Selective Relief Patterning for Self-Aligned Stacked Devices

The patent applies preliminary action by pre-forming relief patterns on the substrate surface before material deposition. The relief pattern serves as a pre-prepared template that guides subsequent selective growth, ensuring precise alignment without requiring complex etch-based alignment corrections. This preliminary structuring eliminates the need for iterative mask alignment and etching steps, thereby reducing defects and improving scaling capability.

The relief pattern acts as a self-aligning feature that automatically guides material deposition to the correct locations. The selective growth process inherently aligns new features with the underlying relief pattern without requiring external alignment interventions. This self-service mechanism eliminates alignment errors that plague conventional etch-based processes, reducing defectivity while enabling better scaling.

The patent implements local quality by creating relief patterns with varying heights and geometries at different locations on the substrate. These localized structural variations enable selective growth control, where material deposits preferentially on certain regions based on their relief pattern characteristics. This local differentiation provides precise control over where and how materials grow, eliminating the insufficient selective growth control of conventional processes while maintaining manageable process complexity.

The relief pattern formation serves as a preliminary action that pre-determines the sites and modes of selective growth. By preparing the substrate surface with specific relief structures before deposition, the process establishes clear growth zones and pathways, simplifying the overall process while enhancing control over selective material growth.

The patent applies the nested doll principle by creating hierarchical relief patterns where multi-level structures are built upon previous levels. Each processing cycle adds a new layer of features that nest within and align to the underlying relief pattern. This nested approach enables high device density through stacked multi-level fabrication while maintaining alignment accuracy, as each level self-aligns to the previous level through the persistent relief pattern template.

The relief pattern serves as a persistent preliminary template that remains throughout multi-level processing. This pre-formed structure guides each subsequent deposition and growth cycle, ensuring that even as device density increases through multiple levels, alignment accuracy is maintained because each level references the same underlying relief pattern.