U.S. patent application number 15/475630 was filed with the patent office on 2018-10-04 for acid-cleavable monomer and polymers including the same.
The applicant listed for this patent is ROHM AND HAAS ELECTRONIC MATERIALS LLC. Invention is credited to Emad Aqad, James W. Thackeray.
Application Number | 20180284605 15/475630 |
Document ID | / |
Family ID | 63668804 |
Filed Date | 2018-10-04 |
United States Patent
Application |
20180284605 |
Kind Code |
A1 |
Aqad; Emad ; et al. |
October 4, 2018 |
ACID-CLEAVABLE MONOMER AND POLYMERS INCLUDING THE SAME
Abstract
A monomer having formula (I): ##STR00001## wherein in formula
(I), groups and variables are the same as described in the
specification.
Inventors: |
Aqad; Emad; (Northborough,
MA) ; Thackeray; James W.; (Braintree, MA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ROHM AND HAAS ELECTRONIC MATERIALS LLC |
Marlborough |
MA |
US |
|
|
Family ID: |
63668804 |
Appl. No.: |
15/475630 |
Filed: |
March 31, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C08F 220/283 20200201;
G03F 7/0046 20130101; G03F 7/0045 20130101; C07C 69/653 20130101;
C08F 220/28 20130101; G03F 7/0392 20130101 |
International
Class: |
G03F 7/004 20060101
G03F007/004; C07C 69/54 20060101 C07C069/54; C08F 220/28 20060101
C08F220/28; G03F 7/038 20060101 G03F007/038; G03F 7/039 20060101
G03F007/039; G03F 7/16 20060101 G03F007/16; G03F 7/20 20060101
G03F007/20; G03F 7/38 20060101 G03F007/38; G03F 7/32 20060101
G03F007/32 |
Claims
1. A monomer having formula (I): ##STR00032## wherein in formula
(I): R.sup.a is H, F, --CN, C.sub.1-10 alkyl group, or C.sub.1-10
fluoroalkyl group; R.sup.1 and R.sup.2 are different and each
chosen from an unsubstituted or substituted C.sub.1-10 linear or
branched alkyl group, an unsubstituted or substituted C.sub.3-10
cycloalkyl group, an unsubstituted or substituted C.sub.3-10
alkenylalkyl group, an unsubstituted or substituted C.sub.3-10
alkynylalkyl group, or an unsubstituted or substituted C.sub.6-30
aryl group, wherein R.sup.1 and R.sup.2 optionally comprise at
least one linking group selected from O and S, and wherein R.sup.1
and R.sup.2 together optionally form a ring; ##STR00033##
represents a monocyclic or polycyclic unsubstituted or substituted
C.sub.6-30 arylene group or a monocyclic or polycyclic
unsubstituted or substituted C.sub.3-30 heteroarylene group,
wherein "*" and "*'" indicate a point of attachment to a
neighboring group or atom; "I" represents iodine; and n is 1, 2, 3,
4, 5, 6, 7, 8, and 9.
2. The monomer of claim 1, wherein the C.sub.6-30 arylene group is
a monocyclic C.sub.6-30 arylene group, a fused bicyclic C.sub.6-30
arylene group, or a singly bonded C.sub.6-30 arylene group.
3. The monomer of claim 1, wherein R.sup.1 and R.sup.2 are
different and each chosen from an unsubstituted C.sub.1-10 linear
or branched alkyl group.
4. The monomer of claim 3, wherein one of R.sup.1 and R.sup.2 is an
unsubstituted C.sub.1-10 linear or branched alkyl group and the
other one of R.sup.1 and R.sup.2 is a C.sub.1-10 linear or branched
alkyl group substituted with at least one fluorine atom.
5. The monomer of claim 1, wherein n is 1, 2, or 3.
6. A copolymer comprising a polymerized product of a monomer of
claim 1.
7. The copolymer of claim 6, further comprising a polymerized
product of a base-soluble monomer, a lactone-containing monomer, or
a combination thereof.
8. The copolymer of claim 7, wherein the base-soluble monomer is
represented by formula (II), and wherein the lactone-containing
monomer is represented by formula (III): ##STR00034## wherein each
R.sup.a is independently H, F, C.sub.1-10 alkyl, or C.sub.1-10
fluoroalkyl; Q.sub.1 is an ester-containing or non-ester containing
group selected from C.sub.1-20 alkyl, C.sub.3-20 cycloalkyl,
C.sub.6-20 aryl, and C.sub.7-20 aralkyl; W is a base-reactive group
comprising --C(.dbd.O)--OH; --C(CF.sub.3).sub.2OH;
--NH--SO.sub.2--Y.sup.1 where Y.sup.1 is F or C.sub.1-4
perfluoroalkyl; an aromatic --OH; or an adduct of any of the
foregoing with a vinyl ether; a is an integer of 1 to 3; and L is a
monocyclic, polycyclic, or fused polycyclic C.sub.4-20
lactone-containing group.
9. The copolymer of claim 6, further comprising a polymerized
product of a monomer comprising a photoacid generator.
10. The copolymer of claim 9, wherein the photoacid generator
monomer comprising a polymerizable group is represented by formula
(VIII): ##STR00035## wherein R.sup.a is independently H, F,
C.sub.1-10 alkyl, or C.sub.1-10 fluoroalkyl; Q.sub.2 is a single
bond or an ester-containing or non-ester containing, fluorinated or
non-fluorinated group selected from C.sub.1-20 alkylene, C.sub.3-20
cycloalkylene, C.sub.6-20 arylene, and C.sub.7-20 aralkylene group;
A is an ester-containing or non ester-containing, fluorinated or
non-fluorinated group selected from C.sub.1-20 alkylene, C.sub.3-20
cycloalkylene, C.sub.6-20 arylene, and C.sub.7-20 aralkylene; Z is
an anionic moiety comprising sulfonate, an anion of a sulfonamide,
or an anion of a sulfonimide; and G.sup.+ has formula (IV):
##STR00036## wherein X is S or I, each R.sup.c is unsubstituted or
substituted, halogenated or non-halogenated and is independently
C.sub.1-30 alkyl; a polycyclic or monocyclic C.sub.3-30 cycloalkyl;
a polycyclic or monocyclic C.sub.4-30 aryl, wherein when X is S,
one of the R.sup.c is optionally attached to one adjacent R.sup.c
by a single bond, and z is 2 or 3, wherein when X is I, z is 2, or
when X is S, z is 3.
11. A photoresist composition comprising: a copolymer of claim 6; a
photoacid generator; and a solvent.
12. The photoresist composition of claim 11, wherein the photoacid
generator has formula G.sup.+A.sup.-, wherein G.sup.+ has formula
(IV): ##STR00037## wherein X is S or I, each R.sup.c is
unsubstituted or substituted, halogenated or non-halogenated, and
is independently C.sub.1-30 alkyl; a polycyclic or monocyclic
C.sub.3-30 cycloalkyl; a polycyclic or monocyclic C.sub.4-30 aryl,
wherein when X is S, one of the R.sup.c is optionally attached to
one adjacent R.sup.c by a single bond, and z is 2 or 3, wherein
when X is I, z is 2, or when X is S, z is 3; and wherein A.sup.- is
a non-polymerizable organic anion.
13. The photoresist composition of claim 12, wherein G.sup.+ has
formula (V), (VI), or (VII): ##STR00038## wherein X is I or S,
R.sup.h, R.sup.i, R.sup.j, and R.sup.k are unsubstituted or
substituted and are each independently hydroxy, nitrile, halogen,
C.sub.1-30 alkyl, C.sub.1-30 fluoroalkyl, C.sub.3-30 cycloalkyl,
C.sub.1-30 fluorocycloalkyl, C.sub.1-30 alkoxy, C.sub.3-30
alkoxycarbonylalkyl, C.sub.3-30 alkoxycarbonylalkoxy, C.sub.3-30
cycloalkoxy, C.sub.5-30 cycloalkoxycarbonylalkyl, C.sub.5-30
cycloalkoxycarbonylalkoxy, C.sub.1-30 fluoroalkoxy, C.sub.3-30
fluoroalkoxycarbonylalkyl, C.sub.3-30 fluoroalkoxycarbonylalkoxy,
C.sub.3-30 fluorocycloalkoxy, C.sub.5-30
fluorocycloalkoxycarbonylalkyl, C.sub.5-30
fluorocycloalkoxycarbonylalkoxy, C.sub.6-30 aryl, C.sub.6-30
fluoroaryl, C.sub.6-30 aryloxy, C.sub.6-30 fluoroaryloxy, or a
C.sub.2-30 acetal group comprising --O--C(R.sup.11R.sup.12)--O--
(wherein R.sup.11 and R.sup.12 are each independently hydrogen or a
C.sub.1-30 alkyl group), each of which is unsubstituted or
substituted; Ar.sup.1 and Ar.sup.2 are independently C.sub.10-30
fused or singly bonded polycyclic aryl groups; R.sup.1 is a lone
pair of electrons where X is I, or a C.sub.6-20 aryl group where X
is S; p is an integer of 2 or 3, wherein when X is I, p is 2, and
where X is S, p is 3, q and r are each independently an integer
from 0 to 5, and s and t are each independently an integer from 0
to 4.
14. A coated substrate, comprising: (a) a substrate having one or
more layers to be patterned on a surface thereof; and (b) a layer
of a photoresist composition of claim 11 over the one or more
layers to be patterned.
15. A method of forming an electronic device, comprising: (a)
applying a layer of the photoresist composition of claim 11 over a
surface of the substrate; (b) pattern-wise exposing the photoresist
composition layer to activating radiation; and (c) developing the
exposed photoresist composition layer to provide a resist relief
image.
16. The monomer of claim 1, wherein one of R.sup.1 and R.sup.2 is
an unsubstituted or substituted C.sub.1-10 linear or branched alkyl
group and the other one of R.sup.1 and R.sup.2 is an unsubstituted
or substituted C.sub.3-10 branched alkyl group, a C.sub.2-10 linear
or branched alkyl group substituted with at least one fluorine
atom, an unsubstituted or substituted C.sub.3-10 cycloalkyl group,
an unsubstituted or substituted C.sub.3-10 alkenylalkyl group, an
unsubstituted or substituted C.sub.3-10 alkynylalkyl group, or an
unsubstituted or substituted C.sub.6-30 aryl group, wherein R.sup.1
and R.sup.2 optionally comprise at least one linking group selected
from O and S, and wherein R.sup.1 and R.sup.2 together optionally
form a ring.
17. The monomer of claim 1, wherein one of R.sup.1 and R.sup.2 is
an unsubstituted C.sub.1-10 linear alkyl group and the other one of
R.sup.1 and R.sup.2 is an unsubstituted C.sub.3-10 branched alkyl
group.
18. A photoresist composition comprising: a copolymer comprising a
polymerized product of a monomer having formula (I): ##STR00039##
wherein in formula (I): R.sup.a is H, F, --CN, C.sub.1-10 alkyl
group, or C.sub.1-10 fluoroalkyl group; R.sup.1 and R.sup.2 are
each independently an unsubstituted or substituted C.sub.1-10
linear or branched alkyl group, an unsubstituted or substituted
C.sub.3-10 cycloalkyl group, an unsubstituted or substituted
C.sub.3-10 alkenylalkyl group, an unsubstituted or substituted
C.sub.3-10 alkynylalkyl group, or an unsubstituted or substituted
C.sub.6-30 aryl group, wherein R.sup.1 and R.sup.2 optionally
comprise at least one linking group selected from O and S, and
wherein R.sup.1 and R.sup.2 together optionally form a ring;
##STR00040## represents a monocyclic or polycyclic unsubstituted or
substituted C.sub.6-30 arylene group or a monocyclic or polycyclic
unsubstituted or substituted C.sub.3-30 heteroarylene group,
wherein "*" and "*'" indicate a point of attachment to a
neighboring group or atom; "I" represents iodine; and n is 1, 2, 3,
4, 5, 6, 7, 8, and 9; a photoacid generator having formula
G.sup.+A.sup.-, wherein G.sup.+ has formula (VI): ##STR00041## and
A.sup.- is a non-polymerizable organic anion; and a solvent.
19. A coated substrate, comprising: (a) a substrate having one or
more layers to be patterned on a surface thereof; and (b) a layer
of a photoresist composition of claim 18 over the one or more
layers to be patterned.
20. A method of forming an electronic device, comprising: (a)
applying a layer of the photoresist composition of claim 18 over a
surface of the substrate; (b) pattern-wise exposing the photoresist
composition layer to activating radiation; and (c) developing the
exposed photoresist composition layer to provide a resist relief
image.
Description
FIELD
[0001] The present disclosure generally relates to polymer
compositions including a photoacid generator. Specifically, the
disclosure provides copolymers derived from an iodine-containing
monomer.
BACKGROUND
[0002] Extreme ultraviolet lithography ("EUVL") is one of the
leading technologies options to replace optical lithography for
volume semiconductor manufacturing at feature sizes <20 nm. The
extremely short wavelength (13.4 nm) is a key enabling factor for
high resolution required at multiple technology generations. In
addition, the overall system concept--scanning exposure, projection
optics, mask format, and resist technology--is quite similar to
that used for current optical technologies. Like previous
lithography generations, EUVL consists of resist technology,
exposure tool technology, and mask technology. The key challenges
are EUV source power and throughput. Any improvement in EUV power
source will directly impact the currently strict resist sensitivity
specification. Indeed, a major issue in EUVL imaging is resist
sensitivity, the lower the sensitivity, the greater the source
power that is needed or the longer the exposure time that is
required to fully expose the resist. The lower the power levels,
the more noise affects the line edge roughness (LER) of the printed
lines.
[0003] Improving EUV sensitivity is a key enabling factor. It has
been shown that EUV light absorption cross-section and secondary
electron generation yield are critical factors for EUV sensitivity.
One way to increase EUV photoresist sensitivity is by increasing
its absorption cross-section at 13.5 nm, which is an atomic
property of the material that can be theoretically calculated using
known atomic absorptions. Typical atoms that make up resist
materials, such as carbon, oxygen, hydrogen, and nitrogen possess
very weak absorption at 13.5 nm. A fluorine atom has slightly
higher absorption and has been used in the search for high EUV
absorbing photoresist.
[0004] Iodine has remarkably high absorption cross-section at EUV
radiation. Recent patent application JP 2015-161823 discloses
iodine-containing monomers and corresponding polymers useful for
lithographic processing. However, none of these monomers could be
readily cleaved by acid. Thus, there remains a need in new
iodine-containing high absorbing monomers to produce
iodine-containing polymer which can be useful for lithographic
processing.
SUMMARY
[0005] An embodiment provides a monomer having formula (I):
##STR00002##
[0006] wherein in formula (I):
[0007] R.sup.a is H, F, --CN, C.sub.1-10 alkyl group, or C.sub.1-10
fluoroalkyl group;
[0008] R.sup.1 and R.sup.2 are each independently an unsubstituted
or substituted C.sub.1-10 linear or branched alkyl group, an
unsubstituted or substituted C.sub.3-10 cycloalkyl group, an
unsubstituted or substituted C.sub.3-10 alkenylalkyl group, an
unsubstituted or substituted C.sub.3-10 alkynylalkyl group, or an
unsubstituted or substituted C.sub.6-30 aryl group, wherein R.sup.1
and R.sup.2 optionally include at least one linking group selected
from O and S, and wherein R.sup.1 and R.sup.2 together optionally
form a ring;
##STR00003##
represents a monocyclic or polycyclic unsubstituted or substituted
C.sub.6-30 arylene group or a monocyclic or polycyclic
unsubstituted or substituted C.sub.3-30 heteroarylene group,
wherein "*" and "*'" indicate a point of attachment to a
neighboring group or atom,
[0009] "I" represents iodine, and
[0010] n is 1, 2, 3, 4, 5, 6, 7, 8, and 9.
[0011] Another embodiment provides a copolymer including a
polymerized product of the monomer having formula (I) and at least
one unsaturated monomer which is different from the monomer having
formula (I).
[0012] Yet another embodiment provides a copolymer including a
polymerized product of a photoacid generator monomer including a
polymerizable group and the monomer having formula (I).
DETAILED DESCRIPTION
[0013] Reference will now be made in detail to exemplary
embodiments, examples of which are illustrated in the accompanying
drawings, wherein like reference numerals refer to like elements
throughout. In this regard, the present exemplary embodiments may
have different forms and should not be construed as being limited
to the descriptions set forth herein. Accordingly, the exemplary
embodiments are merely described below, by referring to the
figures, to explain aspects of the present description. As used
herein, the term "and/or" includes any and all combinations of one
or more of the associated listed items. Expressions such as "at
least one of," when preceding a list of elements, modify the entire
list of elements and do not modify the individual elements of the
list.
[0014] It will be understood that when an element is referred to as
being "on" another element, it can be directly in contact with the
other element or intervening elements may be present therebetween.
In contrast, when an element is referred to as being "directly on"
another element, there are no intervening elements present.
[0015] It will be understood that, although the terms first,
second, third, etc., may be used herein to describe various
elements, components, regions, layers, and/or sections, these
elements, components, regions, layers, and/or sections should not
be limited by these terms. These terms are only used to distinguish
one element, component, region, layer, or section from another
element, component, region, layer, or section. Thus, a first
element, component, region, layer, or section discussed below could
be termed a second element, component, region, layer, or section
without departing from the teachings of the present
embodiments.
[0016] The terminology used herein is for the purpose of describing
particular embodiments only and is not intended to be limiting. As
used herein, the singular forms "a," "an," and "the" are intended
to include the plural forms as well, unless the context clearly
indicates otherwise.
[0017] It will be further understood that the terms "comprises"
and/or "comprising," or "includes" and/or "including" when used in
this specification, specify the presence of stated features,
regions, integers, steps, operations, elements, and/or components,
but do not preclude the presence or addition of one or more other
features, regions, integers, steps, operations, elements,
components, and/or groups thereof.
[0018] "About" or "approximately" as used herein is inclusive of
the stated value and means within an acceptable range of deviation
for the particular value as determined by one of ordinary skill in
the art, considering the measurement in question and the error
associated with measurement of the particular quantity (i.e., the
limitations of the measurement system). For example, "about" can
mean within one or more standard deviations, or within .+-.30%,
20%, 10%, 5% of the stated value.
[0019] Unless otherwise defined, all terms (including technical and
scientific terms) used herein have the same meaning as commonly
understood by one of ordinary skill in the art to which this
invention belongs. It will be further understood that terms, such
as those defined in commonly used dictionaries, should be
interpreted as having a meaning that is consistent with their
meaning in the context of the relevant art and the present
disclosure, and will not be interpreted in an idealized or overly
formal sense unless expressly so defined herein.
[0020] As used herein, when a definition is not otherwise provided,
the term "alkyl group" refers to a group derived from a straight or
branched chain saturated aliphatic hydrocarbon having the specified
number of carbon atoms and having a valence of at least one.
[0021] As used herein, when a definition is not otherwise provided,
the term "fluoroalkyl group" refers to an alkyl group in which one
or more hydrogen atoms are replaced with fluorine atoms.
[0022] As used herein, when a definition is not otherwise provided,
the term "alkoxy group" refers to "alkyl-O--", wherein the term
"alkyl" has the same meaning as described above.
[0023] As used herein, when a definition is not otherwise provided,
the term "fluoroalkoxy group" refers to an alkoxy group in which
one or more hydrogen atoms are replaced with fluorine atoms.
[0024] As used herein, when a definition is not otherwise provided,
the term "cycloalkyl group" refers to a monovalent group having one
or more saturated rings in which all ring members are carbon.
[0025] As used herein, when a definition is not otherwise provided,
the term "alkenyl group" refers to a straight or branched chain,
monovalent hydrocarbon group having at least one carbon-carbon
double bond.
[0026] As used herein, when a definition is not otherwise provided,
the term "alkenylalkyl group" refers to "alkenyl-alkyl-", wherein
the terms "alkenyl" and "alkyl" have the same meaning as described
above.
[0027] As used herein, when a definition is not otherwise provided,
the term "alkynyl group" refers to a straight or branched chain,
monovalent hydrocarbon group having at least one carbon-carbon
triple bond.
[0028] As used herein, when a definition is not otherwise provided,
the term "alkynylalkyl group" refers to "alkynyl-alkyl-", wherein
the terms "alkynyl" and "alkyl" have the same meaning as described
above.
[0029] As used herein, when a definition is not otherwise provided,
the term "aryl", which is used alone or in combination, refers to
an aromatic or heteroaromatic hydrocarbon containing at least one
ring and having the specified number of carbon atoms. The term
"aryl" may be construed as including a group with an aromatic or
heteroaromatic ring fused to at least one cycloalkyl or
heterocycloalkyl ring. The "aryl" group may include one or more
heteroatom(s) independently selected from nitrogen (N), oxygen (O),
P (phosphorus), and sulfur (S).
[0030] As used herein, when a definition is not otherwise provided,
the term "aryloxy group" refers to "aryl-O--", wherein the term
"aryl" has the same meaning as described above.
[0031] As used herein, when a definition is not otherwise provided,
the term "aralkyl group" refers to a substituted or unsubstituted
aryl group covalently linked to an alkyl group that is linked to a
compound.
[0032] As used herein, when a definition is not otherwise provided,
the term "alkylene group" refers to a straight or branched
saturated aliphatic hydrocarbon group having a valence of at least
two, optionally substituted with one or more substituents where
indicated, provided that the valence of the alkylene group is not
exceeded.
[0033] As used herein, when a definition is not otherwise provided,
the term "cycloalkylene group" refers to a cyclic hydrocarbon group
having a valence of at least two, optionally substituted with one
or more substituents where indicated, provided that the valence of
the cycloalkylene group is not exceeded.
[0034] As used herein, when a definition is not otherwise provided,
the term "arylene group" refers to a functional group having a
valence of at least two obtained by removal of two hydrogens in an
aromatic ring, optionally substituted with one or more substituents
where indicated, provided that the valence of the arylene group is
not exceeded.
[0035] As used herein, when a definition is not otherwise provided,
the term "aralkylene group" refers to a functional group having a
valence of at least two obtained by removal of two hydrogens from
the alkyl-substituted aromatic compound, optionally substituted
with one or more substituents where indicated, provided that the
valence of the aralkylene group is not exceeded.
[0036] As used herein, when a definition is not otherwise provided,
the term "heteroarylene group" refers to a functional group having
a valence of at least two obtained by removal of two hydrogens in a
heteroaromatic ring, optionally substituted with one or more
substituents where indicated, provided that the valence of the
heteroarylene group is not exceeded.
[0037] An embodiment of the present disclosure provides a monomer
having formula (I):
##STR00004##
[0038] In formula (I),
[0039] R.sup.a may be H, F, --CN, C.sub.1-10 alkyl group, or
C.sub.1-10 fluoroalkyl group;
[0040] R.sup.1 and R.sup.2 may be each independently an
unsubstituted or substituted C.sub.1-10 linear or branched alkyl
group, an unsubstituted or substituted C.sub.3-10 cycloalkyl group,
an unsubstituted or substituted C.sub.3-10 alkenylalkyl group, an
unsubstituted or substituted C.sub.3-10 alkynylalkyl group, or an
unsubstituted or substituted C.sub.6-30 aryl group, wherein R.sup.1
and R.sup.2 optionally include at least one linking group selected
from O and S, and wherein R.sup.1 and R.sup.2 may together
optionally form a ring;
##STR00005##
may represent a monocyclic or polycyclic unsubstituted or
substituted C.sub.6-30 arylene group or a monocyclic or polycyclic
unsubstituted or substituted C.sub.3-30 heteroarylene group,
wherein "*" and "*'" indicate a point of attachment to a
neighboring group or atom,
[0041] "I" represents iodine, and
[0042] n may be 1, 2, 3, 4, 5, 6, 7, 8, and 9.
[0043] In the above monomer, the C.sub.6-30 arylene group may be a
monocyclic C.sub.6-30 arylene group, a fused bicyclic C.sub.6-30
arylene group, or a singly bonded C.sub.6-30 arylene group. The
C.sub.6-30 arylene group may be a 1,2-phenylene group, a
1,3-phenylene group, and a 1,4-phenylene group. The fused bicyclic
C.sub.6-30 arylene group may be a disubstituted naphthalene group,
a disubstituted anthracene group, or a disubstituted phenanthrene
group. The singly bonded C.sub.6-30 arylene group may be a
disubstituted biphenylene group or a disubstituted terphenylene
group. The C.sub.3-30 heteroarylene group may be a monocyclic
C.sub.3-30 heteroarylene group, a fused bicyclic C.sub.3-30
heteroarylene group, or a singly bonded C.sub.3-30 heteroarylene
group.
[0044] In an embodiment, each of R.sup.1 and R.sup.2 may be an
unsubstituted or substituted C.sub.1-10 linear or branched alkyl
groups. For example, both R.sup.1 and R.sup.2 may be an
unsubstituted or substituted linear C.sub.1-10 alkyl group, one of
R.sup.1 and R.sup.2 may be an unsubstituted or substituted linear
C.sub.1-10 alkyl group and the other one of R.sup.1 and R.sup.2 may
be an unsubstituted or substituted branched C.sub.1-10 alkyl group,
or both R.sup.1 and R.sup.2 may be an unsubstituted or substituted
branched C.sub.1-10 alkyl group. In an example, one of R.sup.1 and
R.sup.2 may be an unsubstituted C.sub.1-10 linear or branched alkyl
group and the other one of R.sup.1 and R.sup.2 may be a C.sub.1-10
linear or branched alkyl group substituted with at least one
fluorine atom.
[0045] Each of R.sup.1 and R.sup.2 may include a linking group
selected from O and S. The linking group may be present either
inside of R.sup.1 and R.sup.2 or at the site of their connection to
a neighboring group. Examples of groups R.sup.1 and R.sup.2 when
the linking group is present inside are CH.sub.3OCH.sub.2--,
CH.sub.3OCH.sub.2CH.sub.2--, CH.sub.3CH.sub.2OCH.sub.2--. Examples
of R.sup.1 and R.sup.2 when the linking group is present at the
site of their connection are CH.sub.3O--, CH.sub.3CH.sub.2O--, and
CH.sub.3CH.sub.2CH.sub.2O--.
[0046] In an embodiment, groups R.sup.1 and R.sup.2 may together
optionally form a ring. For example, when R.sup.1 is methyl and
R.sup.2 is n-propyl, R.sup.1 and R.sup.2 may form a cyclopentane
ring. In another example, when R.sup.1 is ethyl and R.sup.2 is
n-propyl, R.sup.1 and R.sup.2 may form a cyclohexane ring.
[0047] In formula (I), the variable n represents a number of iodine
atoms attached to the divalent group
##STR00006##
The number of iodine atoms n may vary depending on the nature of
this group and may be 1, 2, 3, 4, 5, 6, 7, 8, or 9. For example, n
may be 1, 2, or 3.
[0048] Specific examples of the monomer having formula (I) may be
represented by the following chemical formulae:
##STR00007##
[0049] Another embodiment provides a copolymer including a
polymerized product of the monomer having formula (I) and at least
one unsaturated monomer which is different from the monomer having
formula (I):
##STR00008##
[0050] In formula (I), R.sup.a, R.sup.1, R.sup.2,
##STR00009##
"I", and n are the same as described above.
[0051] The unsaturated monomer which is different from the monomer
having formula (I) may be a base-soluble monomer, a
lactone-containing monomer, or a combination thereof.
[0052] For example, the unsaturated monomer may be a base-soluble
monomer of formula (II):
##STR00010##
[0053] In formula (II), Q.sub.1 may be an ester-containing or
non-ester containing group selected from C.sub.1-20 alkyl,
C.sub.3-20 cycloalkyl, C.sub.6-20 aryl, and C.sub.7-20 aralkyl
group. In an embodiment, where an ester is included, the ester may
form a connective link between Q.sub.1 and the point of attachment
to the double bond. In this way, where Q.sub.1 is an ester group,
formula (II) may be a (meth)acrylate monomer. In another
embodiment, where an ester is not included, Q.sub.1 may be
aromatic, so that formula (II) may be, for example, a styrenic
monomer or vinyl naphthoic monomer. Q.sub.1 may be fluorinated or
non-fluorinated. Further in formula (II), a may be an integer of 1
to 3, for example, a may be 1 or 2.
[0054] Also in formula (II), W may be a base-reactive group
including --C(.dbd.O)--OH; --C(CF.sub.3).sub.2OH;
--NH--SO.sub.2--Y.sup.1 where Y.sup.1 is F or C.sub.1-4
perfluoroalkyl; an aromatic --OH; or an adduct of any of the
foregoing with a vinyl ether. In an embodiment, where Q is
non-aromatic (e.g., where formula (II) includes a (meth)acrylate
structure having an ester linked alkyl or cycloalkyl group Q), W
may be --C(CF.sub.3).sub.2OH. In another embodiment, where Q is
aromatic (e.g., where Q is either ester-linked or non-ester linked
and is an aromatic group such as phenyl or naphthyl), W may be OH
or --C(CF.sub.3).sub.2OH. It is contemplated that any of the
base-reactive groups may further be protected by an acid
decomposable acetal leaving group (e.g., having a generic structure
--O--CH(R')--O--R'' where R' may be a methyl, ethyl, or other alkyl
group) Such groups are adducts of a vinyl ether, such as, for
example, ethyl vinyl ether, propyl vinyl ether, t-butyl vinyl
ether, cyclohexylvinyl ether, the 2-vinyloxyethyl ester of
1-adamantane carboxylic acid, 2-naphthoyl ethyl vinyl ether, or
other such vinyl ethers.
[0055] W may be a base reactive group including a fluorinated ester
of the form --C(.dbd.O)--OCF.sub.2R or --OC(.dbd.O)CF.sub.2R,
wherein R is a C.sub.1-10 alkyl group or a C.sub.1-10 fluoroalkyl
group.
[0056] Exemplary base-soluble monomers having formula (II) may
include:
##STR00011##
or a combination including at least one of the foregoing, wherein
R.sup.a is H, F, C.sub.1-6 alkyl, or C.sub.1-6 fluoroalkyl.
[0057] The unsaturated monomer may also be a lactone-containing
monomer of formula (III):
##STR00012##
[0058] In formula (III), L may be a monocyclic, polycyclic, or
fused polycyclic C.sub.4-20 lactone-containing group. Such lactone
groups may be included to improve both adhesion of the polymer to a
substrate, and to moderate the dissolution of the polymer in a base
developer. In an embodiment, L may be a monocyclic C.sub.4-6
lactone which is attached to a (meth)acrylate moiety through a
monocycle ring carbon; or L may be a C.sub.6-10 fused polycyclic
lactone based on a norbornane-type structure.
[0059] In an embodiment, a lactone-containing monomer may have
formula (IIIa):
##STR00013##
[0060] wherein
[0061] R.sup.a is H, F, C.sub.1-6 alkyl, or C.sub.1-6 fluoroalkyl,
R is a C.sub.1-10 alkyl, cycloalkyl, or heterocycloalkyl, and
[0062] w is an integer of 0 to 6.
[0063] It will be appreciated in formula (IIIa) that R may be
separate or may be attached to the lactone ring and/or one or more
R groups, and that the methacrylate moiety may be attached to the
lactone ring directly, or indirectly through R.
[0064] Exemplary lactone-containing monomers of formulae (III) and
(IIIa) may include:
##STR00014##
or a combination including at least one of the foregoing, wherein
R.sup.a is H, F, C.sub.1-6 alkyl, or C.sub.1-6 fluoroalkyl.
[0065] In an embodiment, the copolymer may include a polymerized
product having the following structure:
##STR00015##
[0066] wherein
[0067] k, l, m, and q represent mole fractions of the corresponding
repeating units, and
[0068] "I" is iodine and variable n is the same as described
above.
[0069] Another embodiment further provides a photoresist
composition including the above copolymer and a non-polymerizable
photoacid generator monomer having formula G.sup.+A.sup.-, wherein
A.sup.- is a non-polymerizable organic anion and G.sup.+ has
formula (IV):
##STR00016##
[0070] In formula (IV),
[0071] X may be S or I,
[0072] each R.sup.c may be halogenated or non-halogenated, and is
independently a C.sub.1-30 alkyl group; a polycyclic or monocyclic
C.sub.3-30 cycloalkyl group; a polycyclic or monocyclic C.sub.4-30
aryl group,
[0073] wherein when X is S, one of the R.sup.c groups is optionally
attached to one adjacent R.sup.c group by a single bond, and z is 2
or 3, and
[0074] wherein when X is I, z is 2, or when X is S, z is 3.
[0075] For example, cation G.sup.+ may have formula (V), (VI), or
(VII):
##STR00017##
[0076] wherein
[0077] X is I or S,
[0078] R.sup.h, R.sup.i, R.sup.j, and R.sup.k are unsubstituted or
substituted and are each independently hydroxy, nitrile, halogen,
C.sub.1-30 alkyl, C.sub.1-30 fluoroalkyl, C.sub.3-30 cycloalkyl,
C.sub.1-30 fluorocycloalkyl, C.sub.1-30 alkoxy, C.sub.3-30
alkoxycarbonylalkyl, C.sub.3-30 alkoxycarbonylalkoxy, C.sub.3-30
cycloalkoxy, C.sub.5-30 cycloalkoxycarbonylalkyl, C.sub.5-30
cycloalkoxycarbonylalkoxy, C.sub.1-30 fluoroalkoxy, C.sub.3-30
fluoroalkoxycarbonylalkyl, C.sub.3-30 fluoroalkoxycarbonylalkoxy,
C.sub.3-30 fluorocycloalkoxy, C.sub.5-30
fluorocycloalkoxycarbonylalkyl, C.sub.5-30
fluorocycloalkoxycarbonylalkoxy, C.sub.6-30 aryl, C.sub.6-30
fluoroaryl, C.sub.6-30 aryloxy, or C.sub.6-30 fluoroaryloxy, each
of which is unsubstituted or substituted;
[0079] Ar.sup.1 and Ar.sup.2 are independently C.sub.10-30 fused or
singly bonded polycyclic aryl groups;
[0080] R.sup.1 is a lone pair of electrons where X is I, or a
C.sub.6-20 aryl group where X is S;
[0081] p is an integer of 2 or 3, wherein when X is I, p is 2, and
where X is S, p is 3,
[0082] q and r are each independently an integer from 0 to 5,
and
[0083] s and t are each independently an integer from 0 to 4.
[0084] In formulae (V), (VI), or (VII), at least one of R.sup.h,
R.sup.i, R.sup.j, and R.sup.k may be an acid-cleavable group. In an
embodiment, the acid-cleavable group may be (i) a tertiary
C.sub.1-30 alkoxy (for example, a tert-butoxy group), a tertiary
C.sub.3-30 cycloalkoxy group, a tertiary C.sub.1-30 fluoroalkoxy
group, (ii) a tertiary C.sub.3-30 alkoxycarbonylalkyl group, a
tertiary C.sub.5-30 cycloalkoxycarbonylalkyl group, a tertiary
C.sub.3-30 fluoroalkoxycarbonylalkyl group, (iii) a tertiary
C.sub.3-30 alkoxycarbonylalkoxy group, a tertiary C.sub.5-30
cycloalkoxycarbonylalkoxy group, a tertiary C.sub.3-30
fluoroalkoxycarbonylalkoxy group, or (iv) a C.sub.2-30 acetal group
including moiety --O--C(R.sup.11R.sup.12)--O-- (wherein
R.sup.11R.sup.12 are each independently hydrogen or a C.sub.1-30
alkyl group).
[0085] The photoresist composition including the copolymer and the
non-polymerizable photoacid generator monomer as disclosed herein
may be used to provide a layer including the photoresist. A coated
substrate may be formed from the photoresist composition. Such a
coated substrate includes: (a) a substrate having one or more
layers to be patterned on a surface thereof; and (b) a layer of the
photoresist composition over the one or more layers to be
patterned.
[0086] Substrates may be any dimension and shape, and are
preferably those useful for photolithography, such as silicon,
silicon dioxide, silicon-on-insulator (SOI), strained silicon,
gallium arsenide, coated substrates including those coated with
silicon nitride, silicon oxynitride, titanium nitride, tantalum
nitride, ultrathin gate oxides such as hafnium oxide, metal or
metal coated substrates including those coated with titanium,
tantalum, copper, aluminum, tungsten, alloys thereof, and
combinations thereof. Preferably, the surfaces of substrates herein
include critical dimension layers to be patterned including, for
example, one or more gate-level layers or other critical dimension
layers on the substrates for semiconductor manufacture. Such
substrates may preferably include silicon, SOI, strained silicon,
and other such substrate materials, formed as circular wafers
having dimensions such as, for example, 20 cm, 30 cm, or larger in
diameter, or other dimensions useful for wafer fabrication
production.
[0087] Further, a method of forming an electronic device includes
(a) applying (casting) a layer of the above photoresist composition
on a surface of the substrate; (b) pattern-wise exposing the
photoresist composition layer to activating radiation; and (c)
developing the exposed photoresist composition layer to provide a
resist relief image.
[0088] Applying may be accomplished by any suitable method,
including spin coating, spray coating, dip coating, doctor blading,
or the like. Applying the layer of photoresist is preferably
accomplished by spin-coating the photoresist in solvent using a
coating track, in which the photoresist is dispensed on a spinning
wafer. During dispensing, the wafer may be spun at a speed of up to
4,000 rpm, preferably from about 200 to 3,000 rpm, and more
preferably 1,000 to 2,500 rpm. The coated wafer is spun to remove
solvent, and baked on a hot plate to remove residual solvent and
free volume from the film to make it uniformly dense.
[0089] The casting solvent can be any suitable solvent known to one
of ordinary skill in the art. For example, the casting solvent can
be an aliphatic hydrocarbon (such as hexane, heptane, and the
like), an aromatic hydrocarbon (such as toluene, xylene, and the
like), a halogenated hydrocarbon (such as dichloromethane,
1,2-dichloroethane, 1-chlorohexane, and the like), an alcohol (such
as methanol, ethanol, 1-propanol, iso-propanol, tert-butanol,
2-methyl-2-butanol, 4-methyl-2-pentanol, and the like), water, an
ether (such as diethyl ether, tetrahydrofuran, 1,4-dioxane,
anisole, and the like), a ketone (such as acetone, methyl ethyl
ketone, methyl isobutyl ketone, 2-heptanone, cyclohexanone, and the
like), an ester (such as ethyl acetate, n-butyl acetate, propylene
glycol monomethyl ether acetate ("PGMEA"), ethyl lactate, ethyl
acetoacetate, and the like), a lactone (such as
.gamma.-butyrolactone, .epsilon.-caprolactone, and the like), a
nitrile (such as acetonitrile, propionitrile, and the like), an
aprotic bipolar solvent (such as dimethylsulfoxide,
dimethylformamide, and the like), or a combination thereof. The
choice of the casting solvent depends on a particular photoresist
composition and can be readily made by one of ordinary skill in the
art based on knowledge and experience.
[0090] Pattern-wise exposure is then carried out using an exposure
tool such as a stepper, in which the film is irradiated through a
pattern mask and thereby is exposed pattern-wise. The method
preferably uses advanced exposure tools generating activating
radiation at wavelengths capable of high resolution including
extreme-ultraviolet ("EUV") or e-beam radiation. It will be
appreciated that exposure using the activating radiation decomposes
the PAG in the exposed areas and generates acid and decomposition
by-products, and that the acid or the by-products then effectuates
a chemical change in the polymer and nanoparticles (deblocking the
acid sensitive group to generate a base-soluble group, or
alternatively, catalyzing a crosslinking reaction in the exposed
areas). The resolution of such exposure tools may be less than 30
nm.
[0091] Developing the exposed photoresist layer is then
accomplished by treating the exposed layer to a suitable developer
capable of selectively removing the exposed portions of the film
(where the photoresist is a positive tone) or removing the
unexposed portions of the film (where the photoresist is
crosslinkable in the exposed regions, i.e., a negative tone).
Preferably, the photoresist is a negative tone, based on a polymer
having pendant and/or free acid groups or by-products (derived from
bound or free PAG following irradiation) that inhibit the
dissolution of the nanoparticles, and the developer is preferably
solvent based. A pattern forms by developing. The solvent developer
can be any suitable developer known in the art. For example, the
solvent developer can be an aliphatic hydrocarbon (such as hexane,
heptane, and the like), an aromatic hydrocarbon (such as toluene,
xylene, and the like), a halogenated hydrocarbon (such as
dichloromethane, 1,2-dichloroethane, 1-chlorohexane, and the like),
an alcohol (such as methanol, ethanol, 1-propanol, iso-propanol,
tert-butanol, 2-methyl-2-butanol, 4-methyl-2-pentanol, and the
like), water, an ether (such as diethyl ether, tetrahydrofuran,
1,4-dioxane, anisole, and the like), a ketone (such as acetone,
methyl ethyl ketone, methyl isobutyl ketone, 2-heptanone,
cyclohexanone, and the like), an ester (such as ethyl acetate,
n-butyl acetate, propylene glycol monomethyl ether acetate
("PGMEA"), ethyl lactate, ethyl acetoacetate, and the like), a
lactone (such as .gamma.-butyrolactone, .epsilon.-caprolactone, and
the like), a nitrile (such as acetonitrile, propionitrile, and the
like), an aprotic bipolar solvent (such as dimethylsulfoxide,
dimethylformamide, and the like), or a combination thereof. In an
embodiment, the solvent developer may be a miscible mixture of
solvents, for example, a mixture of an alcohol (iso-propanol) and
ketone (acetone). The choice of the developer solvent depends on a
particular photoresist composition and can be readily made by one
of ordinary skill in the art based on knowledge and experience.
[0092] The photoresist may, when used in one or more such
pattern-forming processes, be used to fabricate electronic and
optoelectronic devices such as memory devices, processor chips
(CPUs), graphics chips, and other such devices.
[0093] Yet another embodiment provides a copolymer including a
polymerized product of a photoacid generator monomer including a
polymerizable group and the monomer having formula (I):
##STR00018##
[0094] In formula (I), R.sup.a, R.sup.1, R.sup.2,
##STR00019##
"I", and n are the same as described above.
[0095] The photoacid generator monomer including a polymerizable
group may be represented by formula (VIII):
##STR00020##
[0096] In formula (VIII), each R.sup.a may independently be H, F,
C.sub.1-10 alkyl, or C.sub.1-10 fluoroalkyl. As used throughout
this specification, "fluoro" or "fluorinated" means that one or
more fluorine groups are attached to the associated group. For
example, by this definition and unless otherwise specified,
"fluoroalkyl" encompasses monofluoroalkyl, difluoroalkyl, etc., as
well as perfluoroalkyl in which substantially all carbon atoms of
the alkyl group are substituted with fluorine atoms; similarly,
"fluoroaryl" means monofluoroaryl, perfluoroaryl, etc.
"Substantially all" in this context means greater than or equal to
90%, preferably greater than or equal to 95%, and still more
preferably greater than or equal to 98% of all atoms attached to
carbon are fluorine atoms.
[0097] In formula (VIII), Q.sub.2 is a single bond or an
ester-containing or non-ester containing, fluorinated or
non-fluorinated group selected from C.sub.1-20 alkyl, C.sub.3-20
cycloalkyl, C.sub.6-20 aryl, and C.sub.7-20 aralkyl. For example,
where an ester is included, the ester forms a connective link
between Q.sub.2 and the point of attachment to the double bond. In
this way, where Q.sub.2 is an ester group, formula (VIII) may be a
(meth)acrylate monomer. Where an ester is not included, Q.sub.2 may
be aromatic, so that formula (VIII) may be, for example, a styrenic
monomer or vinyl naphthoic monomer.
[0098] Also, in formula (VIII), A is an ester-containing or non
ester-containing, fluorinated or non-fluorinated group selected
from C.sub.1-20 alkyl, C.sub.3-20 cycloalkyl, C.sub.6-20 aryl, or
C.sub.7-20 aralkyl. Useful A groups may include fluorinated
aromatic moieties, straight chain fluoroalkyl, or branched
fluoroalkyl esters. For example, A may be a
--[(C(R.sup.e).sub.2).sub.x(.dbd.O)O].sub.c--(C(R.sup.f).sub.2).sub.y(CF.-
sub.2).sub.z-- group, or an o-, m- or p-substituted
--C.sub.6R.sup.g.sub.4-- group, where each R.sup.e, R.sup.f, and
R.sup.g are each independently H, F, C.sub.1-6 fluoroalkyl, or
C.sub.1-6 alkyl, c is 0 or 1, x is an integer of 1 to 10, y and z
are independently integers of from 0 to 10, and the sum of y+z is
at least 1.
[0099] Also, in formula (VIII), Z.sup.- is an anionic group
including a sulfonate (--SO.sub.3.sup.-), the anion of a
sulfonamide (--SO.sub.2(N.sup.-)R' where R' is a C.sub.1-10 alkyl
or C.sub.6-20 aryl, or the anion of a sulfonimide. Where Z.sup.- is
a sulfonimide, the sulfonimide may be an asymmetric sulfonimide
having the general structure
A-SO.sub.2--(N.sup.-)--SO.sub.2--Y.sup.2, where A is as described
above, and Y.sup.2 is a straight chain or branched C.sub.1-10
fluoroalkyl group. For example, the Y.sup.2 group may be a
C.sub.1-4 perfluoroalkyl group, which may be derived from the
corresponding perfluorinated alkanesulfonic acid, such as
trifluoromethanesulfonic acid or perfluorobutanesulfonic acid.
[0100] In an embodiment, the monomer of formula (VIII) may have the
structure of formula (VIIIa) or (VIIIb):
##STR00021##
[0101] wherein A and R.sup.a are as defined for formula (VIII).
[0102] In formulae (VIII), (VIIIa), and (VIIIb), G.sup.+ may have
formula (IV):
##STR00022##
[0103] wherein X, R.sup.c, and z are the same as described in the
embodiments above.
[0104] The polymerized product may further include a base-soluble
monomer, a lactone-containing monomer, or a combination thereof. In
an embodiment, the base-soluble monomer may be represented by
formula (II) described above, and the lactone-containing monomer
may be represented by formula (III) described above.
[0105] In an embodiment, the copolymer may include a polymerized
product having any of the following structures:
##STR00023## ##STR00024##
[0106] wherein
[0107] k, l, m, and q represent mole fractions of the corresponding
repeating units, and
[0108] "I" is iodine and variable n is the same as described
above.
[0109] Another embodiment provides a photoresist composition
including the above copolymer and a coated substrate including: (a)
a substrate having one or more layers to be patterned on a surface
thereof; and (b) a layer of the above photoresist composition over
the one or more layers to be patterned.
[0110] Yet another embodiment provides a method of forming an
electronic device, including:
[0111] (a) applying a layer of the above photoresist composition on
a surface of the substrate;
[0112] (b) pattern-wise exposing the photoresist composition layer
to activating radiation; and
[0113] (c) developing the exposed photoresist composition layer to
provide a resist relief image.
[0114] Hereinafter, the present disclosure is illustrated in more
detail with reference to examples. However, these examples are
exemplary, and the present disclosure is not limited thereto.
Examples
[0115] The acronyms and chemical structures of monomers used in
these examples are presented in Table 1. The synthesis of the
monomer designated ECPPDBT F2 is described in U.S. Patent
Publication No. 2014/0080058 A1.
TABLE-US-00001 TABLE 1 Monomer Acronym Chemical Structure ECPPDBT
F2 ##STR00025## PPMA ##STR00026## .alpha.-GBLMA ##STR00027## DiHFA
##STR00028##
Monomer Synthesis
[0116] Synthesis of two monomers are described. Grignard reagent
solutions used herein were purchased from Aldrich and used as
received. The synthetic scheme for the monomer designated 4-IPBMA
is summarized in FIG. 1. Under nitrogen atmosphere, an oven dry
flask was charged with 100 mL of THF and 100 mL of 0.3 M
ethylmagnesium bromide solution in THF. The Grignard solution was
cooled to 0.degree. C. and a solution of 4-iodobenzophenone (1,
50.0 g, 0.2 mol) in 200 mL THF was added dropwise under nitrogen
atmosphere. The reaction mixture was warmed up to room temperature
and stirring was continued for 4 h. An aqueous solution of ammonium
chloride (100 mL, 1 M) was added to the reaction mixture. The
resulting mixture was extracted twice with 100 mL of methylene
chloride. The combined organic phase from the extractions was
concentrated under reduced pressure to produce an oily crude
product 2-(4-iodophenyl)butan-2-ol (2), which was used in the next
step without further purification. Yield: 61 g.
[0117] In the next step, a solution of methacrolyl chloride (6.20
g, 59.3 mol) in 100 mL of methylene chloride was added dropwise to
a solution made of 2-(4-iodophenyl)butan-2-ol (15.0 g, 54.2 mol)
and triethylamine (6.2 g, 61.3 mol) in 100 mL of methylene chloride
at 0.degree. C. After the addition was completed, the mixture was
allowed to warm up to room temperature and stirred for 16 h. Thin
Layer Chromatography (TLC) test showed incomplete conversion.
Additional 0.3 equivalents of methacrolyl chloride and 0.3
equivalents of triethylamine were added, and the mixture was
stirred for an additional 12 h. The reaction mixture was washed
with water (3.times.150 mL) and the organic phase was concentrated.
The resulting residue was dissolved in 10 mL methylene chloride and
passed through a short plug of silica-gel initially using heptane
as an eluent followed by methylene chloride to collect fractions
containing the product. To the combined fractions of the pure
product was added 100 mg of the inhibitor dibutylhydroxytoluene
(BHT), and the solvent was fully removed under reduced pressure to
produce 10.5 g of the monomer 4-IPBMA (3) and the product was
dried. Yield: 10.5 g.
[0118] .sup.1H NMR (CDCl.sub.3), .delta.: 7.75 (d, 2H, ArH), 7.25
(d, 2H, ArH), 6.20 (s, 1H, CH.dbd.CH), 5.70 (s, 1H, CH.dbd.CH),
2.01 (s, 3H, CH.sub.3), 1.84-1.54 (m, 5H, CH.sub.3CH.sub.2), 0.8
(t, 3H, CH.sub.3).
##STR00029##
[0119] The synthetic scheme for the monomer designated 3-IPPMA is
summarized in FIG. 2.
[0120] To a solution of methyl 3-iodobenzoate (4, 30 g, 0.122 mol)
in 250 mL dry THF at 0.degree. C. and under nitrogen atmosphere was
slowly added 100 mL of 0.3 M solution of methylmagnesium bromide in
ether. After the addition of the Grignard reagent was completed,
the mixture was slowly warmed up to room temperature and stirring
continued for an additional 3 h. Then, an aqueous solution of
ammonium chloride (50 mL, 0.5 M) was added to the reaction mixture.
The organic solvent was removed by distillation and the product was
extracted with 150 mL methylene chloride. The methylene chloride
solution was washed twice with 100 mL of water. The solvent from
the organic phase was completely removed by distillation to produce
the product 2-(3-iodophenyl)propan-2-ol 5 as colorless oil, which
was used in the next step without further purification. Yield: 32 g
(95%).
[0121] In the next step, a reaction flask was charged with a
solution of 2-(3-iodophenyl)propan-2-ol (5, 32 g. 0.115 mol) in 150
mL of methylene chloride. The solution was cooled to 0.degree. C.
Methacryloyl chloride (18.0 g, 0.17 mol) and triethylamine (20 g,
0.20 mol) were added to the reaction flask, and the mixture was
stirred at room temperature for 16 h. The organic phase was washed
with water (3.times.100 mL), and the solvent was completely removed
under reduced pressure. The crude material was dissolved in 150 mL
of methylene chloride and washed twice with 100 mL of 0.5 M aqueous
solution of sodium carbonate. The organic phase was concentrated
and passed through a short pad of basic aluminum oxide using
methylene chloride/heptane as eluent. The solvent fractions that
contain the product were collected and the solvents were completely
removed under reduced pressure to produce the product as colorless
oil. Yield: 34 g (90%).
[0122] .sup.1H NMR (CDCl.sub.3), .delta.: 7.80 (s, 1H, ArH), 7.65
(d, 1H, ArH), 7.46 (d, 1H, ArH), 7.18 (T, 1H, ArH), 6.12 (S, 1H,
CH.dbd.CH), 5.65 (s, 1H, CH.dbd.CH), 2.10 (s, 3H, CH.sub.3), 1.70
(s, 6H, 2CH.sub.3).
##STR00030##
Copolymer Synthesis
[0123] This example describes the synthesis of three inventive and
two comparative copolymers. Copolymer 1 was prepared from the
monomers 4-IPBMA, .alpha.-GBLMA, DiHFA, at a molar feed ratio of
38.5/49.5/12. A feed solution was made by dissolving 4-IPBMA (7.97
g, 24.13 mmol), .alpha.-GBLMA (5.21 g, 31.0 mmol) and DiHFA (3.32
g, 7.0 mmol in 45.92 g of propylene glycole monomethyl ether
acetate ("PGMEA"). An initiator solution was prepared by dissolving
1.68 g of the azo initiator dimethyl
2,2'-azobis(2-methylpropionate) (obtained as V-601 from Wako Pure
Chemical Industries, Ltd.) in 10.8 g of PGMEA.
[0124] The polymerization was carried out in a 3-neck round bottom
flask fitted with a water condenser and a thermometer to monitor
the reaction in the flask. The reactor was charged with 4-IPBMA
(0.46 g, 1.40 mmol), .alpha.-GBLMA (0.38 g, 2.23 mmol), DiHFA (0.67
g, 1.33 mmol) and in 17.52 g of propylene glycole monomethyl ether
acetate ("PGMEA"), and the contents were heated to 75.degree. C.
The feed solution and the initiator solution were fed into the
reactor using syringe pumps over a 4 h time period. The contents
were then stirred for an additional 2 h. The contents were cooled
to room temperature, diluted with tetrahydrofuran ("THF") to 25
weight percent, and precipitated into 10-fold (by weight) of a 7:3
(w/w) mixture of heptane and iso-propanol. The resulting copolymer
1 was isolated by filtration and dried under vacuum at 50.degree.
C. for 24 h.
[0125] The polymers set forth in Table 2 were prepared using the
similar procedure used to make copolymer 1, except using the
monomer types and molar feed ratios as specified in Table 2.
TABLE-US-00002 TABLE 2 Unit 1 Unit 2 Unit 3 Unit 4 Copolymer (mole
%) (mole %) (mole %) (mole %) 1 4-IPBMA .alpha.-GBLMA DiHFA (38.5)
(49.5) (12.0) 2 3-IPPMA .alpha.-GBLMA DiHFA (38.5) (49.5) (12) 3
3-IPPMA .alpha.-GBLMA DiHFA ECPPDBT F2 (38.0) (46.0) (11) (5.0) 4
(comparative) PPMA .alpha.-GBLMA DiHFA (38.5) (49.5) (12) 5
(comparative) PPMA .alpha.-GBLMA DiHFA ECPPDBT F2 (38.0) (46.0)
(11) (5.0)
Photoresist Preparation and Processing
[0126] Photoresist compositions containing copolymers 1 to 3 were
each independently formulated as summarized in Table 3. Component
amounts in Table 3 are based on total solids, excluding solvents.
The non-polymeric photoacid generator was ECPPDBT AdOH-TFBS, which
has the chemical structure:
##STR00031##
[0127] The quencher was trioctylamine (TOA). The surfactant was a
fluorinated surfactant obtained as POLYFOX.TM. PF-656.
[0128] Compositions of two inventive and one comparative
photoresist compositions are summarized in Table 3, where component
amounts are expressed as weight percent based on total solids,
excluding solvents.
TABLE-US-00003 TABLE 3 Photoresist Copolymer PAG Quencher
Surfactant 1 65.31% 32.0% ECPPDBT 4% 0.1% Copolymer 1 AdOH-TFBS 2
65.31% 32.0% ECPPDBT 4% 0.1% Copolymer 2 AdOH-TFBS 3 65.31% 32.0%
ECPPDBT 4% 0.1 Copolymer 3 AdOH-TFBS 4 65.31% 32.0% ECPPDBT 4% 0.1
(comparative) Copolymer 4 AdOH-TFBS 5 65.31% 32.0% ECPPDBT 4% 0.1%
(comparative) Copolymer 4 AdOH-TFBS
[0129] All formulations in Table 3 used a propylene glycol
monomethyl ether acetate as a solvent. The resists were processed
at a soft bake of 110.degree. C. for 90 seconds and a post-exposure
base at 100.degree. C. for 60 seconds. Contrast curves at 248
nanometers were generated by coating the resist on a thick organic
antireflective layer. The resist was exposed at 248 nanometers on a
Canon TELACT tool. After a post-exposure bake, the resists were
developed for 60 seconds using 0.26 N tetramethylammonium hydroxide
solution. Film thickness values were measured using KLA Tencore
OPTIPROBE.TM. 7341 thermal wave tool. Results from this evaluation
are presented in Table 4, where "248 nm E.sub.0" is the 248
nanometer exposure dose to clear, expressed in
millijoules/centimeter.sup.2.
Contrast Curve Measurement
[0130] Contrast curve measurements with EUV exposure source (13.5
nm) were obtained using a LithoTech Japan EUVES-9000 flood exposure
tool. The resist was spin coated onto either an organic underlayer
or a silicon wafer and baked at 110.degree. C. for 90 seconds to
form a 40-50 nm thick photoresist film. The resist was exposed to
an increasing dose of 13.5 nm radiation in a step-wise manner,
post-exposure baked at 100.degree. C. for 60 seconds, and developed
with 0.26 N aqueous tetramethylammonium hydroxide solution for 60
seconds to form a relief image pattern of exposed and non-exposed
areas. Thickness was measured at each exposed area using a KLA
Thermawave-7 ellipsometer and plotted vs. dose. Dose-to-clear
values (E.sub.0) were calculated at 10% or less remaining film
thickness. As can be seen, photoresists 1 and 2 which contain
terpolymer with 4-IPBMA or 3-IPPMA acid cleavable repeat units have
higher photospeed under EUV exposure compared to the comparative
photoresist 4 which includes terpolymer with "iodo-free" PPMA acid
cleavable repeat units. Photoresist 3 which contains polymer-bound
PAG that includes 3-IPPMA has a higher photospeed under EUV
exposure compared to the comparative photoresist 5 which includes
polymer-bound PAG that includes "iodo free" PPMA acid cleavable
repeat units.
TABLE-US-00004 TABLE 4 Photoresist 248 nm E.sub.0 (mJ/cm.sup.2) EUV
E.sub.0 (mJ/cm.sup.2) 1 9.2 1.7 2 9.4 1.6 3 8.4 1.6 4 (comparative)
7.2 2.1 5 (comparative) 4.8 2.1
[0131] While this disclosure has been described in connection with
what is presently considered to be practical exemplary embodiments,
it is to be understood that the invention is not limited to the
disclosed embodiments, but, on the contrary, is intended to cover
various modifications and equivalent arrangements included within
the spirit and scope of the appended claims.
* * * * *