Research On Technology Of AFM-based Micro/Nano Template Fabrication

Nanotechnology has become a rapidly growing field today. There is a tendency for product to become minimal and integrated. To achieve the goal of miniaturization, cost effect, and high yield of fabrication, constant progress and development of nanotechnology is needed. Finding novel fabrication methods with more efficient and lower cost is becoming a research hotspot. The invention of atomic force microscope (AFM) has provided a new method for micro/nano fabrication. AFM is an instrument to make a height image of a very small part of a surface by scanning the surface with a nano tip. AFM can also be a tool for sequential manufacture. In order to investigate the mechanism of micro/nano machining, based on the practical application of AFM fabrication, a new combined method of sub-micron high aspect ratio structure fabrication is developed which can be used for production of micro/nano template. The process includes AFM scratch nano-machining and inductively coupled plasma (ICP) fabrication. The main contents of this thesis are shown in the following.1. The mechanism of micro/nano fabrication is investigated. AFM diamond tip and film/substrate system is modeled; nano-indentation and nano-scratch processes are simulated using molecular dynamics simulation. The deformation of the film and substrate during the indentation process is analyzed. By using different loading speeds, the relationship between the hardness of the film and the loading speeds is studied. The scratch simulation is also carried out in different orientation. The effect of the front end face of AFM tip on the fabricated structure and the cutting chip is analyzed. The material removal affected by cutting depth is also studied. The study results provide guidance for AFM fabrication.2. The relationship between the deformation of the cantilever and the load force is investigated. The method for measuring the deformation of the cantilever during the AFM fabrication is studied. The real time forces on the AFM tip during the fabrication process are got by reading the output of the photo detector which provides condition for feedback control of the AFM fabrication process.3. The relationship between the scratch depth and the loading force is investigated by the experimental study. With optimized parameters, the structure of parallel grooves is fabricated on the Al film deposited on the single crystal Si wafer by AFM fabrication. Combined the AFM nano machining and the ICP etching process, a high aspect ratio structure of sub-micron template is fabricated.AFM micro/nano fabrication is a process with broad prospect. The study of precision measurement, micro/nano fabrication, nano manipulation and nano modification based on AFM are still in progress. The mechanical machining and micro/nano template fabrication based on AFM are studied in this dissertation, some other applications based on AFM fabrication need further study and improvement.