화학공학소재연구정보센터
홈 로그인 로그아웃 연락처 사이트맵
HWAHAK KONGHAK, Vol.35, No.4, 504-513, August, 1997
Export Citation
HF-산화제-H2O 수용액에서 Si 식각반응의 속도론적 연구
A Study on Kinetics of Silicon Etching Reaction in HF-Oxidizing Agents-H2O Solutions
서영훈, 김선중, 김광철, 오재완, 남기석, 김기주, 이형재
초록
Si의 식각반응을 HF-산화제-H2O 혼합용액에서 HF 농도, 산화제 농도, 교반속도 및 식각온도 등 여러 가지 실험변수를 변화시키면서 연구하였다. 산화제의 농도에 따른 식각반응속도를 조사한 결과 KIO3, K2Cr2O7의 경우는 농도가 증가함에 따라서 식각속도가 증가하였으나, KBrO3의 경우는 농도가 증가함에 따라서 식각속도가 증가하다가 어느 농도 이상부터는 식각된 표면에 K2SiF6가 성장하여 식각속도가 감소함을 알 수 있었다. 낮은 HF 농도에서는 식각속도가 낮게 일정히 유지되고, 높은 HF 농도에서는 식각속도가 갑자기 증가하는 것을 알 수가 있었다. 이로부터 HF가 식각반응동안 형성된 K2SiF6의 제거뿐만 아니라 Si표면에 정공(hole)의 생성속도 증가에도 영향을 미침을 확인할 수 있었다. Si식각반응의 율속단계는 Si표면에 생성되는 정공의 생성속도였으며, 식각반응속도식은 Ev-Eabs, 산화제와 HF의 농도 및 반응온도의 함수로 표시할 수 있었으며, 각 식각용액에 대해 실험적으로 결정할 수 있었다.
The reaction kinetics of silicon etching in HF-oxidizing agent-H2O solutions has been investigated experimentally. The etch rates were examined varying HF and oxidizing agent concentrations, agitation speed, and etching temperature. The etch rates increased with increasing the concentration of oxidizing agent. In a KBrO3-12M HF-H2O solution, however, the rates increased to a maximum at 0.05M KBrO3 and then decreased as the KBrO3 concentration increased. A K2SiF6 layer was found to be deposited on the silicon surface at high KBrO3 concentrations. HF played an important role for accelerating the formation rate of holes at the silicon surface and for the removal rate of K2SiF6 formed on the wafer surface during the reaction. At low HF concentrations, the etch rate increased slightly since the formation rate of holes was very slow. Under the condition of sufficiently high HF concentrations, the higher was the energy difference between the valence band of Si and the solution potential of etchant, the lower was the activation energy and thus faster was the etch rate of Si. The rate limiting step of the silicon etching reaction was proved to be the formation of holes at the surface. The rate law of the silicon etching reaction was determined experimentally.
Keywords:Silicon Wafer;Wet Etching;Solution Potential;Reaction Kinetics;K2SiF6
  1. Ghandhi SK, "VLSI Fabrication Principles," John Wiley & Sons, Inc., N.Y., 475 (1983)
  2. Sze SM, "VLSI Technology," 2nd ed., McGraw-Hill, N.Y., 424 (1985)
  3. Sawin HH, Solid State Technol., Apr., 211 (1985)
  4. Downey DF, Bottoms WR, Hanley PR, Solid State Technol., Feb., 121 (1981)
  5. Booinger D, Liga S, Matsumoto O, Solid State Technol., May, 111 (1984)
  6. Chin BM, Lee KL, J. Electrochem. Soc., 137(2), 663 (1990) 
  7. Vossen JL, Kern W, "Thin Film Processes," Academic Press, 405 (1978)
  8. Vossen JL, Kern W, "Thin Film Processes," Academic Press, 434 (1978)
  9. Sangwal K, "Etching of Crystals," North-Holland, 356 (1987)
  10. Dyment JC, Rozgonyi GA, J. Electrochem. Soc., 118, 1346 (1971)
  11. Mori Y, Watanabe N, J. Electrochem. Soc., 125, 1510 (1978) 
  12. O'Commor JM, Dvorsky EF, Hier HS, Reif WP, J. Electrochem. Soc., 135(1), 190 (1988) 
  13. Robbins H, Schwartz B, J. Electrochem. Soc., 106(6), 505 (1959)
  14. Robbins H, Schwartz B, J. Electrochem. Soc., 107(2), 108 (1960)
  15. Robbins H, Schwartz B, J. Electrochem. Soc., 108(4), 365 (1961)
  16. Robbins H, Schwartz B, J. Electrochem. Soc., 123(12), 1903 (1976) 
  17. Decker H, Pettinger B, Gerischer H, J. Electrochem. Soc., 130(6), 1336 (1983)
  18. Kelly JJ, Noyyen PHL, Electrochim. Acta, 29(5), 589 (1984) 
  19. Gerishu H, Mindt W, Electrochim. Acta, 13, 1329 (1968) 
  20. vandeVen J, VandenMeerakker JEAM, Kelly JJ, J. Electrochem. Soc., 132(12), 3020 (1985) 
  21. Kelly JJ, vandeVen J, vandenMeerakker JEAM, J. Electrochem. Soc., 132(2), 3026 (1985) 
  22. Seidel H, Csepregi L, Heuberger A, Baumgartel H, J. Electrochem. Soc., 137(11), 3512 (1990) 
  23. Eddowes MJ, J. Electroanal. Chem., 280, 297 (1990) 
  24. Seo YH, Nahm KS, Lee KB, J. Electrochem. Soc., 140, 1453 (1993) 
  25. Seo YH, Nahm KS, Hahn YB, Kim CB, Korean J. Chem. Eng., 11(2), 89 (1994)
  26. Nahm KS, Seo YH, Korean J. Chem. Eng., 12(2), 162 (1995)
  27. Dean JA, "Lange's Handbook of Chemistry," 13th ed., McGraw-Hill Co., 6 (1985)
  28. Odenweller T, J. Electrochem. Soc., 137(8), 2457 (1990) 
  29. Pierret RF, Neudeck GW, "Modular Series on Solid Statc Devices: I. Semiconductor Fundamental," Addison-Wesley Publishing Co. (1985)
  30. Weast RC, "Handbook of Chemistry and Physics," 70th ed., 93 (1989)
  31. Butter MA, Ginley DS, J. Electrochem. Soc., 125, 228 (1978) 
  32. Memming R, "Comprehensive Treaties of Electrochemistry," vol. 7, Plenum Press, NY, 535 (1983)
  33. Zhang XG, Collins SD, Smith RL, J. Electrochem. Soc., 136(5), 1561 (1989) 
  34. Gerischer H, Lubke M, J. Electrochem. Soc., 135, 2782 (1988) 
  35. Kern W, J. Electrochem. Soc., 137(6), 1887 (1990)