Tolerable patterning in nanoimprint lithography by one-pass breakthrough etching of residual layer and spin-on-glass

In nanoimprint lithography (NIL), a residual layer inherently exists under the NIL resist features and must be removed in later etching steps. The subsequent etching process, known as breakthrough etching, leads to variations in the device pattern sizes and disrupts process integration because of NIL resist pattern loss. It was reported previously that the residual layer thickness (RLT) should be less than half the feature height (FH) for subsequent high-precision etching. In this work, we develop a one-pass etching process using an atomic-scale cycle stepped etching technique that passes through the residual layer to the spin-on-glass and demonstrate that the process can maintain the pattern width, regardless of RLT variations within the 12–32 nm thickness range. Even in the case of a 32-nm-thick RLT corresponding to 76% of the feature height (0.76 FH), good electrical performances were obtained without electrical failures in the half-pitch 26 nm line-and-space W-damascene interconnect patterns.