US Patent 10256110 Self-aligned patterning process utilizing self-aligned blocking and spacer self-healing

A multiple patterning process is provided with a self-aligned blocking (SAB) technique. The SAB technique trades off difficult overlay requirements for more manageable etch selectivity requirements between the various layers utilized for the patterning process. As disclosed herein, damage to sidewalls resulting from etching at the self-aligned block masking step may still occur. Damage is repaired by providing a plug layer that fills the areas of the damaged spacers. The plug layer may be the same material as forms the spacers. In this manner, the fill process provides a self-healing mechanism for damaged spacers.