Levenson Mask Pattern Formation with Sacrificial Support

The patent performs preliminary actions by forming mandrel patterns and sacrificial patterns before final pattern formation. The sacrificial patterns are intentionally placed at strategic locations to provide support during etching, preventing film stripping. After serving their support function, the sacrificial patterns are removed, leaving the desired fine patterns intact.

The patent introduces sacrificial patterns as intermediary elements that temporarily serve as support structures during the etching process. These sacrificial patterns act as mediators between the undercut portions, providing necessary mechanical support to prevent light-shielding film stripping. The intermediaries are removed after fulfilling their support function.

The patent segments the pattern formation process into multiple distinct exposure steps: first exposure to form mandrel patterns, second exposure to form sacrificial patterns, and third exposure to form final patterns. Each exposure step targets specific pattern elements, allowing precise control over the final pattern geometry and dimensional accuracy.

The patent utilizes parameter changes by adjusting exposure amounts, wavelengths, and focus conditions across different exposure steps. The first exposure uses conditions optimized for mandrel pattern formation, while subsequent exposures use adjusted parameters to form sacrificial and final patterns, enabling precise dimensional control despite increased process steps.