Effects of Wet Cleaning on Si Contaminated with Heavy Metals during Reactive Ion Etching

Abstract

Heavy metal removal from Si wafers contaminated during reactive ion etching (RIE) is studied using wet cleaning techniques, Si wafers are intentionally contaminated during RIE with Fe, Cr, or Ni, which are atomic components of stainless steel, the material used in dry etching apparatus. The Si wafers are washed with several reagents, and heavy metal removal results are estimated using secondary ion mass spectrometry and stacking fault observation. The results show that Fe and Cr are removed by wet etching the Si wafers to approximately a 30 nm depth but that Ni cannot be removed. The results indicate that to protect Si wafers against heavy metal contamination during RIE, Ni‐free materials should be used for fixtures in the dry etching chamber.