Fluorescent tag based metrology for self-assembled molecular devices

Directed self-assembly is being researched as a promising alternative to manufacturing nanoscale-devices. Properly designed self-assembly methods may reduce the high cost of manufacturing nanoscale-devices using lithography, at the same time pushing the device dimensions to the realm of molecular. In this paper, a method of molecular device self-assembly is discussed. Because of the uniqueness of this method, new metrology challenges are likely to be encountered in manufacturing. To monitor the self-assembly process, in-line metrology systems will be needed to inspect nanotubes / nanowires, measure dimensions, test chemical properties, and provide fast feedback in real time. To meet this requirement, new techniques of inicrography are needed to achieve molecular level resolution without complicated sample preparation. Also, because of water or other solvent based environments likely for self-assembly, the future metrology systems may be required to operate in environments significantly different from those found in conventional semiconductor processing. One possible method is to exploit self assembly methods as an aid to metrology. By using fluorophores or quantum dots to tag various elements in self assembled structures we have developed a means whereby we can assess the accuracy of the self assembly process and make determinations of error rates. The paper will discuss the available technologies for suitability, drawbacks and promise to meet metrology requirements for self-assembled molecular device fabrication.