Lift-off process for nanoimprint lithography

• We report a novel a lift-off method for nanoimprint lithography. This is a bi-layer method, using a polymethyl methacrylate (PMMA) on lift-off layer (LOL) resist scheme. For the imprint step, direct evidence for good pattern transfer down to 20 nm is shown. Oxygen plasma ashing is required to remove residual PMMA. A liquid solvent, MF 319, is used to transfer the pattern down to the silicon. The LOL is dissolved isotropically while the PMMA is unaffected. Ashing time can kept to a minimum through the wet etch method. This reduces the line widening effect. After metal evaporation a two-step lift-off process prevents metal flakes from adhering to the surface electrostatically. At first warm acetone breakes apart the metal layer and dissolves the PMMA, then warm Remover S-1165 removes the LOL and remaining metal. Structures of lines down to 50 nm and dots with a diameter of sub 20 nm are presented.

Ämnesord

NATURVETENSKAP  -- Fysik -- Den kondenserade materiens fysik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Condensed Matter Physics (hsv//eng)

Nyckelord

lift off method

nanoimprint lithography

polymethyl methacrylate

PMMA

pattern transfer

oxygen plasma

liquid solvent

silicon

wet etch method

metal evaporation

50 nm

20 nm

SiO2

Au

surface adhesion

metal flakes

acetone

dissolution

bilayer method

metal layer

line widening effect

Publikations- och innehållstyp

kon (ämneskategori)

ref (ämneskategori)