Nonplanar photolithography with computer-generated holograms

We outline a method for accomplishing photolithography on grossly nonplanar substrates. First we compute an approximation of the diffraction pattern that will produce the desired light-intensity distribution on the substrate to be patterned. This pattern is then digitized and converted into a format suitable for manufacture by a direct-write method. The resultant computer-generated hologram mask is then used in a custom alignment tool to expose the photoresist-coated substrate. The technique has many potential applications in the packaging of microelectronics and microelectromechanical systems.