AVS 62nd International Symposium & Exhibition
    Plasma Science and Technology Thursday Sessions
       Session PS-ThP

Paper PS-ThP15
The Study on the Etching Characteristics of the High Aspect Ratio Amorphous Carbon Layer(ACL)

Thursday, October 22, 2015, 6:00 pm, Room Hall 3

Session: Plasma Science and Technology Poster Session
Presenter: Yonghyun Kwon, Samsung Electronics Co., LTD., Republic of Korea
Authors: Y.H. Kwon, Samsung Electronics Co., LTD., Republic of Korea
Z.H. Gang, Samsung Electronics Co., LTD., Republic of Korea
K.S. Shin, Samsung Electronics Co., LTD., Republic of Korea
G.Y. Yeom, Sungkyunkwan University, Republic of Korea
Correspondent: Click to Email
High aspect ratio etch is the key process step in the fabrication of vertically stacked(3D) memory, which is currently the most promising approach for ultra high density and high performance data storage applications. Superior hole dry etch capability, such as wide aspect ratio coverage, good vertical profile control, short throughput, etc, determines the satisfying vertical extendibility, memory cell performance and yield of the 3D memory. The hole etch usually takes a long process time(e.g., >1000 s). Therefore, a fine patterned thick(e.g.,>10um) hard mask must be required. Amorphous carbon layer(ACL) is a proper hard mask material due to its advantageous properties such as high selectivity, ease of deposition and removal and fine profile controllability. In this study, the control knob of thick ACL etch is investigated and solutions for high aspect ratio ACL etch is proposed. By reviewing the scanning electron microscopy(SEM) image after ACL de-capsulation, major/minor axis and the angle is investigated, and ACL tilting and distortion is observed at the aspect ratio 17. A model of ACL tilting induced by wafer warpage and sheath tilting, and ACL distortion formation due to non-uniform indirect ion scattering and by-product deposition is proposed. In addition, possible solutions for improving the ACL tilting and distortion by tuning the bias power, pulse and COS gas flow rate is discussed.