Removal of aspect-ratio-dependent etching by low-angle forward reflected neutral-beam etching

Abstract

In this study, the effect of using a neutral beam formed by low-angle forward reflection of a reactive ion beam on aspect-ratio-dependent etching (ABDE) has been investigated. When a SF6 inductively coupled plasma and SF6 ion beam etching are used to etch poly-Si, ARDE is observed, and the etching of poly-Si on SiO2 shows a higher ABDE effect than the etching of poly-Si on Si. However, by using neutral beam etching with neutral beam directionality higher than 70 %, ARDE during poly-Si etching by SF6 can be effectively removed, regardless of the sample conditions. The mechanism for the removal of ARDE via a directional neutral beam has been demonstrated through a computer simulation of different nanoscale features by using the two-dimensional XOOPIC code and the TRIM code.