Abstract
Compared to other lithography methods that can fabricate nanoscale structures, laser interference lithography (LIL) is maskless and exhibits long depth of focus (DOF), low cost, and efficiency. Thus, LIL has become widely used to fabricate large-area nanoscale periodic structures. In this thesis, we set up two LIL systems that used a pinhole and an optical fiber, respectively, as a spatial filter. To increase the throughput of the LIL system and reduce the need for human input, we designed and developed automated LIL equipment. The components include the cassette-to-cassette mechanism, dose controller, edge searcher, and automated feeder. The LIL system and equipment were also been to fabricate a silicon (Si) mold with nanogratings, nanopatterned sapphire substrate (NPSS), and wire grid polarizer (WGP). The Si mold with nanoscale structures is used in nanoimprint lithography to fabricate a large-area optical device. Uniformity is an important characteristic of optical elements. We applied the LIL method to fabricate photoresist nanoscale gratings on Si and improved the uniformity of the gratings by increasing the dose during LIL. We also designed a specific multilayer etching process to adjust the line width of the Si mold. Finally, a Si mold with higher uniformity was obtained. The NPSS has high potential to enhance the light output of light-emitting diodes (LEDs). We used LIL to fabricate photoresist periodic nanopillars on the sapphire substrate and a dry etching process to etch the substrate. Then, an NPSS with different pitches and shapes was obtained. The highest light output power of the LED grown on the NPSS is 1.28 times higher than that of an LED grown on a planar sapphire substrate. The WGP is a used mostly as an optical element in liquid crystal displays. In this thesis, we patterned photoresist nanowires on an organic flexible substrate by LIL. The WGP was completed after inorganic metal deposition and photoresist removal. Its pitch and line width can be adjusted by a mechanical stress-controlled post-lithography technique. Further, the post-lithography pattern modification process window can be enlarged by matching the Poisson’s ratio of the interlayers of the WGP to enhance the WGP’s performance. Therefore, nanoscale periodic structures can be applied in many fields, and the LIL equipment (system) is worth developing.