Browsing by Author "Hsiao, Wen-Tse"

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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.
Fabrication of a double-sided micro-lens array by a glass molding technique
(2011-08-01)
Huang, Chien-Yao
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Hsiao, Wen-Tse
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Huang, Kuo-Cheng
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Chang, Keng-Souo
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Chou, Hsiao-Yu
In recent years, micro-lens arrays (MLAs) have become important elements of optical systems. One function of MLAs is to create a uniform intensity of light. Compared with one-sided MLAs, the uniformity of light intensity increases with double-sided MLAs. MLAs fabricated by glass can be used in higher temperature environments or in high-energy systems. Glass-based MLAs can be fabricated by laser machining, photolithography, precision diamond grinding process and precision glass molding (PGM) technologies, but laser machining, photolithography and precision diamond grinding process technologies are not the perfect approach for mass production. Therefore, this paper proposes a method to fabricate a mold by laser micro-machining and a double-sided MLA by a PGM process. First, a micro-hole array was fabricated on the surface of a silicon carbide mold. A double-sided MLA using two molds was then formed by a PGM process. In this paper, the PGM process parameters including molding temperature and molding force are discussed. Moreover, the profile of a double-sided MLA is discussed. Finally, a double-sided MLA with a diameter of 20 mm, and lenses with a height of 52 mu m, a radius of 851 mu m and a pitch of 700 mu m were formed on glass.
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.
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.
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.
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.
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
;
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.