Atomic layer etching pitch splitting (APS™): a new alternative to self-aligned double patterning

We have developed Atomic Layer Etching Pitch Splitting (APS™), as a novel cost-effective process alternative to Self-Aligned Double Patterning (SADP). It integrates atomic level-controlled processes with existing production technologies and cuts the number of processing steps while avoiding underlying material damage for a sustainable patterning of advanced on-device features. We demonstrate this process on various substrates using lithographically defined line patterns and achieve a half-pitch of 20 nm with critical dimensions (CDs) below 15nm on both single-crystalline and amorphous silicon wafers, CDs of 3nm on GaP wafers. The split structures can be directly used as a split mask for further etching. This process avoids some problems typical for SADP processes and promises up to 40% cost reduction per mask layer as well as higher throughput.