Array Micro Research Articles

Servo scanning 3D micro EDM for array micro cavities using on-machine fabricated tool electrodes

Array micro cavities are useful in many fields including in micro molds, optical devices, biochips and so on. Array servo scanning micro electro discharge machining (EDM), using array micro electrodes with simple cross-sectional shape, has the advantage of machining complex 3D micro cavities in batches. In this paper, the machining errors caused by offline-fabricated array micro electrodes are analyzed in particular, and then a machining process of array servo scanning micro EDM is proposed by using on-machine fabricated array micro electrodes. The array micro electrodes are fabricated on-machine by combined procedures including wire electro discharge grinding, array reverse copying and electrode end trimming. Nine-array tool electrodes with Φ80 µm diameter and 600 µm length are obtained. Furthermore, the proposed process is verified by several machining experiments for achieving nine-array hexagonal micro cavities with top side length of 300 µm, bottom side length of 150 µm, and depth of 112 µm or 120 µm. In the experiments, a chip hump accumulates on the electrode tips like the built-up edge in mechanical machining under the conditions of brass workpieces, copper electrodes and the dielectric of deionized water. The accumulated hump can be avoided by replacing the water dielectric by an oil dielectric.

Effect of Annealing on Mechanical Property and Formability of Cu/Al Clad Bipolar Plates in Proton Exchange Membrane Fuel Cells

The effect of annealing on the mechanical property in uniaxial tension tests and formability in micro coining processes of Cu/Al clad bipolar plates in proton exchange membrane fuel cells (PEMFC) is investigated. The results indicate both the thickness and the micro hardness of the interface layer increase with the increase of the holding time. The stress decreases firstly then increases with the increase of the holding time. The elongation decreases monotonically with the increase of the holding time. The micro coining of array micro channels results indicate that the height of micro rib increases with loading. The height of micro rib increases from the center to the edge along the transverse direction of the specimen. The simulation result by finite element method (FEM) verifies the experimental one.

A diet high in fat and sugar reverses anxiety-like behaviour induced by limited nesting in male rats: Impacts on hippocampal markers

Stress exposure during early development is known to produce long-term mental health deficits. Stress promotes poor lifestyle choices such as poor diet. Early life adversity and diets high in fat and sugar (HFHS) are known to affect anxiety and memory. However additive effects of HFHS and stress during early development are less explored. Here, we examined whether early life stress (ELS) simulated by limited nesting (LN) induces anxiety-like behaviour and cognitive deficits that are modulated by HFHS diet. We examined key hippocampal markers involved in anxiety and cognition, testing the hypothesis that post-weaning HFHS following ELS would ameliorate anxiety-like behaviour but worsen memory and associated hippocampal changes. Sprague-Dawley rats were exposed to LN, postnatal days 2–9, and at weaning, male siblings were given unlimited access to chow or HFHS resulting in (Con-Chow, Con-HFHS, LN-Chow, LN-HFHS, n=11–15/group). Anxiety-like behaviour was assessed by Elevated Plus Maze (EPM) at 10 weeks and spatial and object recognition tested at 11 weeks of age. Rats were culled at 13 weeks. Hippocampal mRNA expression was measured using TaqMan® Array Micro Fluidic cards (Life Technologies). As expected HFHS diet increased body weight; LN and control rats had similar weights at 13 weeks, energy intake was also similar across groups. LN-Chow rats showed increased anxiety-like behaviour relative to control rats, but this was reversed by HFHS diet. Spatial and object recognition memory were unaltered by LN exposure or consumption of HFHS diet. Hippocampal glucocorticoid receptor (GR) protein was not affected by LN exposure in chow rats, but was increased by 45% in HFHS rats relative to controls. Hippocampal genes involved in plasticity and mood regulation, GSKα and GSKβ were affected, with reductions in GSKβ under both diet conditions, and reduced GSKα only in LN-HFHS versus Con-HFHS. Interestingly, HFHS diet and LN exposure independently reduced expression of Akt3 mRNA, a key gene involved post-natal brain development. In summary, while an energy rich diet ameliorated anxiety-like behaviour induced by LN exposure, it significantly altered key genes that are essential for hippocampal development.

The Flow Resistance and Heat Transfer Characteristics of Micro Pin-Fins with Different Cross-Sectional Shapes

The flow resistance and heat transfer characteristics of deionized water flowing through a rectangular channel (60 mm × 5.2 mm × 0.5 mm) with staggered array micro pin-fin circular, diamond, and elliptical groups are experimentally investigated over Reynolds numbers ranging from 8 to 1,000, and the investigation shows that the flow resistance increases due to the endwall effect and large pin-fins density at low Re. With the increase in Re, the endwall effect is weakened, but the flow resistance still increases due to the appearance of vortex resistance, and the heat transfer is enhanced due to the flow disturbance or transition from laminar flow to turbulent flow. The experimental results are also compared with predictions of the theoretical correlations for the staggered array micro pin-fin groups, and the comparisons indicate that only the correlation related to the diamond shaped micro pin-fin groups approximately agrees with experimental data, and the other correlations do not describe well the flow and heat transfer characteristics covering laminar, transitional, and turbulent states in circular and elliptical test sections.

Prognostic Value of Circulating Exosomal microRNAs in 112 Patients with Multiple Myeloma

Introduction.Exosomes are small vesicles (50-100 nm) of endocytic origin, which are released in the extra-cellular milieu by several cell types. Exosomes play a role in tumor progression since they have been shown to carry and transfer microRNAs (miRNAs) to recipient cells. In this study, we sought to characterize circulating exosomes in Multiple Myeloma (MM) patients and to assess the prognostic value of circulating exosomal miRNAs in a cohort of 112 newly diagnosed MM patients.Methods. Exosomes were isolated from peripheral blood (serum samples) using an ultracentrifugation protocol and Exoquick® solution. They were characterized using electron microscopy with immunogold labeling for the detection of CD63 and CD81, as well as for size using Nanosight® analysis. MiRNAs were isolated using miRNeasy micro kit (Qiagen®) and profiled using nCounter miRNA expression assay (Nanostring® Technologies) in 5 healthy donors (HD) and 10 MM patients. We next studied a cohort of 112 newly diagnosed MM patients uniformly treated with Bortezomib-Dexamethasone (4 cycles) followed by high dose Melphalan and autotransplant on the IFM 2005-01 Phase III Trial. After exosome isolation and miRNA extraction, we performed a low density qRT-PCR miRNA array using Taqman Array Micro Fluidic Cards for a panel of 23 specific miRNAs. Data were normalized by robust median global normalization and conditional inference tree was used to select the cut-point for miRNA levels. Kaplan-Meier estimation, Log-Rank test and Cox regression were used to assess progression-free survival (PFS).Results. Circulating exosomes were first characterized from 5 HD and 10 MM patients. CD63 and CD81 expression was demonstrated by immunogold labeling and electron microscopy. The size (approx. 100nm) and concentration of peripheral blood exosomes did not differ between HD and MM patients using Nanosight® analysis. We next performed a miRNA array (Nanostring) and identified differentially expressed miRNAs in circulating exosomes from MM patients compared to HD. Notably, the miR-17/92, -106b/25, -106a/363 clusters were more highly expressed and the cluster miR-15a/16 and let-7 family members were down regulated in circulating exosomes from MM patients as compared to HD. We then designed a panel of 23 specific miRNAs from circulating exosomes in MM and performed a Taqman Low Density Array on a cohort of 112 patients who were newly diagnosed and therapy-naive in the IFM 2005-01 Phase III Trial or treated as such. The mean patient’s age was 61 years, 36% of patients had a 13q deletion, 7% a t(4;14) and 4% a 17p deletion. ISS stage I, II and III distribution was 37%, 39% and 21% respectively. The median follow up was 5.4 years. Among tumor suppressor miRNAs, we found that patients with lower let-7e levels before treatment had significantly shorter PFS compared to patients with higher levels of let-7e (P<0.001). The median PFS was 2.46 years and 4.06 years respectively in low and high let-7e level groups (Figure). A multivariate Cox proportional hazards model was fitted and included ISS (III vs. I), cytogenetics (17p deletion and t(4;14) vs. no abnormality) and let-7e expression (high vs. low). This indicated that decreased let-7e expression is associated with decreased PFS [hazard ratio (HR) = 0.4; P=.0004] after adjusting for the effects of ISS stage (HR=1.4; P=.261) and adverse cytogenetic status (HR=1.8; P=.096).Conclusion.These findings indicate that circulating exosomes differ between normal and MM patients in terms of miRNA content. In this study, we report for the first time the prognostic impact of exosomal miRNA content in MM. The data presented here indicate that circulating exosomal levels of let7-e are an independent predictor of PFS in patients with MM who are therapy-naive. [Display omitted] DisclosuresAnderson:Celgene: Consultancy; Sanofi-Aventis: Consultancy; Onyx: Consultancy; Acetylon: Scientific Founder, Scientific Founder Other; Oncoprep: Scientific Founder Other; Gilead Sciences: Consultancy. Ghobrial:Sanofi: Research Funding; Noxxon: Research Funding; BMS: Advisory board, Advisory board Other, Research Funding; Onyx: Advisory board Other.

Precision machining of micro tool electrodes in micro EDM for drilling array micro holes

Micro electro discharge machining (micro EDM) is suitable for machining micro holes on metal alloy materials, and the micro holes can be machined even to several microns by use of wire electro discharge grinding (WEDG) of micro electrodes. However, considering practicability of micro holes <Φ100μm in batch processing, the controllable accuracy of holes’ diameter, the consistency accuracy of repeated machining and the processing efficiency are required to be systematically improved. On the basis of conventional WEDG method, a tangential feed WEDG (TF-WEDG) method combined with on-line measurement using a charge coupled device (CCD) was proposed for improving on-line machining accuracy of micro electrodes. In TF-WEDG, removal resolution of micro-electrode diameter (the minimum thickness to be removed from micro electrode) is greatly improved by feeding the electrode along the tangential direction of wire-guide arc, and the resolution is further improved by employing negative polarity machining. Taking advantage of the high removal resolution, the precise diameter of micro-electrode can be achieved by the tangential feed of electrode to a certain position after diameter feedback of on-line measurement. Furthermore, a hybrid process was presented by combining the TF-WEDG method and a self-drilled holes method to improve the machining efficiency of micro electrodes. A cyclic alternating process of micro-electrode repeated machining and micro holes’ drilling was implemented for array micro holes with high consistency accuracy. Micro-EDM experiments were carried out for verifying the proposed methods and processes, and the experimental results show that the repeated machining accuracy of micro electrodes was less than 2μm and the consistency accuracy of array micro holes was ±1.1μm.

Purinergic signaling on leukocytes infiltrating the LPS-injured lung.

Extracellular nucleotides and nucleosides have been implicated as important signaling molecules in the pathogenesis of acute lung injury (ALI). While adenosine is known to inhibit T cell activation, little information is available as to ATP and NAD degrading enzymes, the expression of ATP and adenosine receptors/transporters in different T cell subsets. ALI was induced by challenging mice with intra-tracheal instillation of 60 µl (3 µg/g) LPS. After 3 d and 7 d blood, lung tissue and bronchoalveolar lavage was collected and immune cells were analyzed using flow cytometry. The transcriptional phenotype of T helper cells, cytotoxic and regulatory T cells sorted by FACS was assessed by measuring the expression profile of 28 genes related to purinergic signaling using TaqMan Array Micro Fluidic Cards. Catabolism of ATP, NAD and cAMP by activated CD4+ T cells was evaluated by HPLC. CD73 was found to be highly abundant on lymphoid cells with little abundance on myeloid cells, while the opposite was true for CD39. After ALI, the abundance of CD39 and CD73 significantly increased on all T cell subsets derived from lung tissue and bronchoalveolar space. Expression analysis in T cell subsets of the lung revealed ATP (Cd39, Cd73) and NAD (Cd38, Cd157, Cd296, Pc-1) degrading enzymes. However, only transcription of Cd38, Cd39, Cd73, Ent1 and A2a receptor was significantly upregulated after ALI in T helper cells. CD4+ T cells from injured lung rapidly metabolized extracellular ATP to AMP and adenosine but not NAD or cAMP. These findings show that lung T cells – the dominant cell fraction in the later phase of ALI – exhibit a unique expression pattern of purinergic signaling molecules. Adenosine is formed by T cells at an enhanced rate from ATP but not from NAD and together with upregulated A2a receptor is likely to modulate the healing process after acute lung injury.

Controlled synthesis of hierarchical CoxMn3−xO4array micro-/nanostructures with tunable morphology and composition as integrated electrodes for lithium-ion batteries

Hierarchical CoxMn3−xO4 array micro-/nanostructures with tunable morphology and composition have been grown on conductive stainless steel with robust adhesion by a facile solvothermal route and a subsequent annealing treatment. By simply controlling the volume ratio of components in the mixed solvent, the morphology of the products can be tailored from hierarchical nanowires to nanosheets. Benefitting from the unique structural features, the resultant CoMn2O4nanowires and MnCo2O4nanosheets exhibit excellent electrochemical performance with remarkable specific capacities (540–207 mA h g−1) at various current rates (1–10 C) and good cycling stability for highly reversible lithium storage. The enhanced electrochemical performance suggests their promising use as integrated binder-free electrodes for microscale lithium-ion batteries.

Fabrication of Microsensors on Bipolar Plate of Portable Fuel Cell

Measuring the temperature and humidity inside the fuel cell is currently a difficult task. Accordingly, in this study, microsensors are fabricated on the bipolar plate of the portable fuel cell to measure the temperature and humidity. The advantages of array micro sensors are their small volume, high accuracy, short response time, simplicity in fabrication, suitability for mass production. The experimental results reveal that the temperature is almost linearly related to the resistance and that the accuracy and sensitivity are less than 0.5°C and 3.77 × 10−3/°C, respectively. The accuracy and sensitivity of the humidity sensor are less than 3% RH and 0.6 pF/% RH, respectively.

Die Design of Aluminum Bipolar Plate Fabrication by Stamping Process and its Investigation

A Proton Exchange Membrane Fuel Cell (PEMFC) is a type of fuel cell being developed for automotive applications as well as for stationary fuel cell applications and portable fuel cell applications. Its performance such as power density can be improved by the use of the bipolar plate with a new lightweight material which is one of core components making up PEMFC stack. Aluminum alloy has good mechanical properties not only in terms of density, electrical resistivity and thermal conductivity, but also in terms of corrosion resistant compared with stainless steel and graphite composites bipolar plate. Furthermore, the use of aluminum for a bipolar plate reduces simultaneously the cost and weight of it, and it contributes to the ease of machining. For these reason, an aluminum alloy is selected in this study. This study presents the feasibility of the simulation for the development of aluminum bipolar plates that consists of multi array micro channels. The analytical solutions obtained by the simulation are validated by the comparison with the experimental results. From the results, it is ensured that the stamping processes for the bipolar plate could be predicted and designed by the results of the by FE-Simulation.

1.25 Impact of Bone Marrow Microenvironment on 93 Apoptotic Pathway Target mRNA Expression in CLL Cells

Chronic lymphocytic leukemia (CLL) was thought to arise due to dysregulated apoptosis rather than uncontrolled proliferation. Recent reports reveal that the CLL cell accumulation is not merely due to intrinsic defects in apoptosis, but in part due to extrinsic signals delivered by microenvironment. Although several entities within the bone marrow microenvironment have been unveiled, the critical components involved in CLL survival remain obscure. Previously, we showed that CLL primary cells co-cultured on MSCs (marrow stromal cells) are rescued from spontaneous apoptosis. At the molecular level, the mechanism of MSC-promoted CLL cell survival involves transcriptional as well as translational accumulation of antiapoptotic protein Mcl-1. In the present study, using microarray mRNA analysis, we investigated the essential apoptotic gene transcripts (n 93) that are involved in cell survival. Primary cells obtained from CLL patients (n 8) were co-cultured with MSC (Nktert, human stromal cell line that mimics bone marrow microenvironment) in a ratio of 100:1. At the end of incubation times(d1andd3),percentageapoptosisandmRNAmicroarrayof93 target genes were evaluated. When CLL lymphocytes were co-cultured on MSC for 6 days, the viability of CLL cells, measured by Annexin/PI staining, increased by 6-18% at d1 and d2 (n 16; p 0.001, two-tailed paired t-test) and 16-27% at d3-d6 of incubation (n 28, p 0.0001) compared to time matched controls. Next we investigated the effect of MSC on global transcription, there was a consistent increase in the global RNA synthesis (1.7 0.5 (d1, n 13, p 0.001) and 2.5 1.0 (d3, n 7, p 0.0084) fold change measured by uridine incorporation method). In order to evaluate changesinindividualtranscriptsundertheMSCmicroenvironment, we screened mRNAs using a ‘human apoptotic array micro fluidic card’ (93 targets) for d1 and d3 samples of controls and co-cultures from 8 CLL patients. Expression levels of mRNA were normalized using global normalization. Based on the functions and functional domains of target genes, the 93 genes were categorized into 7 groups and their response with respect to MSC microenvironment was elucidated. In a group that contained members ofBcl2family members, mRNA levels of pro-apoptotic members such as Bcl2l13 (MIL1), BAK1 and BIK decreased, while mRNA levels of anti-apoptotic, Bcl2, Bcl2A1 (BFL-1), Bcl-xl, and Mcl1 increased at d1 (1.36 0.32 [fold increase; mean standard deviation], p 0.0156; 1.64 0.58, p 0.0174; 2.27 0.97, p 0.04; 1.16 0.3,p 0.15 respectively). Among eight targets containing a caspase recruitment domain (CARD), pro apoptotic APAF1 mRNA level significantly decreased at d1; however, pro-apoptotic NALP1 (Card7) mRNA levelsincreasedsignificantly(1.480.59,p0.05),suggestingthis gene may have an alternate function in the apoptosis pathway. Transcript levels of HIP1 and HIPPI1 of Huntington pathway, which generally function as pro-apoptotic members, increased significantly (1.68 0.68, p 0.038; 1.43 0.50, p 0.043) in the presence ofMSCs.Inaddition,NFKB-RELcomplexfamilymembersthatare

Evaluation of Multiple Input Multiple Output (MIMO) System Capacity with Spatial Correlations

Problem statement: Today's wireless technologies just won't get us to the hyper connectivity of uninterrupted access from any mobil e device with unlimited bandwidth at real-time speeds. This is due to the low data throughput and scarcity in spectrum. Approach: Under the condition of uncorrelated antenna elements, capacit y of the Multiple Input Multiple Output (MIMO) system can be increased linearly with the number of antennas. But in practice correlation among the antenna elements exists and it can reduce the chann el capacity. The effect of correlation can be reduced by using spatial diversity techniques. Results: The capacity of various MIMO configurations were analyzed and simulated. The effect of capacity of MIMO system due to correlation was presented with and without Eigen value distribution of the ch annel. The spatial correlation of dipole array and rectangular micro strip patch arrays were simulated with respect to various element spacing. Conclusion/Recommendations: The simulation results showed that, the capacity o f MIMO system without spatial correlation was higher than with co rrelation effect. By comparing, the rectangular micro strip patch array has low correlation than di pole array and provides high capacity which can be utilized for high data rate applications.

Study on simulation and experiment of array micro Faraday cup ion detector for FAIMS

An array micro Faraday cup ion detector for FAIMS (High-field Asymmetric Waveform Ion Mobility Spectrometry) was introduced, with which the size of the FAIMS system was reduced. With simple structure, good stability, low noise, large measurements range, this detector can work under the condition of atmospheric pressure. The array micro Faraday cup was composed of gate electrode, sensitive electrode and shielding electrode. The sensitive electrode was made of tens of crossing silicon columns with diameter of 200 μm. It was fabricated through typical MEMS technology, which was compatible completely with plane FAIMS. It was shown from FLUENT simulation result that the resistance to gas motion was low and the flow field distribution was helpful for full absorption of the ion in this array design. Through electricity simulation, the method to reduce interference on the detection signal of the micro Faraday cup was given out. Connecting with KEITHLEY 237 ampere meter, the noise level of the array micro Faraday cup was lower than 0.5 pA. The output signal of the acetone sample measured by experiment was about 210 pA. Through contrast experiment, the design parameter of the micro Faraday cup was obtained primarily. This array micro Faraday cup can meet the requirements of the FAIMS system.

A polymer lab-on-a-chip for magnetic immunoassay with on-chip sampling and detection capabilities

This paper presents a new polymer lab-on-a-chip for magnetic bead-based immunoassay with fully on-chip sampling and detection capabilities, which provides a smart platform of magnetic immunoassay-based lab-on-a-chip for point-of-care testing (POCT) toward biochemical hazardous agent detection, food inspection or clinical diagnostics. In this new approach, the polymer lab-on-a-chip for magnetic bead-based immunoassay consists of a magnetic bead-based separator, an interdigitated array (IDA) micro electrode, and a microfluidic system, which are fully incorporated into a lab-on-a-chip on cyclic olefin copolymer (COC). Since the polymer lab-on-a-chip was realized using low cost, high throughput polymer microfabrication techniques such as micro injection molding and hot embossing method, a disposable polymer lab-on-a-chip for the magnetic bead-based immunoassay can be successfully realized in a disposable platform. With this newly developed polymer lab-on-a-chip, an enzyme-labelled electrochemical immunoassay (ECIA) was performed using magnetic beads as the mobile solid support, and the final enzyme product produced from the ECIA was measured using chronoamperometry. A sampling and detection of as low as 16.4 ng mL(-1) of mouse IgG has been successfully performed in 35 min for the entire procedure.

Monitoring of Temperature Distribution within a Silicon-Based Micro Reformer Using Array Micro Sensors

With advances in micro fuel cell development, the production of hydrogen for micro reformer has become increasingly important. However, some problems regarding the micro reformer are yet to be resolved. These include reducing the size, reducing the quantity of CO and combining the fuel cell, among others. Accordingly, in this investigation, array micro temperature sensors and heaters were combined within a silicon-based micro reformer to measure and control the temperature and thus improve performance and minimize the concentration of CO. In this work, micro-electro-mechanical-systems (MEMS) of the micro channel type were fabricated on a silicon substrate to enhance the methanol conversion ratio. Array micro temperature sensors and heaters were made of platinum and placed inside the micro reformer. Although the micro temperature sensor and heater have already been used to measure and control temperature in numerous fields, they have not been employed in micro reformer and commercial products. Therefore, this study presents a new approach for combining array micro temperature sensors and heaters within a silicon-based micro reformer to minimize the size and improve performance.

Metal Bipolar Plate with Micro Sensors

The fuel cell has the potential to become an indispensable source of electric power. However, some problems have not yet been resolved. Measuring the temperature and humidity inside the fuel cells is currently difficult. Accordingly, in this study, micro sensors were fabricated within the fuel cell, in which the temperature and humidity distributions were measured. The substrate of the fuel cell was made of stainless steel (SS-304) and etching was employed to fabricate the channel on the stainless steel substrate. Then micro-electro-mechanical-systems (MEMS) technology was used to fabricate the array micro temperature and humidity sensors on the rib of channel of stainless steel. The advantages of array micro temperature sensors are their small volume, their high accuracy, their short response time, the simplicity of their fabrication, their mass production and their ability to measure the temperature at a precise location more effectively than the traditional thermocouple. The micro humidity sensors were made from gold and titanium as down and up electrodes in the channel. The performance curve of the single cell was operating at 41.54 °C and gas flow rates of H2/O2 at 200/200ml/min. The max power density of the bipolar with micro sensor was 56 mW/cm2.

Integration of Micro Array Sensors in the MEA on Diagnosis of Micro Fuel Cells

The temperature and humidity conditions of a membrane electrode assembly (MEA) determine the performance of fuel cells. The volume of traditional temperature and humidity sensors is too large to allow them to be used to measure the distribution of temperature and humidity in the MEA of fuel cells. Measurements cannot necessarily be made where required. They measure only the temperature and humidity distribution outside the fuel cells and yield results with errors that exceed those of measurements made in MEA. Therefore, in this study, micro-electro-mechanical-systems (MEMS) fabrication technology was employed to fabricate an array of micro sensors to monitor in situ the temperature and humidity distributions within the MEA of fuel cells. In this investigation, an array of micro temperature and humidity sensors was made from gold on the MEA. The advantages of array micro gold temperature and humidity sensors are their small volume, which enable them to be placed on MEA and their high sensitivity and accuracy. The dimensions of the temperature and humidity sensors are 180μm × 180μm and 180μm × 220μm, respectively. The experiment involves temperatures from 30 to 100 °C. The resistance varied from 23.084 to 28.196 /. The experimental results reveal that the temperature is almost linearly related to the resistance and the accuracy and sensitivity are less than 0.3 °C and 3.2×10-3/°C, respectively. The humidity sensor showed that the capacitance changed from 15.76 to 17.95 pF, the relative humidity from 20 to 95 %RH, and the accuracy and sensitivity were less than 0.25 %RH and 0.03 pF/%RH.

Laterally stacked glass substrates with high density electrical feedthroughs

This paper reports a novel method to produce high density feedthrough glass wafers with sufficient thickness for the packaging and interconnection of high density array micro electromechanical systems (MEMS). Pyrex glass wafers with thin film metal lines on the surface are stacked and bonded with each other using phenyl methyl siloxane-based adhesive. The stacked glass wafer block is then sliced using a wire saw as the slicing surfaces cross the adhesive bonding interfaces vertically. Prototyped feedthrough glass wafers were subjected to anodic bonding to a silicon wafer with diaphragms. The anodic bonding was successful, but hermetic sealing was not achieved. The bending of the bonded sample can be reduced by annealing the sample at 400 °C in a vacuum before anodic bonding.

Fabrication of Micro Components to Silicon Wafer Using EDM Process

In this paper, the machining possibilities of silicon wafers by the EDM process are described. Micro components of silicon wafer were processed by EDM process. A fine tungsten carbide rod was machined as tool electrode for EDM process. Performance was investigated utilizing serious experiments. Micro hole was process with the fine electrode using EDM drilling. Micro slots were also processed on the surface of a silicon plate by a copper section electrode. The surface roughness of the silicon wafers in the EDM process was investigated. Array-micro-hole was machined by a tungsten carbide multi-electrode. Array micro holes on the coaxial circle were processed by a graphite-copper electrode of Dia.0.45mm. Batch production technology for economical EDM machining of micro holes were proposed.