Search / Korean Journal of Chemical Engineering
HWAHAK KONGHAK,
Vol.39, No.6, 721-726, 2001
갈바니 치환 증착 방법을 이용한 확산방지막 위에서의 구리 시드층 형성
Fabrication of Cu Seed Layer on TiN Barrier using Galvanic Displacement Deposition
본 논문에서는 갈바니 치환(galvanic displacement)방법을 이용하여 MOCVD TiN(100Å)/Ti(150Å)/Si 웨이퍼 위에 전기증착용 구리 시드층(seed layer)을 형성하였다. 티타늄(Ti) 산화막을 제거하는 과정, 팔라듐(Pd) 표면 활성화 과정을 거쳐, NH4F, H2SO4, CuSO4·5H2O를 조성으로 하는 용액 내에서 증착을 시도하였다. 용액의 최적조성을 결정하기 위해 NH4F의 양은 0.45 M로 일정하게 유지하고 H2SO4의 농도는 0.05 M에서 0.5 M까지, CuSO4·5H2O의 농도는 0.01 M에서 0.05 M까지 변화시켰으며, 면저항의 감소와 박막의 균일성을 고려하여 최적 조성을 결정하였다. 팔라듐 표면 활성화(Pd surface activation)과정은 작은 크기의 결정을 형성하는데 결정적이었으며, 비저항 4.55 μΩ·cm의 표면이 균일한 박막을 얻기 위해 필수적이었다. 본 실험에서는 갈바니 치환 증착 방법을 이용하여 우수한 특성을 갖는 구리 시드층(seed layer)을 형성하는 방법을 제시하였다.
Cu seed layer for Cu electroplating was formed on TiN(100Å)/Ti (150Å)/Si wafer using galvanic displacement deposition. After titanium(Ti) oxide cleaning step and palladium(Pd) surface activation step, the wafer was dipped in solution that contained NH4F, H2SO4 and CuSO4·5H2O. In order to find optimized solution condition, H2SO4 concentration was changed from 0.05 M to 0.5 M and CuSO4·5H2O concentration from 0.01 M to 0.05 M while NH4F concentration was fixed as 0.45 M. Optimized condition was ditermined considering sheet resistance decrease and film uniformity. Pd surface activation step was essential to a thin film uniformity with small grains having resistivity of 4.55 μΩ·cm. In this experiment, the possibility of high quality Cu seed layer deposition using galvanic displacement method was clearly suggested.
[References]
  1. Gau WC, Chang TC, Lin YS, Hu JC, Chen LJ, Chang CY, Cheng CL, J. Vac. Sci. Technol. A, 18(2), 656, 2000
  2. Lee SY, Choi SH, Park CO, Thin Solid Films, 359(2), 261, 2000
  3. Lopatin S, Shacham-Diamond Y, Duvin V, Vasudev PK, Kim Y, Smy T, "Advanced Metallization and Interconnection System for ULSI Applications in 1997," Master. Res. Soc., 437, 1998
  4. Andricacos PC, Uzoh C, Dukovic IO, Horkans J, Deligianni H, J. Res. Develop., 42, 567, 1998
  5. Kroger R, Eizenberg M, Cong D, Yoshida N, Chen LY, Ramaswami S, Carl D, J. Electrochem. Soc., 146(9), 3248, 1999
  6. Kern FW, Mitsushi M, Kawanabe I, Miyashita M, Rosenberg RW, Ohmi T, "Proceedings of the 37th Ann. Tech. Mtg," Intitute of Environmental Sciences, San Diego, CA, 1991
  7. Nagahara LA, Ohmori T, Hashimoto K, Fujishima A, J. Vac. Sci. Technol. A, 11, 763, 1993
  8. Mouche L, Tardif F, Derrien J, J. Electrochem. Soc., 142(7), 2395, 1995
  9. Grundner M, Schulz R, "AIP Conf. Proc," Rubloff, G.W. and Lucovsky, G. Editors, American Institute of Physics, New York, 167, 329, 1987
  10. Grundner M, Jacob H, Appl. Phys. A-Mater. Sci. Process., 39, 73, 1986
  11. Bender H, Verhaverbeke S, Heyns MM, J. Electrochem. Soc., 141(11), 3128, 1994
  12. dos Santos FSG, Martins LFO, D'Ajello PCT, Pasa AA, Hasenack CM, Microelectronic Eng., 33, 59, 1997
  13. dos Santos Filho SG, Pasa AA, Hasenack CM, Microelectronic Eng., 33, 149, 1997
  14. Takano N, Niwa D, Yamada T, Osaka T, Electrochim. Acta, 45(20), 3263, 2000
  15. Rossiter C, Suni II, Surf. Sci., 430, L553, 1999
  16. Gorostiza P, Servat J, Morante JR, Sanz F, Thin Solid Films, 275(1-2), 12, 1996
  17. Lee MK, Wang HD, Wang JJ, Solid State Electron., 41(5), 695, 1997
  18. Magagnin L, Maboudian R, Carraro C, Electrochem. Solid State Lett., 4(1), C5, 2001
  19. Kim JJ, Cha SH, Jpn. J. Appl. Phys., 40, 715, 2001