Low Temperature Nafion Bonding of Silicon Wafers

Ilić, B.; Neužil, Pavel; Stanczyk, T.; Czaplewski, David A.; Maclay, G. Jordan

doi:10.1149/1.1390743

Cited by 27 publications

(14 citation statements)

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“…From a standard Nafion liquid dispersion (Nafion DE 521, DuPont), we formed a 0.83% Nafion solution via 1∶5 dilution in 2-propanol. In a modified version of the protocol described in [49] , we used a spin-on process to coat our wafers with the resulting dispersion, spinning the wafers at 750–1000 rpm for 3–10 s. In order to cure the Nafion and facilitate bonding to the substrate [50] , we heated the wafers in a convection oven at 120°C for 20 minutes. This process generates Nafion layers approximately 60–420 nm in thickness, as measured by spectroscopic ellipsometry (Filmetrics, San Diego, California).…”

Section: Methodsmentioning

confidence: 99%

A Glucose Fuel Cell for Implantable Brain–Machine Interfaces

2012

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We have developed an implantable fuel cell that generates power through glucose oxidation, producing steady-state power and up to peak power. The fuel cell is manufactured using a novel approach, employing semiconductor fabrication techniques, and is therefore well suited for manufacture together with integrated circuits on a single silicon wafer. Thus, it can help enable implantable microelectronic systems with long-lifetime power sources that harvest energy from their surrounds. The fuel reactions are mediated by robust, solid state catalysts. Glucose is oxidized at the nanostructured surface of an activated platinum anode. Oxygen is reduced to water at the surface of a self-assembled network of single-walled carbon nanotubes, embedded in a Nafion film that forms the cathode and is exposed to the biological environment. The catalytic electrodes are separated by a Nafion membrane. The availability of fuel cell reactants, oxygen and glucose, only as a mixture in the physiologic environment, has traditionally posed a design challenge: Net current production requires oxidation and reduction to occur separately and selectively at the anode and cathode, respectively, to prevent electrochemical short circuits. Our fuel cell is configured in a half-open geometry that shields the anode while exposing the cathode, resulting in an oxygen gradient that strongly favors oxygen reduction at the cathode. Glucose reaches the shielded anode by diffusing through the nanotube mesh, which does not catalyze glucose oxidation, and the Nafion layers, which are permeable to small neutral and cationic species. We demonstrate computationally that the natural recirculation of cerebrospinal fluid around the human brain theoretically permits glucose energy harvesting at a rate on the order of at least 1 mW with no adverse physiologic effects. Low-power brain–machine interfaces can thus potentially benefit from having their implanted units powered or recharged by glucose fuel cells.

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Section: Methodsmentioning

confidence: 99%

A Glucose Fuel Cell for Implantable Brain–Machine Interfaces

2012

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“…12 In order to create a hermetic seal between two substrates via an intermediate, a thermal or photo curable resin (thickness at least several microns) is dispensed on one substrate, contacted with another substrate after pre-curing, and cured at temperatures below 300 C. Although spin-on sodium silicate solution (spin-on-glass; SOG) yields good bonds at temperatures in the range 90-200 C, [13][14][15] polymers are mostly used as an intermediate layer, because most polymer-based materials can be patterned photolithographically, which allows localized adhesive bonding. Voidfree, low-temperature adhesive silicon-silicon, glass-glass and silicon-glass bonds are realized with polydimethylsiloxane (PDMS) or its precursor at 60-65 C, 16,17 Nafion (a perfluorinated ion exchange polymer) at 120 C, 18 polyimide, SU-8 and cyclic perfluoropolymer (Cytop) at 150-160 C, [19][20][21][22] and benzocyclobutene (BCB) at 180-270 C, [23][24][25] whereas roomtemperature glass-glass adhesive bonding is possible with UV curable epoxy resins. [26][27][28][29] The quality of the adhesive bond, i.e.…”

Section: Introductionmentioning

confidence: 99%

Room-temperature intermediate layer bonding for microfluidic devices

et al. 2009

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In this work a novel room-temperature bonding technique based on chemically activated Fluorinated Ethylene Propylene (FEP) sheet as an intermediate between chemically activated substrates is presented. Surfaces of silicon and glass substrates are chemically modified with APTES bearing amine terminal groups, while FEP sheet surfaces are treated to form carboxyl groups and subsequently activated by means of EDC-NHS chemistry. The activation procedures of silicon, glass and FEP sheet are characterized by contact angle measurements and XPS. Robust bonds are created at room-temperature by simply pressing two amine-terminated substrates together with activated FEP sheet in between. Average tensile strengths of 5.9 MPa and 5.2 MPa are achieved for silicon-silicon and glass-glass bonds, respectively, and the average fluidic pressure that can be operated is 10.2 bar. Moreover, it is demonstrated that FEP-bonded microfluidic chips can handle mild organic solvents at elevated pressures without leakage problems. This versatile room-temperature intermediate layer bonding technique has a high potential for bonding, packaging, and assembly of various (bio-) chemical microfluidic systems and MEMS devices.

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“…Thirdly, this bonding process remains timeconsuming and labor-intensive and requires the access to dedicate equipment such as clean-room facilities. [8][9][10] Next, direct bonding is mostly applicable for only conventional materials in microfabrication technology, i.e. glass and silicon except for plasma activation used for one polymer, PDMS.…”

Section: Introductionmentioning

confidence: 99%

Low-temperature, simple and fast integration technique of microfluidic chips by using a UV-curable adhesive

2010

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In the fields of MicroElectroMechanical Systems (MEMS) and Lab On a Chip (LOC), a device is often fabricated using diverse substrates which are processed separately and finally assembled together using a bonding process to yield the final device. Here we describe and demonstrate a novel straightforward, rapid and low-temperature bonding technique for the assembly of complete microfluidic devices, at the chip level, by employing an intermediate layer of gluing material. This technique is applicable to a great variety of materials (e.g., glass, SU-8, parylene, UV-curable adhesive) as demonstrated here when using NOA 81 as gluing material. Bonding is firstly characterized in terms of homogeneity and thickness of the gluing layer. Following this, we verified the resistance of the adhesive layer to various organic solvents, acids, bases and conventional buffers. Finally, the assembled devices are successfully utilized for fluidic experiments.

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Low Temperature Nafion Bonding of Silicon Wafers

Cited by 27 publications

References 0 publications

A Glucose Fuel Cell for Implantable Brain–Machine Interfaces

A Glucose Fuel Cell for Implantable Brain–Machine Interfaces

Room-temperature intermediate layer bonding for microfluidic devices

Low-temperature, simple and fast integration technique of microfluidic chips by using a UV-curable adhesive

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