Dual frequency mid-gap capacitively coupled plasma (m-CCP) for conventional and DSA patterning at 10 nm node and beyond

摘要

In this paper, we demonstrate the unique advantage of dual-frequency mid-gap capacitively coupled plasma (m-CCP) in advanced node patterning process with regard to etch rate / depth uniformity and critical dimension (CD) control in conjunction with wider process window for aspect ratio dependent & microloading effects. Unlike the non-planar plasma sources, the simple design of the mid-gap CCPs enables both metal and non-metal hard-mask based patterning, which provides essential flexibility for conventional and DSA patterning. We present data on both, the conventional multi patterning as well as DSA patterning for trenches / fins and holes. Rigorous CD control and CDU is shown to be crucial for multi patterning as they lead to undesirable odd-even delta and pitch walking. For DSA patterning, co-optimized N_e / V_(dc) of the dual frequency CCPs would be demonstrated to be advantageous for higher organic-to-organic selectivity during co-polymer etching.