Production of x-ray mask blanks for a point source stepper

Many requirements of a point-source x-ray membrane mask are unique, in comparison with masks used with synchrotron sources. Membranes must be thinner, flatter and stronger, for example. We characterize our choices of polysilicon and silicon-rich nitride for membranes, and a simplified one-piece (monolithic) mask blank. We use a dual strength testing technique which discerns whether membrane strength is limited by defects in the film growth process, or defects in the attachment of membrane to support. We find our membrane films are stronger than previously thought, and that improvements in membrane/support attachment will effect a more durable membrane mask.