X-ray lathe: An x-ray lithographic exposure tool for nonplanar objects

An X-ray lithography lathe has been developed that can pattern cylindrical, ellipsoidal, and other nonplanar objects. This lathe is capable of patterning on a micron scale a wide variety of shapes including shapes impossible to achieve with a conventional lathe. A cylindrical core covered with a suitable resist is rotated while being exposed with a collimated X-ray source through a mask. The mask absorbs X rays up to a particular radius from the center of the core and the resist beyond that radius is removed in a developer, Several cylindrical cores were coated with poly(methylmethacrylate) (PMMA) 5 to 125 mu m thick and patterned with x-rays down to a 250-mu m horizontal scale (along the lathe aids). The exposure time for a cylindrical PMMA layer is similar to three-four times longer than a planar layer with the same thickness. The capabilities of this technology, lathe apparatus, dose calculations, and initial exposure results are described in this paper.