Highly selective etching of silicon nitride to physical-vapor-deposited a-C mask in dual-frequency capacitively coupled CH{sub 2}F{sub 2}/H{sub 2} plasmas
- School of Advanced Materials Science and Engineering, Center for Human Interface Nanotechnology, and Center for Advanced Plasma Surface Technology, Sungkyunkwan University, Suwon, Kyunggi-do 440-746 (Korea, Republic of)
A multilevel resist (MLR) structure can be fabricated based on a very thin amorphous carbon (a-C) layer ( congruent with 80 nm) and Si{sub 3}N{sub 4} hard-mask layer ( congruent with 300 nm). The authors investigated the selective etching of the Si{sub 3}N{sub 4} layer using a physical-vapor-deposited (PVD) a-C mask in a dual-frequency superimposed capacitively coupled plasma etcher by varying the process parameters in the CH{sub 2}F{sub 2}/H{sub 2}/Ar plasmas, viz., the etch gas flow ratio, high-frequency source power (P{sub HF}), and low-frequency source power (P{sub LF}). They found that under certain etch conditions they obtain infinitely high etch selectivities of the Si{sub 3}N{sub 4} layers to the PVD a-C on both the blanket and patterned wafers. The etch gas flow ratio played a critical role in determining the process window for infinitely high Si{sub 3}N{sub 4}/PVD a-C etch selectivity because of the change in the degree of polymerization. The etch results of a patterned ArF photoresisit/bottom antireflective coating/SiO{sub x}/PVD a-C/Si{sub 3}N{sub 4} MLR structure supported the idea of using a very thin PVD a-C layer as an etch-mask layer for the Si{sub 3}N{sub 4} hard-mask pattern with a pattern width of congruent with 80 nm and high aspect ratio of congruent with 5.
- OSTI ID:
- 22053603
- Journal Information:
- Journal of Vacuum Science and Technology. A, International Journal Devoted to Vacuum, Surfaces, and Films, Vol. 28, Issue 1; Other Information: (c) 2010 American Vacuum Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1553-1813
- Country of Publication:
- United States
- Language:
- English
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