| Diblock copolymers are of great interest to produce large arrays of repeating nanometer scale features because they are self-assembling systems. A significant processing speed advantage can be obtained over serial processes such as electron-beam lithography, as transferring the diblock pattern is parallel in nature. Their use as pattern masks in nanolithography is demonstrated in this dissertation with the fabrication of polarizing grids on quartz wafers. The performance of these grids, which have a period from 35nm to 55nm, is discussed for wavelengths ranging from the visible down to the vacuum UV using a simple analytical model, in the infinite wavelength limit. A numerical approach, using a transfer matrix formalism, confirms the validity of the infinite wavelength approximation and adds insight on the grid size's effects. The fabrication process is given in detail and a UV-vis spectrometer is used for measurements of the polarization efficiency as a function of wavelength.; Practical application of diblock copolymers as pattern masks benefit greatly from long range order of their microdomains. The second part of this dissertation presents expansions to the technique of annealing under shear developed in this lab. A rheometer is used to shear samples via a high viscosity liquid layer, providing a linearly varying shear stress on a single sample. Quantitative measurements of the shear effect on cylindrical microdomain thin films can be extracted, and a saturation stress is found, above which alignment quality as a function of shear stress saturates close to perfection. A recrystallization model is used to fit the data, and a mean field cell dynamics model is also used to simulate shear alignment and provides results in agreement with the experiments. Pressurized high viscosity fluid in a channel is also presented as a way to shape the microdomain alignment direction on the millimeter scale. Wedge shaped channels are demonstrated to be another viable means of obtaining varying shear stress on a sample. |
