Thermal probe nanolithography: in-situ inspection, high-speed, high-resolution, 3D

Heated tips offer the possibility to create arbitrary high-resolution nanostructures by local decomposition and evaporation of resist materials. Turnaround times of minutes are achieved with this patterning method due to the high-speed direct-write process and an in-situ imaging capability. Dense features with 10 nm half-pitch can be written into thin films of organic resists such as self-amplified depolymerization (SAD) polymers or molecular glasses. The patterning speed of tSPL has been increased far beyond usual scanning probe lithography (SPL) technologies and approaches the speed of Gaussian shaped electron beam lithography (EBL) for <30 nm resolution. A single tip can write complex patterns with a pixel rate of 500 kHz and a linear scan speed of 20 mm/s. Moreover, a novel scheme for stitching was developed to extend the patterning area beyond the ≤100 μm range of the piezo stages. A stitching accuracy of 10 nm is obtained without the use of markers. Furthermore, the patterning depth can be controlled independently and accurately (~1 nm) at each position. Thereby, arbitrary 3D structures can be written in a single step. Finally, we demonstrated an all-dry tri-layer pattern transfer concept to create high aspect ratio structures in silicon. Dense fins and trenches with 27 nm half-pitch and a line edge roughness (LER) below 3nm (3σ) have been fabricated.