Browsing by Author "Fu, Yu-Min"

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A Combined Process of Liftoff and Printing for the Fabrication of Scalable Inkjet Printed Microstructures on a Flexible Substrate
(2015-04-01)
Fu, Yu-Min
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Liang, Yen R.
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Cheng, Yu-Ting
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Wu, Pu-Wei
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材料科學與工程學系
In this paper, a combined process of liftoff and printing (CPLoP) techniques is introduced to realize size-scalable printed silver microstructures with line widths ranging from 5 to 70 mu m and resistivities of similar to 9.8 mu Omega . cm on a flexible polyimide substrate via thermal sintering at 300 degrees C for 30 min. In addition, a printed interdigitated capacitor with an electrode line width and spacing of 10 mu m and a printed spiral square inductor with a 10-mu m line width and 5-mu m spacing in an area of 1 mm(2) have been successfully demonstrated with an area capacitance and inductance of 0.43 pF/mm(2) at 10 KHz and 1.054 mu H/mm(2) up to 100 KHz, respectively, which are the orders of magnitude performance improvement in comparison with the contemporary inkjet-printed capacitors and inductors. Owing to the significant reduction of energy demand in processing tools and waste generation in processing materials, the results have revealed that the CPLoP process can facilitate the advancement of printing manufacture technology for microelectronics applications.
A COMBINED PROCESS OF SILICON SHADOW MASKING AND INKJET PRINTING (SSMP) FOR MAKING GRAPHENE OXIDE AND REDUCED GRAPHENE OXIDE MICROSTRUCTURES FOR SELECTIVE CELL CULTURING APPLICATIONS
(2019-01-01)
Kang, Che-Hao
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Fu, Yu-Min
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Kao, Chin-Chuan
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Yang, Jia-Wei
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Tseng, Ming-Liang
This paper demonstrates a combined process of silicon shadow masking and inkjet printing (SSMP) to fabricate graphene oxide (GO) and reduced graphene oxide (rGO) line features with a width ranging from 20 to 70 mu m on varieties of substrates, such as PDMS, SiO2 , Kapton, etc. for selectively cell (RPE and PC-12 cells) culturing applications. The rGO with an electrical resistance of 33.48k Omega/ is characterized via a printed four point resistivity measurement structure. Owing to the characteristics of low chemical usage, low process temperature and complexity, and high fault tolerance of inkjet printers, the process technique has shown its potential for biomedical applications in terms of flexible cell culturing platform fabrication.
A FlexibleWO(3)-Based pH Sensor Array for 2-D pH Monitoring Using CPLoP Technique
(2018-06-01)
Fu, Yu-Min
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Pan, Jia-Chyi
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Tsou, Kun-Lin
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Cheng, Yu-Ting
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電子工程學系及電子研究所
In this letter, we demonstrate an inkjet-printed WO3-based pH sensor array using WO3/Ag and Ag/AgCl as working and reference electrodes, respectively, on a flexible polyimide substrate. Pre-treated by Tollen's reagent, the printed Ag lines as sensor interconnects can exhibit a denser microstructure with lower electrical resistivity. As a result, the WO3 nanoparticles can be well printed and sintered at 120 degrees C on the Ag lines as the working electrodes of the pH sensors. Experimental results show the sensitivity of the pH sensor to be as high as -24.4 mV/pH. The array comprising six pH sensors shows potential for real-time 2-D pH sensing applications.
A LOW TEMPERATURE INKJET PRINTING AND FILLING PROCESS FOR LOW RESISTIVE SILVER TSV FABRICATION IN A SU-8 SUBSTRATE
(2017-01-01)
Yang, Tsung-Han
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Guo, Zi-Li
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Fu, Yu-Min
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Cheng, Yu-Ting
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Song, Yen-Fang
The paper presents a low temperature (with 60 degrees C) inkjet printing and filling process to realize low resistive Ag TSV (Through Substrate Vias) with the aspect ratio of via depth vs. diameter from 2 to 5 in a SU-8 substrate potential for flexible microsystem packaging applications. Combining humidity control and layer-by-layer Ag mirror reaction, the proposed process technology can accomplish a fully filled TSV with the lowest electrical resistivity of similar to 450 mu Omega.cm in comparison with the prior printing and filling technologies.
A Microfabricated Coil for Implantable Applications of Magnetic Spinal Cord Stimulation
(2015)
Fu, Yu-Min
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Chen, Che-Yu
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Qian, Xin-Hong
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Cheng, Yu-Ting
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Wu, Chung-Yu
In this paper, a microfabricated inductive coil comprising of 125-turn coil windings and a MnZn-based magnetic core in a volume of 200 mm(3) is presented for the magnetic neural stimulation in a spinal cord. The coil winding with the parallel-linkage design instead of the typical serial-linkage one is proposed not only to provide better design flexibility to the current mode driving circuit but also to simplify the fabrication process of the 3-D inductive coil, which can further advance the coil miniaturization. Experimental results show the microcoil with a 1.5 A, 1 kHz square-wave current input can induce a voltages of 220 mu V on the conducting wire with an impedance of similar to 0.2 Omega @ kHz, 1 mm separation.
AN ALIGNMENT SCHEME FOR LOW COST AND HIGH PRECISION SLOB FABRICATION USING AN ELECTROMAGNETIC MICROACTUATOR WITH 5 DOF
(2019-01-01)
Chen, Chih-Chung
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Fu, Yu-Min
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Hsu, Hsin-Feng
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Cheng, Yu-Ting
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電子工程學系及電子研究所
This paper presents an alignment scheme for SiOB fabrication using an electromagnetic force-driven microactuator with five degrees of freedom (5 DOF) of movement. The actuator comprising four sets of corrugated springs and spiral coils driven by Lorentz and reluctant force respectively can accomplish linearly horizontal and vertical displacement and tilt angle ranging within 2 and 10.5Am, and 0.1 degrees for positioning optical lens with a resolution of 0.mu m, which has been experimentally validated to facilitate h scheme feasibly.
AN INKJET PRINTED PIEZORESISTIVE BACK-TO-BACK GRAPHENE TACTILE SENSOR FOR ENDOSURGICAL PALPATION APPLICATIONS
(2017-01-01)
Fu, Yu-Min
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Chou, Meng-Chuin
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Cheng, Yu-Ting
;
Secor, Ethan B.
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Hersam, Mark C.
The paper presents a tactile sensor design mimicking human finger touch to differentiate tissue hardness for endosurgical palpation applications. The sensor comprises two inkjet-printed piezoresistive graphene-based sensing elements linked back-to-back for force and displacement detection, respectively. Experimental results indicate the sensor registers 2.1 and 5.3 mN force feedback from the fat and muscle tissues of pig, respectively, when pressed to the tissues with the same 100 mu m displacement. This difference of similar to 2.5 times in force feedback provides a compelling method by which doctors can more intuitively perceive hardness and tissue differences during endosurgery in comparison with the prior arts.
An Inkjet Printing Technique for Scalable Microfabrication of Graphene-Based Sensor Components
(2020-01-01)
Fu, Yu-Min
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Chou, Meng-Chuin
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Kang, Che-Hao
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Cheng, Yu-Ting
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Wu, Pu-Wei
This paper presents a versatile and precise graphene patterning technique using the combined process of masking and inkjet printing. A graphene-based structure is fabricated by first defining the structural pattern and position using a masking mold, which can be either electroplated copper or deep reactive ion etching (DRIE) silicon shadow mask, followed by inkjet deposition of graphene ink and lift-off. The hybrid technique can realize high-fidelity, high-resolution graphene-based microstructures including free-standing and cantilever beams, four-point resistive measurement structures, and piezoresistive sensing elements with a minimum line width of similar to 20 mu m. Moreover, this method can facilitate the micropatterning of graphene oxide (GO) and reduced graphene oxide (rGO) on substrates such as polydimethylsiloxane (PDMS) and SiO2/Si for selective cell culturing applications. Owing to the characteristics of low chemical usage, low process temperature and complexity, and high fiexibility and fault tolerance of inkjet printing, this technique demonstrates compelling potential for a variety of biomedical applications.
Characteristic Improvement of Inkjet Printed Ag Interconnects Using Tape On-Off and Mirror-Reaction Processes
(2015)
Guo, Zi-Li
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Fu, Yu-Min
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Cheng, Yu-Ting
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Shew, Bor-Yuan
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Wu, Pu-Wei
In the paper, we develop and implement the processes of tape on-off and Ag mirror-reaction to the previously developed size scalable inkjet printing process technique, i.e. CPLoP (Combined Process of Lift-off and Printing) for continuing its future interconnect applications in flexible microelectronics. The newly developed processes not only reduce coffee ring effect but also improve better electrical conductivity of the printed Ag interconnects at low process temperature. A 10 mu m wide Ag interconnect with flat surface morphology and low electrical resistivity, i.e. 7.7 mu Omega center dot cm, has been realized.
Printable Graphene Oxide Micropatterns for a Bio-Subretinal Chip
(2018-09-19)
Yang, Jia-Wei
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Tseng, Ming-Liang
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Fu, Yu-Min
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Kang, Che-Hao
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Cheng, Yu-Ting
Recently, implantable artificial subretinal chips using electronic components have replaced photoreceptors to serve as the most feasible treatment for retinal diseases. As such a chip that is meant to be implanted and used for very long periods, growing retinal cells on it to improve the electrical stimulation efficiency and attraction of neuronal elements remains a challenge. Here, an inkjet printing technology is employed to create graphene oxide (GO) micropatterns onto microelectrodes of a photovoltaic-powered implantable retinal chip. These GO micropatterns allow human retinal pigment epithelium (RPE) cells to specially attach and grow in each microelectrode. In addition, the cell proliferation, viability, and tight junction of RPE cells are improved during culturing. The development of a simple surface-coating technology would pave the way for the development of the first fully integrated and encapsulated retinal prostheses with biocompatible on-chip microelectrodes for long-term implantation, which could be effectively applied in retina tissue engineering and therapy.
PROCESS DEVELOPMENT OF LOW RESISTIVE Ag-BASED THROUGH SILICON VIAS USING INKJET PRINTING TECHNIQUE FOR 3D MICROSYSTEM INTEGRATION
(2019-01-01)
Yang, Jia-Han
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Tsou, Kun-Lin
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Fu, Yu-Min
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Cheng, Yu-Ting
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Song, Yen-Fang
This paper presents an inkjet printing and filling process to produce 250 mu m deep Ag-based fully filled through silicon vias with the aspect ratio of via depth vs. diameter up to 5. With the optimization of the printing pattern, humidity control, and silver mirror reaction, the Ag TSV subjected to 400 degrees C thermal anneal for 60 mins can exhibit a resistivity of 26 mu Omega.cm, the lowest resistivity and highest AR ever reported. Process simplicity and no need of metal liners make the technique with great potential for 3D microsystem integration.
Size Scaling of Printed Microstructures Using a Lift-off Printing (LoP) Process
(2014-01-01)
Fu, Yu-Min
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Liang, Yen-Ju
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Cheng, Y. T.
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Wu, Pu-Wei
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材料科學與工程學系
Inkjet printing has been one of fascinating techniques for microfabrication owing to the characteristics of low manufacturing cost, low processing temperature, low material usage,. etc. [1, 2]. In this work, a Lift-off Printing (LoP) process combining conventional photolithography and inkjet printing processes is introduced to realize printed size-scalable silver microstructures with the line width of 5 up to 70 m and the resistivity of similar to 5.7 mu Omega.cm on a silicon substrate. In addition, an as-printed interdigitated capacitor with the electrode size and spacing of 10 mu m has been successfully demonstrated with a capacitance of 2.3 pF/mm(2)@10kHz.
The Methodology in the Accuracy Improvement of the Flexible Current Sensing Coil Tag for Household Two-Wire Power Lines
(2015-10-01)
Lin, Chen-Hsuan
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Cheng, Yu-Ting
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Chen, Yung-Chang
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Fu, Yu-Min
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Hsu, Wei-Hung
The paper presents the methodology including the deployment of a structure comprising of C-clamp magnetic stripes and a self-calibration scheme using a four-coil design to resolve the issues of the interference and misplacement problems existing in the flexible nonintrusive current sensor tag for the current detection of household two-wire power lines. Experimental results show that the stripe structure can effectively screen out the magnetic flux originating from the nearby power line for the reduction of sensing error caused by the electromagnetic field interference and the calibration scheme containing the correction of horizontal misplacement and the analysis of power cable thickness via the four-coil design can provide the information of sensor location for accurate current sensing. Less than 4% of sensing error indicates that the proposed methodology can indeed facilitate the flexible current sensor tag for practical use.
THE PERFORMANCE ENHANCEMENT SCHEME OF ON-CHIP SPIRAL INDUCTORS USING METAL-OXIDE BASED AAO NANOCOMPOSITE
(2017-01-01)
Chen, Jyun-How
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Fu, Yu-Min
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Cheng, Y. T.
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電子工程學系及電子研究所
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Department of Electronics Engineering and Institute of Electronics
The paper presents a scheme to improve the performance of on-chip spiral inductors using metal-oxide based anodic alumina oxide (AAO) nanocomposites such as Fe3O4-AAO nanocomposite used here for demonstration. The fundamental enhancement principle is to eliminate eddy current loss but keep a high ferromagnetic resonance frequency in terms of the additive of nonconductive magnetic nanorod structures. Experimental results show the nH inductors with the nanocomposite magnetic core can exhibit inductance enhancement up to GHz range with Q factor higher than 25.