Nanoscale thermal lithography by local polymer decomposition using a heated atomic force microscope cantilever tip

Nanopatterning of polymer thin films is the basis for the vast majority of current microlithography processes used in integrated circuit manufacturing. Future scaling of such polymer patterning methods will require innovative solutions to overcome the prohibitively high tool and mask costs associated with current optical lithography methods, which will prevent their use in many applications. Scanning probe-based methods for surface modification are desirable in that they offer high resolution patterning while also offering the ability to perform in situ metrology. We report a new scanning probe lithography method that uses heated atomic force microscope cantilevers to achieve nanoscale patterning in thin polymer films via the local thermal decomposition of the polymer and in situ postdecomposition metrology. Specifically, cross-linked polycarbonate thin films are developed in this work and are shown to be excellent writing media for this process. This new method has the advantage that the tip can be heated and cooled on microsecond time scales and thus material can be removed and patterned without need for the disengagement of the tip from the polymer surface. This ability to write while the tip is constantly engaged to the surface offers significantly higher writing speeds for discontinuous patterns relative to other scanning probe techniques.