The replication of three dimensional structures using UV curable nanoimprint lithography (original) (raw)
2008, Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures
The study investigates the use of ultraviolet nanoimprint lithography ͑UV-NIL͒ for patterning three dimensional ͑3D͒ structures. Generating the 3D structures is a challenging task especially on an insulating substrate such as quartz. These transparent molds are essential for the UV-NIL process. The 3D profiles were created on the negative tone photoresist, Microresist ma-N2403 using a Raith150 electron beam lithography ͑EBL͒ tool in a single step variable dose controlled exposure. The developed 3D resist profiles subsequently were utilized as the 3D masking layer. The 3D patterns were transferred into the quartz mold substrates by a single-step reactive ion etching ͑RIE͒. The replication of the 3D mold structure by using the UV-NIL technique requires a two-step imprint process. The master mold profile was replicated onto a Microresist Ormocomp US-S4 resist on the first imprint to become the soft mold. The cured Ormocomp soft mold, subsequently was used as a mold for replicating the 3D pattern structures on the Microresist mr-UVCur06 resist in the second imprint step to create a positive replica of the original mold. A test pattern of a 3D pyramid-shaped array with multilevel features was successfully been replicated using this technique. The replicated 3D pattern on the resist could be utilised as the final 3D masking layer for the pattern transfer onto final substrate using RIE.
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A Three‐Dimensional Ultraviolet Curable Nanoimprint Lithography (3D UV‐NIL)
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The study investigates the use of ultraviolet nanoimprint lithography (UV-NIL) for patterning three dimensional (3D) structures. Generating the 3D structures is a challenging task especially on an insulating substrate such as quartz. The transparent mold is essential for the UV-NIL process. The 3D profiles were created on the negative tone photoresist, Microresist ma-N2403 using a Raith150 electron beam lithography (EBL) tool in a single step variable dose controlled exposure. The developed 3D resist profiles subsequently were utilised as the 3D masking layer. The 3D patterns were transferred into the quartz mold substrates by a single-step reactive ion etching (RIE). Surface roughness below 2 nm has been achieved when the RIE process pressure is lower than 6 mTorr. The replication of the 3D mold structure by using the UV-NIL technique requires a two-step imprint process. The master mold profile was replicated onto a Microresist Ormocomp US-S4 resist on the first imprint to become the soft mold. The cured Ormocomp soft mold, subsequently was used as a mold for replicating the 3D pattern structures on the Microresist mr-UVCur06 resist in the second imprint step to create a positive replica of the original mold. A test pattern of a 3D pyramid-shaped array with multilevel features was successfully been replicated using this technique. The replicated 3D pattern on the resist could be utilised as the final 3D masking layer for the pattern transfer onto final substrate using RIE.
28 Three-Dimensional Patterning using Ultraviolet Nanoimprint Lithography
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Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures, 2007
In three dimensional ͑3D͒ printing the most challenging aspect is in the mold making process. The authors have developed a process for making 3D structures in a simple two-step process. The 3D profiles are created on a negative tone photoresist using electron beam lithography with variable dose and critical-energy electron beam exposure. Resist contrast profiles have been obtained with a negative tone photoresist from Microresist ͑ma-N2403͒ and subsequently have been utilized as the 3D masking layer. The 3D patterns have been transferred into a quartz mold by single-step reactive ion etching ͑RIE͒ with suitable resist-to-substrate selectivity. The precision of the fabricated structures is important, especially for micro-optic devices. Surface roughness below 2 nm has been achieved when the RIE process pressure is lower than 6 mTorr. The differences between intended and final dimensions are also analyzed. By employing this technique, complex structures for 3D quartz molds can be fabricated with simplified steps.
Journal of Vacuum Science & Technology B, Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phenomena, 2011
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Applied Physics A, 2015
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Fabrication process of 3D-photonic crystals via UV-nanoimprint lithography
SPIE Proceedings, 2007
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