to meet the demand for micro/nanofluidic devices and the bonding interfaces can be separated in ethanol. As a result, we succeed in the experiment of bonding and detaching of glass substrates without fracturing, which is repeated for three times.
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investigation of fluorine containing Plasma Activation for room temperature bonding of si based materials
Microelectronics Reliability, 2012Co-Authors: Chenxi Wang, Tadatomo SugaAbstract:Abstract Wafer direct bonding of Si based materials, such as silicon, silicon oxide and silicon nitride, is a generic technique enabling realization of innovative structures in semiconductor industry. In this paper, a fluorine containing Plasma activated bonding method is developed to achieve sufficient bonding at room temperature in air ambient with no heating process. The whole process is facile and cost effective without requiring high-vacuum system. It does work well for bonding of Si-based materials except for Si 3 N 4 /Si 3 N 4 bonded pairs. The bonding strengths of specimens prepared by fluorine containing oxygen Plasma are significantly improved at room temperature compared with those by oxygen Plasma. The improved bonding strength is possibly attributed to the formation of fluorinated oxide layers on wafer surfaces after the Plasma treatment.
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room temperature direct bonding using fluorine containing Plasma Activation
Journal of The Electrochemical Society, 2011Co-Authors: Chenxi Wang, Tadatomo SugaAbstract:Room-temperature Si/Si wafer direct bonding has been achieved successfully without wet chemistry treatment as well as no requiring annealing. Very strong bonding strength of Si/Si pairs, close to the bulk-fracture strength of silicon, is demonstrated at room temperature thanks to adding small amount of carbon tetrafluoride (CF 4 ) into oxygen Plasma treatment. The surface energies of bonded Si/Si wafer pairs were influenced by Plasma treatment parameters. Moreover, the wafer surfaces and the bonding interfaces are analyzed to explore the bonding mechanism. Adding small amount of CF 4 into O 2 Plasma does not etch the Si surface in a short time (~60 s), but it renders fluorinated oxide grown on the Si surface, which should be less hydrophilic than the surface treated by O 2 Plasma. Therefore, fewer water molecules at bonding interface may be prone to produce many covalent bonds via polymerization reaction and result in strong bonding at room temperature.