Nano Imprinting Lithography Ultrafast process and its chemical and physical effects on advanced plastic materials

The main goal of this PhD was to understand the effects of the Pulsed Nanoimprint Lithography (Pulsed-NIL) technique on thermoplastic materials, by performing the imprinting process on a range of different materials and using different stamps and characterization techniques to assess how this process affects chemically and physically the plastic materials. This study has been conducted comparing the imprinting results by the standard Thermal Nano Imprint Lithography technique (standard T-NIL) and by the Pulsed Thermal NIL (Pulsed-NIL). The study on the material was necessary because, even if both techniques heat up the material at a temperature higher than the glass temperature and, with the application of the pressure, there is a replica of the pattern from the stamp to the sample, the parameters (in particularly, time and temperature of imprint) are very different. The standard technique has a large diffusion in the research and fabrication in micro and nanotechnology field. The Pulsed-NIL represents an innovation but it was important to demonstrate the capability to realize the imprint maintaining a quality of the structures same as the standard T-NIL and an absence or a limited existence of degradation of the materials due to the high temperature of the imprint. At the ``Istituto Officina dei Materiali'' of CNR (IOM-CNR) laboratories at Elettra - Area Science Park (Basovizza, Trieste), January 2014, a first prototype (Thunder 1.0), for Pulsed- NIL of small areas (40*40mm2), based on the patent of ThunderNIL S.r.L., was operational and the second (ULISS), for the micro and nano imprint of bigger areas (4'' wafers), was nearing the end of design. The early months of the PhD were used for the design and executive drawings process, and also completed the assembling process of the machine used for the experimental part. The drawings are not in this thesis because they are not significant for the researching field. To better understand the innovation introduced by ThunderNIL, it is important to have, at first, an overview of the standard process. In chapter 4 the technique is presented together with the intrinsic disadvantages. Chapter 5 enters more in detail with the innovative technique. Two chapters (6 and 7) are dedicated to the fabrication of the stamps for the imprint with both techniques. In particular the first is an introduction, whereas the second is a step by step logbook to better explain the processes involved, the work flow and time consuming behind the stamp. At the end of that chapter also the main parameters of two examples of imprint (one for standard, the other for Pulsed-NIL) were presented. The second part is dedicated to the analysis of the selected material and focuses on the quality of the imprint, in particular with the use of AFM (Chapter 8) that is here introduced. Chapter 9 is completely dedicated to the comparison between the standard and Pulsed-NIL imprinted structures and chapter 10 is a discussion about the results which includes a conclusion summary.