A novel "mesa" type of x-ray mask is introduced which utilizes the flip-bonding method of anodic bonding to join the mask membrane to a rigid, mechanically stable Pyrex ring. The new design eliminates several debilitating problems of conventional mesa masks, including the membrane overhang and resist edge bead problems. Flip-bond masks are much flatter than conventional mesa masks, typically < 500 nm mask total flatness and < 150 nm membrane flatness. A novel method of strengthening mesa masks is introduced, involving a polysilicon shock collar in the inner diameter of the mask ring designed to distribute the strain of mechanical disturbances. Flip-bond fabrication procedures have been designed to be amenable to volume manufacturing.