- Email: [email protected]
Microfabrication of freestanding microstructures
results vedfy the validity of the approach. An order-of-magnitude improvement in the accuracy of the machine, with respect to a calibration frame, was observed. 31 Refs. 42. Scholle, Jerome V. Metrology. Addison-Wesley; 1993 Feb. ISBN 0-201-63414-7. 43. Moore, D. F; Hoole, A. C. F; Heaver, A. Microfabrication of freestanding microstructures, International Conference on Microfabrication; 1992 Sept. 21; Erlangen, Germany; 1993 Apt. 459-62. Suspended microstructures which can be deflected electrostatically are potentially useful in sensors, especially with tunnel junction readout schemes. The authors describe an integrated device geometry which compensates for the effects of thin film stress in the freestanding parts, and allows a contact to be made by deflecting beams electrostatically. 44. Golini, Donald; Czajkowski, Walter. Microgrinding makes ultrasmooth optics fast. Laser Focus. 1992 Jul; 28(7): 146-150. The Center for Optics Manufacturing (COM), University of Rochester (Rochester, NY), has developed a deterministic microgrinding process that generates optical surfaces with extraordinary surface figure accuracy specular microground surfaces, with 1-2 lira subsurface damage and 1-wave peak-to-valley figure, were manufactured in five minutes. This dramatic breakthrough in optics manufacturing would be impossible to achieve on current conventional equipment. It underscores the importance of COM's work in developing a new generation of computer numerically controlled manufacturing equipment, referred to as Opticam (optics automation and management), for modernizing the optics industry. 7 Refs. Naoya; Shimada, Shoichi; Tanaka, Hiroaki. Minimum thickness of cut in micromachining. Nanotechnology. 1992 Jan; 3(1): 6-9. This paper discusses the significance of the minimum thickness of cut (MTC) which is defined as the minimum undeformed thickness of chip removed from a work surface at a cutting edge under perfect performance of a metal cutting system. Following a brief look at the relation between MTC and the extreme machining accuracy attainable for a specific cutting condition, it is shown that a very fine chip with an undeformed thickness of the order of a nanometer can be obtained from experimental face turning of electroplated copper by a well-defined diamond tool. To understand the nanometric metal cutting process, a computer simulation using an atomistic model is proposed. 9 Refs. 45. Ikawa,
46. Liu, J. J; Dornfeld, D. A. Modeling and analysis of acoustic emission in diamond turning, Precision Machining: Technology and Machine Development and Improvement - Production Engineering Division. New York, NY: American Society of Mechanical Engineers; 1992: 43-58. Vol. PED 58. To estimate the AE energy released in diamond turning, a quantitative model, which contains the energy from primary, secondary, tertiary cutting zones and the rubbing zones, is proposed and compared with experimental data. As part of the model developed here the plowing energy, that is, the energy released in the tertiary zone, is approximated by the forming load in the rolling process where the roller is stationary. This load is theoretically calculated by the upper bound method and used in the estimation. A series of diamond turning tests were conducted to check the validity of the model. It was found that the energy content of the AE signal is close to the theoretical predictions. The spectral analysis of the AE signal in these tests is also carried out. It was noticed that when the diamond tool first touches the workplace without producing any chip, more high frequency components were observed and this stage was recognized as the rubbing stage. The results further support the previous findings, that is, that abnormal rubbing always increases the mean frequency of the raw AE signal. 14 Refs. 47. Sugimura, H; Uchida, T; Kitamura, N; Masuhara, H. Nanofsbrication of titanium surface by tip-induced anodization in scanning tunneling microscopy. Japanese Journal of Applied Physics, Part 2 (Letters). 1993 Apr; A titanium (Ti) surface was arbitrarily oxidized by a scanning tunneling microscope (STM). Oxidation of the Ti surface was induced by scanning an STM tip with the sample (Ti) bias of more than +3 V, and a dot or line pattern of oxide was fabricated on Ti with the spatial resolution of 70 nm. The results were discussed in terms of tip-induced anodization of Ti due to water adsorbed on the surface. 48. Majumdar, A. Nanofsbricstion using scanning probe microscopes. Precision Machining: Technology and Machine Development and Improvement- Production Engineering Division. New York, NY: Amedcan Society of Mechanical Engineers; 1992: 59-73. Vol. PED 58. The inventions of the scanning tunneling microscope (STM) and the atomic force microscope (AFM) in the 1980s have revolutionized the way scientists and engineers study solid surfaces with atomic and nanometer-scaie resolution. The added ability to manipulate matedals at nanometer and atomic scales makes the STM and AFM one of most powerful expedmental tools for nanofabrication. This paper gives an overview of the current state-of-the-art of nanometer-scale matedal manipulation using scanning probe microscopes. Current trends suggest that these instruments will form the backbone of expedmental research in the new and rapidly-developing area of nanotechnology. 49. Otsuka, Jiro. Nanometer level positioning using three kinds of lead screws. Nanotechnology. 1992 Jan; 3(1): 29-36. A one-dimensional table unit with a laser feedback control system is manufactured, aiming at ultraprecision positioning of nanometer level accuracy by step response, with the use of one of the three kinds of lead screws (a precision sliding screw, a precision ball screw, and a rolled ball screw). The following items are made clear. (i) A quantified error (offset error) is caused by the proportional gain and D/A converter, (ii) In an effort to overcome this obstacle, the author devises a 'bit control'. This control method proves to be very effective in dealing with the quantified errors for three kinds of lead screws allowing one to obtain nanometer accuracy for all three. (iii) The charactedstics of these three kinds of lead screws in the very short stroke range (0.1 lim) are clarified. The precision sliding screw has a stick-slip between the screw and nut. The precision ball screw behaves elastically between them. The rolled ball screw shows a nanometer level positioning in spite of its large vadation in fdction torque and it having lowest accuracy. 6 Refs.
300
OCTOBER 1993 VOL 15 NO 4
46. Liu, J. J; Dornfeld, D. A. Modeling and analysis of acoustic emission in diamond turning, Precision Machining: Technology and Machine Development and Improvement - Production Engineering Division. New York, NY: American Society of Mechanical Engineers; 1992: 43-58. Vol. PED 58. To estimate the AE energy released in diamond turning, a quantitative model, which contains the energy from primary, secondary, tertiary cutting zones and the rubbing zones, is proposed and compared with experimental data. As part of the model developed here the plowing energy, that is, the energy released in the tertiary zone, is approximated by the forming load in the rolling process where the roller is stationary. This load is theoretically calculated by the upper bound method and used in the estimation. A series of diamond turning tests were conducted to check the validity of the model. It was found that the energy content of the AE signal is close to the theoretical predictions. The spectral analysis of the AE signal in these tests is also carried out. It was noticed that when the diamond tool first touches the workplace without producing any chip, more high frequency components were observed and this stage was recognized as the rubbing stage. The results further support the previous findings, that is, that abnormal rubbing always increases the mean frequency of the raw AE signal. 14 Refs. 47. Sugimura, H; Uchida, T; Kitamura, N; Masuhara, H. Nanofsbrication of titanium surface by tip-induced anodization in scanning tunneling microscopy. Japanese Journal of Applied Physics, Part 2 (Letters). 1993 Apr; A titanium (Ti) surface was arbitrarily oxidized by a scanning tunneling microscope (STM). Oxidation of the Ti surface was induced by scanning an STM tip with the sample (Ti) bias of more than +3 V, and a dot or line pattern of oxide was fabricated on Ti with the spatial resolution of 70 nm. The results were discussed in terms of tip-induced anodization of Ti due to water adsorbed on the surface. 48. Majumdar, A. Nanofsbricstion using scanning probe microscopes. Precision Machining: Technology and Machine Development and Improvement- Production Engineering Division. New York, NY: Amedcan Society of Mechanical Engineers; 1992: 59-73. Vol. PED 58. The inventions of the scanning tunneling microscope (STM) and the atomic force microscope (AFM) in the 1980s have revolutionized the way scientists and engineers study solid surfaces with atomic and nanometer-scaie resolution. The added ability to manipulate matedals at nanometer and atomic scales makes the STM and AFM one of most powerful expedmental tools for nanofabrication. This paper gives an overview of the current state-of-the-art of nanometer-scale matedal manipulation using scanning probe microscopes. Current trends suggest that these instruments will form the backbone of expedmental research in the new and rapidly-developing area of nanotechnology. 49. Otsuka, Jiro. Nanometer level positioning using three kinds of lead screws. Nanotechnology. 1992 Jan; 3(1): 29-36. A one-dimensional table unit with a laser feedback control system is manufactured, aiming at ultraprecision positioning of nanometer level accuracy by step response, with the use of one of the three kinds of lead screws (a precision sliding screw, a precision ball screw, and a rolled ball screw). The following items are made clear. (i) A quantified error (offset error) is caused by the proportional gain and D/A converter, (ii) In an effort to overcome this obstacle, the author devises a 'bit control'. This control method proves to be very effective in dealing with the quantified errors for three kinds of lead screws allowing one to obtain nanometer accuracy for all three. (iii) The charactedstics of these three kinds of lead screws in the very short stroke range (0.1 lim) are clarified. The precision sliding screw has a stick-slip between the screw and nut. The precision ball screw behaves elastically between them. The rolled ball screw shows a nanometer level positioning in spite of its large vadation in fdction torque and it having lowest accuracy. 6 Refs.
300
OCTOBER 1993 VOL 15 NO 4