Thermal scanning probe lithography

Being able to create nanometer accurate patterns and structures is at the heart of nanoscale science and technology. We use a heated scanning probe tip to trigger locally the decomposition reaction of a thermally sensitive resist material. With each contact of the hot tip, a well-defined void is created, resulting in a pattern with high accuracy of its lateral and vertical dimensions. For 2D fabrication, we achieve <10 nm lateral resolution in the resist without it suffering from proximity effects. Linear speeds of up to 20 mm/s and pixel rates of up to 500 kHz have been demonstrated.

In t-SPL, the pattern is created and imaged on the fly, providing direct feedback of the lithography result to the user. The nanometer-precise imaging of the surface prior to patterning enables a sub-5-nanometer precise overlay to existing structures on the sample. Using a dedicated transfer stack, we obtained high-resolution patterns with feature sizes down to 11 nm half pitch in substrate etching, metal lift-off or ion milling. A unique feature of t‑SPL is the capability to write 3D profiles with nanometer accuracy in a single patterning run. We exploit this feature to gain control over objects in nanofluidic confinement.