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Showing papers on "Anodic bonding published in 2018"


Journal ArticleDOI
TL;DR: In this paper, a direct diffusion bonding method is designed to bond tungsten and copper without using an interlayer metal at a temperature close to the melting point of copper (TmCu).

60 citations


Journal ArticleDOI
TL;DR: In this paper, a novel understanding was proposed to explain the bonding process of a cold sprayed Cu particle deposition, which was proved by the observation of oxides fragments located at the periphery of detached particle, which promoted the formation of metallurgical bonding around central area.

47 citations


Journal ArticleDOI
TL;DR: In this paper, a silicon carbide (SiC) based thermal flow sensor on a transparent and electrically insulating glass substrate via anodic bonding process is presented, where three resistive heater size configurations of dimensions 100μm, 300μm and 1000μm were fabricated.
Abstract: This paper presents a silicon carbide (SiC) based thermal flow sensor on a transparent and electrically insulating glass substrate via anodic bonding process. The paper elaborates on the fabrication steps of the thermal flow sensor. Three resistive heater size configurations of dimensions 100 μm × 100 μm, 300 μm × 300 μm, and 1000 μm × 1000 μm were fabricated. The thermoresistive properties of 3C-SiC on glass were investigated from ambient temperature to 443 K. The characterization of the SiC heater and temperature sensors revealed a high thermoresistive effect with a temperature coefficient of resistance (TCR) of approximately −20,716 ppm/K at ambient temperature(298 K) and −9367 ppm/K at 443 K respectively. The performance of the sensors was evaluated based on the sensitivity of the flow sensor. For a turbulent flow velocity of 7.4 m/s, the sensitivity of the sensor operating in the constant -voltage mode is 0.091 s/m with a power consumption of 133.50 mW for the 1000 μm × 1000 μm heater. Finally, a study on the flow direction was conducted to confirm the operation of 2-D direction independent hot-film flow sensor. Results indicated that the performance of the sensor remained the same when the flow direction was perpendicular to SiC heater and sensor respectively. However, the best sensitivity was achieved by passing air flow perpendicular to the sensing elements. The high TCR of the single crystalline 3C-SiC material, the relatively low power consumption on the order of milliwatts and the high sensitivity of our sensor demonstrates its potential use for high temperature flow sensing applications.

38 citations


Journal ArticleDOI
28 Dec 2018-Sensors
TL;DR: The proposed packaging scheme was successfully applied to a capacitive gyroscope and the packaging failure was less than 1%, which demonstrated the feasibility and reliability of the technique for high-performance MEMS vacuum packaging.
Abstract: A novel three-dimensional (3D) hermetic packaging technique suitable for capacitive microelectromechanical systems (MEMS) sensors is studied. The composite substrate with through silicon via (TSV) is used as the encapsulation cap fabricated by a glass-in-silicon (GIS) reflow process. In particular, the low-resistivity silicon pillars embedded in the glass cap are designed to serve as the electrical feedthrough and the fixed capacitance plate at the same time to simplify the fabrication process and improve the reliability. The fabrication process and the properties of the encapsulation cap were studied systematically. The resistance of the silicon vertical feedthrough was measured to be as low as 263.5 mΩ, indicating a good electrical interconnection property. Furthermore, the surface root-mean-square (RMS) roughnesses of glass and silicon were measured to be 1.12 nm and 0.814 nm, respectively, which were small enough for the final wafer bonding process. Anodic bonding between the encapsulation cap and the silicon wafer with sensing structures was conducted in a vacuum to complete the hermetic encapsulation. The proposed packaging scheme was successfully applied to a capacitive gyroscope. The quality factor of the packaged gyroscope achieved above 220,000, which was at least one order of magnitude larger than that of the unpackaged. The validity of the proposed packaging scheme could be verified. Furthermore, the packaging failure was less than 1%, which demonstrated the feasibility and reliability of the technique for high-performance MEMS vacuum packaging.

15 citations


Journal ArticleDOI
TL;DR: In this article, a direct bonding process by using the conventional hot pressing was applied to prepare the dissimilar materials consisting of the thermoplastic resin and pure titanium (Ti) material.

15 citations


Journal ArticleDOI
TL;DR: In this article, the application of an electric field promoted the migration of Na+ ions on the glass substrate, and a sodium-depleted layer was formed on the surface, playing a key role in successful bonding.

13 citations


Journal ArticleDOI
TL;DR: In this article, the authors used a magnetron sputtering in a high-pressure environment and a loose structure with NPs was obtained, and the results demonstrated that a reliable low-temperature short-time Cu-Cu bonding was realized by the sintering process of Ag NPs between the bonding pairs.
Abstract: Silver nanoparticles (Ag NPs) fabricated by physical vapor deposition (PVD) were introduced in Cu-Cu bonding as surface modification layer. The bonding structure consisted of a Ti adhesive/barrier layer and a Cu substrate layer was fabricated on the silicon wafer. Ag NPs were deposited on the Cu surface by magnetron sputtering in a high-pressure environment and a loose structure with NPs was obtained. Shear tests were performed after bonding, and the influences of PVD pressure, bonding pressure, bonding temperature and annealing time on shear strength were assessed. Cu-Cu bonding with Ag NPs was accomplished at 200°C for 3 min under the pressure of 30 MPa without a post-annealing process, and the average bonding strength of 13.99 MPa was reached. According to cross-sectional observations, a void-free bonding interface with an Ag film thickness of around 20 nm was achieved. These results demonstrated that a reliable low-temperature short-time Cu-Cu bonding was realized by the sintering process of Ag NPs between the bonding pairs, which indicated that this bonding method could be a potential candidate for future ultra-fine pitch 3D integration.

13 citations


Journal ArticleDOI
TL;DR: The detailed fabrication of the cavity, its edges, and details of the junction between the coin silver fill line and the silicon base of the cavities that enables a low internal-friction joint are discussed, important for mass coupling torsional oscillator experimental assays of the superfluid inertial contribution.
Abstract: We demonstrate the fabrication of ∼1.08 μm deep microfluidic cavities with characteristic size as large as 7 mm × 11 mm or 11 mm diameter, using a silicon-glass anodic bonding technique that does not require posts to act as separators to define cavity height. Since the phase diagram of 3He is significantly altered under confinement, posts might act as pinning centers for phase boundaries. The previous generation of cavities relied on full wafer-bonding which is more prone to failure and requires dicing post-bonding, whereas these cavities are made by bonding a pre-cut piece of Hoya SD-2 glass to a patterned piece of silicon in which the cavity is defined by etching. Anodic bonding was carried out at 425 °C with 200 V, and we observe that pressurizing the cavity to failure (>30 bars pressure) results in glass breaking, rather than the glass-silicon bond separation. In this article, we discuss the detailed fabrication of the cavity, its edges, and details of the junction between the coin silver fill line and the silicon base of the cavity that enables a low internal-friction joint. This feature is important for mass coupling torsional oscillator experimental assays of the superfluid inertial contribution where a high quality factor (Q) improves frequency resolution. The surface preparation that yields well-characterized smooth surfaces to eliminate pinning sites, the use of transparent glass as a cover permitting optical access, low temperature capability, and attachment of pressure-capable ports for fluid access may be features that are important in other applications.

13 citations


Journal ArticleDOI
TL;DR: In this article, a novel structural piezoresistive pressure sensor with a four-beams-bossed-membrane (FBBM) structure that consisted of four short beams and a central mass to measure micro-pressure is presented.
Abstract: This paper presents a novel structural piezoresistive pressure sensor with a four-beams-bossed-membrane (FBBM) structure that consisted of four short beams and a central mass to measure micro-pressure. The proposed structure can alleviate the contradiction between sensitivity and linearity to realize the micro measurement with high accuracy. In this study, the design, fabrication and test of the sensor are involved. By utilizing the finite element analysis (FEA) to analyze the stress distribution of sensitive elements and subsequently deducing the relationships between structural dimensions and mechanical performance, the optimization process makes the sensor achieve a higher sensitivity and a lower pressure nonlinearity. Based on the deduced equations, a series of optimized FBBM structure dimensions are ultimately determined. The designed sensor is fabricated on a silicon wafer by using traditional MEMS bulk-micromachining and anodic bonding technology. Experimental results show that the sensor achieves the sensitivity of 4.65 mV/V/kPa and pressure nonlinearity of 0.25% FSS in the operating range of 0–5 kPa at room temperature, indicating that this novel structure sensor can be applied in measuring the absolute micro pressure lower than 5 kPa.

13 citations


Journal ArticleDOI
TL;DR: In this paper, a facile bonding process for combining silicon and quartz glass wafers by a two-step wet chemical surface cleaning was demonstrated, and strong bonding interfaces with no defects or micro-cracks were obtained.
Abstract: We demonstrate a facile bonding process for combining silicon and quartz glass wafers by a two-step wet chemical surface cleaning. After a post-annealing at 200 °C, strong bonding interfaces with no defects or microcracks were obtained. On the basis of the detailed surface and bonding interface characterizations, the bonding mechanism was explored and discussed. The amino groups terminated on the cleaned surfaces might contribute to the bonding strength enhancement during the annealing. This cost-effective bonding process has great potentials for silicon- and glass-based heterogeneous integrations without requiring a vacuum system.

13 citations


Journal ArticleDOI
TL;DR: In this paper, a devising electrode for low-temperature anodic bonding between the silicon and Pyrex glass using destructive and non-destructive mechanisms has been investigated, and the results showed that the induced bow height reduced from 30.3 to 0.3 µm.
Abstract: Excellence in the performance of MEMS-based devices such as RF switches, microfluidics, and pressure sensors are well known and by now reported. Operations of these devices are very sensitive to the environmental factors such as contamination, humidity, vibrations etc. Thus, the integration of these micro-devices with the real-life systems could be challenging without a hermetic sealing. A very common practice for these sealing is to bond a recessed cap onto a micromachined wafer using low-temperature wafer bonding mechanism known as anodic bonding or high-temperature sealing techniques such as fusion bonding for vacuum packages. Considering the limit of high-temperature bonding due to thin-film metals like nickel and gold present on the wafer and the induced bow associated with this high-temperature, this paper reveals a devising electrode designed that successfully bonded the samples at a reduced temperature well below at 250 °C. The reliability and effects of this low-temperature bonding between the silicon and Pyrex glass using destructive and non-destructive mechanisms have been investigated in this paper. The tensile strength measurements indicated a superior bonding strength of 14.12 MPa for the sample bonded at 250 °C. The induced bow height reduced from 30.3 µm (at 450 °C) to 0.3 µm (at 250 °C) meaning a significant reduction of bow up to 80.2%. Elemental composition was studied at the interface using energy dispersive X-ray spectroscopy (EDAX). To evaluate the bond quality, infra-red (IR) imaging was performed on the bonded sample pair. The interfaces were examined and analysed by scanning electron microscopy (SEM). Finally, we implemented this technique for a MEMS based pressure sensor application to prove the feasibility of low-temperature anodic bonding.

Journal ArticleDOI
01 Jul 2018-Optik
TL;DR: In this article, a microelectromechanical system pressure sensor based on Fabry-Perot interference using anodic bonding is presented, and the design principles and basic mechanical model are introduced.

Journal ArticleDOI
TL;DR: In this article, composites of Li-Al-B-Si-O (LABS) glass and β-Al 2 O 3 have been synthesized for low-temperature co-fired ceramics (LTCC) technology application.

Journal ArticleDOI
17 Apr 2018-Sensors
TL;DR: The demands for this kind of SOG MEMS device can be fulfilled using the optimized process, and the structures are well defined without the footing effect by the use of the modified DRIE process.
Abstract: MEMS fabrication that is based on the silicon-on-glass (SOG) process requires many steps, including patterning, anodic bonding, deep reactive ion etching (DRIE), and chemical mechanical polishing (CMP). The effects of the process parameters of CMP and DRIE are investigated in this study. The process parameters of CMP, such as abrasive size, load pressure, and pH value of SF1 solution are examined to optimize the total thickness variation in the structure and the surface quality. The ratio of etching and passivation cycle time and the process pressure are also adjusted to achieve satisfactory performance during DRIE. The process is optimized to avoid neither the notching nor lag effects on the fabricated silicon structures. For demonstrating the capability of the modified CMP and DRIE processes, a z-axis micro gyroscope is fabricated that is based on the SOG process. Initial test results show that the average surface roughness of silicon is below 1.13 nm and the thickness of the silicon is measured to be 50 μm. All of the structures are well defined without the footing effect by the use of the modified DRIE process. The initial performance test results of the resonant frequency for the drive and sense modes are 4.048 and 4.076 kHz, respectively. The demands for this kind of SOG MEMS device can be fulfilled using the optimized process.

Journal ArticleDOI
TL;DR: This study demonstrates that the LTCC and LTCC side vias scheme can be a potential approach for high density CMUT array fabrication and indirect integration of CMUT-IC for miniature size packaging, which eliminates problems related with direct integration.
Abstract: This paper presents fabrication and packaging of a capacitive micromachined ultrasonic transducer (CMUT) using anodically bondable low temperature co-fired ceramic (LTCC). Anodic bonding of LTCC with Au vias-silicon on insulator (SOI) has been used to fabricate CMUTs with different membrane radii, 24 µm, 25 µm, 36 µm, 40 µm and 60 µm. Bottom electrodes were directly patterned on remained vias after wet etching of LTCC vias. CMUT cavities and Au bumps were micromachined on the Si part of the SOI wafer. This high conductive Si was also used as top electrode. Electrical connections between the top and bottom of the CMUT were achieved by Au-Au bonding of wet etched LTCC vias and bumps during anodic bonding. Three key parameters, infrared images, complex admittance plots, and static membrane displacement, were used to evaluate bonding success. CMUTs with a membrane thickness of 2.6 µm were fabricated for experimental analyses. A novel CMUT-IC packaging process has been described following the fabrication process. This process enables indirect packaging of the CMUT and integrated circuit (IC) using a lateral side via of LTCC. Lateral side vias were obtained by micromachining of fabricated CMUTs and used to drive CMUTs elements. Connection electrodes are patterned on LTCC side via and a catheter was assembled at the backside of the CMUT. The IC was mounted on the bonding pad on the catheter by a flip-chip bonding process. Bonding performance was evaluated by measurement of bond resistance between pads on the IC and catheter. This study demonstrates that the LTCC and LTCC side vias scheme can be a potential approach for high density CMUT array fabrication and indirect integration of CMUT-IC for miniature size packaging, which eliminates problems related with direct integration.

Journal ArticleDOI
TL;DR: This unique solution makes it possible to achieve a 10−6 Torr vacuum level inside the cell in the presence of saturated rubidium vapor, paving the way to building a new class of optical reference cells for atomic spectroscopy.
Abstract: The high-vacuum self-pumping MEMS cell for atomic spectroscopy presented here is the result of the technological achievements of the author and the research group in which he works. A high-temperature anodic bonding process in vacuum or buffer gas atmosphere and the influence of the process on the inner gas composition inside a MEMS structure were studied. A laser-induced alkali vapor introduction method from solid-state pill-like dispenser is presented as well. The technologies mentioned above are groundbreaking achievements that have allowed the building of the first European miniature atomic clock, and they are the basis for other solutions, including high-vacuum optical MEMS. Following description of the key technologies, high-vacuum self-pumping MEMS cell construction and preliminary measurement results are reported. This unique solution makes it possible to achieve a 10−6 Torr vacuum level inside the cell in the presence of saturated rubidium vapor, paving the way to building a new class of optical reference cells for atomic spectroscopy. Because the level of vacuum is high enough, experiments with cold atoms are potentially feasible.

Journal ArticleDOI
TL;DR: In this article, an etch-back process of (PE)CVD silicon dioxide combined with an additional spin-on glass (SOG) layer is used for the planarisation of the lateral feedthroughs.
Abstract: This paper reports on a method for hermetic sensor housing including lateral feedthroughs and room-temperature anodic bonding. The planarisation of the lateral feedthroughs, essential for the purpose of hermetic sealing, is realised by means of an etch-back process of (PE)CVD silicon dioxide combined with an additional spin-on glass (SOG) layer. The quality of the planarisation technique with regard to the main process variables is evaluated by FIB and tactile measurements. It is proven that 3D surfaces, represented here by the wiring and feedthrough layer, can be planarised almost completely. The applied bonding process features thin-films of a highly ionic conductive glass, enabling anodic bonding at unique conditions (room temperature and low applied voltages in order of 100 V). The general applicability of the packaging method is demonstrated with a setup of encapsulated, commercially available thermoelectric radiation sensors, which are used for the verification of the hermeticity of the setup as well.

Journal ArticleDOI
TL;DR: The test results demonstrated that this microelectromechanical torsional resonant magnetometer based on Lorentz force could meet the requirements for attitude determination systems in low earth orbit satellites.
Abstract: A microelectromechanical system (MEMS) torsional resonant magnetometer based on Lorentz force was investigated, consisting of torsional structures, torsional beams, metal plates, a coil, and a glass substrate. The Lorentz force, introduced by the interaction between the current in the MEMS coil and an external horizontal magnetic field, leads to displacement of the torsional structure. The strength of the magnetic field is proportional to this displacement, and can be detected with two sensing capacitors fabricated on the torsion structure and the substrate. To improve sensor sensitivity, a folded torsional beam and a double-layer excitation coil were introduced. The fabrication processes included lift-off, anodic bonding, chemical mechanical planarization, silicon nitride (SiNx) deposition, plasma-enhanced chemical vapor deposition, and inductively coupled plasma release. The prototype of the magnetometer was finished and packaged. The sensor performance, including its sensitivity and repeatability, was tested in a low-pressure environment. Additionally, the influences of structural parameters were analyzed, including the resistance of the excitation coil, the initial value of the capacitors, the elastic coefficient of the torsional beam, and the number of layers in the excitation coil. The test results demonstrated that this sensor could meet the requirements for attitude determination systems in low earth orbit satellites.

Journal ArticleDOI
TL;DR: In this paper, the authors demonstrate the fabrication of microfluidic cavities with characteristic size as large as 7 mm/times$ 11 mm or 11 mm diameter using a silicon$-$glass anodic bonding technique.
Abstract: We demonstrate the fabrication of $\sim$1.08 $\mu$m deep microfluidic cavities with characteristic size as large as 7 mm $\times$ 11 mm or 11 mm diameter, using a silicon$-$glass anodic bonding technique that does not require posts to act as separators to define cavity height. Since the phase diagram of $^3$He is significantly altered under confinement, posts might act as pinning centers for phase boundaries. The previous generation of cavities relied on full wafer-bonding which is more prone to failure and requires dicing post-bonding, whereas the these cavities are made by bonding a pre-cut piece of Hoya SD-2 glass to a patterned piece of silicon in which the cavity is defined by etching. Anodic bonding was carried out at 425 $^{\circ}$C with 200 V, and we observe that pressurizing the cavity to failure ($>$ 30 bar pressure) results in glass breaking, rather than the glass-silicon bond separation. In this article, we discuss the detailed fabrication of the cavity, its edges, and details of the junction between the coin silver fill line and the silicon base of the cavity that enables a low internal-friction joint. This feature is important for mass coupling torsional oscillator experimental assays of the superfluid inertial contribution where a high quality factor ($Q$) improves frequency resolution. The surface preparation that yields well-characterized smooth surfaces to eliminate pinning sites, the use of transparent glass as a cover permitting optical access, low temperature capability and attachment of pressure-capable ports for fluid access may be features that are important in other applications.

Journal ArticleDOI
TL;DR: In this paper, a novel method for ultrasonic bonding of thermoplastic microfluidic devices was demonstrated, where the CO 2 laser beam scanned around the microchannel of the microdevice, a small bulge was formed in the rim of the laser-ablated groove (LG).

Journal ArticleDOI
TL;DR: In this article, the authors describe the fabrication and evaluation of the Knudsen pump for on-chip vacuum pumping that works based on the principle of thermal transpiration, and the fabricated device is evaluated by monitoring the quality (Q) factor of the integrated cantilevers.
Abstract: This work describes the fabrication and evaluation of the Knudsen pump for on-chip vacuum pumping that works based on the principle of a thermal transpiration. Three AFM (atomic force microscope) cantilevers are integrated into small chambers with a size of 5 mm × 3 mm × 0.4 mm for the pump's evaluation. Knudsen pump is fabricated using deep RIE (reactive ion etching), wet thermal oxidation and anodic bonding processes. The fabricated device is evaluated by monitoring the quality (Q) factor of the integrated cantilevers. The Q factor of the cantilever is increased from 300 –1150 in cases without and with a temperature difference approximately 25 °C between the top (the hot side at 40 °C) and bottom (the cold side at 15 °C) sides of the fabricated device, respectively. The evacuated chamber pressure of around 10 kPa is estimated from the Q factor of the integrated cantilevers.

Journal ArticleDOI
TL;DR: In this article, diffusion bonding experiments are reported for austenitic, ferritic, and martensitic stainless steels possessing varying alloying elements and contents, and it is shown that it is very easy to obtain good bonding results at low deformation.
Abstract: Solid state diffusion bonding is used to produce monolithic parts exhibiting mechanical properties comparable to those of the bulk material. This requires diffusion of atoms across mating surfaces at high temperatures, accompanied by grain growth. In case of steel, polymorphy helps to limit the grain size, since the microstructure is transformed twice. The diffusion coefficient differs extremely for ferritic and austenitic phases. Alloying elements may shift or suppress phase transformation until the melting range. In this paper, diffusion bonding experiments are reported for austenitic, ferritic, and martensitic stainless steels possessing varying alloying elements and contents. Passivation layers of different compositions are formed, thus affecting the local diffusion coefficient and impeding diffusion across faying surfaces. As a consequence, different bonding temperatures are needed to obtain good bonding results, making it difficult to control the deformation of parts, since strong nonlinearities exist between temperature, bonding time, and bearing pressure. For martensitic stainless steel, it is shown that it is very easy to obtain good bonding results at low deformation, whereas ferritic and austenitic stainless steels require much more extreme bonding parameters.

Journal ArticleDOI
Xi Shu1, Huiqin Liu1, Yezi Zhu1, Bo Cai1, Yanxia Jin1, Yongchang Wei1, Fuling Zhou1, Wei Liu1, Shishang Guo1 
TL;DR: In this paper, a polydimethylsiloxane (PDMS) layer was used as the adhesive between cover glass and silicon substrate, and a standing wave field was formed in the microchannels.
Abstract: In this work, we developed a feasible way to package bulk acoustic waves chip with sandwich structure by inserting a polydimethylsiloxane (PDMS) layer as the adhesive between cover glass and silicon substrate. After spin-coating and curing process, a PDMS layer was formed on one side of the cover glass and then bonded to the silicon substrate with microchannels by oxygen plasma treating. Both simulation and experiment showed that the chip was not leaking and the acoustic waves produced by the piezoelectric transducer could be propagated through the PDMS layer. Finally, a standing wave field was formed in the microchannels. Compared with traditional chip bonded by anodic bonding, simulation results showed that this packaging method did decrease the acoustic pressure in the channel, but the reduction was acceptable. After optimizing the experimental parameters, we successfully aggregated 15-μm silica spheres under a very low input power (21 dBm) at a flow velocity of 1 ml/h, and the enrichment efficiency of silica spheres was greater than 97%.

Journal ArticleDOI
TL;DR: In this article, the effect of the silicon bonding temperature with thermoplastic adhesive has been investigated and it was shown that 275°C appears as the optimal bonding temperature in order to optimize the TTV from 55 µm down to 5µm.
Abstract: This paper deals with the effect of the silicon bonding temperature with thermoplastic adhesive. The bonding temperature exhibits a significant effect on the morphology and on the adherence energy of the bonded stack. A suitable temperature control leads to an excellent homogeneity of the bonded structure and an optimal total thickness variation (TTV) value. Using Brewer Bsi5150 adhesive material, 275 °C appears as the optimal bonding temperature in order to optimize the TTV from 55 µm down to 5 µm. The adherence of the structure is also increased with high bonding temperatures. Indeed, the adherence energy is above 10 J/m2 when the temperature is above 250 °C. On the contrary, when the temperature is less than 150 °C, the adherence is only around 1 J/m2. Noteworthy, this value is suitable for back side processing and a mechanical debonding of the structure without any need of other specific layer which could lead to a very simple temporary bonding process.

Journal ArticleDOI
TL;DR: In this article, a conductive polymer material containing rare earth oxide (PEG-LiClO4-CeO2) was designed and synthesized, and the bonding performance was analyzed via AC impedance, X-ray diffraction (XRD), infrared spectroscopy (FTIR), scanning electron microscopy (SEM), tensile strength, ball milling and anodic bonding experiments.
Abstract: Herein, a conductive polymer material containing rare earth oxide (PEG–LiX–CeO2) was designed and synthesized. The bonding performance of the conductive polymer was analyzed via AC impedance, X-ray diffraction (XRD), infrared spectroscopy (FTIR), scanning electron microscopy (SEM), tensile strength, ball milling and anodic bonding experiments. The AC impedance, XRD and FTIR experiments demonstrate that the introduction of alkali metal lithium salt and cerium oxide (CeO2) can effectively reduce the crystallinity of the composites and increase the ion migration. The results of ball milling show that increasing the milling time (< 10 h) and speed (< 250 r min−1) can improve the conductivity of the composites. The anodic bonding experiment of PEG–LiClO4–CeO2 with AL foil and the SEM characterization of the bonding interface demonstrate the existence of a well-defined bonding layer between the bonding interface.

Journal ArticleDOI
TL;DR: In this article, a low pressure of 0.4 MPa was applied during bonding by micro-sized Ag particle paste for lower bonding temperature and higher joint strength, which showed a linear relationship to the shear strength, regardless of the bonding conditions.
Abstract: Bonding technology using a Ag nanoparticle paste has been a promising substitute for high-Pb-containing solder joining. However, it has some drawbacks, such as high cost and low compatibility, due to its high sintering temperature. Recently, the bonding process using the micro-sized Ag particle paste has been studied for cost-effectiveness, but it is limited in terms of high applied pressure or relatively low joint strength. In this study, a low pressure of 0.4 MPa was applied during bonding by micro-sized Ag particle paste for lower bonding temperature and higher joint strength. The micro-sized Ag paste was composed of chestnut-burr-like and spherical particles. Under low applied pressure, the joint with a high shear strength of 54.6 MPa was achieved when the bonding temperature and time were 260 °C and 10 min, respectively. It was also possible to reduce the bonding temperature and time for the joints having similar strength to that of the pressureless process. The microstructure showed a linear relationship to the shear strength, regardless of the bonding conditions.

Journal ArticleDOI
TL;DR: In this article, a simple, cleanroom-free, low-cost and highly adaptable bonding method for various polymer and glass-based microfluidic systems was proposed using the cross-linked dry film photoresist.
Abstract: Dry film has been widely used as a low-cost photoresist in the print circuit board industry which consists of a thin layer of photoresist sandwiched between two protective polymer layers. In this research, a simple, cleanroom-free, low-cost and highly adaptable bonding method for various polymer and glass-based microfluidic systems was proposed using the cross-linked dry film photoresist. In this proposed approach, the uncross-linked dry film photoresist was sandwiched between substrates and cover plate, then using UV exposure for the crosslinking of the photoresist to reach a secured bonding, after bonding, a cleaning process for the removal of photoresist residuals trapped inside the microchannels was also applied. The proposed bonding method is highly adaptable for different kinds of polymer or glass-based microfluidic devices, even the hybrid bonding between polymer and glass substrates could be achieved, which is usually very challenging using the conventional bonding technologies. Comparing with the traditional adhesive bonding method, the proposed method is simple, low-cost and without the requirement for toxic organic solvents, in addition, the cleaning procedure proposed in this study could effectively remove the residual of the adhesives trapped in the microchannels.

Journal ArticleDOI
TL;DR: In this paper, a solid polymer electrolyte was prepared via mechanized alloying and hot pressing, and the final product was obtained through different cooling modes and the effects of these cooling modes on the bonding properties of the composites system were studied via AC impedance, DTA, XRD, and anodic bonding experiments.
Abstract: In this study, a solid polymer electrolyte was prepared via mechanized alloying and hot pressing, and the final product was obtained through different cooling modes. The effects of different cooling modes on the bonding properties of the composites system were studied via AC impedance, DTA, XRD, and anodic bonding experiments. The crystallinity of the composites decreased, the glass transition temperature decreased, the amorphous region increased, and the ionic conductivity increased with increasing cooling rate. At the same time, the composites of rapid cooling treatment (cooled in ice water), the peak current during the bonding process, and both thickness and the tensile strength of the bonding layer increased significantly. Therefore, improving the cooling rate of the composites also improved the bonding properties of the composites to a certain extent. This study extends the application of solid polymer electrolytes as encapsulating materials in anode bonding.

Patent
20 Jul 2018
TL;DR: In this article, an anodic bonding is used to enhance the vacuum glass sealing to achieve a low temperature sealing process, and an adopted edge sealing material is lead-free lowmelting-point glass powder, and the glass powder is characterized by being low in sealing temperature and adjustable in thermal expansion coefficient.
Abstract: The invention relates to the technical field of vacuum glass manufacturing, in particular to a vacuum glass sealing material and an anodic bonding enhanced sealing method thereof. An adopted edge sealing material is lead-free low-melting-point glass powder, and the glass powder is characterized by being low in sealing temperature and adjustable in thermal expansion coefficient, the requirements for low temperature sealing can be met, and the anodic bonding is used to enhance the vacuum glass sealing to achieve a low temperature sealing process. The lead-free low-melting-point glass powder is fully melted and does not crack during the sintering process at 300-450 DEG C, and forms a good infiltration with substrate; and at the same time, an anodic bonding sealing technology is used to further lower the sealing temperature and improve the sealing strength and quality. A new technical scheme is provided for vacuum glass edge sealing, a vacuum glass sealing process is improved, and a new solution is provided for preparing the vacuum glass excellent in performance.

Proceedings ArticleDOI
21 May 2018
TL;DR: In this paper, the applicability of anodic bonding as a sealing method for vapor cells, which preserves vacuum levels down to 10-7 mbar for several years, while being compatible with thin-film electronics on glass.
Abstract: Rydberg atoms in room temperature vapor cells are promising candidates for realizing new kinds of quantum devices and sensors. However, the alkali vapor, which is most commonly used, introduces new technological challenges. We demonstrate the applicability of anodic bonding as a sealing method for vapor cells, which preserves vacuum levels down to 10-7 mbar for several years, while being compatible with thin-film electronics on glass. We furthermore prove, that the implementation of such thin-film electronics inside a highly reactive atmosphere of alkali vapor is possible. We also propose a new kind of gas sensor based on Rydberg excitations as a competitive and promising application of our Rydberg detection scheme.