Polyphenol derivatives of porphyrins containing fluorene units: Synthesis and positive-tone photoresists for 22-nanometer lithography

Article abstract of DOI:10.1134/S0012500816060045

A new strategy was proposed for the synthesis of polyphenol derivatives of fluorene-containing porphyrins to be used as the base for positive-tone photoresists for lithography with exposure at 13.5 nm wavelength, which allow fabrication of microchips with a size of down to 22 nm. Polyphenols based on fluorenecontaining porphyrins were synthesized for the first time. It was shown that these polyphenol derivatives can be used to obtain positive-tone photoresists with a resolution of 22 nm.

Full text of DOI:10.1134/S0012500816060045

ISSN 0012ꢀ5008, Doklady Chemistry, 2016, Vol. 468, Part 2, pp. 174–178. © Pleiades Publishing, Ltd., 2016.
Original Russian Text © A.Ya. Vainer, K.M. Dyumaev, A.M. Kovalenko, Ya.L. Babuskin, S.A. Krichevskaya, G.R. Lubenskii, 2016, published in Doklady Akademii Nauk, 2016,
Vol. 468, No. 5, pp. 525–529.
CHEMISTRY
Polyphenol Derivatives of Porphyrins Containing Fluorene Units:
Synthesis and PositiveꢀTone Photoresists
for 22ꢀNanometer Lithography
A. Ya. Vainer, Corresponding Member of the RAS K. M. Dyumaev,
A. M. Kovalenko, Ya. L. Babuskin,
S. A. Krichevskaya, and G. R. Lubenskii
Received January 26, 2016
Abstract—A new strategy was proposed for the synthesis of polyphenol derivatives of fluoreneꢀcontaining
porphyrins to be used as the base for positiveꢀtone photoresists for lithography with exposure at 13.5 nm waveꢀ
length, which allow fabrication of microchips with a size of down to 22 nm. Polyphenols based on fluoreneꢀ
containing porphyrins were synthesized for the first time. It was shown that these polyphenol derivatives can
be used to obtain positiveꢀtone photoresists with a resolution of 22 nm.
DOI: 10.1134/S0012500816060045
The extreme ultraviolet (EUV) nanolithography development of new effective photoresists for EUV
using the radiation wavelength of 13.5 nm is quite
promising for the manufacture of microchips with 22ꢀ
nanometer standards [1, 2]; however, development of
EUV lithography with such characteristics proved to
be fairly expensive and is now substantially hampered.
lithography resulted in selection of aromatic hydroꢀ
carbons such as fluorenes and porphyrins possessing
unique chemical, light, and thermal stability. Funcꢀ
tionalization of these aromatic structures can lead to
new compounds with a set of valuable properties for
the development of innovative products. In particular,
recently reported fluoreneꢀcontaining porphyrins [3]
are of practical interest for the manufacture of lightꢀ
emitting materials.
A highly complicated task in the development of
this type of lithography on an industrial scale is the
design of resists adequately meeting the high requireꢀ
ments to parameters such as light sensitivity, resoluꢀ
tion, line edge roughness, and plasma resistance.
These properties are balanced in a certain way:
improvement of one parameter is accompanied by
deterioration of other parameters [1]. The few existing
resists for EUV lithography described in the accessible
literature [1] do not meet the existing requirements.
These systems are usually designed in terms of the
concept of molecular resists [1, 2], according to which
they are formed from monodisperse lowꢀmolecularꢀ
weight polyphenol type organic compounds with high
filmꢀforming properties, glass transition temperature,
and thermal stability.
Here, we propose a new strategy for the synthesis of
polyphenol derivatives of fluoreneꢀcontaining porꢀ
phyrins as the base of positiveꢀtone photoresists for
lithography with exposure radiation at 13.5 nm, which
would allow the manufacture of microchips with sizes
of down to 22 nm.
We performed the first synthesis of new polypheꢀ
nols of the indicated chemical nature via successive
chemical transformations of 5,15ꢀbis[4'ꢀ(
di[9",9"ꢀbis(3",5"ꢀdimethoxybenzyl)fluorenylꢀ
2"]aminophenyl)]ꢀ10,20ꢀbis[4'ꢀ( 'ꢀdi(4"ꢀiodoꢀ
phenyl)aminophenyl)]porphyrin ( ), which we prepared.
N,N'ꢀ
Our search for aromatic compounds that could be
functionalized to give polyphenols promising for the
N,N
I
The phenolic hydroxyls in the synthesized fluoꢀ
reneꢀcontaining porphyrins were partly protected with
various acidꢀlabile groups. We evaluated the lithoꢀ
graphic parameters of the positiveꢀtone EUV resists
AllꢀRussia Institute of Medicinal and Aromatic Plants,
Russian Academy of Agricultural Sciences, ul. Grina 7,
Moscow, 113628 Russia
eꢀmail: nvbarannik@mail.ru
174

POLYPHENOL DERIVATIVES OF PORPHYRINS CONTAINING FLUORENE UNITS
175
based on the modified porphyrins during the formaꢀ (United States) chemicals were used. The successive
tion of topological structures with a size of down to
22 nm.
chemical transformations for the synthesis of polypheꢀ
nol fluorene porphyrin derivative are shown in
I
Unless otherwise specified, SigmaꢀAldrich Schemes 1 and 2.
a
b
J
RH2C
d
J
RH2C
RH2C CH2R
II
N
c
RH2C CH2R
IV
O
Br
e
B
CMe2
O CMe2
RH2C CH2R
RH2C
RH2C
III
OMe
OMe
N
R =
RH2C CH2R
V
CHO
Scheme 1.
Scheme 1 presents the synthesis of intermediate Kasei Kogyo Co. Ltd., Japan) in dimethyl sulfoxide
(DMSO) [4] to give 2ꢀiodoꢀ9,9'ꢀbis(3',5'ꢀdimethoxyꢀ
benzyl)fluorene (II). The latter product was converted
to 2ꢀ(4',4',5',5'ꢀtetramethylꢀ1',3',2'ꢀdioxaborolanꢀ2'ꢀ
yl)ꢀ9,9'ꢀbis(3',5'ꢀdimethoxybenzyl)fluorene (III) in
tetrahydrofuran (THF) according to procedure [5]. 4ꢀ
fluorene derivatives needed for the subsequent transꢀ
formations. The initial 2ꢀiodofluorene was prepared
by the procedure reported in [4]. This compound was
treated with 3,5ꢀdimethoxybenzyl bromide (Tokyo
Bromoꢀ[N,N'ꢀdi(9,9'ꢀbis(3',5'ꢀdimethoxybenzyl)fluꢀ
Molecular weights of the synthesized products
orenꢀ2'ꢀyl)]aniline (IV) was synthesized by procedure
[6]. The fluoreneꢀcontaining aniline obtained in
this way by procedure [3] was converted to benzaldeꢀ
Molecular weight, g/mol
Comꢀ
Formula
pound
found
*
calculated
hyde (V).
I
C192H158N8J4O16 3341.0704
3341.0617
592.4788
592.5468
1101.1632
1050.2728
4695.7416
4246.8747
Reagents and conditions: (a) J2, H5JO6, AcOH,
II
C31H29JO4
592.4756
592.5476
H2SO4, H2O, 110 C, 4 h, 78%; (b) 3,5ꢀdimethoxyꢀ
benzyl bromide, triethylbenzylammonium chloride,
50% aq. NaOH, DMSO, 22 С, 6 h, 67%; (c) nꢀBuLi,
THF, 2ꢀisopropoxyꢀ4,4,5,5ꢀtetramethylꢀ1,3,2ꢀdioxaꢀ
borolane, –78 С, 12 h, 72%; (d) 4ꢀbromoaniline,
CuCl, 1,10ꢀphenanthroline, KOH, toluene, 125 С,
12 h, 72%; (e) nꢀBuLi, –78 to+22 С, 4 h, DMF,
–78 С...+22 °C, 8 h, 58%.
°
III
IV
V
C37H41BO6
C68H62BrNO8
C69H63NO9
C316H274N8O32
1101.1598
1050.2744
4695.7438
4246.8753
°
°
VII
°
VIII C284H210N8O32
°
С
°
* MALDIꢀTОF.
°
DOKLADY CHEMISTRY Vol. 468
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176
VAINER et al.
N(Ar')2
CHO
+ 2
CHO
а
4
+ 2
N
H
N(Ar'')2
N(Ar')2
V
VI
NH
N
N
(Ar'')2N
N(Ar'')2
HN
I
N(Ar')2
b, c
(Ar''')2
N(Ar')2
(Ar''')
Ar'
(Ar''')
Ar'
NH
N
N
N
HN
N
(Ar''')
Ar'
Ar'
(Ar''')
VII–VIII
Ar' =
(Ar''')2
N(Ar')2
OH
R
R
R' =
Ar'' =
J
OH
Ar''' =
R'
R'
Scheme 2.
We synthesized (Scheme 2) porphyrin I for the first completed, pꢀchloranil (2,3,5,6ꢀtetrachloroꢀ1,4ꢀbenꢀ
time and used it as a new building block for the prepaꢀ
ration of polyphenol fluorene porphyrin derivatives.
zoquinone) was added to the reaction mixture. Then,
substituted fluorene moieties were introduced into
porphyrin I via the reaction of I with dioxaborolanylꢀ
containing fluorene III by procedure [9] using
dichloro[1,1ꢀbis(diphenylphosphino)ferrocene]palꢀ
ladium ([dppf]Fe]PdCl2) (Strem Chemical, United
State) as the catalyst. Porphyrin VII thus formed
Compound
[7] by condensation of pyrrole (Janssen Chimics, Belꢀ
gium), benzaldehyde ( ), and 4ꢀ[ 'ꢀdi(4'ꢀiodopheꢀ
I was prepared by a procedure reported in
V
N,N
nyl)amino]benzaldehyde (VI), which was prepared by
procedure [8]. The reaction was carried out in CH2Cl2
under argon using standard Schlenk technique. After
formation of the intermediate porphyrinogen was was subjected to exhaustive demethylation by proceꢀ
DOKLADY CHEMISTRY Vol. 468
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POLYPHENOL DERIVATIVES OF PORPHYRINS CONTAINING FLUORENE UNITS
177
dure [2] to give polyphenol fluorene porphyrin derivꢀ degree of substitution of phenolic hydroxyls in the
ative VIII
.
modified VIII was determined from the intensity
change of the proton signals of these groups at
10.24 ppm.
δ
Reagents and conditions: (a)
OEt2, CH2Cl2, 22 C, 8 h, then 45
(b) III, ([(dppf)Fe]PdCl2), KOAc, DMSO, 80
71%; (c) BBr3, CН2Cl2, 22 C, 3 h, 94%.
V
,
VI, pyrrole, BF3–
C, 1 h, 3.5%;
C, 6 h,
°
°
°
The positiveꢀtone photoresist film based on modiꢀ
fied porphyrin derivative VIII and triphenylsulfonium
perfluorobutanesulfonate as the acid photogenerator
(5% relative to the porphyrin weight) formed on a siliꢀ
con substrate from a solution in 1ꢀmethoxypropanꢀ
2ꢀol was exposed to EUV light (extreme ultraviolet
region) at 13.5 nm. The irradiation was performed on
a small exposure field pilot setup (Canon, USA) with
a numerical aperture of 0.3. The resist film was dried at
°
The newly synthesized compounds were purified
by preparative high performance liquid chromatograꢀ
phy (HPLC). The product structures were established
1
13
by MALDIꢀTOF mass spectrometry and H and C
NMR and IR spectroscopy and confirmed by analytiꢀ
cal HPLC and elemental analysis data. The table gives
the molecular weights of the products.
130
formed at 110
standard 2.38% aqueous solution of tetramethylamꢀ
minium hydroxide (NMDꢀ3 developer, Tokyo Ohka
Co., Japan).
°
С
for 90 s and the postꢀexposure drying was perꢀ
(90 s). The resist was developed by a
The analytical data were illustrated in more detail
in relation to the polyphenol fluorene porphyrin
derivative VIII. We indicated only those bands and sigꢀ
nals that have diagnostic value. For example, the IR
spectrum of compound VIII exhibits absorption bands
at 3311 and 1469 cm–1 (NH in the pyrrole moieties)
and a band at 1440 cm–1 (C=N in the same moieties).
°С
This resist has an extremely high resolution: topoꢀ
logical structures with line and gap widths of 22 nm
In the H NMR spectrum of VIII, the porphyrin were formed in a 50ꢀnm thick resist film. The line edge
1
moieties are responsible for the signals at –2.89 ppm
(2H, NH) and in the 8.75–8.92 ppm range ( –Н in
the pyrrole rings). The phenyl groups in the fluorene
side groups account for the proton signals at .79–
roughness was 3.2 nm, which is quite acceptable for
the fabrication of microchips with topological stanꢀ
dards of 20 nm [1, 2]. Attention is attracted by the
rather high light sensitivity of the developed EUV
resist (7.9 mJ/cm2). The photoresist has plasma resisꢀ
tance adequate to the modern nanolithography and
comparable with that attained in the plasma etching of
industrial positiveꢀtone novolacꢀbased photoresists.
β
δ
7
7.77, 7.68–7.66, 7.47–7.45, 6.85, 6.73–6.72, 6.69–
1
6.67, and 6.62–6.60 ppm. The H NMR spectrum
exhibits an intense signal at 10.24 ppm corresponding
to the phenolic hydroxyl protons, while the singlet at
δ
3.89 ppm, corresponding to methoxy group protons is
missing.
Thus, we synthesized for the first time a polyphenol
derivative of fluoreneꢀcontaining porphyrin via several
successive transformations of the initial porphyrin.
The phenolic hydroxyls in the resulting derivative were
partially protected by introducing two different types
of protective groups, pentaspiran and tertꢀbutyl
butyrate ones. The degrees of substitution of the pheꢀ
nolic hydroxyls in the porphyrin derivative by these
groups were 11 and 25 mol %, respectively. The modiꢀ
fied compound was shown to be suitable for the design
of promising positiveꢀtone photoresists exhibiting high
characteristics for EUVꢀnanolithography on exposure
to light at 13.5 nm in the manufacture of 20ꢀnanomeꢀ
ter generation microchips. The analytical procedures
were described in previous papers [2, 7].
13
The C NMR spectrum of modified porphyrin
VIII contains carbon signals at 151.7, 139.35, 127.65,
127.22, 125.95, 120.32, and 63.56 ppm for the fluoꢀ
rene moieties. The porphyrin macrocycles account for
a number of signals in this spectrum. In particular, the
mesoꢀcarbon atoms are responsible for 119.1, 123.1,
and 123.7 ppm signals. The signal at 117.3 ppm refers
to Cꢀ2 and Cꢀ5 pyrrole carbon atoms, while the signal
at 107.6 ppm is due to the Cꢀ3 and Cꢀ4 pyrrole atoms.
Considering the development of positiveꢀtone
EUV resists based on the polyphenol fluorene porphyꢀ
rin derivative VIII, we partly protected the phenolic
hydroxyls by successive introduction of two protective
groups—pentaspiran and tertꢀbutyl butyrate ones.
The degrees of protection of phenolic hydroxyls in
VIII by these groups were 11 and 25 mol %, respecꢀ
tively; the desired degree of protection was attained by
varying the amounts of the chloromethyl ether of penꢀ
taspiro[3.0.2.0.3.0.2.0.3.1]nonadecanꢀ19ꢀol [10] and
tertꢀbutyl 2ꢀbromobutyrate (Alfa Aesar, China),
respectively, added to the reaction mixture. The modꢀ
ification was accomplished by procedure [10]. The
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DOKLADY CHEMISTRY Vol. 468
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2016