SiNx TEOS SiO2 Si
SiO removed in 1%HF.2h
a
Si <110> wafer with 15 nm LPCVD SiN
(silicon rich nitride) and 80 nm TEOSannealed 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.
of
SiN undercut etching in 85%
.x H PO acid
@180 C3 4
oe
Si etching in OPD4262.d
SiN etching in 85% H PO acid @180 C.x 3 4
o
c
Patterned by normal photolithography of4 µm gratings. TEOS etching in 1%HF.b
To facilitate demolding, before imprint, the wafer template is treatedwith 1H,1H,2H, 2H-perfluorodecyltri-chlorosilane from a gas phaseunder vacuum condition in a desiccator. The imprint process isperformed onto a device wafer coated with an imprint polymer, bothmr-I 7010E and PMMA, using an Obducat T-NILmachine.
Si nanoridge with a depth of 100nm 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 Applications1,2 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 inthermal nanoimprint lithography (T-NIL). The stamp is created in<110> single crystalline silicon using a full-wet etch-procedureincluding local oxidation of silicon (LOCOS) and employing anadapted edge lithography (detailed review of edgelithography can be found in reference [1]) on top of conventionalphoto-lithography. Ridges down to 10 nm in width have beenproduced. The silicon ridges have no inbuilt stress and are thereforeless fragile than previously fabricated oxide ridges [2,3]. The ridgesample is used as a template in T-NIL and a full 100 mm wafer sizeimprint has been successfully carried out in both polymethyl-methacrylate (PMMA) and mr-I 7010E polymer. Moreover, theimprinted pattern in PMMA is subsequently transferred into a devicewafer.
technique
Experimental Nanoimprint
Pattern Transfer
AcknowledgmentReferences
Si NanoridgesIntroduction
The grating pattern istransferred from PMMA intothe silicon device wafer. Thescallops are caused by thepulsed mode RIE procedure(SF /C F ) and can be
reduced by proper tuning ofthe etch tool.
6 4 8
SEM pictures of imprint in mr-I 7010E
Mark Smithers is acknowledged for his help in taking the SEMpictures. The project is financed by Nanoned through StrategicResearch Orientation (SRO) program Nanofabrication at theMESA+ 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. 2005Journal of
Micromechanics and Microengineering
Journal of Micromechanics andMicroengineering