Makyoh method has replaced the laborious and unstable naked-eye wafer inspection lines. It has also been proved to be effective in monitoring wafer processes like thermal and epitaxial processes. 12 Refs. Proceedings of the Third International Symposium on Defect Recognition and Image Processing in III-V Compounds (DRIP III).
15, P. O. Hahn, M. Grundner, A. Schnegg, H. Jacob, "Characterization of the Morphological and Chemical Surface of Si Wafers for MEGA Applications," Sixth International Symposium on Silicon Materials Science and Technology, Montreal, Que, Can, 1990. pp. 296-312. Electrochemical Soc. Pennington, NJ, USA. The morphology of Si surfaces has been investigated in a multi-technique approach from microscopic to atomic scale. Scanning optical microscopy, angle resolved light scattering, thermal wave measurements, electron diffraction, and scanning tunneling microscopy have been exploited for investigations, concluding that chemo-mechanical polishing and epitaxy produce nearly perfect surfaces. The chemical state of Si surfaces, however, depends on final cleaning and aging of the wafers. During wafer processing this perfect structure is deteriorating. The possible influence of oxidation, cleaning, etching, precipitation, ion and plasma treatments, and contaminations on morphology is demonstrated. The impact on electrical properties (mobility, interface states, dielectric breakdown) will be discussed.
16, D. Szepesi, M. Huijbers, P. H. Knol, R. Stakemann, "CNC Turning of Rotationally Asymmetrical Components," IPE (International Industrial and Production Engineering), (4), pp. 50, 52-54, 56, 59. (Dec. 1989). The machining of asymmetrical components in CNC lathes with movement of toolside up to 30 Hz and positioning accuracy of + 0.005 mm is detailed in terms of developments of a fast response electro-hydraulic servo system, advanced construction materials of alumina and Ti and dedicated software system with adaptive precompensation using fast Fourier transform (FFT). A case study is presented on the asymmetric turning of polygon profile standardized to DIN 32711. Advantages of the turning machine include flexibility, accuracy and high production output. Graphs.
17, Zhang Honghai, Chen Zhixiang, Chen Riyao, Luo Zhengzuan, "The Control of Surface Roughness with a Fuzzy Control Technique in a Precision Metal Cutting Process," Fourth International Conference on Computer-Aided Production Engineering, Edinburgh, UK, Nov. 1988. pp. 429-34 558. Mech. Eng. Publications. Bury St. Edmunds, UK. It is well known that there is not a strict mathematical relationship between machined surface roughness and cutting conditions. So, it is impossible that the manufacturing process is controlled by the classical and modem control theories. In this paper, a controller based upon fuzzy subsets theory and an on-line measurement system for surface roughness with optical fibres developed by the authors are presented. In terms of the definitions of fuzzy variables and fuzzy conditional statements the particular fuzzy linguistic algorithms of the controller are designed. Through the cutting test, the working state of cutting system can recover from initial unstable state to desired state by taking three sampling intervals.
18, W. Anheuer, H. J. Grimberg, "Controlling of Complete Machining on Lathes," Werkstatt und Betrieb, pp. 627-30. (Aug. 1990). Due to decreasing batch sizes, complete machining has become firmly established in the recent years. It eliminates elaborate scheduling and thus reduces production run times and working capital requirements. An indispensable condition is availability of a numerical control system capable of either synchronizing the majority of production equipment or of controlling it independently, and that can also be programmed for the respective technology. (German)
19, J. Shibata, T. Goto, T. Akiyama, "Cooling Action of Grinding Fluid in the Gap of the Contact Area Between a Grinding Wheel and Work," Transactions of the Japan Society of Mechanical Engineers, Part C, 56(527), pp. 1940-1946. (Jul 1990). The purpose of this paper is to investigate quantitatively the cooling action of grinding fluid which actually exists in the microgap of the wheel-work contact area. The results obtained here are summarized as follows. (1) The cooling action of grinding fluid in the contact area was estimated numerically from its mean film thickness. Generally, the larger the mean film thickness is, the more effective its cooling action becomes. Zero to fifty percent of the grinding heat generated in the grinding could be absorbed into the fluid film. (2) The thermal boundary layer should exist in the fluid film flowing over the grinding heat source at high speed. (3) In order to improve the cooling efficiency, it would be a useful countermeasure to increase the thermal boundary layer if compared under the same grinding speed. 4 Refs. (Japanese)
20, A. A. Torrance, "The Correlation of Process Parameters in Grinding," Wear, 139(2), pp. 383-401. (Aug. 1990). An energy method, which had previously been shown to represent well the cutting action of model abrasive grits, was combined with the usual relationships of grinding mechanics to obtain a mathematical model of grinding forces and surface roughness. It was found that the model would predict accurately the experimental grinding charts of Peters, provided certain assumptions were made about the grit profiles. Good predictions were also obtained for the results of Lindsay, suggesting that it should be possible to develop the model further to account for all aspects of grinding. The materials used in these tests were brass and 4165, 100Cr6, and bearing steels. Graphs, Photomicrographs. 31 ref.
21, A. Ishibashi, S. Tanaka, S. Ezoe, "Design and Manufacture of a CNC Gear Grinder Capable of Mirrorlike Finishing," JSME International Journal, Series 3: Vibration, Control Engineering, Engineering for Industry, 33(2), pp. 245-250. (Jun 1990). In order to efficiently obtain mirrorlike ground gears, the authors designed and made a computer numerically controlled (CNC) gear grinder. For obtaining the desired surface finish, a cubic boron nitride (CBN) grinding wheel with a medium grain size was used under creep-feed grinding conditions with grinding fluid. The profiles of the gear being ground were generated by a rolling motion produced by a master worm gear and a high-accuracy ball screw. The trial gear grinder could produce spur gears with mirror- like tooth surfaces having a roughness of about 0.2 p_m Rma x. By controlling the two servomotors, gears with any type of tooth profile modification could be ground easily. 7 Refs.
22, J. Wangler, J. Liegel, M. J. Lacombat, S. Wittekoek, "Design Principles for an Illumination System Using an Excimer Laser as a Light Source.," SPIE, Optical microlithography and metrology for microcircuit fabrication, Vol 1138, Paris (France), 24-28 Apr 1989. pp. 129-136. Society of Photo-Optical Instrumentation Engineers. Bellingham, WA (USA). Design
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