The authors present a novel global contact planarization technique based on the spin-on-glass material hydrogen silsequioxane (HSQ) and demonstrate its excellent performance on patterns of 70 nm up to several microns generated by UV-based nanoimprint lithography. The HSQ layer (165nm) is spin coated on the imprinted organic layer and planarized by pressing it with a flat wafer at room temperature. Before retracting the planarization wafer, the HSQ is hardened by baking at 120 or 70°C, depending on the underlying material. Fluorine-based reactive ion etching (RIE) is used to etch the HSQ (etch-back) down to the top of the features in the organic imprint layer. Subsequently, oxygen-based RIE is used to etch the organic imprint layer in the exposed regions, thereby transferring the imprinted pattern down to the substrate. The etch selectivity between the HSQ and the underlying layers is found to be more than 1:100, enabling very accurate pattern transfer with excellent critical dimension control and well-defined undercut profile suitable for further metal liftoff processes. The dependence of the contact planarization quality on the HSQ spinning speed and pressure is investigated, achieving a global planarization degree as good as 93%, an improvement of 45% compared to standard spin-coating planarization.

1.
S.
Wolf
,
Silicon Processing for the VLSI Era-Process Integration
(
Lattice
,
California
,
1990
), Vol.
2
, p.
229
.
2.
D. L. W.
Yen
and
G. K.
Gopal
,
Proceedings of the 5th International IEEE VMIC Conference
(IEEE, New York,
1998
).
3.
4.
S.
Ramaswami
and
A.
Nagy
,
J. Electrochem. Soc.
139
,
591
(
1992
).
5.
W. -S.
Shih
,
J.
Yota
,
H.
Ly
,
K.
Itchhaporia
, and
A.
Smith
,
Technical Digest of the CS MANTECH Conference
(
CS Mantech
,
Beaverton, OR
,
2007
).
6.
Y.
Igaku
,
S.
Matsui
,
H.
Ishigaki
,
J.
Fujita
,
M.
Ishida
,
Y.
Ochiai
,
H.
Namatsu
,
M.
Komuro
, and
H.
Hiroshima
,
Jpn. J. Appl. Phys., Part 1
41
,
4198
(
2002
).
7.
K.
Nakamatsu
and
S.
Matsui
, in
Nanomanufacturing Handbook
, edited by
A.
Busnaina
(
CRC
,
Boca Raton
,
2007
), Vol.
2
, pp.
162
180
.
8.
X.
Sun
,
L.
Zhuang
,
W.
Zhang
, and
S. Y.
Chou
,
J. Vac. Sci. Technol. B
16
,
3922
(
1998
).
9.
S. V.
Sreenivasan
,
A.
McMackin
,
F.
Xu
,
D.
Wang
, and
N.
Stacey
,
Micro Magazine
23
,
37
(
2005
).
10.
P.
Maury
,
M.
Peter
,
V.
Mahalingam
,
D. N.
Reinhoudt
, and
J.
Huskens
,
Adv. Funct. Mater.
15
,
451
(
2005
).
11.
Y.
Yoon
,
C.
Choi
,
Y.
Oh
,
D.
Hong
,
S.
Jin
, and
F. E.
Talke
,
IEEE Trans. Magn.
45
,
3527
(
2009
).
You do not currently have access to this content.