Browsing by Author "Tseng, Shih-Feng"

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Characteristics of Ni-Ir and Pt-Ir hard coatings surface treated by pulsed Nd:YAG laser
(2010-12-25)
Tseng, Shih-Feng
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Hsiao, Wen-Tse
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Huang, Kuo-Cheng
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Chen, Ming-Fei
;
Lee, Chao-Te
The subjects of the presented paper are to develop a laser surface treatment technology for the protective coatings of glass-molding dies and to better understand the interaction between laser beam and materials coated on the die surface. A variety of alloy films, including Ir-25 at.% Pt. Ir-50 at.% Pt, Ir-75 at.% Pt. Ir-25 at.% Ni, Ir-50 at.% Ni, and Ir-75 at.% Ni compositions are deposited by the ion source assisted magnetron sputtering system (ISAMSS). A Cr layer that functioned as a buffer layer is deposited between the alloy film and die surface. After an alloy film and the buffer Cr layer were sequentially coated on tungsten carbide (WC) surface, Nd:YAG laser was directly applied in the writing process. The temperature profile of the film stack structure is simulated by ANSYS software. The surface roughness was analyzed by atomic force microscopy (AFM) to compare the coating surface roughness before and after the laser surface treatments. The treated coatings for oxidation prevention test were examined by energy dispersive x-ray spectrometry (EDS). Nanoindentation instrument was performed to evaluate microhardness and reduced modulus of the coatings. The cross-sectional structures between the hard coating layer and buffer layer were also inspected by a scanning electron microscope (SEM). The Pt-Ir and Ni-Ir film coatings are unable to withstand the working temperature over 1500 degrees C, which is considered for quartz molding process and hot embossing process. The films showed high roughness, low microhardness and low reduced modulus because the film oxidation occurred in a high working temperature process. Crown Copyright (C) 2010 Published by Elsevier B.V. All rights reserved.
Development of a Novel Rapid Manufacturing Process for Micro-Cylindrical Lens Array
(2011)
Huang, Chien-Yao
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Huang, Kuo-Cheng
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Chen, Jun-Cheng
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Chang, Keng-Souo
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Tseng, Shih-Feng
This paper proposed a novel method to fabricate micro-cylindrical lens array (mu-CLA) by using wire electrical discharge machining (WEDM) and precision glass molding (PGM) technique. Micro slits fabricated on the surface of tungsten carbide mold material with outline dimensions from 0.3mm to 2.1mm, the width and depth of 1 mm. The PGM processing parameters including width of slits, molding temperature, molding force and stroke were discussed. Moreover, the characteristics of mu-CLA were measured by contact profilometer. In addition, the relationship between the dimensions of the slit on tungsten carbide mold and the characteristics of mu-CLA also discussed.
Glass biochip fabrication by laser micromachining and glass-molding process
(2012-03-01)
Huang, Chien-Yao
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Kuo, Chao-Hui
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Hsiao, Wen-Tse
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Huang, Kuo-Cheng
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Tseng, Shih-Feng
Due to their low cost, small size, and high-speed performance, biochips are often used in various bio-experiments. Compared with polymer-based biochips, glass-based substrates are less sensitive to heat and organic environments. This study presents a hybrid processing approach that uses laser micromachining (LMM) and precision glass molding (PGM) techniques to mass-produce glass-based biochips. A silicon carbide (SiC) mold with an outside diameter of 20 mm was used to hot emboss biochip channels measuring 200 mu m wide and 185 mu m deep. This study also identifies the optimal conditions for glass molding when processing soda-lime glass for biochip applications, and discusses the influence of the major processing parameters on biochip channel depth. This study uses the Taguchi method to assess the effects of several molding parameters on larger-the-better performance characteristics. The experiments in this study consider the effects of several molding parameters, such as molding temperature, pressing force, moving speed, temperature holding time, and vacuum environment, to achieve optimum characteristics for biochip channels. Orthogonal array analysis indicates that the optimal process parameters includes a 620 degrees C molding temperature, 1 kN pressing force, 5 mm/min moving speed, 60s temperature holding time, and a vacuum-free environment. This study also investigates the surface roughness of glass biochip channels. (C) 2011 Elsevier B.V. All rights reserved.
Graphene-based chips fabricated by ultraviolet laser patterning for an electrochemical impedance spectroscopy
(2016-04-01)
Tseng, Shih-Feng
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Haiso, Wen-Tse
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Cheng, Pi-Ying
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Chung, Chien-Kai
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Lin, Yung-Sheng
This study aims to develop graphene-based impedance chips for an electrochemical impedance instrument fabricated by ultraviolet (UV) laser patterning. The finger-like electrode structure on multilayer graphene films coated on glass substrates was performed in a one-cycle laser patterning process. After a series of laser ablated line tests, the ablated line widths increased with increasing laser fluences. The optimal laser patterning parameters involved the laser fluence of 3.4 J/cm(2), scanning speed of 600 mm/s, and pulse repetition frequency of 100 kHz to remove completely a graphene electrode layer without damaging glass substrate. The patterned regions had no significant heat-affacted zones (HAZs) due to graphene materials with high thermal diffusivity. To clarify graphene removal completely, the patterned regions on graphene/glass substrates were detected by a Raman microscope. The developed impedance-sensing chips had been successfully applied to detect the phase separation for emulsions containing emulsifiers with 15%, 17.5%, and 20% Polysorbate 80 (Tween 80) concentrations. We found that the separation time increased with increasing the emulsifier concentration. (C) 2015 Elsevier B.V. All rights reserved.
High-performance graphene-based heaters fabricated using maskless ultraviolet laser patterning
(2019-06-01)
Tseng, Shih-Feng
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Cheng, Pi-Ying
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Hsiao, Wen-Tse
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Chen, Ming-Fu
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Chung, Chien-Kai
Graphene-based film heaters (GFHs) with laser-patterned electrode structures can be used in microheaters, thermal sensors, and thermostatic apparatuses for various high-value-added medical devices and creative products. To obtain uniform and higher temperatures, this study aims to design, fabricate, and measure GFHs with net-like electrode structures using ANSYS Workbench software, an ultraviolet laser processing system, and an infrared thermal imaging camera, respectively. The electric heating experiments (which were measured with an infrared thermal imaging camera) demonstrated that the temperatures of GFHs with net-like electrode structures were significantly higher than those of devices without patterned graphene films. Moreover, the temperatures of GFHs with net-like electrode structures increased rapidly with time when DC voltages higher than 12V were applied for at least 10s. A maximum temperature of 91.5 degrees C was obtained at 200s when a DC voltage of 18V was applied. Besides, minimal and maximal deviations of steady-state temperatures between experimental and simulated values were 6.9 degrees C and 10 degrees C under each corresponding DC voltage, respectively.
Hydrophobic Templates with Rough Patterns Fabricated by Laser Micromachining for Liquid Droplets Generation
(2011)
Tseng, Shih-Feng
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Huang, Kuo-Cheng
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Chiang, Donyau
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Chen, Ming-Fei
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Hsiao, Sheng-Yi
This paper presents an approach to utilize high precision pulsed Nd:YAG laser to fabricate a rough array-pattern on a soda-lime glass plate by a laser-induced backside writing (LIBW) process, and a laser-induced plasma assisted ablation (LIPAA) technique. The current study investigates the effect of process parameters such as single-shot laser exposure time and number of passes on the material removal rate. After depositing 695 nm thick Teflon thin film on the glass plate, the surface of the laser micro-machined template becomes hydrophobic. The surface roughness, annular groove profile and surface micrograph were measured by an atomic force microscope, a profilometer, and a scanning electron microscope, respectively. A uniform liquid droplet by the sessile drop method is generated on the hydrophobic template. Droplet characteristics, such as contacted angle, size, and shape, are measured with a surface tension analyzer and microscope. This work also discusses the relationship between the formed droplets and the process recipe of the micro-machined template. The proposed approach can apply to future for uniform lens array formation.
Laser Direct Imaging of Transparent Indium Tin Oxide Electrodes Using High Speed Stitching Techniques
(2014-09-01)
Cheng, Pi-Ying
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Hsiao, Wen-Tse
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Chung, Chien-Kai
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Tseng, Shih-Feng
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Liao, Ien-Chang
To accomplish an electrode patterning in large area, we present a high speed stitching technique used in an ultraviolet laser processing system and investigate the interaction between laser beams and indium tin oxide (ITO) thin films deposited on glass substrates. After optimizing the process parameters of the laser direct imaging (LDI) for the large-area electrode patterning, the ablated lines looked like regularly fish-scale marks of about a 40 mu m diameter and a 120 nm depth around the processing path. The parameters includes the laser power of 1 W, the scanning speed of galvanometers of 800 mm/s, and the laser pulse repetition frequency of 50 kHz. Moreover, the resistance value of the ablated ITO thin film is larger than 200M Omega that is electrically insulated from the other regions of electrode structure. LDI technology with UV laser beam has great potential applications in patterning on wafer or sapphire substrates and patterning a conductive layer deposited on the touch panels for semiconductor and optoelectric industries, respectively. (C) 2014 The Japan Society of Applied Physics
Laser scribing of indium tin oxide (ITO) thin films deposited on various substrates for touch panels
(2010-12-15)
Tseng, Shih-Feng
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Hsiao, Wen-Tse
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Huang, Kuo-Cheng
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Chiang, Donyau
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Chen, Ming-Fei
In this study, a Nd:YAG laser with wavelength of 1064nm is used to scribe the indium tin oxide (ITO) thin films coated on three types of substrate materials, i.e. soda-lime glass, polycarbonate (PC), and cyclic-olefin-copolymer (COC) materials with thickness of 20 nm, 30 nm, and 20 nm, respectively. The effect of exposure time adjusted from 10 mu s to 100 mu s on the ablated mark width, depth, and electrical properties of the scribed film was investigated. The maximum laser power of 2.2W was used to scribe these thin films. In addition, the surface morphology, surface reaction, surface roughness, optical properties, and electrical conductivity properties were measured by a scanning electron microscope, a three-dimensional confocal laser scanning microscope, an atomic force microscope, and a four-point probe. The measured results of surface morphology show that the residual ITO layer was produced on the scribed path with the laser exposure time at 10 mu s and 20 mu s. The better edge qualities of the scribed lines can be obtained when the exposure time extends from 30 mu s to 60 mu s. When the laser exposure time is longer than 60 mu s, the partially burned areas of the scribed thin films on PC and COC substrates are observed. Moreover, the isolated line width and resistivity values increase when the laser exposure time increases. Crown Copyright (C) 2010 Published by Elsevier B.V. All rights reserved.
Laser structuring of parallel electrode array on graphene/glass substrates for rapid inspections of moisturizing efficacy
(2017-08-01)
Tseng, Shih-Feng
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Haiso, Wen-Tse
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Cheng, Pi-Ying
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Lin, Yung-Sheng
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Chang, Tien-Li
This research aims to structure thin layers of graphene materials for impedance sensing chips with a parallel electrode array and to investigate the interaction between nanosecond pulsed Nd:YVO4 lasers and graphene films coated on glass substrates. The optimal laser structuring conditions consisted of pulse repetition rate of 100 kHz, the scanning speed of two galvano scanners of 600 mm/s, the laser fluence of 3.4 J/cm(2), and parallel lines of the laser processing path with the line-scan spacing of 1 mu m in one-cycle process to produce the parallel electrode structures. The surface morphology, cross-sectional profile, optical spectra, and material characterizations on graphene/glass substrates were detected by a confocal laser scanning microscope, a scanning electron microscope (SEM), a spectrophotometer, and a Raman spectroscopy, respectively. The parallel electrode sensing chips had been successfully used to detect the moisturizing efficacy of solutions containing moisturizers with 0, 3, 6, and 9 wt% 1,3-Butylene Glycol concentrations. The experimental results showed that the electrochemical impedance spectroscopy combined with graphene sensing chips had high sensitivity and saving time than weight loss of solutions detected by the precision electronic balance.
Mechanical and optoelectric properties of post-annealed fluorine-doped tin oxide films by ultraviolet laser irradiation
(2011-06-01)
Tseng, Shih-Feng
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Hsiao, Wen-Tse
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Chiang, Donyau
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Huang, Kuo-Cheng
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Chou, Chang-Pin
The fluorine-doped tin oxide (FTO) thin film deposited on a soda-lime glass substrate was annealed by a defocus ultraviolet (UV) laser irradiation at ambient temperature. The mechanical and optoelectric properties of FTO films annealed by using the various laser processing parameters were reported. After the FTO films were subjected to laser post-annealing, the microhardness were slightly less but the reduced modulus values were larger than that of unannealed FTO films, respectively. The average optical transmittance in the visible waveband slightly increased with increasing the laser annealing energy and scan speed. Moreover, all the sheet resistance of laser annealed films was less than that of the unannealed ones. We found that the sheet resistance decrease was obviously influenced by annealing. The suitable annealing conditions could maintain the film thickness and relief the internal stress generated in the film preparation process to improve the electrical conductivity via decreasing laser energy or increasing scan speed. Crown Copyright (C) 2011 Published by Elsevier B.V. All rights reserved.
Mechanical Properties of Pt-Ir and Ni-Ir Binary Alloys for Glass-Molding Dies Coating
(2011-10-01)
Tseng, Shih-Feng
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Lee, Chao-Te
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Huang, Kuo-Cheng
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Chiang, Donyau
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Huang, Chien-Yao
In this study, the different compositions of Pt-Ir and Ni-Ir alloys were deposited by utilizing ion source assisted magnetron sputtering system (ISAMSS). The surface roughness and crystallite size of the Pt-Ir and Ni-Ir coatings were analyzed by atomic force microscopy (AFM) and X-ray diffraction (XRD), respectively. In addition, coatings were soaked at 700 degrees C and maintained 10 min under N(2) atmosphere using a glass-molding machine. The annealed coatings for oxidation test were examined by energy dispersive X-ray spectrometry (EDS) and for microhardness and reduced modulus test were evaluated by nanoindentation instrucment. The cross-sectional structures between the Pt-Ir and Ni-Ir coating layer and substrates were also examined by field emission scanning electron microscope (FESEM). The results show that surface roughness Ra from 1.25 nm to 3.426 nm was observed with increasing the Ni elements. However, the Ra is less than 2 nm measured in Ir-based coatings doped with Pt concentrations under this study. With increasing Pt and Ni doping, the microhardness of both coatings decreased significantly and the values of reduced modulus of Pt-Ir alloys are larger than that of Ni-Ir alloys. After oxidation process, the oxygen concentration of Pt-Ir coatings is less than that of Ni-Ir coatings and the Pt-Ir coatings exhibit superior properties including oxidation resistance, low surface roughness and high reduced modulus over Ni-Ir coatings, especially for the high Pt concentration coatings such as Pt-Ir 2 (55.25 at.% Pt) and Pt-Ir 3 (79.42 at.% Pt) coatings. The surface roughnesses of all specimens annealed at 700 degrees C were slightly larger than as-deposited coatings. Moreover, due to the serious oxidation occurred in Ni-Ir 3 (73.45 at.% Ni) coatings, the value of reduced modulus of this specimen coating is the lowest and the corrsponding Ra value is the largest compared with the rest of Ir-based coatings in the oxidation testing.
Surface wettability of silicon substrates enhanced by laser ablation
(2010-11-01)
Tseng, Shih-Feng
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Hsiao, Wen-Tse
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Chen, Ming-Fei
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Huang, Kuo-Cheng
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Hsiao, Sheng-Yi
Laser-ablation techniques have been widely applied for removing material from a solid surface using a laser-beam irradiating apparatus. This paper presents a surface-texturing technique to create rough patterns on a silicon substrate using a pulsed Nd:YAG laser system. The different degrees of microstructure and surface roughness were adjusted by the laser fluence and laser pulse duration. A scanning electron microscope (SEM) and a 3D confocal laser-scanning microscope are used to measure the surface micrograph and roughness of the patterns, respectively. The contact angle variations between droplets on the textured surface were measured using an FTA 188 video contact angle analyzer. The results indicate that increasing the values of laser fluence and laser pulse duration pushes more molten slag piled around these patterns to create micro-sized craters and leads to an increase in the crater height and surface roughness. A typical example of a droplet on a laser-textured surface shows that the droplet spreads very quickly and almost disappears within 0.5167 s, compared to a contact angle of 47.9A degrees on an untextured surface. This processing technique can also be applied to fabricating Si solar panels to increase the absorption efficiency of light.
Surface wettability of silicon substrates enhanced by laser ablation
(2010-11-01)
Tseng, Shih-Feng
;
Hsiao, Wen-Tse
;
Chen, Ming-Fei
;
Huang, Kuo-Cheng
;
Hsiao, Sheng-Yi
Laser-ablation techniques have been widely applied for removing material from a solid surface using a laser-beam irradiating apparatus. This paper presents a surface-texturing technique to create rough patterns on a silicon substrate using a pulsed Nd:YAG laser system. The different degrees of microstructure and surface roughness were adjusted by the laser fluence and laser pulse duration. A scanning electron microscope (SEM) and a 3D confocal laser-scanning microscope are used to measure the surface micrograph and roughness of the patterns, respectively. The contact angle variations between droplets on the textured surface were measured using an FTA 188 video contact angle analyzer. The results indicate that increasing the values of laser fluence and laser pulse duration pushes more molten slag piled around these patterns to create micro-sized craters and leads to an increase in the crater height and surface roughness. A typical example of a droplet on a laser-textured surface shows that the droplet spreads very quickly and almost disappears within 0.5167 s, compared to a contact angle of 47.9A degrees on an untextured surface. This processing technique can also be applied to fabricating Si solar panels to increase the absorption efficiency of light.
The Glass-Molding Process for Planar-Integrated Micro-Optical Component
(2011-01-01)
Huang, Chien-Yao
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Sze, Jyh-Rou
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Huang, Kuo-Cheng
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Kuo, Chao-Hui
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Tseng, Shih-Feng
This paper presents a precision glass-molding process to fabricate planar-integrated micro-optical components (PIMOC) applied to a micro projection display system, optical interconnection system and optical storage system. The PIMOC was designed based on wave propagation theory, and fabricated using a glass molding process. Experimental results are discussed in this article. The experiment showed that the PIMOC fabricated in a vacuum environment meets the design value with precision glass-molding technology (PGMT) at a molding force of 2.75 kN, a molding temperature of 750 degrees C and a cooling rate of 49 degrees C/min. (C) 2011 The Japan Society of Applied Physics