Characterization of sidewall roughness inside porous anodic alumina template holes by scanning electron microscopy

Resist line edge roughness (LER) and sidewall roughness of micro/nano structures are becoming important issues of increasing concern in the sub-100 nm fabrication regime due to their critical impact on device performance. LER and sidewall roughness metrology is used to monitor individual nanostructure fabrication. Porous anodic alumina (PAA) membranes are typical nanoscale templates and can be fabricated with different pore sizes through second oxide technique by changing the acid electrolyte and the anodization voltage. The LER of sidewall inside anodic porous alumina template holes has been evaluated by analyzing top-down scanning electron microscopy (SEM) images off-line. And RMS roughness (3σ) and height-height correlation function are used to characterize the sidewall roughness inside nanoscale holes of porous alumina template.