Methods for determining a focus position of a lens system based on astigmatism. The methods can be used to monitor the focus of the lens system or to determine the flatness of a surface.
A photolithography method for creating very small line dimensions includes making a mask by exposing a mask blank through a reticle in a reduction photolithography exposure tool, at a reduction of N. The fabricated mask is then placed in a second photolithography exposure tool at a secon
A technique for improving across field dimensional control in a microlithography tool. In a lithography imaging process in which a pattern on a mask is projected to form latent images in a photosensitive medium, the critical dimension distribution across the imaging field varies due to
