Research On The Nano-direct Writing Process Technology Using Fountain Pen Nanolithography

Micro/Nano technology is a multi-disciplinary crossing high-tech field that shows great vitality and is listed as one of the important frontier of future technology. Scanning probe lithography, which based on SPM, is a kind of simple and flexible method to produce micro/nano materials and has got rapid development in recent years. As a new scanning probe technology based on AFM, Fountain pen nanolithography(FPN) possesses outstanding performances such as high accuracy and resolution, strong operability, general environment requests, continued writing and so on. FPN has been used to place a variety of inks in spatially precise locations on different substrates, write different patterns and fabricate high accurate devices. And FPN has a broad application prospect in biology and microelectronics.Due to the lack of studying controlled deposition of FPN, the working progress of FPN should be studied firstly. The formation and working mechanism of capillary force, which provide the theoretical basis for the mechanism of FPN, are analyzed. According to the strategy above, three steps of the FPN progress including the formation of the liquid bridge between the tip and substrate, the transfer of ink molecules in the liquid bridge and the diffusion in the substrate, are studied. And the contact force between the tip and substrate is analyzed and modeled.Then experiments of FPN writing with silver nanoparticle ink on gold substrate are carried out. The influences of various parameters on the diameters of dots and the sizes of lines are discussed, respectively. The diameters of dots are mainly affected by the contact time while the sizes of lines are affected by various parameters including the aperture size of the probe, writing mode, writing speed, the set point, the applied voltage and so on. On the basis, the optimal parameters of FPN, namely as probe aperture of 200 nm, writing speed of 2μm/s and setpoint of 0.2V, are chosen to write complex patterns including letters“S” “Z” “D” “X” and star on the substrate.Finally, lines are written on non-conductive mica substrate using FPN, the topography of lines are characterized by means of Atomic force microscopy(AFM) and scanning electron microscopy(SEM). Using Keithley4200 SCS and Cascade 150, we are able to perform two-probe and four-probe resistance measurements to analyze the resistivity of lines. Compare to two-probe resistance measurement, four-probe resistance measurement can accurately measure the resistivity of single line. The resistivity measured is 4.82μΩ·cm, slightly larger than the bulk resistivity of silver. The Increased contribution of surface scattering effects to the resistivity due to the nanoscale proportions of the wires...