Micro-structure Patterning Technology&Its Application In Printed Electronics

In this thesis, we focus on the research about laser direct writing patterningtechnology and its application in the fabrication of printed electronic devices. Recently,owing to the continuous emergence of new organic semiconductor materials, it is possibleto make electronic devices by some low-cost printing approaches. Printed electronicdevices, such as flexible paper, flexible displays and flexible illuminating diodes, havebeen regarded as the next generation of semiconductor manufacturing technology. One ofthe key components in printed electronics, known as transparent conductive film, hasattracted wide attention in both academic and industrial society. More and more researchersare devoted to the development of novel materials, equipments and process for therealization of mass-production of flexible transparent conductive film with low-cost, highefficiency and stability. However, the state-of-art techniques can not satisfy the criticaldemand in printing electronics yet.In this thesis, with the combination of micro-scratching technique and nanoimprintlithography, a novel conductive transparent film on PET substrate, is realized by patterningwith fine meshes, which width is2.5μ m, utilizing our parallel laser direct writingtechnology based on spatial light modulator. At first, a photomask with designed pattern isdirect wrote on glass coated with Cr as mask, the z-axis correction technique and the flightstroboscopic tiled technique are adopted in the exposure process to guarantee the accuratestitching between neighbor patterning areas with high-efficiency. We also investigate theinfluence of the phase modulation of in digital mirror devices (DMD) under theillumination of coherent lights on the patterning process theoretically and experimentally. The results show that the micromirror deflection angle error (±1o) of DMD can greatlyaffect energy utilization ratio in system. Secondly, a soft PDMS template is obtained by thereplication of surface texture on photoresist patterned by contact UV exposure lithography.The haze of two types of samples, fabricated by negative and positive photoresist, aremeasured. The experimental results suggest that the haze of former one(8%) is only halfthat of the latter one (19%). Thirdly, the patterned surface texture on PDMS is transferredto PET substrate by UV curable nanoimprint lithography. Finally, silver is filled in thetrenches in above samples by micro-scratching and transparent conductive film is obtained,which sheet resistance is3Ω/. The depth, width of trenches and the surface physicalhydrophilicity has great influence on the conductivity.In this thesis, with the technology of micro-scratching and nanoimprint lithography,we achieve the production of metal mesh flexible transparent conductive film with highefficiency, low cost and high precision. We discussed the basic fabrication process ofprinted electronics, provides a process basis for achieving the application ofmicro-structure patterning technology in printed electronics and further study in process ofprinted electronics.