Tham khảo tài liệu 'microengineering mems and interfacing - danny banks part 13', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 222 Microengineering MEMS and Interfacing A Practical Guide There are two other limitations of SPMs of which to be aware. The first is that the area examined is a tiny fraction of the surface and may not be typical. The second is particularly applicable when using ATMs. These often come with software that will allow the rms surface roughness to be calculated at the push of a button. At ATM scales this is not necessarily a very useful absolute measurement because the rms roughness is fractal in nature as you increase magnification you are measuring a different rms roughness . The spring constant of ATM probes needs to be calibrated. This is normally performed by measuring the fundamental frequency at which the probe oscillates. When working to atomic-scale resolution it is possible to calibrate the microscope using an atomically flat surface with a known interatomic spacing. The arrangement of carbon atoms in graphite sheets provides one possibility. Mica provides another. Adhesive tape applied to the sample and pulled away reveals a clean atomically flat surface. NANOELECTROMECHANICAL SYSTEMS As suggested in the introduction micro- and nanotechnologies are converging. One strand of this convergence is the demand placed on lithography systems by the integrated circuit industry. Another avenue is NEMS. Lithography techniques can be adapted to produce nanostructures but there are also some micromachining techniques covered in Part I that can be adapted to produce nanostructures. Nanolithography The principal tool for nanolithography was covered in Chapter 1 direct-write e-beam lithography. This can be used to pattern structures down to 10-nm minimum feature size but there are several limits to this. Highest resolutions are achieved with thin resist films therefore the processes employed to form structures have to take this into account harsh etches for instance have to be used with care . UV Photolithography for Nanostructures The use of UV .
