Reducing collapse in high aspect ratio structures

Many defects are generated during micro- and nano-fabrication processes, especially for high aspect ratio structures. The aspect ratio of structures is an important parameter for subsequent processes. However, the top of high aspect ratio structures usually adheres to each other; moreover, pattern with high aspect ratio even can collapse or peel off from the substrate during the drying process, which is mainly ascribed to the capillary force. In this paper, a new method that puts supporting structures on the fabrication structures to reduce collapse has been proposed. The conventional method and new method were compared by calculating the deformations for different line widths and aspect ratios. The new method was also applied in fabricating nanostructures. The results indicated that the new method can effectively decrease the deformation and increase the aspect ratio.