Step and Flash® imprint lithography
is a bilayer pattern transfer technique
using a low viscosity, silicon-containing, UV curable imprint
material deposited on an underlying organic planarization layer.
As shown in the illustration below, a halogen breakthrough
etch is used to eliminate the residual layer, and an oxygen
etch is used to etch through the planarization layer.

Photos courtesy of
the University of Texas and Sematech