Joining Dip-Pen Nanolithography and Microcontact Printing Into a Nanolithographic Process: From Engineering Design to Parallel Fabrication

Abstract

One nanomanufacturing concern is the precise, controlled deposition of materials at the nanoscale, commonly referred to as nanolithography. One promising technique, dip-pen nanolithography (DPN), can deposit a multitude of organic and inorganic materials. Simple and accurate, DPN uses an atomic force microscope (AFM) cantilever to deposit inks under ambient conditions. However, from a manufacturing perspective, DPN’s main drawback is its inherent serial nature. Another more promising technique is microcontact printing (μCP), which can repeatedly cover larger areas in a parallel fashion. As interest in nanomanufacturing processes increases, the demand for user-friendly, automated nanolithography processes become a priority. This paper presents a nanolithography process that begins with a design plan and ends with a manufactured product using a unique progression from design environment to serial nanolithographic technique to parallel nanolithographic technique. The process begins with the creation of a design template using conventional CAD software. The design template is then transformed into a vector signal that serves as input to the AFM used in the DPN process. A custom AFM has been designed for nanometer scale precision in three axes using real-time, digital feedback methodologies. Using the appropriate DPN ‘ink’ coated on the AFM cantilever, the design template is automatically reproduced onto the substrate, where the appropriate features are filled in with predetermined chemical functionalities. Specifically, alkanethiol chemistry is used as a resist for wet chemical etching of a gold substrate to create raised surface features which mimic the original design template. This substrate is used as a positive mask for the creation of polymeric stamps for μCP. These stamps are then used to create replicas of the original design template in a parallel fashion and qualitatively examined for their completeness and reproducibility.