Inductively Coupled Plasma Etching of Chemical-Vapor-Deposited Amorphous Carbon in N₂/O₂/Ar Chemistries

Abstract

In this study, we investigated the etching characteristics and mechanism of an amorphous carbon (a-C) layer for a multi-level resist (MLR) structure. Chemical-vapor-deposited (CVD) a-C layers with a SiO 2 hard-mask were etched in an inductively coupled plasma (ICP) etcher by varying the process parameters such as top electrode power, bottom electrode power, and gas flow ratio in N 2 /O 2 /Ar plasmas. The etch rate and profile angle of the CVD a-C thin films were decreased with increasing N 2 flow ratio in the N 2 /O 2 /Ar plasmas. As the N 2 flow ratio increased, the etch rate and the profile angle were reduced due to the enhanced formation of CN x on the etched surface. The etch rate of the CVD a-C thin films was increased with increasing the top and bottom electrode powers.

Study on the etching characteristics of amorphous carbon layer in oxygen plasma with carbonyl sulfide

“…11,[16][17][18][19][20][21][22] However, during the patterning of an ACL using oxygen plasma in a reactive ion etcher, oxygen radicals existing in the oxygen plasma tend to cause unwanted sidewall etching of the patterned ACL, which leads to a bow-like etch profile and increased top pattern opening. 16,24,25 However, the uses of N 2 and H 2 instead of oxygen as the main etchant have caused another problem such as low etch rates due to the low reactivities of the gases with the carbon in the ACL. 16,24,25 However, the uses of N 2 and H 2 instead of oxygen as the main etchant have caused another problem such as low etch rates due to the low reactivities of the gases with the carbon in the ACL.…”