Drying of High Aspect Ratio Structures: A Comparison of Drying Techniques via Electrical Stiction Analysis

Nanostructures with high aspect ratios, HAR, (ratio of height to lateral feature size) are of interest for many applications. One of the immediate advantages is the large surface area of these structures. In the field of DRAM manufacturing for example, the capacitance of cylindrical DRAM capacitors increases linearly with height. Wet etching and drying of these fragile high aspect ratio structures without lateral collapse (stiction) is a big challenge for the fabrication of DRAM capacitors. The problem with HAR structures is stiction during drying [1]. In order to reduce stiction by improvement of drying techniques, a good metric to quantify the occurrence of stiction is needed. However, currently used methods like SEM or brightfield defect inspection are extremely time-consuming.