Application of Soft Lithography for Nano Functional Devices

Abstract

Since photolithography method that is for producing minuteness electronic devices was developed, attempts against the new methods are progressing constantly as increasing demands for the electronic devices. Currently, because of the resolution required for the integrated element is decreased to below 100 nm, the lithography method using ultraviolet rays is developed as various methods like EUV(Extreme UV), X-ray, E-beam lithography. However, the methods mentioned previously are basically non-environmental friendly, and the development of photoresist that reacted on the source should be preceded. Also, it has limitations such as substrate and material selections, low throughput and high cost of methods. To overcome these limitations and guarantee the high throughput, the soft lithography method is a new counter plan, so a lot of researches are executed. This indicates the producing technique that making patterns with mechanical method by using the master of polydimethylsiloxane (PDMS) stamp, so it has advantages to micro and nano structure patterning on the substrate that is not uniform than photolithography producing technique. Specially, it is useful to produce of optics, mechanics and heat fluid structure of MEMS/NEMS. The detail methods related to nano imprint lithography (NIL) and nano moldings, and each of them are effected on the producing structure that size of between 25 ~ 100 nm, 10 ~ 100 nm, respectively. NIL is the technique that can effectively produce nano pattern that line width below 100 nm, the limitation of UV lithography, and nano contact printing method produces and uses the stamp with polymer such as PDMS by using patterned master by electron beam, and after transfer to the self-assembled monolayer (SAM) substrate that created by contacting of the stamp that has ink by arranging ink element on the stamp and substrate, use them in the wet etch mask to produce the structure. So, we fabricated gas chamber that is for collecting gas diffused on the skin, optical waveguide, and pixel definition for polymer light-emitting diode (PLED) by using above mentioned methods and evaluated the possibilities. Soft Lithography mentioned above can overcome the resolution limitation that photolithography method has, and the method is simple and it has advantages on cost saving. Also, like lens and optical fiber, it is available on the method in large area like non planar surface, so it can be applied to the not only cell biology industry but microelectronics, optics and display areas.