Papers by Keyword: Photolithography

Abstract: Tetramethylammonium hydroxide (TMAH) and N-methyl pyrrolidinone (NMP) are commonly used in photoresist developing and stripping process, however, both of TMAH and NMP have been confirmed with CMR (Carcinogenic, Mutagenic and Reprotoxic) concerns. With more attention attracted to TMAH and NMP replacements, Huntsman developed a range of new quaternary amines products, including E-GRADE^® Choline OH (Choline Hydroxide), E-GRADE^® THEMAH (Tris (2-hydroxyethyl) methylammonium Hydroxide), XHE-125, XHE-128, XHE-138, XHE-145 and XHE-148, and solvents, E-GRADE^® MEOX (3-Methyl-2-oxazolidinone) and XHE-123, which have been evaluated in comparison with the performance of TMAH and NMP.

Abstract: This paper presents a simple approach to selectively synthesize the ZnO nanowires between interdigitated electrodes by integrating the hydrothermal method with the photolithography process. The printed circuit board (PCB) was adopted as the substrate. Interdigitated electrodes were fabricated by etching the copper foil of PCB. Then, both the positive and negative photoresists were used to control the growth of nanowires through lift-off concept. No costly materials and expensive apparatuses are required. Biotin–streptavidin reaction was used as an example to examine this proposed device. When histidine-tagged biotin was added and the reaction of biotin–streptavidin was completed, the distinguishable I-V curves were detected, respectively. The experimental results reveal that this proposed device is sensitive.

Abstract: Titanium implants with porous surface arranged orderly were fabricated by micromachining through photolithography and chemical etching. The titanium discs were implanted into the canine mandible alveolar bone for 3 and 21 days, for animal experiments. Neogenetic bone was observed onto porous surface after 7 days‘ implantation. This result allows us to expect application of titanium with porous surface as biomaterials.

Abstract: The authors have developed 4H-SiC trench MOSFETs with orthogonal Deep-P structures (ODSs) to improve the trade-off between the on-resistance and the gate oxide field. The conditions of photolithography to realize a miniaturized Deep-P pattern have been optimized. The fabricated MOSFETs with ODS have demonstrated a low on-resistance of 2 mΩcm² and a high breakdown voltage of 1.8 kV.

Abstract: This work presents a photolithographic rapid prototyping process for producing thin films ("Rapid Phototyping"). This process allows a quick and cost-effective generation of scalable thermopile microstructures using commercial equipment and materials. Structural widths of 100x250μm can be produced reproducible in a lift-off process with an accuracy of 5 microns vertically and 30 microns horizontally.

Abstract: To perform the entire laboratory activities on a centimeter limit scale electronic chip, the most important aspect is to fabricate a device which persist sensitive and selective for the delivery of fluids flow and have the ability to execute a fast mixing of distinctive chemicals and bio samples. To resolve this issues the current paper is one of the good struggle, therefore the objective was arranged in according to the scope of research such as; to design and fabricate a polydimethylsiloxane (PDMS) material made, micro channel and its structure characterization for the investigation of internal subterranean area. By using an AutoCAD software the channel was first designed, however for the fabrication process the design was transferred to mask. Starting from SU-8 resist the pattern was transferred, and then by using the polydimethylsiloxane (PDMS) the mold was fabricated by adopting a low cost photolithography technique. Finally by employing Hawk 3 D surface nanoprofiler the structure was characterized. In our forthcoming research the device will be tested for real biological samples using a simple hand-operated inoculation technique.

Abstract: In this work, we use photolithography in order to fabricate micro-grating structures on silicon. The first step of device was coated by 3.5 μm thick silicon dioxide (SiO₂) film on top side, whereas the bottom side was coated with 4.5 μm. Next, we deposited silicon nitride (Si₃N₄) film of 2 μm by plasma-enhanced chemical vapor deposition, and used photolithography to prepare the gratings. We compared micro-grating period sizes of 1 μm, 0.8 μm and 0.5 μm, and found the 0.5 μm gave the best sensitivity. These devices can be applied with detection in biosensing in the future.

Abstract: An optical biosensor based on a grating to be utilized for the detection of DNA target molecules was fabricated by photolithographic techniques. The sensor surface implements a grating to create a low effective refractive index platform via the combination of Si₃N₄ and SiO₂ which allows the detection via changes of the reflectivity spectra. The active surface carried a layer of probe biomolecules for specific binding of the target DNA. Immobilization of the probe molecules was carried out via streptavidin using biotin modified ssDNA complementary to the target ssDNA. When molecules attached to the surface of the device, the position of the reflectance spectrum shifted due to the change of the optical path of light that is coupled into the grating structure. The extent of the wavelength shift of the peaks could be used to quantify the amount of materials bound to the sensor surface thereby allowing detection of the surface modifications as well as the quantification of the DNA analyte. The advantages of this device are that it works with a small sample volumes (few microlitres), are integratable in micro array type of setups and can be used at room temperature.

Abstract: Commercial planar power transformer core majorly inserted manually as stand-alone components sandwiched on the stacked multilayer PCB of the power supply system. The indispensible gap within the layers still seems to produce significant losses due to leakage inductance meanwhile the low thermal conductivity of the PCB worsen the generated heat dispersion process. Thus this paper is to explore a new approach in order to attain a higher efficiency, high thermal conductivity dispersion and low cost mass production on this magnetic device using CMOS development procedure on a silicon wafer substrate. Considerations for the optimum mask design process for power transformer based pattern micromachining on the Silicon substrate process using low cost wet etching process are presented and discussed. The process are to manipule the anisotropy properties using concave and convex mask pattern to produce a correct final angle and pattern using recognized KOH solutions optimized ratio. The conventional wet etching concept has been explored with a several mask design template and comparison between several pattern size in order to attain the best fine structure and correct angle pattern up to 100 um depth. Several convex corner corners compensation methods has been reviewed which finally concluded to method proposed by Wei Fan and Dacheng Zhang has been verified within the 40% KOH:IPA in 50°C solutions experiment.

Abstract: The important role of reactive ion etching (RIE) technique is to etch the semiconductor surface directionally. The purpose of the current research is to fabricate polysilicon micro-gap structures by RIE technique for future biosensing application. Therefore zero-gap microstructure of butterfly topology was designed by using AutoCAD software and finally the designed was transferred to commercial chrome glass photomask. Ploysilicon wafer samples were selected to achieve high conductivity during electrical characterization measurement. The fabrication process starts from samples resist coating and then by employing photolithography through chrome glass photomask the zero-gap pattern of butterfly topology was transferred to resist coated sample wafer followed by resist stripping from exposed area and finally by reactive ion etching (RIE) technique the open area of polysilicon was etched directionally at different etching time to fabricate micro-gap structure on wafer samples. The spacing of fabricated micro-gap structures will be further shrink by thermal oxidation (size reduction technique) until to nanosize gap spacing. The proposed nanospacing gap will definitely show the capability to detect the bio molecule when inserted into the gap spacing.