Fabrication And Application Of A Dual-Responsive And Degradable Resist

Nanoimprint lithography (NIL) is the most promising and new lithography technology for fabricating integrated circuits and plays an important role in the progress of information technology, which has overcome the limitation of shortest exposure wavelength in traditional optical lithography. In order to improve the service life of NIL molds through solving the problem of interface and making the NIL molds refreshed easier to decrease production cost and pollution, we have developed a degradable photoresist that is responsive to pH and ultraviolet light (UV). This dual-responsive resist can be photocurable using thiol-ene polymerization and photodimerization of coumarin moieties to form cross-linked networks whose backbones contain hydrolysable anhydride groups and photoreversible crosslinkers. Then, it was used to fabricate micro-patterns.Firstly, we have designed and synthesized a photoreversible crosslinker named 5,7-diacryloyloxy-4-methylcoumarin (DAMC), whose structure was characterized by NMR, FTIR, mass spectrum and elemental analysis. Then,it was mixed with acrylic anhydride (ALA), 3,6-dioxa-1,8-dithiooctane(EGDT), and photoinitiator 2,2-dimethoxy-1,2-diphenylethanone(DMPA) to constitute the dual-responsive and degradable photoresist.Secondly, the chemical and physical properties of this photoresist were measured such as reaction kinetics, volume shrinkage, transparency, thermal properties, surface performance. Its degradation performance was studied by mass loss and fluorescence spectrum in the solution with various pH values,and the relationship between its photoreversibility and degradation was also studied immediately.Lastly, we have studied the pattern transfer property of the photoresist and obtained the replicas of micro-patterns with high resolution by nanoimprint lithography and UV lithography. Besides, the fluorescent micro-patterns with different colors were also obtained due to the fluorescence characteristics of coumarin.