The study on the sidewall films formed during Si trench etching in Cl_2/HBr based plasmas

概要

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The trench sidewall passivation films produced with photoresist mask materials were examined in two different etch systems of helicon and inductively coupled plasma types. Compared to the trench profiles obtaind from the helicon etching system, under the inductively coupled plasma etching system, the trench profiles were obseved to be more tapered with thicker sidewall films. Moreover, the trench etch profiles obtained from Cl_2/HBr/O_2 plasma in the inductively coupled plasma etching system appeared to be double-sloped. X-ray Photolelectron Spectroscopy (XPS) analysis results indicated that the N. addition to Cl_2/HBr/O_2 plasma induced the formation of Si-N bond in the sidewall films besides Si-O and Si-Br bonds observed in Cl_2/HBr/O_2 plasma. In addition, the sidewall films formed in Cl_2/HBr/O_2 plasma showed higher oxygen intensities and chemical binding energies compared to those formed in Cl_2/HBr/N_2/O_2 plasma. The microscopic Si defects with cone shape were detected during Si trench etching regardless of etching chemisty and etching system. The wafers etched with nitride mask showed more Si defects than those etched with photoresist mask.
社団法人電子情報通信学会の論文
1999-07-23