Abstract
Conventionally, the master stamp for nanoimprint lithography (NIL) is made of silicon by e-beam lithography when pursuing very high precision, which needs a great amount of time and cost for manufacturing. In addition, diverse applications require variable linewidth and pitches for obtaining demanded performance. This study proposes an efficient method for making working stamps with tunable linewidth or pitch using the identical master stamp. The pattern of the master stamp was, first, replicated to the imprint resist, underneath which silicon oxide as the release layer was deposited on silicon wafers. Then, resist trimming process was applied to reduce the linewidth of imprinted resist structures from 57 nm to 37 nm by controlling the etching time and double oblique deposition was utilized (by controlling the deposition angle and thickness) for making symmetric aluminum onto the specific region of the resist grating, herein, the top and sidewall regions. The thicknesses of deposited aluminum ranged from 10 nm to 20 nm, which resulted in different linewidth of the grating. Finally, the required duty cycle of the working stamp was formed on the substrate by reactive ion etching using the resist and aluminum as the etching mask, which was followed by immersing the etched substrate in buffered oxide etch solution to remove silicon oxide and the material above. Compared with previous researches, this proposed technique could provide the wide linewidth adjustment range at least 65% of the original one. In summary, the study can fabricate the working stamp either the identical pattern of the master one, or tunable linewidth or pitches, even though the original one is contaminated after a number of imprints. Instead of using CVD for depositing metallic etching mask that is usually accompanied with high process temperature, this paper employed PVD for providing more adaptability of handling polymeric substrates for the applications of flexible electronics.