Photolithography

Microfluidics is a promising technology that is increasingly attracting the attention of researchers due to its high efficiency and low-cost features. Micropumps, micromixers, and microvalves have been widely applied in various biomedical applications due to their compact size and precise dosage controllability. Nevertheless, despite the vast amount of research reported in this research area, the ability to implement these devices in portable and implantable applications is still limited. To date, such devices are constricted to the use of wires, or on-board power supplies, such as batteries. This thesis presents novel techniques that allow wireless control of passive microfluidic devices using an external radiofrequency magnetic field utilizing thermopneumatic principle. Three microfluidic devices are designed and developed to perform within the range of implantable drug-delivery devices. To demonstrate the wireless control of microfluidic devices, a wireless implantable thermopneumatic micropump is presented. Thermopneumatic pumping with a maximum flow rate of 2.86 μL/min is realized using a planar wirelessly-controlled passive inductor-capacitor heater. Then, this principle was extended in order to demonstrate the selective wireless control of multiple passive heaters. A passive wirelessly-controlled thermopneumatic zigzag micromixer is developed as a mean of a multiple drug delivery device. A maximum mixing efficiency of 96.1% is achieved by selectively activating two passive wireless planar inductor-capacitor heaters that have different resonant frequency values. To eliminate the heat associated with aforementioned wireless devices, a wireless piezoelectric normally-closed microvalve for drug delivery applications is developed. A piezoelectric diaphragm is operated wirelessly using the wireless power that is transferred from an external magnetic field. Valving is achieved with a percentage error as low as 3.11% in a 3 days long-term functionality test. The developed devices present a promising implementation of the reported wireless actuation principles in various portable and implantable biomedical applications, such as drug delivery, analytical assays, and cell lysis devices.

The dissertation will be defended under open consideration in the Council of Materials
Science on the 18th of December, 2015, 15:00 h at the Laser Research Center
of Vilnius University, room 306, Sauletekio Ave. 10, Vilnius, Lithuania.
The summary of the dissertation was distributed on the 18th of November, 2015.

Microelectronics technologies have contributed a lot of facilities to fabricate small scale devices especially in biological and medical fields where the full advantage in development of transducers and sensors which are capable of characterizing bio-species.

This paper proposes a computer model that simulates the emission of acoustic signals produced by a wave energy device. It analyses these signals with the aid of the audiogram of marine mammals, in this case the Harbour seal. This enables us to estimate the levels of acoustic noise experienced by marine mammals due to the presence of ocean deployed devices.

This paper reports a novel wireless control of a thermopneumatic zigzag micromixer achieved by selectively activating two passive wireless heaters enabled by an external radiofrequency magnetic field. The two heaters, which are designed to have different resonant frequency (fr) values of 100 and 130 MHz, are selectively activated by modulating the field frequency to their corresponding fr values. Each heater is responsible for heating an air-heating chamber that is connected to a loading reservoir through a microdiffuser element, while the solutions pumped from each reservoir are mixed in a zigzag micromixing element that ends with an outlet hole. Mixing is achieved in a relatively short mixing length of a 2 mm, and was investigated over a low range of Reynold's number (Re) ≤ 10 that is suitable various biomedical applications. The numerically simulated and measured results of the proposed micromixer have shown mixing efficiencies values higher than 82% for the whole range of Re. The optimal activation switching time of the heaters is 10 s, at which the micromixer achieves a steady value of the maximum mixing efficiency after ~65 s. The micromixer provides mixing-ratio controllability with a maximum flow rate and pressure drop of ~3.4 μL/min and ~385.22 Pa, respectively.

An efficient and practical photoresist development simulator based on cellular automata is presented. Image reversal and chemical amplification processes are also simulated using this simulator. To verify the simulator, a series of experiments have been designed and performed using the Shipley SNR-248 negative resist, a stepper, and a deep ultraviolet source at 248 nm. Experiments were performed for periodic and isolated lines with pitches 300, 400, 500, and 1000 nm, for exposure energy doses of 11, 13, 17, and 23 mJ/cm2, and with developer temperatures of 0, 20, and 80 C. In all cases, the simulator results were found to be in very good agreement with the corresponding experimental results. The simulator has also successfully reproduced the incomplete opening effect observed in the case of close-spaced parallel lines.

Use of a warm water soak midway during development results in improved resist profiles, particularly as a function of focus. Three positive resists are examined in order to qualitatively determine their particular time temperature response to such a process. We find that the expected trade off between temperature and time holds, furthermore there is no need to spin dry wafers during treatment. Control of the time and temperature gives rise to improved profiles relative to samples utilising interrupted development. The warm water IDB also requires lower overheads in development time, as well as being applicable to a wider range of Novolac/DNQ chemistries. The use of multiple warm water IDB treatments may be required in extending the focus latitude of both lines and contacts printed over topography.

This paper investigates the electrical behavior of the Al/SiO2/Si MOS structure. We have used the complex admittance method to develop an analytical model of total capacitance applied to our proposed equivalent circuit. The charge density, surface potential, semiconductor capacitance, flatband and threshold voltages have been determined by resolving the Poisson transport equations. This modeling is used to predict in particular the effects of frequency, parallel and series resistance on the capacitance-voltage characteristic. Results show that the variation of both frequency and parallel resistance causes strong dispersion of the C-V curves in the inversion regime. It also reveals that the series resistance influences the shape of C-V curves essentially in accumulation and inversion modes. A significant decrease of the accumulation capacitance is observed when R s increases in the range 200–50000 Ω. The degradation of the C-V magnitude is found to be more pronounced when the series resistance depends on the substrate doping density. When Rs varies in the range 100 Ω–50 kΩ, it shows a decrease in the flatband voltage from −1.40 to −1.26 V and an increase in the threshold voltage negatively from −0.28 to −0.74 V, respectively. Good agreement has been observed between simulated and measured C-V curves obtained at high frequency. This study is necessary to control the adverse effects that disrupt the operation of the MOS structure in different regimes and optimizes the efficiency of such electronic device before manufacturing.

Single suspended carbon nanowires (CNWs) integrated on carbon-MEMS (CMEMS) structures are fabricated by electrospinning of SU-8 photoresist followed by pyrolysis. These monolithic CNW-CMEMS structures enable fabrication of very high aspect ratio CNWs of predefined length. The CNWs thus fabricated display core− shell structures having a graphitic shell with a glassy carbon core. The electrical conductivity of these CNWs is increased by about 100% compared to glassy carbon as a result of enhanced graphitization. We suggest some tunable fabrication and pyrolysis parameters that may improve graphitization in the resulting CNWs, making them a good replacement for several carbon nanostructure-based devices.

A comparative examination is presented of materials and approaches for the fabrication of microfluidic devices for small-angle neutron scattering (SANS). Representative inorganic glasses, metals, and polymer materials and devices are evaluated under typical SANS configurations. Performance criteria include neutron absorption, scattering background and activation, as well as spatial resolution, chemical compatibility and pressure resistance, and also cost, durability and manufacturability. Closed-face polymer photolithography between boron-free glass (or quartz) plates emerges as an attractive approach for rapidly prototyped microfluidic SANS devices, with transmissions up to $98% and background similar to a standard liquid cell (I ' 10 À3 cm À1). For applications requiring higher durability and/or chemical, thermal and pressure resistance, sintered or etched boron-free glass and silicon devices offer superior performance, at the expense of various fabrication requirements, and are increasingly available commercially.

209-212 209 Elsevier Improved Resist Contrast with Novolac based E-beam Resists using Modified Development Procedures. R. Jonckheere, N. Samarakone, L. Van den hove, and I. Daraktchiev* IMEC, Kapeldreef 75, B-3030, Leuven, Belgium *Olin Hunt NV, Europark-Noord 17-18, B-2700, St Niklaas, Belgium Improvements in the contrast of e-beam exposed resists have been reported via the use of multiple interrupted development techniques. Additional baking is claimed to effect greater improvements in optical lithography. This so called intermediate development bake or (IDB) process, has recently been further simplified through adoption of a warm water treatment for the baking step. In the w_arm water IDB process, the need to spin dry wafers is eliminated, thereby improving development throughput. We report on the application of all of these treatments to resists exposed using e-beam. Contrast curves obtained with multiple ww IDB processes at different temperatures and times are presented and compared with those obtained utilizing conventional development with varying PEB conditions. The effect on sizing both the top and base of the resist image as a function of exposure is also examined. Olin Hunt HEBR 214 has been at the focus of our work, although we additionally report on HEBR 242 and HPR 204, as well as Aspect System 912.

In this report we examine the dewetting of spin-cast poly (styrene) films in a confined geometry. We designed a platform for laterally confining PS by photo-patterning crosslinks in spin-coated thin films. Heating the patterned film above the glass transition temperature of PS results in localized dewetting patterns in regions that were not crosslinked, while the crosslinked pattern serves as a rigid barrier that confines the retraction of the uncrosslinked polymer in micron-sized domains. The barriers also provide a favorable surface that the liquid PS wets onto, forming a rim at the boundary of crosslinked and uncrosslinked polymer. The resulting patterns are shown to be dependent on the irradiation and annealing time, the dimensions of the uncrosslinked region and the thickness of the film.The dewetting of poly (styrene) thin films containing photoactive benzophenone additives was spatially controlled by irradiation through a photomask, which selectively crosslinks defined areas of the film.► Crosslinks can be spatially delivered to polymer films containing a photoactive bifunctional benzophenone molecule that photo-crosslinks irradiated regions of the film. ► When annealed, uncrosslinked poly (styrene) (PS) preferentially localizes onto photo-crosslinked PS. ► The patterns are qualitatively affected by film thickness, areal dimensions of the uncrosslinked regions, irradiation and heating times.

Purposeto introduce the Innovative Electronics Manufacturing Research Centre (IeMRC) Flagship Project: Integrated Optical and Electronic Interconnect PCB Manufacturing (OPCB), its objectives, its consortium of 3 Universities and 10 companies and to describe the university research being carried out. This paper briefly reviews the motivation for developing novel polymer formulations, fabrication techniques, layout design rules and characterisation techniques for hybrid electronic and optical printed circuit boards using multimode polymer optical waveguide interconnects.

A process for applying a film of uniform thickness of photoresist solids onto a substrate comprising the steps of: (a) forming a liquid photoresist composition comprising photoresist solids in a solvent; the solids content of said photoresist composition being in the range from about 10% by weight to about 22% by weight; (b) forming atomized spray droplets of said liquid photoresist composition; (c) allowing said atomized spray droplets to settle by gravity onto a substrate surface, thereby forming a photoresist coating on that surface; and (d) spinning said coated substrate at a pre-determined spin speed and for a pre-determined time to remove substantially all of said solvent from said photoresist coating and to form a film of uniform thickness of photoresist solids on the substrate.

One of the delicate processes in semiconductor microfabrication is the photolithography. It is the process that sets the design dimensions on various parts of the device. In order to complete this process, two requirements need to be satisfied. First is to create, the exact dimensions and pattern as established in design phase, which in other word can be referred as the resolution of the images on the wafer. The second is the correct placement of the device pattern on the wafer relative to the crystal orientation of the wafer substrate. This is called alignment or registration of patterns in correct position. This registration requirement is similar to the correct alignment of the different floors of a building. It is easy to visualize that misalignment of elevator shafts and stair wells would render the building useless. In a circuit, the effects of misaligned mask layers can cause the entire circuit to fail. In this paper we have reported a couple of results that leads to photoresist development and optimization technique as a standard manufacturing process to form 1μm microbridge for later process of size reduction to form nanogap. Therefore, at the final stage of fabrication, a nano-diagnostic biochip device is developed to use it as a biomolecule detection biosensor. The development of biosensors is still an open field and much remains to be done before many of these bioelectronic devices become commercialized. In this research, the key factors such as resist thickness, post-exposure bake (PEB) time and developer concentration are taken into account to study the optimum measurements and process. The thickness of resist will affect the resolution of image transferred and developing time. Both PEB and developer concentration also has the tendency to affect the device pattern and developing time. As the result, the photoresist thickness is optimized at 1500nm, the developer RD6 concentration diluted at 10:25 (DI water: RD6) and PEB time optimized at 65s.

Standard positive photoresist techniques were adapted to generate micropatterns of proteins on glass and oxide surfaces. Both lift-off and plasma-etching techniques were used to transfer the photoresist pattern into a layer of covalently immobilised protein.

The synthesis of Ni-filled multi-walled carbon nanotubes was performed by atmospheric pressure chemical vapor deposition with propane on Si at 850 °C using a simple mixture of (N, N'-bis(salicylidene)-ethylenediiminato) nickel(II), commonly known as Ni(salen), and a conventional photoresist. Analysis of the carbon nanotubes using scanning electron microscopy together with high-resolution transmission electron microscopy show that the nanotubes have grown by a tip-growth mechanism and exhibit a multi-walled structure with partial Ni filling. The high quality of the Ni-filled nanotubes is evidenced by Raman spectroscopy. The magnetic properties of Ni-filled nanotubes were analyzed using a superconducting quantum interference device which revealed their ferromagnetic behavior with large coercivity. A scalable as well as site-selective growth of high quality Ni-filled carbon nanotubes is achieved by a simple photolithographic method.

Purposeto introduce the Innovative Electronics Manufacturing Research Centre (IeMRC) Flagship Project: Integrated Optical and Electronic Interconnect PCB Manufacturing (OPCB), its objectives, its consortium of 3 Universities and 10 companies and to describe the university research being carried out. This paper briefly reviews the motivation for developing novel polymer formulations, fabrication techniques, layout design rules and characterisation techniques for hybrid electronic and optical printed circuit boards using multimode polymer optical waveguide interconnects. Design/methodology/approach-We are investigating a number of different fabrication techniques which we compare with each other and with modelled calculations waveguide components. The fabrication techniques include photolithography, laser ablation, direct laser writing, embossing, extrusion and ink jet printing. Findings-A number of design rules for polymer multimode waveguides have been found and published. Techniques for ink jetting polymer to print waveguides and laser ablation techniques have been developed. New formulations of polymer which cure faster for direct writing have also been developed. Research limitations/implications-Further work is needed to thicken the ink jet printed polymer and to investigate side wall roughness of the ablated waveguides and development of new polymer formulations for dry film. Further research is also needed on construction of prototype system demonstrators. Practical Implications-the fabrication techniques being developed are designed to be transferred to industrial PCB manufacturers to enable them to make higher value optical printed circuit boards. The design rules being discovered are being entered into commercial PCB layout software to aid designers of optical printed circuit boards. Originality/value-The paper is of interest to PCB manufacturers who wish to upgrade their processes to be able to manufacture optical printed circuit boards. The university research is original and some published to date in the publications in the reference list.

This paper reports a novel wireless control of a thermopneumatic zig-zag micromixer by selectively activating two passive wireless heaters enabled by an external radiofrequency magnetic field. Each heater generates heat when the external field frequency is tuned to the corresponding resonant frequency (fr) of the heater. The two heaters that are designed to have different f of 100 MHz and 130 MHz are selectively activated with a constant input power of 0.2 W by modulating the field frequency to their corresponding fr. Each heater is responsible for heating an air-heating chamber that is connected to a loading reservoir through a microdiffuser element, while the solutions pumped from each reservoir are mixed in a zig-zag micromixing element that ends with an outlet hole. The micromixer provides a mixing-ratio controllability with a flow rate of ~0.28 μL/min and biocompatibility, making it promising for biomedical applications, such as local drug delivery and cells culturing.

Photo-lithography and etching processes are routinely used in both art printmaking and in semiconductor micro-fabrication. The objective of this collaboration is to produce two series of prints: Macro-prints: These will be of medical electrodes which were designed and fabricated at Newcastle University as a part of a project aiming to study the human skeletal muscle (“Multi-electrode Electromyography”, uEMG, www.microemg.com). These prints will be produced using the methods and materials that are common in art printmaking. Micro-prints: In contrast, a second series of prints which focus in societal themes of Mexican popular culture, will be produced at the micro-scale using semiconductor fabrication techniques. These prints will be the size of fractions of a millimeter and will be mounted on glass slides to view under a microscope using a HD digital camera. Erika Servin will lead the work for the “macro-prints”, while Enrique Escobedo-Cousin will lead the work of “micro-prints”.

Standard positive photoresist techniques were adapted to generate micropatterns of proteins on glass and oxide surfaces. Both lift-off and plasma-etching techniques were used to transfer the photoresist pattern into a layer of covalently immobilised protein.

We present a series of experiments for a cluster of parallel lines and an isolated one on Shipley SNR-248 negative resist coated Si wafers using a stepper and a Deep Ultra Violet source at 248 nm. The profiles obtained show that if the parallel lines are close-spaced they do not open up completely.We use the cellular automata model in order to simulate this effect. We attribute this effect to the change of the {developer–developer products} solution into a viscous one due to the presence of slowly diffusing dissolved resist molecules and free (dissolved) resist chunks in close proximity in the developer. This effectively reduces the development speed. The effect that we observe experimentally is a direct result of the thermodynamics of quasi-irreversible processes applied to a viscous continuous medium. The physics are incorporated in our model. Development depends on volume effects in addition to the ‘‘surface’’ etching phenomenon. The simulation results are in very good agreement with the experimental ones. This effect is expected to be pronounced in 193 nm photolithography and below and, therefore, the model presented here may contribute to the design of new low wavelength resists.

To extract useful work from biological motor proteins, it is necessary to orient microtubules traveling over kinesin-coated surfaces properly. Toward this goal, we have used microfabrication to construct 1.5-µm-deep channels in SU-8 photoresist patterned on glass. Although motor proteins bind to all surfaces, these channels localize motility exclusively to the glass surface, and the photoresist creates steep walls that direct microtubule movement. This technique provides a general approach for lithographically patterning enzyme activity.

As biomolecular detection systems shrink in size, there is an increasing demand for systems that transport and position materials at micron- and nanoscale dimensions. Our goal is to combine cellular transport machinery—kinesin molecular motors and microtubules—with integrated optoelectronics into a hybrid biological/engineered microdevice that will bind, transport, and detect specific proteins, DNA/RNA molecules, viruses, or cells. For microscale transport, 1.5 μm deep channels were created with SU-8 photoresist on glass, kinesin motors adsorbed to the bottom of the channels, and the channel walls used to bend and redirect microtubules moving over the immobilized motors. Novel channel geometries were investigated as a means to redirect and sort microtubules moving in these channels. We show that DC and AC electric fields are sufficient to transport microtubules in solution, establishing an approach for redirecting microtubules moving in channels. Finally, we inverted the geometry to demonstrate that kinesins can transport gold nanowires along surface immobilized microtubules, providing a model for nanoscale directed assembly.

A novel photolithography-based technique was developed to fabricate a quasi-2D heterogeneous calcite micromodel of representative elementary volume size. The effect of brine-chemistry on the mobilization of capillarity and heterogeneity trapped oil after high salinity water injection was evaluated by using diluted seawater, and seawater modified with calcium, sulphate, and silica nanoparticles. Preliminary brine screening was performed based on modified contact angle experiments under dynamic salinity alteration. The main findings are that the chemical composition of brine impacts both the ultimate oil recovery and its speed. The highest and fastest oil recovery was obtained with diluted seawater and seawater augmented with nanoparticles. We also found that the ex-situ contact angle results, indicative of wettability alteration, can be predictive of each brine performance at the pore network-scale. A slow recovery process, from 7 days up to 12 days, without any oil banking, was observed with all the brines. Due to the time-dependent nature of the wettability alteration process, mere injection of brines, even several pore-volumes and the viscous force exerted by flooding, were not sufficient to result in any additional oil production. Oil production was obtained only during the shut-in period via enhanced spontaneous imbibition of brine into the pores and throats. This highlights that a sufficient soaking time (at least for laboratory scale experiments) would be necessary to assess suitability of brines and determine accurately the incremental oil recovery by low salinity waterflooding (LSWF).

Sugar is carbohydrate sweet-flavoured substance that composed of carbon, oxygen and hydrogen. It is an important component to provide sweet taste in food. Besides, it also provides immediate energy to complete daily routine life. However, uncontrolled amount of sugar can lead to serious health complications and diseases such as Hypoglycemia (low sugar in blood), syndrome X, diabetes and heart disease. Low amount of sugar in bloodstream may cause nausea and dizziness. Besides that, it also can be used as sensor to detect the amount of sugar in beverages. Here, sugar is used as a reference measurement to test the functionality of the device before testing it in real life using glucose samples. In future, real urine samples will be used to measure concentration of glucose in diabetic patients. In this paper, sugar concentration measurement based on microgap biosensor is fabricated by using conventional photolithography process. Silicon was used as the substrate material and followed by layers of Silicon dioxide (SiO2), Polysilicon, Titanium (Ti) and Gold (Au). Chrome mask were used to transfer pattern of microgap and contact pads onto the silicon substrate. The device design has been optimised to achieve few performance factors that includes accuracy, sensitivity, response time and fabrication cost. A number of sugar concentrations were prepared by diluting it with DI water for measurement process by electrical characterization. In this work, studies and analysis were conducted based on different concentration of sugar on constant sized microgap and based on different size of microgap structure on constant sugar concentration. As the result, the experiment has been successfully yielded a high sensitive microgap sensor and the lowest detected sugar concentration sample is 0.0245gml -1 . This method of biosensing provides a very simple and promising detection tech-nique for any kind of biomolecules that includes proteins, DNA, enzymes, antibody and antigen.

Single suspended carbon nanowires (CNWs) integrated on carbon-MEMS (CMEMS) structures are fabricated by electrospinning of SU-8 photoresist followed by pyrolysis. These monolithic CNW-CMEMS structures enable fabrication of very high aspect ratio CNWs of predefined length. The CNWs thus fabricated display core− shell structures having a graphitic shell with a glassy carbon core. The electrical conductivity of these CNWs is increased by about 100% compared to glassy carbon as a result of enhanced graphitization. We suggest some tunable fabrication and pyrolysis parameters that may improve graphitization in the resulting CNWs, making them a good replacement for several carbon nanostructure-based devices.

We present the fabrication and characterization of large arrays of inkjet-printed superparamagnetic polymer composite (SPMPC) hemispherical microstructures. SPMPCs are appealing for applications in microsystems and nanorobotics due to the added functionality of polymers and the significant magnetic attributes of embedded nanostructures. SPMPC-based microarchitectures can be used to perform different functions wirelessly in various media (e.g. water, solvents) using external magnetic fields: handling and assembling small objects, delivering drugs or biomass, or sensing specific physical or chemical changes. In this work superparamagnetic magnetite nanoparticles are dispersed in SU-8 to form magnetic hemispheres. Magnetically anisotropic hemispheres as well as standard SPMPC hemispheres are fabricated. Magnetic anisotropy is programmed by applying a magnetic field during curing. The distribution of nanoparticles inside the polymer matrix and magnetic characteristics of the SPMPC are investigated. Magnetic manipulation of hemispheres is demonstrated at liquid–liquid interfaces. Different assembly strategies to form lines or geometric shapes from hemispheres as well as their independent dynamic control are demonstrated. Finally, a two-interface assembly strategy is demonstrated to assemble hemispheres into complete spheres for advanced self-assembly tasks.

Purposeto introduce the Innovative Electronics Manufacturing Research Centre (IeMRC) Flagship Project: Integrated Optical and Electronic Interconnect PCB Manufacturing (OPCB), its objectives, its consortium of 3 Universities and 10 companies and to describe the university research being carried out. This paper briefly reviews the motivation for developing novel polymer formulations, fabrication techniques, layout design rules and characterisation techniques for hybrid electronic and optical printed circuit boards using multimode polymer optical waveguide interconnects.

The synthesis of Ni-filled multi-walled carbon nanotubes was performed by atmospheric pressure chemical vapor deposition with propane on Si at 850 °C using a simple mixture of (N, N'-bis(salicylidene)-ethylenediiminato) nickel(II), commonly known as Ni(salen), and a conventional photoresist. Analysis of the carbon nanotubes using scanning electron microscopy together with high-resolution transmission electron microscopy show that the nanotubes have grown by a tip-growth mechanism and exhibit a multi-walled structure with partial Ni filling. The high quality of the Ni-filled nanotubes is evidenced by Raman spectroscopy. The magnetic properties of Ni-filled nanotubes were analyzed using a superconducting quantum interference device which revealed their ferromagnetic behavior with large coercivity. A scalable as well as site-selective growth of high quality Ni-filled carbon nanotubes is achieved by a simple photolithographic method.

The synthesis of Ni-filled multi-walled carbon nanotubes was performed by atmospheric pressure chemical vapor deposition with propane on Si at 850 °C using a simple mixture of (N, N'-bis(salicylidene)-ethylenediiminato) nickel(II), commonly known as Ni(salen), and a conventional photoresist. Analysis of the carbon nanotubes using scanning electron microscopy together with high-resolution transmission electron microscopy show that the nanotubes have grown by a tip-growth mechanism and exhibit a multi-walled structure with partial Ni filling. The high quality of the Ni-filled nanotubes is evidenced by Raman spectroscopy. The magnetic properties of Ni-filled nanotubes were analyzed using a superconducting quantum interference device which revealed their ferromagnetic behavior with large coercivity. A scalable as well as site-selective growth of high quality Ni-filled carbon nanotubes is achieved by a simple photolithographic method.

Standard positive photoresist techniques were adapted to generate micropatterns of proteins on glass and oxide surfaces. Both lift-off and plasma-etching techniques were used to transfer the photoresist pattern into a layer of covalently immobilised protein.