Additive, nanoscale patterning of metal films with a stamp and a surface chemistry mediated transfer process: Applications in plastic electronics

Abstract

We describe a method for contact printing metal patterns with nanometer features over large areas. This nanotransfer printing ͑nTP͒ technique relies on tailored surface chemistries to transfer metal films from the raised regions of a stamp to a substrate when these two elements are brought into intimate physical contact. The printing is purely additive, fast ͑Ͻ15 s contact time͒, and it occurs in a single processing step at ambient conditions. Features of varying dimensions, including sizes down to ϳ100 nm, can be printed with edge resolution better than 15 nm. Electrical contacts and interconnects for high-performance organic transistors and complementary inverter circuits have been successfully fabricated using nTP.Advanced techniques for nanofabrication are in widespread use for research in biology, physics, chemistry and materials science. They are also essential manufacturing tools for electronics, photonics and many other existing and emerging areas of technology. Established nanolithographic methods ͑e.g., electron-beam lithography, deep ultraviolet photolithography, etc.͒ require elaborate, expensive systems that are capable of only patterning a narrow range of specialized materials over small areas on ultraflat surfaces of rigid inorganic substrates. These limitations have created substantial interest in alternative techniques, such as those based on forms of contact printing, molding, embossing, and writing. 1,2 Although the basic operating principles of these techniques are conceptually old, recent research has demonstrated that their resolution can be extended into the micron and nanometer regimes by combining them with advanced materials and processing approaches. For example, elastomeric stamps and self-assembled monolayer inks 3 form the basis of a relatively new high-resolution printing technique. 4,5 This method, known as microcontact printing ͑CP͒, is rapidly becoming important for a range of applications in biotechnology, 6 plastic electronics, 7,8 and fiber optics 9 where the relevant patterning requirements cannot be satisfied easily with conventional methods. Although the resolution of CP is only ϳ0.25 m, this method and other emerging printing techniques, such as those that rely on imprinted polymer resists 10 and cold-welded metals, 11 offer fast and low-cost approaches for patterning flat or curved surfaces over large areas in a single processing step. While these methods appear to be useful for many patterning tasks, they are all generally subtractive in operation, i.e., they typically require the use of sacrificial resists, etching procedures or postpatterning deposition steps.In this letter we describe a purely additive printing tech-nique that has nanometer resolution. The method, which we refer to as nanotransfer printing ͑nTP͒, allows us to transfer metal films from the raised regions of a stamp onto various oxide surfaces. Using nTP, we have been able to transfer metal patterns from elastomeric ͓e.g., poly͑dimethylsiloxane͒ ͑PDMS͔͒ as well as hard ͑e.g., GaAs͒ stamps onto both conf...

Fabricating nanowire devices on diverse substrates by simple transfer-printing methods

“…The three transfer-printing methods basically rely on the differences in adhesion to transfer NWs, metal films, and even entire NW devices from weakly adhesive donor substrates to more strongly adhesive receiver substrates when these two substrates are brought into close physical contact. Previously reported transfer-printing methods, such as microcontact printing, nanoscale-transfer printing, and metal transfer printing (16,(19)(20)(21)(22)(23), have been used mainly to transfer metal films to receiver substrates by using PDMS stamps. Our methods significantly broaden the transferred substances from metals to the entire NW devices with not only PDMS but also tapes.…”

“…Correspondingly, a strong adhesion between the metal electrodes and the receiver substrate is essential for reliable transfer and the robustness of the final devices. Although chemical or plasma treatments can enhance adhesion between Au or Pd films and polymers (20,29), these treatments can change the surface chemistry of NWs and cause surface damage. Instead, we added a layer of Ti (5 nm) to the top of the metal contact during the metal evaporation step to enhance the adhesion between the metal electrodes and PDMS (20) while avoiding any damage to the NWs.…”

Requerimientos de Energía en los Procesos de Fabricación a Nanoescala

“…Aquí, un material deseado se evapora en un sello o molde y luego se transfiere a un sustrato planar (Loo et al, 2002) (Jo et al, 2005). La resolución del nCP pueden ser de hasta 40nm.…”

Sub-Micrometer Patterning Using Soft Lithography

“…Using surface chemistry, it is possible to design interfacial glue and release layers on both substrate and stamp, respectively. Nanotransfer printing (nTP) [109][110][111][112][113][114] -a variant of µCP that has been developed by Rogers and co-workers -involves coating of a topographic stamp with a thin film of metal, which is released as a continuous layer or in the form of individual features when brought in contact with a proper substrate. Interfacial chemistries that have been used to this end include covalent bonding of coinage metals via thiol-terminated SAMs as well as condensation of hydroxyl-terminated oxides [109].…”