Process development and edge-placement yield modeling of alternating-material self-aligned multiple patterning

Abstract

We propose and discuss a modular technology to reduce the edge-placement-error effect by combining selective etching and alternating-material (dual-material) self-aligned multiple patterning (altSAMP) processes. A geometrical cut-process yield model considering the joint effect of overlay errors, cut-hole, and line CD variations is developed to analyze its patterning performance. In addition to the contributions from the above three process variations, the impacts of key control parameters (such as cut-hole overhang and etching selectivity) on the patterning yield are examined. It is shown that the optimized altSAMP patterning process significantly improves the patterning yield compared with conventional SAMP processes, especially when the half pitch of device patterns is driven down to 7 nm and below. Moreover, the corresponding layout decomposition and synthesis strategy are also discussed. The experimental results of altSAMP process development and material screening are reported.