Korean Chemical Engineering Research

The Korean Institute of Chemical Engineers (한국화학공학회)
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Particle Removal on Silicon Wafer Surface by Ozone-HF-NH4OH Sequence

불산-오존-희석 암모니아수 세정에 의한 실리콘 웨이퍼 표면의 미세입자 제거

  • Received : 2006.10.18
  • Accepted : 2006.12.07
  • Published : 2007.04.30
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Abstract

In this paper efficient method for particle removal from silicon wafers by usage of HF and ozone was studied. It was found that at least 0.3 vol% concentration of HF was required for particle removal and removal efficiency increased with the application of megasonic in ozonated water. Additional cleaning with minute amount of ammonia (0.01 vol%) after HF/Ozone step showed over 99% in removal efficiency. It is proposed that the superior cleaning efficiency of HF-Ozone-ammonia is due to micro-etching of silicon surface and impediment of particle re-adsorption in alkali environment. Compared to SC-1 cleaning method micro roughness has also been slightly improved. Therefore it is expected that HF-ozone-ammonia cleaning method is a viable alternative to the conventional wet cleaning methods.

불산과 오존 세정 시 실리콘 웨이퍼 표면의 미세입자를 효과적으로 제거할 수 있는 세정 방법에 대하여 연구하였다. 불산의 농도가 0.3 vol% 이상이 되어야 미세입자가 제거 되었으며, 초음파가 인가된 오존수를 사용 시 제거 효율은 증가되었다. 오존과 불산 세정 단계 이후에 추가로 극미량의(0.01 vol%) 희석 암모니아수 세정을 하면 미세입자가 99%이상 제거됨을 확인하였다. 이는 암모니아수에 의한 웨이퍼 표면의 미세 에칭 효과와 알칼리 영역에서의 재흡착 방지 효과가 동시에 작용함에 기인된다고 보인다. 한편, 불산-오존-희석 암모니아수 세정은 통상의 SC-1 세정과 비교할 때 표면 미세 거칠기가 개선되는 경향을 보였다. 불산-오존-희석 암모니아수 세정은 상온에서도 미세입자를 효과적으로 제거할 수 있는 세정 방법으로, 고온 공정 및 과다한 화학액을 사용하는 기존 습식세정의 대안으로서 기대된다.

Keywords

References

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