Self-modulating polymer resist patterns in pressure-assisted capillary force lithography

We present pressure-assisted capillary force lithography (CFL) to generate self-modulating polymer resist patterns without residual layers and film instability. The method utilizes roof collapse of a patterned, deformable poly(dimethyl siloxane) (PDMS) mold that is placed on a thermoplastic polymer film with a constant external pressure (∼4 bars) and the resulting shape-variable capillary filling of a polymer melt into the reduced void space. A constraint on the coated polymer layer thickness was derived in order to ensure that there is no residual layer left after patterning and at the same time that film stability is guaranteed without film dewetting within the cavity. In addition, the height of a polymer pattern at the center of the filled void was estimated as a function of initial polymer layer thickness based on the assumption of the hemispherical shape of a meniscus and full capillary rise, which agrees well with the experimental data.

The mold’s ceiling is collapsed initially during the contact (roof collapse) and recovers from continuous mass supply from the neighboring regions, which can suppress dewetting of a filled polymer film.Figure optionsDownload high-quality image (71 K)Download as PowerPoint slide