Journal of the Korean Society for Precision Engineering (한국정밀공학회지)

Korean Society for Precision Engineering (한국정밀공학회)
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Autofocus system for off-line focusing error compensation in micro laser fabrication process

레이저 미세가공용 자동초점장치를 이용한 오프라인 초점 오차 보상에 관한 연구

  • Kim, Sang-In (Center for Robot & Manufacturing Tech., Institute for Adv. Eng.) ;
  • Kim, Ho-Sang (Center for Robot & Manufacturing Tech., Institute for Adv. Eng.)
  • 김상인 (고등기술연구원 로봇/생산기술센터) ;
  • 김호상 (고등기술연구원 로봇/생산기술센터)
  • Published : 2009.06.01
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Abstract

Micro laser fabrication techniques can potentially be used for the manufacture of microstructures on the thin flat surfaces with large diameter that are frequently used in semiconductor industries. However, the large size of wafers can cause the degraded machining accuracy of the surface because it can be tilted or distorted by geometric errors of machines or the holding fixtures, etc. To overcome these errors the off-line focusing error compensation method is proposed. By using confocal autofocus system, the focusing error profile of machined surface is measured along the pre-determined path and can be compensated at the next machining process by making the corrected motion trajectories. The experimental results for silicon wafers and invar flat surfaces show that the proposed method can compensate the focusing error within the level of below $6.9{\mu}m$ that is the depth of focus required for the laser micromachining process.

Keywords

References

  1. Li, C., Shi, X., Si, J., Chen, T., Chean, F., Liang, S., Wua, Z. and Hou, X., "Alcohol-assisted photoetching of silicon carbide with a femtosecond laser," Optics Communications, Vol. 282, No. 1, pp. 78-80, 2009 https://doi.org/10.1016/j.optcom.2008.09.072
  2. Kimura, S. and Wilson, T., "Confocal scanning optical microscope using single-mode fiber for signal detection," Applied Optics, Vol. 30, No. 16, pp. 2143-2150, 1991 https://doi.org/10.1364/AO.30.002143
  3. Lin, Q., Bai, L., Xue, S. and Chen, L., "Autofocus system for Microscope," Optical Engineering, Vol. 41, No. 6, pp. 1289-1294, 2002 https://doi.org/10.1117/1.1473639
  4. Lee, J. S., Sohn, Y. I., Park, K. Y. and Lee, K. D., "Development of intelligent filler wire feeding device for improvement of weld quality," Journal of the Korean Society of Precision Engineering, Vol. 23, No. 7, pp. 59-66, 2006
  5. Yoo, H. K., Kang, D. K., Lee, S. W. and Gweon, D. G., "Error analysis and alignment tolerancing for confocal scanning microscope using Monte Carlomethod," J. of KSPE, Vol. 21, No. 2, pp. 92-99, 2004
  6. Kang, Y. J., Song, D. H., Ryu, W. J. and Baik, S. H., "A study on the con-focal microscope for the surface measurements," Journal of the Korean Society ofPrecision Engineering, Vol. 20, No. 5, pp. 73-81, 2003
  7. Park, J. J., Kim, S. W. and Lee, H. J., "Autofocus of infinity-corrected optical microscopes by confocal principle and fiber source modulation technique,"Journal of the Optical Society of Korea, Vol. 15, No. 6, pp. 583- 590, 2004 https://doi.org/10.3807/KJOP.2004.15.6.583
  8. Kim, S. I., Lee, K. I., Kim, H. S. and Lee, K. D., "Autofocus system for off-line error compensation in micro laser fabrication process," Proceedings of KSPE Spring Conference, pp. 603-604, 2008
  9. Neumann, B., Damon, A., Hogenkamo, D., Beckmann, E. and Kollmann, J., "A laser-autofocus for automatic microscopy and metrology," Sensors and Actuators, Vol. 17, No. 1-2, pp. 267-272, 1989 https://doi.org/10.1016/0250-6874(89)80090-3