SiNx TEOS SiO2 Si
SiO removed in 1%HF.2
h a
Si <110> wafer with 15 nm LPCVD SiN (silicon rich nitride) and 80 nm TEOS annealed at 900 C for 1 hr in a N atmosphere tube. x 2 o SiN removal in 85% H PO @ . Si etching in OPD4262. x 3 4 180 C o g TEOS removal in 1%HF.
The substrate is dry oxidized at 950 C.o
f
SiN undercut etching in 85% . x H PO acid @180 C 3 4 o e S i e t c h i n g i n O P D 4 2 6 2 . d
SiN etching in 85% H PO acid @180 C.x 3 4 o
c
Patterned by normal photolithography of 4 µm gratings. TEOS etching in 1%HF.
b
To facilitate demolding, before imprint, the wafer template is treated with 1H,1H,2H, 2H-perfluorodecyltri-chlorosilane from a gas phase under vacuum condition in a desiccator. The imprint process is performed onto a device wafer coated with an imprint polymer, both mr-I 7010E and PMMA, using an Obducat T-NIL machine.
Si nanoridge with a depth of 100 nm and width down to 10 nm.
An ‘overview’ of Si nanoridges.
UNIVERSITY OF TWENTE
Silicon Ridge Nanofabrication by Advanced Edge
Lithography for Sub-10 nm NIL Applications
1,2 1 1 1 2
1
1 2
Yiping Zhao, Erwin Berenschot, Henri Jansen, Niels Tas, Jurriaan Huskens, Miko Elwenspoek
Transducers Science and Technology, Molecular Nanofabrication, MESA+ Institute for Nanotechnology, University of Twente,
POBox 217, 7500AE, Enschede, the Netherlands
A new nanofabrication scheme is presented to form stamps useful in thermal nanoimprint lithography (T-NIL). The stamp is created in <110> single crystalline silicon using a full-wet etch-procedure including local oxidation of silicon (LOCOS) and employing an adapted edge lithography (detailed review of edge lithography can be found in reference [1]) on top of conventional photo-lithography. Ridges down to 10 nm in width have been produced. The silicon ridges have no inbuilt stress and are therefore less fragile than previously fabricated oxide ridges [2,3]. The ridge sample is used as a template in T-NIL and a full 100 mm wafer size imprint has been successfully carried out in both polymethyl-methacrylate (PMMA) and mr-I 7010E polymer. Moreover, the imprinted pattern in PMMA is subsequently transferred into a device wafer. technique
Experimental
Nanoimprint
Pattern Transfer
Acknowledgment
References
Si Nanoridges
Introduction
The grating pattern is transferred from PMMA into the silicon device wafer. The scallops are caused by the pulsed mode RIE procedure (SF /C F ) and can be reduced by proper tuning of the etch tool.
6 4 8
SEM pictures of imprint in mr-I 7010E
Mark Smithers is acknowledged for his help in taking the SEM pictures. The project is financed by Nanoned through Strategic Research Orientation (SRO) program Nanofabrication at the MESA+ Institute for Nanotechnology at the University of Twente.
[1] Gates, B. D.; Xu, Q.; Stewart, M.; Ryan, D.; Willson, C. G.; Whitesides, G. M., , 105, (4), 1171-1196.
[2] Haneveld, J.; Berenschot, E.; Maury, P.; Jansen, H. 2006, 16, S24.
[3] Zhao, Y.; Berenschot, E.; Boer, M. d.; Jansen, H.; Tas, N.; Huskens, J.; Elwenspoek, M.
2008, 18, (6), 064013
Chem. Rev. 2005
Journal of Micromechanics and Microengineering
Journal of Micromechanics and Microengineering
