Modeling innovations in EUV and nanoimprint lithography

This thesis investigates the application and use of electromagnetic simulation and modeling to a broad range of emerging lithography techniques. The scope of the work includes the extensions of the Finite-Difference Time-Domain algorithm as well as the creation of auxiliary programs for the construction of the input and application specific analysis of the near field output. The dissertation also gives in-depth characterization studies of applications to defect printability and mask performance in EUV lithography, nanoimprint alignment and inspection, and the design of optoelectronic mirrors.; A geometry to refractive index converter, SAM2TEM was developed to link TEM-PEST with 3D topography simulation in SAMPLE-3D, and thus extend the capability of electromagnetic simulation to a large range of applications involving modeling topographic changes during process. An average material properties technique was developed to provide subcell resolution description of the geometry. This improved accuracy without memory and runtime penalty enables electromagnetic simulation on large 3D EUV multilayer structures on a network of workstations.; Simulation of the printability for EUV Gaussian defects shows that analytical models are limited by the coherent illumination assumption when defects are large, while its single surface approximation limits the model's validity for small but relatively high defects. Exploration of using d-spacing modified or patterned multilayer directly as photomask in EUV Lithography shows the feasibility of this approach. Lithography imaging performance studies show that the etched and refilled multilayer masks have better image quality in H-V bias, IPE, smaller CD variations, and larger depth of focus than the EUV multilayer masks with absorber stacks.; Electromagnetic simulation was also used to explore the novel Step and Flash Imprint Lithography process with clear-opaque binary molds. This study assesses the material choices and provides design data for the exposure and differential alignment process, The study of complementary inspection shows a cross polarization of up to 15% of incident UV radiation. It is shown that the inspection signal can be improved with the use of shorter wavelength, higher material contrast and immersion liquid.; Electromagnetic simulation was also successfully applied to optoelectronic Bragg mirrors and yielded a design of novel sub-wavelength gratings which has a very broad reflection spectrum and very high reflectivity.