A macro-micro motion system for a scanning tunneling microscope

As nano-lithography technology improves, more companies and research groups have the capability to create nano-scale structures. Scanning tunneling microscopes (STMs) are commonly used to create these structures and evaluate them after-ward. One difficulty is that these nano-structures are difficult, to find on a one centimeter-size die cut from a silicon wafer without very specialized hardware and post-processing and analysis. The National Institute of Standards and Technology (NIST) is conducting research into developing a macro-micro motion system that would allow these nano-structures to be more effectively located and identified on the die. An XY stage system using linear piezo actuators will perform the macro motion by moving the sample to where the STM tip can scan a particular region of the die to make an analysis. The STM tip would then perform the micro motion by scanning the region for the nano-structure. A vibration isolation system has been designed for this macro-micro motion system using springs and eddy current dampers. This vibration isolation system will isolate the entire system from the outside world and the individual components from each other. Along with the motion systems described above, a high-precision interferometer system will be installed to independently monitor a flexure driven stage for the STM tip. A graphical programming system has been developed for controlling the motion of the STM tip. All of these systems - the macro-micro motion system, the vibration isolation system, the interferometer system, and the graphical programming system - combine to form the initial steps toward coordinated closed-loop control of the STM.