Photo Mask Dummy Patterns for Electron Beam Proximity Effect

The patent applies local quality by introducing dummy patterns specifically in low-density regions adjacent to high-density pattern areas. This creates a non-uniform distribution of patterns where the density varies locally to compensate for the electron beam proximity effect, which is most severe at boundaries between high and low density regions. The dummy patterns are strategically placed to provide local density adjustment without affecting the overall circuit design.

The patent implements preliminary anti-action by pre-calculating the electron beam proximity effect and compensating for it through the addition of dummy patterns before the actual lithography process. The proximity effect calculation unit computes the expected blur and distortion, and the dummy patterns are designed in advance to counteract these effects, ensuring that the final pattern after exposure matches the intended design.

The patent uses local quality by creating regions with different pattern densities to balance electrical charging effects. High-density regions are compensated with surrounding dummy patterns to prevent excessive charging, while low-density regions receive dummy patterns to prevent insufficient charging. This local adjustment ensures uniform critical dimensions across the entire mask.

The patent applies parameter changes by modifying the pattern density parameter through the addition of dummy patterns. The pattern density is adjusted locally in different regions of the mask to optimize the electrical charging characteristics during electron beam exposure, thereby achieving uniform critical dimensions across varying pattern densities.