Plasma etch removal of poly(methyl methacrylate) in block copolymer lithography
Two types of block copolymer structure: (a) cylindrical and (b) lamellar.
Patterning process with diblock copolymer nanostructure on silicon substrate: (a) PS-b-PMMA nanostructure formation, (b) after PMMA removal, and (c) after etching of underlying material.
Plasma etcher with helicon plasma source and interferometry system for in situ etch rate measurement.
(a) PS etch rate, (b) PMMA etch rate, (c) PS/PMMA etch rate ratio with different etch gas mixtures.
Block copolymer samples etched with plasma of different chemistries: (a) Ar: rough and “swollen” PS, (b) : bumpy roughness on the top of PS domain. (c) : smooth surface and negligible CD loss,(d) , and (e) .
AFM measurement of surface roughness of PS and PMMA blanket films etched with plasmas of different chemistries: (a) Ar, (b) , (c) , (d) , and (e) .
etched PS film with bias voltage of (a) 0 V shows bumpy surface and of (b) 110 V with smooth surface.
etched PMMA film with bias voltages of (a) 0 V and (b) 110 V show similar morphology.
Plasma parameters and ion saturation current density measurement.
Etch performance comparison.
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