2005.10
About Instruments Today No. 148
The Front-Wing Conductive Probe Applied to Electrical Scanning Probe Microscopy [ 下載 PDF ]
Mao-Nan Chang, Chih-Yuan Chen
Electrical scanning probe microscopy (E-SPM) is one of the well-known techniques applying to the nano-characterizations of electronic materials and devices. Unfortunately, photoperturbation induced by atomic force microscopy (AFM) laser beam could lead to false E-SPM images and the related spectroscopy, resulting in many difficulties in synchronously obtaining electrical images and the corresponding AFM images. The front-wing structure of the cantilever can effectively inhibit the optical perturbation in the electrical scanning probe microscopes and obviously promote the analysis accuracy thereof. In this work, we demonstrated the influences of photoperturbation on E-SPM characterization. The applications of the front-wing conductive probe on E-SPM are also illustrated with examples.
Microfluidic Chips Integrated with Pneumatic Microvalves and Micropumps for Applications of Disease Detection [ 下載 PDF ]
Chih-Hao Wang, Gwo-Bin Lee
The present study reports a microfluidic system using the concept of membrane-movement to design and fabricate micro-pneumatic valves and pumps to form a multiple bio-sensing diagnostic chip. The automatic-bio-sampling system includes a micro-diagnostic chip fabricated by using MEMS (Micro-electro-mechanical-systems) technology and an automatic platform comprising a control circuit, a compressed air source and electromagnetic valve switches. The control circuit is used to regulate the electromagnetic valve switches, causing PDMS membranes to deflect pneumatically and generate valving and pumping effects. The micro-diagnostic chip allows fast detection of diseases, namely, HCV and syphilis. Instead of using traditional pneumatic micropumps, the current study adopts a new design called 'spider-web' pumps to increase the pumping rate, and more importantly, improve the uniformity of flow rates in multiple channels. Experimental data show that for multiple diseases diagnosis, the multi bio-sensing chips integrated with the micro-pneumatic valves and the peristaltic micropumps could successfully execute ELISA (enzyme-linked immunosorbent assay) tests. The development of the multi bio-sensing chips could provide a useful tool for bio-sensing and be crucial for micro-total-analysis system.
A Novel Structure of Reflective Type Attenuated- Phase-Shifting-Masks for Sub-25 nm Extreme Ultraviolet ExposureTools [ 下載 PDF ]
Hsuen-Li Chen, Hsu-Chun Cheng, Ying-Ling Hong, Tieh-Chi Chu
Phase-shifting-masks are vital resolution enhance technique that will be used in extreme ultraviolet (EUV) lithography beyond the 25 nm node. In this paper, we demonstrated a novel structure for a reflective type attenuated phase-shifting-mask, which is based on a Fabry-Perot structure with common materials in EUV masks. The mask structure not only performs 180° phase-shift with highreflectance at EUV wavelength but also has high inspection-contrast at deep ultraviolet (DUV) wavelength. The top layer of mask structures exhibits good conductivity, which can alleviate the charging effect during electron-beam patterning. The reflectance ratio of the absorber stack could be tuned from 32.6% (TaN/SiO2/Mo) to 4.4% (TaN/SiO2/TaN) by choosing different bottom layers and thickness. The inspection contrast could be raised to 99% with large thickness-control-tolerance.
Disassembling Scanning Tunneling Microscope [ 下載 PDF ]
Wen-Bin Jian, Chih-Yuan Wu
Scanning tunneling microscope is the most powerful instrument to study science at the nano scale. We introduce the principle of operation and instrumentation of scanning tunneling microscope. Instrumentation is separated into three main parts, i. e. mechanical design, electronic controller, and computer programming. We describe the composing elements in detail and illustrate the fabrication technique for some components. Instrumentation is one way to save money as maintaining your machine, and it is the only way to initiate high level research work.
A Collimated LED Light Module for Absorbance Detection [ 下載 PDF ]
Chun-Jen Weng, Jerwei Hsieh, Hung-Lin Huang, Feng-Chang Hsu, Ming-Yu Lin
In the bio absorbance detection systems, sensitivity of detection depends on collimation length of light module. Although the conventional LEDs have the advantages of low cost and compact, their light is diverged with divergence angle larger than 10 degree. Therefore, conventional LEDs are not suitable for bio-chip absorbance detection. By exploiting the concept of fiber collimator, this project proposes a design to realize a collimated light module. The advantages of low cost, miniaturized, and multi-channel capability are then achieved. The divergence angle of this collimator is about 1.2 degree within 1.5 cm optical path length. The power variation of this module is under 1% within an hour. The absorbance experiment to measure sodium pyruvate range from 0 to 82 µM using fabricated light module was conducted, where sensitivity of 7.7 × 103 / M and linearity of 0.9995 R2 is obtained.
An Introduction to the Principle of Atomic Force Microscope (I) [ 下載 PDF ]
Ming Yen Lin, Chia-Seng Chang, Wenlung Li
Atomic force microscope (AFM) has been widely used in the field of surface measurement. It is helpful for any of user, especially for most of users who are not familiar with the functions of AFM, to operate AFM properly if they understand more with the principle and characteristics of AFM. In this article, the principle of tapping mode, which is the most frequently used, is mainly introduced. An effective physic model of motion, experimental data and experiences on AFM measurement are used to describe the physic characteristics of cantilever tip motion, tip-sample interaction and the principle of tapping mode.
A Quick Method of Evaluation for Commercial Atomic Force Microscope [ 下載 PDF ]
Ming Yen Lin, Shao Kang Hung, Sean Ying, Chi-Yen Juan, Wei Che Liu, Yang Chih Su, Ya Rou Chen, Chin Wen Yang
Atomic force microscope (AFM) has been widely used in the field of surface measurement. Selection of a proper AFM with cost-effective performance from numerous domestic and oversea makers becomes an important purchasing issue for most of users, especially who are not familiar with the functions of AFM. In this article, five characteristics of AFM scanned images under the most frequently used tapping mode are thoroughly deliberated. They are the best image resolution of Z axis, the spatial repetitions of the images, the sharpness of single step line (the real image resolution of lateral axis), the distortion of a single step line and the spatial drift of the images (the long term of stability for continuous use) on HOPG. The outcome of these qualities can serve as a quick guide for evaluating an AFM.
Development of Aspherics Polishing System [ 下載 PDF ]
Jung-Ru Yu, Shih-Feng Tseng, Kuo-Cheng Huang, Ching-Hsiang Kuo
Instrument Technology Research Center (ITRC) accumulates a lot of experiments in lenses fabrication, and announced the launch of aspherical lenses made from special material for aerospace applications. Because of the demand of aspherical lenses, ITRC combines optical, mechanical and electrical technology to develop an aspherics polishing system using negative-shape polishing method. ITRC will keep on increasing the technology of aspherics fabrication.
Development and Prospect of Micro/Nano BioElectronic Devices [ 下載 PDF ]
Cheng-Che Lee, Min-Chieh Chuang, Pei-Yu Lin, Yuh-Shyong Yang
The semiconductor industry is facing a new challenge to manufacturing novel nano-scaled electronic device. A unique opportunity in bioelectronics has emerged as the sizes of the electronic device and biomolecule such as DNA, RNA and protein become comparable. A variety of artificially hybrid configurations such as 'biomolecular sensors' for highly sensitive and selective detection in biomedical applications and 'bio-hybrid devices' possessing both specific biochemical function and brand-new electronic property are innovatively approached where unexpected merit arises in both biochemical and electronics areas. This article gives a few examples to explain what would be anticipated in this cutting-edge domain of bioelectronics. We would describe the fundamentals, characteristics, theories, and corresponding functions and applications that may provide the readers an informative introduction in bioelectronics.
Adaptive Optics Systems with Liquid-Crystal Phase- Shift Interferometers [ 下載 PDF ]
Cheng-Ying Chung, Keng-Chi Cho, Chih-chiang Chang, Wei-Chung Yen, Shean-Jen Chen
An adaptive optics system has been developed to real-time correct optical aberrations due to external disturbances. In wavefront sensing, a novel wavefront sensing system based on liquid-crystal phaseshift interferometry is proposed to precisely and fast detect optical wavefront variation with the helps of precise phase correction and transient nematic driving methods. A home-made digital signal processing controller using the feedback wavefront information from the phase-shift interferometry wavefront sensor drives deformable mirrors to reduce optical aberrations successfully. The developed multichannel adaptive optics system has the dynamic bandwidth of control loop up to 30 Hz. The experimental results to compensate several hertz thermal turbulence demonstrate that the steady state error of the wavefront phase was under 0.02 π rms and the signal-to-noise ratio improvement is better than 20 dB. Also, the Strehl ratio of the focusing spot can be increased from 0.5 to 0.9.
