Electron shading effects in high density plasma processing for very high aspect ratio structures

Numerical simulations of feature scale charging due to plasma processing and the resulting injection current reveal an interesting trend as the aspect ratio is varied. For a particular set of high density ICP metal etch processing conditions, the aspect ratio is varied by changing the line spacing of a line and space antenna test structure in which the conductive layer in the space has not yet cleared, i.e. a latent antenna has formed. The simulation results indicate that after initially increasing with aspect ratio, the stress current begins to decrease with aspect ratio for those structures with very small line spacings, predicting reduced oxide damage