Morphology of nanoimprinted polyimide films fabricated via a controlled thermal history

Abstract

Fabricating nanopatterns on polyimide (PI) films directly by nanoimprint lithography (NIL) is difficult owing to the high glass transition temperature (T g ). In this study, a nanopatterned PI film was successfully obtained by nanoimprinting poly(amic acid) (PAA) film and curing it afterward. Differential scanning calorimetry, thermogravimetry and dynamic mechanical analysis were carried out to study the state of thermal molecular motion in PAA thick films that have the same content of residual solvent as the PAA thin films used in NIL. The thermal and dynamic mechanical behaviors of PI thick films were studied for comparison. An appropriate nanoimprinting process was proposed based on an understanding of the thermal and dynamic mechanical properties of PAA and PI films. Atomic force microscopy showed that the line pattern was transferred without distortion from the PAA film to the PI film, even though a larger shrinkage took place during the hard baking.

Structural Evolution of Low‐Molecular‐Weight Poly(ethylene oxide)‐block‐polystyrene Diblock Copolymer Thin Film

“…The formation of diverse patterns in polymer thin films is of considerable technological and scientific importance in coatings, adhesives, photoresists, electronics, biomaterials, and optical devices [ 1 – 5 ]. By thermal [ 2 , 6 ] or solvent [ 7 , 8 ] annealing, melt-wetting templates [ 9 , 10 ], and nanoimprint lithography [ 11 , 12 ], patterned surface with unique topography and properties can be constructed. For example, poly( ε -caprolactone) (PCL) film with hierarchical nanowire patterns fabricated by melt-wetting anodic aluminum oxide templates showed a higher capability of protein adsorption and better cell growth than that with smooth surface [ 9 ].…”

A novel MEMS compatible lab-on-a-tube technology

“…It is well known that the nanoimprint process of polyimide polymer is difficult. 15 However, because of its excellent thermal and chemical stability, the polyimide capillary is utilized as the substrate. The microelectrode is 630 μm long and 280 μm wide.…”

Molecular reorientation of polyimide film induced by thermal nanoimprint lithography and liquid crystals alignment on it

“…In addition, imidization process is usually accompanied with the shrinkage of the film. We have studied the shrinkage of nanoimprinting topography before and after hard baking by atomic force microscopy (AFM) [27], and the result illustrates the line-patterned film experienced the shrinkage and the shrinkage of every line is uniform. Because of special topography of the imprinted film, the shrinkage perpendicular to the lines is larger, which makes the C]O bonds align along the line direction.…”