Lithography-based microfabrication: Diffractive optics and ULSI nanostructures

X-ray microscopy is becoming a powerful tool for material study. Fresnel zone plates (FZP) are the key focusing elements in the hard X-ray region. The main challenge in the fabrication of efficient high-resolution FZP is to produce fine structures with high resolution, high placement accuracy and high aspect ratio. X-ray lithography, which is capable of providing sub-100 nm resolution and high aspect ratio patterns, has been applied to the fabrication of these structures.; The effect on performance of non-idealities due to fabrication limitations are discussed. Many useful formulas have been obtained to evaluate the performance of zone plates.; Processes to fabricate diffractive optics have been developed. Standard semiconductor processing tools, including e-beam lithography, X-ray lithography and electroplating, are employed in the process. The problems of high aspect ratio pattern replication have been investigated, and processes to increase pattern aspect ratio ({dollar}>{dollar}10) have been developed. Many challenges of lithography, such as high resolution (sub-100 nm), placement accuracy and process control are also discussed. Various kinds of zone plates have been fabricated with focus length ranging from 5 cm to 3 m, resolution ranging from 0.25 {dollar}mu{dollar}m to 80 nm and energy ranging from 8 to 20 keV.; All zone plates fabricated in CXrL are applied to scanning X-ray microscope in Advanced Photon Source (APS). Optical parameters of FZP close to theoretical limits have been achieved. The FZPs have been successfully used for several applications. In addition, X-ray phase masks have been explored to print nanostructures with larger process latitude. Lines as small as 70 nm and sub-0.1 {dollar}mu{dollar}m dots using APEX-E are printed at the gap of 25 {dollar}mu{dollar}m, which is significant for X-ray nanolithography.