Development of an Immersion Maskless Lithography System

As lithography quickly approaches its limits with current technologies, a host of new ideas is being proposed in hopes of pushing lithography to new levels of performance. The work presented in this thesis explores the use of an immersion scheme to improve the performance of a maskless lithographic technique known as Zone-Plate-Array Lithography (ZPAL). This is believed to be the first implementation of an immersion scheme in a maskless lithography system. This thesis provides a complete description of the Immersion Zone-Plate-Array Lithography (iZPAL) system. Since the zone plate component of the system is largely responsible for its lithographic performance, a thorough analysis of zone plate theory, design, and fabrication is also presented. The focusing performance of an immersion zone plate is then characterized through the experimental reconstruction of its pointspread function. Finally, lithography results obtained with the iZPAL system are compared to those obtained with the non-immersion ZPAL system, demonstrating the improvement in resolution, exposure latitude, and depth-of-focus achieved with the immersion scheme. Thesis Supervisor: Henry I. Smith Title: Keithley Professor of Electrical Engineering