排气方式及工艺参数对等离子体刻蚀a-Si 均一性的影响

摘要

本文对在等离子体刻蚀工艺中,功率、压强、气体比例重要参数对 a-Si 刻蚀均一性的影响进行了研究。采用PECVD 成膜、RIE 等离子体刻蚀,并通过台阶仪和光谱膜厚测定仪对膜厚进行表征。结果表明压强在10~15 Pa,功率在5500~6500 W 的参数区间,a-Si 刻蚀均一性波动不大,适合工业化生产。a-Si 刻蚀速率及刻蚀均一性对气体比例较为敏感,SF6∶HCl＝800∶2800 mL/min 时 a-Si 刻蚀均一性为最佳。四角排气方式对维持等离子体浓度作用明显,有利于刻蚀均一性的提升。四周排气方式会破坏等离子体浓度进而破坏 a-Si 刻蚀的均一性。%The influence of power,pressure and gas ratio on uniformity plasma etching a-Si was stud-ied.The results show that the process of pressure in 10 ~ 15 Pa,power in 5 500 ~ 6 500 W is suit-able for industrial production because a-Si etching uniformity is very stable.Etching rate and uniformi-ty of a-Si is more sensitive to etching gas ratio.When SF6 ∶ HCl = 800∶2 800 mL/min ,the etching uniformity of a-Si is the best.Gas exhausting from corners can maintain the plasma concentration ob-vious,which is conducive to enhance the uniformity of plasma etching.Gas exhausting from around will undermine plasma concentration and thus undermine the uniformity of a-Si etching.