EUV Photomask Reflection Correction for Pattern Dimension Accuracy

The patent applies local quality by dividing the mask plane into multiple subregions and assigning different reflection correction coefficients to each subregion based on local dimensional differences. This allows the reflection coefficient to be locally adjusted in specific areas where dimensional corrections are needed, rather than uniformly across the entire mask. The absorber pattern's reflection coefficient is modified locally to achieve accurate pattern dimension correction while maintaining adaptability across different regions of the mask.

The patent employs parameter changes by dynamically adjusting the reflection correction coefficient based on the specific dimensional difference in each subregion. Instead of using a fixed rule, the correction coefficient is varied as a parameter to match the local dimensional requirements. This allows accurate correction of pattern dimensions by changing the reflection coefficient parameter according to the measured dimensional differences, achieving both precision and adaptability.

The patent implements feedback by using the measured dimensional differences of the absorber pattern as input to calculate and determine the appropriate reflection correction coefficients for each subregion. The measurement results feed back into the correction process, where the dimensional information is converted into reflection coefficient distribution information. This feedback mechanism ensures that the reflection coefficient distribution is accurately determined based on actual measurement data, preventing information loss.