Issue
Korean Journal of Chemical Engineering,
Vol.17, No.1, 111-117, 2000
Design for Control: Temperature Uniformity in Rapid Thermal Processor
It is well known that the design of the heating source imposes an inherent limitation on the performance of the rapid thermal processor (RTP). In this work, the similarities and differences between flat and angled reflectors are studied. The discontinuous characteristic of the angled reflector can be used to compensate for the edge that loss of the thin wafer and, consequently, a better temperature uniformity can be achieved. A design procedure is proposed to place the lamp ring as well as the angle of the reflectors. For the control system design, the measurement selection criterion of Huang et al. is employed to find candidate measurement sets followed by a structured singular value criterion. Once the control structure is determined, multivariable temperature controllers were designed according to the internal model control (IMC) principle. From porcess insight, a farily simple nonlinear compensation is also devised. Simulation results show that while only half of the thermal budget is used improved temperature uniformity can be obtained by using proposed approach.
[References]
  1. Apte PP, Saraswat KC, IEEE Trans. Semicond. Manuf., 5, 180, 1992
  2. Badwell TA, Breedijk T, Bushman SG, Butler SW, Chatterjee S, Edgar TF, Toprac AJ, Trachtenberg I, Comput. Chem. Eng., 19(1), 1, 1995
  3. Cho YM, Kailath T, IEEE Trans. Semicond. Manuf., 6, 233, 1993
  4. Crowley JL, DeBolski TJ, Kermani A, Lassing SE, U.S. Patent, 4,755,654, 1988
  5. Dilhac JM, Nolhier N, Ganibal C, Zanchi C, IEEE Trans. Semicond. Manuf., 8, 432, 1995
  6. Fan YH, Qiu T, IEEE Trans. Semicond. Manuf., 10, 433, 1997
  7. Gyurcsik RS, Riley TJ, Sorrell FY, IEEE Trans. Semicond. Manuf., 4, 9, 1991
  8. Huang CJ, Yu CC, Shen SH, IEEE Trans. Semicond. Manuf., (revised), 1999
  9. Huang CJ, Yu CC, Shen SH, Automatica, (in press), 36, 2000
  10. Huang I, "Control of Rapid Thermal Processor: Design for Temperature Uniformity," MS Thesis, National Taiwan University of Sci. Technol., Taipei, 1997
  11. Hebb JP, Jensen KF, IEEE Trans. Semicond. Manuf., 11, 99, 1998
  12. Lord HA, IEEE Trans. Semicond. Manuf., 1, 105, 1988
  13. Merchant TP, Cole JV, Knutson KL, Hebb JP, Jensen KF, J. Electrochem. Soc., 143(6), 2035, 1996
  14. Morari M, Zafiriou E, "Robust Process Control," Prentice-Hall, Englewood Cliff, NJ, 1989
  15. National Technology Roadmap for Semiconductors, Semiconductor Industry Association, San Jose, CA, Dec., 1994
  16. Norman SA, IEEE Trans. Electron Devices, 39, 205, 1992
  17. Roozeboom F, "Manufacturing Equipment Issues in Rapid Thermal Processing," Academic Press, New York, 1992
  18. Sachs E, Guo R, Ha S, Hu A, IEEE Trans. Semicond. Manuf., 4, 134, 1991
  19. Sorrell FY, Harris JA, Gyurcsik RS, IEEE Trans. Semicond. Manuf., 3, 183, 1990
  20. Stuber JD, Trachtenberg I, Edgar TF, IEEE Trans. Semicond. Manuf., 11, 442, 1998