| AVS 54th International Symposium | |
| Plasma Science and Technology | Wednesday Sessions |
| Session PS2-WeA |
| Session: | Plasmas and Polymers |
| Presenter: | D.Y. Lee, University of Maryland College Park |
| Authors: | D.Y. Lee, University of Maryland College Park G.S. Oehrlein, University of Maryland College Park D.R. Hines, University of Maryland College Park C.M. Stafford, National Institute of Standards and Technology C.L. Soles, National Institute of Standards and Technology D.M. DeLongchamp, National Institute of Standards and Technology E.K. Lin, National Institute of Standards and Technology |
| Correspondent: | Click to Email |
Recently, nanoimprint lithography (NIL) and nanotransfer printing (NTP) have attracted much attention because these techniques can be used to fabricate submicron structures at a lower cost and with higher throughput than conventional photo and electron-beam lithographies. For NTP involving thermoplastic polymer materials, a low processing temperature (below the glass transition temperature (Tg) of the polymers) is attractive to minimize distortion of printed layers and to control volume shrinkage of the polymers. One key factor influencing pattern transfer is the strength of adhesion between a printed polymer layer and a thermoplastic substrate. In this study, we systematically survey the factors controlling the adhesion between two polymer surfaces treated by plasma activation. Plasma treated poly(methyl methacrylate) (PMMA) films were transfer printed onto plasma treated polyethylene terephthalate (PET) substrates using NTP at 80 and 100 °C, 500 psi for 3 min. An inductively coupled plasma (ICP) process employing either O2 or N2 was used for surface activation of the polymers. In addition, we compared direct and remote plasma with gap structure to investigate the effect of ion bombardment on interfacial adhesion. With plasma activated samples, pattern transfer using NTP was possible at temperatures below the glass transition temperature (Tg) of both polymers. The enhancement of the polymer-polymer adhesion has been attributed to terminated functional group generated by the plasma surface activation and it mainly depends on the processing temperature and chemical composition of polymer and plasma chemistry. In-situ ellipsometry was used to measure changes in the refractive index and the thickness of the surface modified layer. Atomic force microscopy (AFM) and x-ray photoelectron spectroscopy (XPS) measurements were performed on the plasma treated polymers immediately after treatment to minimize contamination effects due to atmospheric exposure. Surface energy and water contact angle of the modified films were also measured. Adhesion was evaluated both from a wedge test and from the NTP transfer efficiency, i.e., the aerial % of PMMA film successfully transferred to the PET substrate.