A study on the formation and removal of residue and damaged layer on the overched silicon surface during the contact oxide etching using $C_4$F$_8$/H$_2$ helicon were plasmas

C$_4$F$_8$/H$_2$ helicon were 플라즈마를 이용한 contact 산화막 식각 공정시 과식화된 실리콘 표면의 잔류막과 손상층 형성 및 이의 제거에 관항 연구

In this study, the residue remaining on the silicon wafer during the oxide overetching using $C_4F_8/H_2$ helicon were plasmas and effects of various cleaning and annealing methods on the removal of the remaining residue were investigated. The addition of 30%$H_2$ to the C4F8 plasma increased the C/F ratio and the thickness of the residue on the etched silicon surface. Most of the residuse on the etched surfaces colud be removed by the oxygen plasmsa cleaning followed by thermal annealing over $450^{\circ}C$. Hydrogen-coataining residue formed on the silicon by 70%$C_4F_8/30%H_2$ helicon plasmas was more easily removed than hydrogen-free residue formed residue formed by $C_4F_8$ helicon wear plasmas. However, damage remaining on the silicon surface overetched using 70%$C_4F_8/30%H_2$ helicon plasmas was intensive and the degree of reocvery duing the post-annealing was lower.