Abstract: Methods, apparatus, and systems are provided herein for processing a substrate. Generally, the processing involves Spacer-on-Spacer (SoS) Self-Aligned Quadruple Patterning (SAQP) techniques. The disclosed techniques provide a novel process flow that reduces defects by ensuring that cores are not removed from the substrate until the substrate is transferred to a deposition chamber used to deposit a second spacer layer. This reduces or eliminates the risk of structural damage to features on the substrate while the substrate is being transferred or cleaned. Such structural damage is common when the cores are removed from the substrate prior to cleaning and transfer.