Clean Technology (청정기술)

The Korean Society of Clean Technology (한국청정기술학회)
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Repair of Plasma Damaged Low-k Film in Supercritical Carbon Dioxide

초임계이산화탄소를 이용한 플라즈마 손상된 다공성 저유전 막질의 복원

  • Jung, Jae-Mok (Division of Image and Information Engineering, Pukyung National University) ;
  • Lim, Kwon-Taek (Division of Image and Information Engineering, Pukyung National University)
  • 정재목 (부경대학교 화상정보공학부) ;
  • 임권택 (부경대학교 화상정보공학부)
  • Received : 2010.05.19
  • Accepted : 2010.09.10
  • Published : 2010.09.30
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Abstract

Repair reaction of plasma damaged porous methyl doped SiOCH films was carried out with silylation agents dissolved in supercritical carbon dioxide ($scCO_2$) at various reaction time, pressure, and temperature. While a decrease in the characteristic bands at $3150{\sim}3560cm^{-1}$ was detectable, the difference of methyl peaks was not identified apparently in the FT-IR spectra. The surface hydrophobicity was rapidly recovered by the silylation. In order to induce effective repair in bulk phase, the wafer was heat treated before reaction under vacuum or ambient condition. The contact angle was slightly increased after the treatment and completely recovered after the subsequent silylation. Methyl groups were decreased after the plasma damage, but their recovery was not identified apparently from the FT-IR, spectroscopic ellipsometry, and secondary ion mass spectroscopy analyses. Furthermore, Ti evaporator was performed in a vacuum chamber to evaluate the pore sealing effect. The GDS analysis revealed that the open pores in the plasma damaged films were efficiently sealed with the silylation in $scCO_2$.

초임계이산화탄소에서 실릴화제를 사용하여 반응시간, 압력, 온도를 변화하며 플라스마에 의해 손상된 다공성 p-SiOCH 필름의 실릴화 보수반응을 진행하였다. FT-IR 분석 결과 $3150{\sim}3560cm^{-1}$ 영역의 $SiOH/H_2O$ 특성밴드의 감소는 다소 확인할 수 있었지만, 메틸화 peak의 변화치는 관찰하기 어려웠다. 그러나 실릴화에 따른 표면 소수성은 빠른 반응시간 내에 복원되었다. 내부 복원반응을 효과적으로 유도하기 위하여 열 전처리 공정을 상압 또는 진공 조건에서 진행하였으며, 전처리에 따라 표면 접촉각이 약간 상승하였고, 뒤이은 초임계 실릴화반응으로 표면 소수성이 완전히 복원되는 것을 관찰하였다. 플라스마 손상과정에서 표면 내부 메틸기의 감소가 나타나지만 실릴화 보수반응에 따라 메틸기의 복원은 눈에 띄게 나타나지 않음을 FT-IR, spectroscopic ellipsometry 와 secondary ion mass spectroscopy의 분석결과를 통하여 확인하였다. 막질에 대한 Ti 증착 후 glow discharge spectrometry로 내부 Ti 원소를 분석한 결과, 초임계 실릴화반응을 통하여 손상된 p-SiOCH막질의 열린 기공의 봉인효과가 나타나는 것을 확인하였다.

Keywords

References

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