Unique solution to measure and improve CDU

WLCD measures the CD based on proven aerial imaging technology and defines the mask CD non-uniformity. This data can be used as input to the CDC32 process.

CDC32 utilizes an ultrafast femto-second laser to write intra-volume shading elements inside the bulk material of the mask. By adjusting the density of the shading elements the light transmission through the mask is locally changed in a manner that improves wafer CDU when the corrected mask is printed.

The CDC32 improvement can finally be verified by WLCD predicting the intra-field CD Uniformity at wafer-level.

This is why WLCD builds up a unique closed loop solution with CDC32 - measure critical dimension uniformity on photomasks and correct non-CDU, if it does not meet the target specifications.