U.S. patent application number 15/252522 was filed with the patent office on 2018-03-01 for photoacid-generating compound, polymer derived therefrom, photoresist composition including the photoacid-generating compound or polymer, and method of forming a photoresist relief image.
The applicant listed for this patent is Rohm and Haas Electronic Materials LLC. Invention is credited to Emad Aqad, Cong Liu, William Williams, III.
Application Number | 20180059542 15/252522 |
Document ID | / |
Family ID | 61242402 |
Filed Date | 2018-03-01 |
United States Patent
Application |
20180059542 |
Kind Code |
A1 |
Aqad; Emad ; et al. |
March 1, 2018 |
PHOTOACID-GENERATING COMPOUND, POLYMER DERIVED THEREFROM,
PHOTORESIST COMPOSITION INCLUDING THE PHOTOACID-GENERATING COMPOUND
OR POLYMER, AND METHOD OF FORMING A PHOTORESIST RELIEF IMAGE
Abstract
A photoacid-generating compound has the structure ##STR00001##
where R.sup.1, R.sup.2, R.sup.3, R.sup.4, Q, and X are defined
herein. The photoacid-generating compound can be used as a
component of a photoresist composition, or as a monomer
incorporated into a polymer useful in a photoresist composition.
The photoacid-generating compound provides a desired balance of
solubility and line width roughness.
Inventors: |
Aqad; Emad; (Northborough,
MA) ; Williams, III; William; (Ipswich, MA) ;
Liu; Cong; (Shrewsbury, MA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Rohm and Haas Electronic Materials LLC |
Marlborough |
MA |
US |
|
|
Family ID: |
61242402 |
Appl. No.: |
15/252522 |
Filed: |
August 31, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C07C 2603/74 20170501;
C08F 232/08 20130101; G03F 7/38 20130101; G03F 7/0046 20130101;
C07D 493/18 20130101; C07C 303/32 20130101; C07C 69/753 20130101;
C07D 327/08 20130101; C07C 381/12 20130101; C07D 335/16 20130101;
C08F 2/50 20130101; C07D 409/12 20130101; G03F 7/0397 20130101;
C07C 2602/42 20170501; C07D 317/72 20130101; G03F 7/0045 20130101;
C07D 303/40 20130101; C07D 333/76 20130101; C07D 317/34 20130101;
C07D 339/08 20130101; C07C 309/12 20130101; C07C 309/00 20130101;
G03F 7/30 20130101; C08F 220/281 20200201; C08F 220/1818 20200201;
C08F 220/20 20130101; C08F 220/281 20200201; C08F 220/1818
20200201; C08F 220/20 20130101 |
International
Class: |
G03F 7/004 20060101
G03F007/004; C08F 218/14 20060101 C08F218/14; G03F 7/039 20060101
G03F007/039; G03F 7/20 20060101 G03F007/20; G03F 7/32 20060101
G03F007/32; C07C 309/12 20060101 C07C309/12; C07C 321/30 20060101
C07C321/30 |
Claims
1. A photoacid-generating compound having the structure
##STR00035## wherein R.sup.1 is a C.sub.6-20 polycyclic hydrocarbyl
group comprising a hydroxyl group, a lactone group, or a
combination thereof; R.sup.2 is a C.sub.6-20 polycyclic hydrocarbyl
group comprising a hydroxyl group, a lactone group, or a
combination thereof, or
--[(CH.sub.2).sub.n--Y--SO.sub.3.sup.-Z.sup.+] wherein n is 0, 1,
or 2; Y is a C.sub.1-4 alkylene group comprising at least one
fluorine atom, provided that when n is 0, Y is a C.sub.2-4 alkylene
group comprising at least one fluorine atom; and Z.sup.+ is an
organic cation; R.sup.3 and R.sup.4 are each independently
hydrogen, cyano, C.sub.1-6 alkyl, C.sub.1-6 fluoroalkyl, optionally
substituted C.sub.6-12 aryl, or --C(O)O--R.sup.11 wherein R.sup.11
is a C.sub.1-20 alkyl group optionally comprising one or more
heteroatoms; and Q is ##STR00036## wherein R.sup.5 and R.sup.6 are
each independently hydrogen, fluorine, cyano, trifluoromethyl,
C.sub.1-6 alkyl, C.sub.6-20 hydrocarbyl comprising a lactone group,
or --OR.sup.12 wherein R.sup.12 is C.sub.1-20 alkyl, or C.sub.6-20
hydrocarbyl comprising a lactone group; and R.sup.7, R.sup.8,
R.sup.9, and R.sup.10 are each independently hydrogen; hydroxyl:
--OR.sup.13 wherein R.sup.13 is a C.sub.1-20 hydrocarbyl group
optionally comprising one or more heteroatoms; --SR.sup.13 wherein
R.sup.13 is defined above; --OC(O)R.sup.13 wherein R.sup.13 is
defined above; --N(R.sup.14)C(O)R.sup.13 wherein R.sup.13 is
defined above and R.sup.11 is hydrogen or a C.sub.1-20 hydrocarbyl
group optionally comprising one or more heteroatoms;
--[OC(O)C(R.sup.a).dbd.CH.sub.2] wherein R.sup.a is hydrogen or
fluoro or cyano or C.sub.1-10 alkyl or C.sub.1-10 fluoroalkyl;
--[O--(CH.sub.2).sub.n--Y--SO.sub.3.sup.-Z.sup.+] wherein n, Y, and
Z.sup.+ are defined above,
--[S--(CH.sub.2).sub.n--Y--SO.sub.3.sup.-Z.sup.+] wherein n, Y, and
Z.sup.+ are defined above, or
--[O--C(O)--(CH.sub.2).sub.n--Y--SO.sub.3.sup.-Z.sup.+] wherein n,
Y, and Z.sup.+ are defined above; and X is --CH.sub.2--, --O--,
--C(O)--, --S(O)--, or --S(O).sub.2--; provided that the
photoacid-generating compound comprises exactly one occurrence of
--[(CH.sub.2).sub.n--Y--SO.sub.3.sup.-Z.sup.+], 1 or 2 occurrences
of the C.sub.6-20 polycyclic hydrocarbyl group comprising a
hydroxyl group, a lactone group, or a combination thereof, and 1,
2, or 3 total occurrences of hydroxyl groups and lactone groups;
and provided that when Q is ##STR00037## and R.sup.5, R.sup.6,
R.sup.7, R.sup.8, R.sup.9, and R.sup.10 are hydrogen, and R.sup.2
is --[(CH.sub.2).sub.n--Y--SO.sub.3.sup.-Z.sup.+], then R.sup.1
excludes --C(O)O-- groups and --S(O).sub.2-- groups.
2. The photoacid-generating compound of claim 1, wherein Q is
##STR00038## wherein R.sup.5 and R.sup.6 are hydrogen; and R.sup.2
is --[(CH.sub.2).sub.n--Y--SO.sub.3.sup.-Z.sup.+], wherein n is 0,
1, or 2; Y is a C.sub.1-4 alkylene group comprising at least one
fluorine atom, provided that when n is 0, Y is a C.sub.2-4 alkylene
group comprising at least one fluorine atom; and Z.sup.+ is an
organic cation.
3. The photoacid-generating compound of claim 1, wherein Q is
##STR00039## wherein one of R.sup.7 and R.sup.8 is hydroxyl and the
other of R.sup.7 and R.sup.8 is hydrogen; wherein one of R.sup.9
and R.sup.10 is --[O--(CH.sub.2).sub.n--Y--SO.sub.3.sup.-Z.sup.+],
--[OC(O)--(CH.sub.2).sub.n--Y--SO.sub.3.sup.-Z.sup.+], or
--[S--(CH.sub.2).sub.n--Y--SO.sub.3.sup.-Z.sup.+], and the other of
R.sup.9 and R.sup.10 is hydrogen; and R.sup.2 is a C.sub.8-12
polycyclic hydrocarbyl group comprising a hydroxyl group, a lactone
group, or a combination thereof.
4. The photoacid-generating compound of claim 1, wherein Q is
##STR00040## wherein R.sup.7 and R.sup.9 are hydrogen; wherein one
of R.sup.8 and R.sup.10 is
--[O--(CH.sub.2).sub.n--Y--SO.sub.3.sup.-Z.sup.-] or
--[S--(CH.sub.2).sub.n--Y--SO.sub.3.sup.-Z.sup.+] or
--[O--C(O)--(CH.sub.2).sub.n--Y--SO.sub.3.sup.-Z.sup.+] wherein n
is 0, 1, or 2, Y is a C.sub.1-4 alkylene group comprising at least
one fluorine atom, and Z.sup.+ is an organic cation, and the other
of R.sup.8 and R.sup.10 is hydrogen; and R.sup.2 is a C.sub.8-12
polycyclic hydrocarbyl group comprising a hydroxyl group, a lactone
group, or a combination thereof.
5. The photoacid-generating compound of claim 1, wherein Q is
##STR00041## and R.sup.2 is
--[(CH.sub.2).sub.n--Y--SO.sub.3.sup.-Z.sup.+], wherein n is 0, 1,
or 2; Y is a C.sub.1-4 alkylene group comprising at least one
fluorine atom, provided that when n is 0, Y is a C.sub.2-4 alkylene
group comprising at least one fluorine atom; and Z.sup.+ is an
organic cation.
6. The photoacid-generating compound of claim 1, selected from the
group consisting of ##STR00042## ##STR00043## wherein Z.sup.+ is an
organic cation.
7. The photoacid-generating compound of claim 1, wherein Q is
##STR00044## wherein one of R.sup.7 and R.sup.9 is hydrogen or
hydroxyl and the other of R.sup.7 and R.sup.9 is hydrogen; wherein
one of R.sup.8 and R.sup.10 is --[OC(O)C(R.sup.a).dbd.CH.sub.2]
wherein R.sup.a is hydrogen, fluoro, cyano, C.sub.1-10 alkyl, or
C.sub.1-10 fluoroalkyl, and the other of R.sup.8 and R.sup.10 is
hydrogen; and wherein R.sup.2 is
--[(CH.sub.2).sub.n--Y--SO.sub.3.sup.-Z.sup.+], wherein n is 0, 1,
or 2; Y is a C.sub.1-4 alkylene group comprising at least one
fluorine atom, provided that when n is 0, Y is a C.sub.2-4 alkylene
group comprising at least one fluorine atom; and Z.sup.+ is an
organic cation.
8. A polymer comprising repeat units derived from the
photoacid-generating compound of claim 7.
9. A photoresist composition comprising the photoacid-generating
compound of claim 1.
10. A method of forming a photoresist relief image, comprising: (a)
applying a layer of the photoresist composition of claim 9 on a
substrate to form a photoresist layer; (b) pattern-wise exposing
the photoresist layer to activating radiation to form an exposed
photoresist layer; and (c) developing the exposed photoresist layer
to provide a photoresist relief image.
11. A photoresist composition comprising the polymer of claim 8.
Description
FIELD
[0001] The present invention relates to a photoacid-generating
compound, a polymer formed from an embodiment of the
photoacid-generating compound comprising a polymerizable group, a
photoresist composition comprising the photoacid-generating
compound, the polymer, or a combination thereof, and a method of
forming a photoresist relief image with the photoresist
composition.
INTRODUCTION
[0002] Advance lithographic techniques such as electron beam and
Extreme Ultraviolet (EUV) lithographies are being used for the
formation of fine patterns. Further shrinking of pattern size to 25
nanometers and less requires, in addition to other process and
exposure tool related requirements, the development of highly
resolving chemically amplified photoresist compositions. The use of
slow diffusion photoacid-generating (PAG) compounds has proved to
be critical for the improvement in resolution and pattern quality.
Slow acid diffusion in a chemically amplified photoresist
composition was achieved by attaching the acidic unit to one or
more bulky substituents. However, the use of bulky substituents
often decreases the solubility of the PAG compound, which is
associated with PAG compound aggregation and/or inhomogeneous PAG
compound distribution in the photoresist layer, and with the
formation of defects during and after lithographic processing.
[0003] There remains a need for photoacid-generating compounds that
exhibit an improved balance of solubility and line width roughness,
without compromising the short acid diffusion characteristic of
low-solubility PAG compounds with bulky substituents.
SUMMARY
[0004] One embodiment is a photoacid-generating compound having the
structure
##STR00002##
wherein R.sup.1 is a C.sub.6-20 polycyclic hydrocarbyl group
comprising a hydroxyl group, a lactone group, or a combination
thereof; R.sup.2 is a C.sub.6-20 polycyclic hydrocarbyl group
comprising a hydroxyl group, a lactone group, or a combination
thereof; or
--[(CH.sub.2).sub.n--Y--SO.sub.3.sup.-Z.sup.+],
wherein n is 0, 1, or 2; Y is a C.sub.1-4 alkylene group comprising
at least one fluorine atom, provided that when n is 0, Y is a
C.sub.2-4 alkylene group comprising at least one fluorine atom; and
Z.sup.+ is an organic cation; R.sup.3 and R.sup.4 are each
independently hydrogen, cyano, C.sub.1-6 alkyl, C.sub.1-6
fluoroalkyl, optionally substituted C.sub.6-12 aryl, or
--C(O)O--R.sup.11 wherein R.sup.11 is a C.sub.1-20 alkyl group
optionally comprising one or more heteroatoms; and Q is
##STR00003##
wherein R.sup.5 and R.sup.6 are each independently hydrogen,
fluorine, cyano, trifluoromethyl, C.sub.1-6 alkyl, C.sub.6-20
hydrocarbyl comprising a lactone group, or --OR.sup.12 wherein
R.sup.12 is C.sub.1-20 alkyl, or C.sub.6-2o hydrocarbyl comprising
a lactone group; and R.sup.7, R.sup.8, R.sup.9, and R.sup.10 are
each independently hydrogen; hydroxyl: --OR.sup.13 wherein R.sup.13
is a C.sub.1-20 hydrocarbyl group optionally comprising one or more
heteroatoms; --SR.sup.13 wherein R.sup.13 is defined above;
--OC(O)R.sup.13 wherein R.sup.13 is defined above;
--N(R.sup.14)C(O)R.sup.13 wherein R.sup.13 is defined above and
R.sup.11 is hydrogen or a C.sub.1-20 hydrocarbyl group optionally
comprising one or more heteroatoms;
--[OC(O)C(R.sup.a).dbd.CH.sub.2] wherein R.sup.a is hydrogen or
fluoro or cyano or C.sub.1-10 alkyl or C.sub.1-10 fluoroalkyl;
--[O--(CH.sub.2).sub.n--Y--SO.sub.3.sup.-Z.sup.+] wherein n, Y, and
Z.sup.+ are defined above,
--[S--(CH.sub.2).sub.n--Y--SO.sub.3.sup.-Z.sup.+] wherein n, Y, and
Z.sup.+ are defined above, or
--[O--C(O)--(CH.sub.2).sub.n--Y--SO.sub.3.sup.-Z.sup.+] wherein n,
Y, and Z.sup.+ are defined above; and X is --CH.sub.2--, --O--,
--C(O)--, --S(O)--, or --S(O).sub.2--; provided that the
photoacid-generating compound comprises exactly one occurrence of
--[(CH.sub.2).sub.n--Y--SO.sub.3.sup.-Z.sup.+], 1 or 2 occurrences
of the C.sub.6-20 polycyclic hydrocarbyl group comprising a
hydroxyl group, a lactone group, or a combination thereof, and 1,
2, or 3 total occurrences of hydroxyl groups and lactone groups;
and provided that when Q is
##STR00004##
and R.sup.5, R.sup.6, R.sup.7, R.sup.8, R.sup.9, and R.sup.10 are
hydrogen, and R.sup.2 is
--[(CH.sub.2).sub.n--Y--SO.sub.3.sup.-Z.sup.+], then R.sup.1
excludes --C(O)O-- groups and --S(O).sub.2-- groups.
[0005] Another embodiment is polymer comprising repeat units
derived from a polymerizable embodiment of the photoacid-generating
compound wherein Q is
##STR00005##
wherein one of R.sup.7 and R.sup.9 is hydrogen or hydroxyl and the
other of R.sup.7 and R.sup.9 is hydrogen; wherein one of R.sup.8
and R.sup.10 is --[OC(O)C(R.sup.a).dbd.CH.sub.2] wherein R.sup.a is
hydrogen, fluoro, cyano, C.sub.1-10 alkyl, or C.sub.1-10
fluoroalkyl, and the other of R.sup.8 and R.sup.10 is hydrogen; and
wherein R.sup.2 is
--[(CH.sub.2).sub.n--Y--SO.sub.3.sup.-Z.sup.+],
wherein n is 0, 1, or 2; Y is a C.sub.1-4 alkylene group comprising
at least one fluorine atom, provided that when n is 0, Y is a
C.sub.2-4 alkylene group comprising at least one fluorine atom; and
Z.sup.+ is an organic cation.
[0006] Another embodiment is a photoresist composition comprising
the polymer.
[0007] Another embodiment is a method of forming a photoresist
relief image, comprising: (a) applying a layer of a photoresist
composition of claim 9 on a substrate to form a photoresist layer;
(b) pattern-wise exposing the photoresist layer to activating
radiation to form an exposed photoresist layer; and (c) developing
the exposed photoresist layer to provide a photoresist relief
image.
[0008] These and other embodiments are described in detail
below.
BRIEF DESCRIPTION OF THE DRAWING
[0009] The FIGURE is a chemical scheme for the synthesis of the
photoacid generator compound designated TPS NB-AdOH-DFES.
DETAILED DESCRIPTION
[0010] The present inventors have determined that photoresist
compositions exhibit an improved balance of solubility and line
width roughness when they incorporate a photoacid-generating
compound having the structure
##STR00006##
wherein R.sup.1 is a C.sub.6-20 polycyclic hydrocarbyl group
comprising a hydroxyl group, a lactone group, or a combination
thereof; R.sup.2 is a C.sub.6-20 polycyclic hydrocarbyl group
comprising a hydroxyl group, a lactone group, or a combination
thereof, or
--[(CH.sub.2).sub.n--Y--SO.sub.3.sup.-Z.sup.+],
wherein n is 0, 1, or 2; Y is a C.sub.1-4 alkylene group comprising
at least one fluorine atom, provided that when n is 0, Y is a
C.sub.2-4 alkylene group comprising at least one fluorine atom; and
Z.sup.+ is an organic cation; R.sup.3 and R.sup.4 are each
independently hydrogen, cyano, C.sub.1-6 alkyl, C.sub.1-6
fluoroalkyl, optionally substituted C.sub.6-12 aryl, or
--C(O)O--R.sup.11 wherein R.sup.11 is a C.sub.1-20 alkyl group
optionally comprising one or more heteroatoms; and Q is
##STR00007##
wherein R.sup.5 and R.sup.6 are each independently hydrogen,
fluorine, cyano, trifluoromethyl, C.sub.1-6 alkyl, C.sub.6-20
hydrocarbyl comprising a lactone group, or --OR.sup.12 wherein
R.sup.12 is C.sub.1-20 alkyl, or C.sub.6-20 hydrocarbyl comprising
a lactone group; and R.sup.7, R.sup.8, R.sup.9, and R.sup.10 are
each independently hydrogen; hydroxyl: --OR.sup.13 wherein R.sup.13
is a C.sub.1-20 hydrocarbyl group optionally comprising one or more
heteroatoms; --SR.sup.13 wherein R.sup.13 is defined above;
--OC(O)R.sup.13 wherein R.sup.13 is defined above;
--N(R.sup.14)C(O)R.sup.13 wherein R.sup.13 is defined above and
R.sup.11 is hydrogen or a C.sub.1-20 hydrocarbyl group optionally
comprising one or more heteroatoms;
--[OC(O)C(R.sup.a).dbd.CH.sub.2] wherein R.sup.a is hydrogen or
fluoro or cyano or C.sub.1-10 alkyl or C.sub.1-10 fluoroalkyl;
--[O--(CH.sub.2).sub.n--Y--SO.sub.3.sup.-Z.sup.+] wherein n, Y, and
Z.sup.+ are defined above,
--[S--(CH.sub.2).sub.n--Y--SO.sub.3.sup.-Z.sup.+] wherein n, Y, and
Z.sup.+ are defined above, or
--[O--C(O)--(CH.sub.2).sub.n--Y--SO.sub.3.sup.-Z.sup.+] wherein n,
Y, and Z.sup.+ are defined above; and X is --CH.sub.2--, --O--,
--C(O)--, --S(O)--, or --S(O).sub.2--; provided that the
photoacid-generating compound comprises exactly one occurrence of
--[(CH.sub.2).sub.n--Y--SO.sub.3.sup.-Z.sup.+], 1 or 2 occurrences
of the C.sub.6-20 polycyclic hydrocarbyl group comprising a
hydroxyl group, a lactone group, or a combination thereof, and 1,
2, or 3 total occurrences of hydroxyl groups and lactone groups;
and provided that when Q is
##STR00008##
and R.sup.5, R.sup.6, R.sup.7, R.sup.8, R.sup.9, and R.sup.10 are
hydrogen, and R.sup.2 is
--[(CH.sub.2).sub.n--Y--SO.sub.3.sup.-Z.sup.+], then R.sup.1
excludes --C(O)O-- groups and --S(O).sub.2-- groups.
[0011] As used herein, "substituted" means including at least one
substituent such as a halogen (i.e., F, Cl, Br, I), hydroxyl,
amino, thiol, carboxyl, carboxylate, amide, nitrile, sulfide,
disulfide, nitro, C.sub.1-18 alkyl, C.sub.1-18 alkoxyl, C.sub.6-18
aryl, C.sub.6-18 aryloxyl, C.sub.7-18 alkylaryl, or C.sub.7-18
alkylaryloxyl. It will be understood that any group or structure
disclosed with respect to the formulas herein may be so substituted
unless otherwise specified. "Alkyl" includes linear, branched,
cyclic, and polycyclic alkyl, and alkyl groups having a combination
of at least two types of linear, branched, cyclic, and polycyclic
alkyl fragments. "Fluorinated" means having one or more fluorine
atoms incorporated into the group. For example, where a C.sub.1-18
fluoroalkyl group is indicated, the fluoroalkyl group can include
one or more fluorine atoms, for example, a single fluorine atom,
two fluorine atoms (e.g., as a 1,1-difluoroethyl group), three
fluorine atoms (e.g., as a 2,2,2-trifluoroethyl group), or fluorine
atoms at each free valence of carbon (e.g., as a perfluorinated
group such as --CF.sub.3, --C.sub.2F.sub.5, --C.sub.3F.sub.7, or
--C.sub.4F.sub.9). It will be understood that carbon counts for
substituted groups include any carbon atoms of substituents. For
example, the C.sub.1-8-alkylene group in "substituted
--C(.dbd.O)--(C.sub.1-8-alkylene)-C(.dbd.O)--" has 1 to 8 carbon
atoms, including any carbon atoms derived from substitution.
[0012] As used herein, the term "hydrocarbyl", whether used by
itself, or as a prefix, suffix, or fragment of another term, refers
to a residue that contains only carbon and hydrogen unless
otherwise specified. The hydrocarbyl residue can be aliphatic or
aromatic, straight-chain, cyclic, bicyclic, polycyclic, or
branched, saturated or unsaturated. It can also contain
combinations of aliphatic, aromatic, straight chain, cyclic,
bicyclic, polycyclic, and branched groups, as well as saturated and
unsaturated hydrocarbon moieties. When the hydrocarbyl residue is
described as substituted, it can contain heteroatoms in addition to
carbon and hydrogen.
[0013] One embodiment is a photoacid-generating compound having the
structure
##STR00009##
wherein R.sup.1, R.sup.2, R.sup.3, R.sup.4, Q, and X are defined
herein. No particular stereochemistry is implied or required for
the ring carbon atoms bearing the R.sup.3 and R.sup.4
substituents.
[0014] In the photoacid-generating compound structure, R.sup.1 is a
C.sub.6-20 polycyclic hydrocarbyl group comprising a hydroxyl
group, a lactone group, or a combination thereof. In some
embodiments, R.sup.1 is
##STR00010##
[0015] R.sup.2 is a C.sub.6-20 polycyclic hydrocarbyl group
comprising a hydroxyl group, a lactone group, or a combination
thereof, or
--[(CH.sub.2).sub.n--Y--SO.sub.3.sup.-Z.sup.+],
wherein n is 0, 1, or 2; Y is a C.sub.1-4 alkylene group comprising
at least one fluorine atom, provided that when n is 0, Y is a
C.sub.2-4 alkylene group comprising at least one fluorine atom; and
Z.sup.+ is an organic cation. In some embodiments in which R.sup.2
is a C.sub.6-20 polycyclic hydrocarbyl group comprising a hydroxyl
group, a lactone group, or a combination thereof, R.sup.2 is
##STR00011##
In some embodiments in which R.sup.2 is
--[(CH.sub.2).sub.n--Y--SO.sub.3.sup.-Z.sup.+], n is 1. In other
such embodiments, n is 2. In some embodiments in which R.sup.2 is
--[(CH.sub.2).sub.n--Y--SO.sub.3.sup.-Z.sup.+], Y is --CF.sub.2--.
In other such embodiments, Y is --CF.sub.2CF.sub.2--.
[0016] When R.sup.2 is
--[(CH.sub.2).sub.n--Y--SO.sub.3.sup.-Z.sup.+], and in any other
compound or fragment in which Z.sup.+ appears, Z.sup.+ is an
organic cation. Organic cations include, for example, ammonium ion
substituted with 1 to 4 alkyl groups, aryl groups, or a combination
of alkyl and aryl groups; iodonium ions substituted with 2 alkyl
groups, aryl groups or a combination of alkyl and aryl groups; and
sulfonium ion substituted with 3 alkyl groups, aryl groups, or a
combination of alkyl or aryl groups. In some embodiments, Z.sup.+
is an iodonium or sulfonium cation. In some embodiments, Z.sup.+ is
an iodonium ion substituted with 2 alkyl groups, aryl groups or a
combination of alkyl and aryl groups; or a sulfonium ion
substituted with 3 alkyl groups, aryl groups, or a combination of
alkyl or aryl groups.
[0017] In some embodiments, Z.sup.+ has the structure
##STR00012##
wherein T is I and m is 2, or T is S and m is 3; each R.sup.15 is
independently a halogen, --CN, --OH, a C.sub.1-10 alkyl group, a
C.sub.1-10 fluoroalkyl group, a C.sub.1-10 alkoxyl group, a
C.sub.1-10 fluoroalkoxyl group, a C.sub.3-10 cycloalkyl group, a
C.sub.3-10 fluorocycloalkyl group, a C.sub.3-10 cycloalkoxyl group,
or a C.sub.3-10 fluorocycloalkoxy group; and each n is an integer
of 0, 1, 2, 3, 4, or 5.
[0018] In some embodiments, Z.sup.+ has the structure
##STR00013##
[0019] In other embodiments, Z.sup.+ has the structure
##STR00014##
wherein R.sup.16, R.sup.17, R.sup.18, R.sup.19, R.sup.20, R.sup.21,
and R.sup.22 are each independently a halogen, --CN, --OH, a
C.sub.1-10 alkyl group, a C.sub.1-10 fluoroalkyl group, a
C.sub.1-10 alkoxyl group, a C.sub.1-10 fluoroalkoxyl group, a
C.sub.3-10 cycloalkyl group, a C.sub.3-10 fluorocycloalkyl group, a
C.sub.3-10 cycloalkoxyl group, or a C.sub.3-10 fluorocycloalkoxy
group, each of which except a halogen, --CN, and --OH may be
substituted or unsubstituted; J is a single bond or a divalent
group selected from --S--, --O--, and --C(.dbd.O)--; each
occurrence of p is independently an integer of 0, 1, 2, 3, or 4; r
is 0, 1, 2, 3, 4, or 5; and s and t are each independently 0, 1, 2,
3, or 4. R.sup.16, R.sup.17, R.sup.18, R.sup.19, R.sup.20,
R.sup.21, and R.sup.22 may optionally comprise an acid cleavable
group, for example, a C.sub.6-10 alkoxycarbonylalkyleneoxyl group.
An example of a C.sub.6-10 alkoxycarbonylalkyleneoxyl group is
t-butyloxycarbonylmethoxyl group as shown in the following
compounds:
##STR00015## ##STR00016##
[0020] In other embodiments, Z.sup.+ has the structure
##STR00017## ##STR00018##
[0021] In another embodiment, Z.sup.+ has the structure
##STR00019##
wherein Ar is a C.sub.5-30 unsubstituted or substituted aromatic
group and R.sup.23 and R.sup.24 are each independently a C.sub.1-10
alkyl group, wherein R.sup.23 and R.sup.24 are optionally connected
together to form a ring. Examples of sulfonium cations in which
R.sup.23 and R.sup.24 are connected together to form a ring are
##STR00020##
[0022] In the photoacid-generating compound structure, R.sup.3 and
R.sup.4 are each independently hydrogen, cyano, C.sub.1-6 alkyl,
C.sub.1-6 fluoroalkyl, optionally substituted C.sub.6-12 aryl, or
--C(O)O--R.sup.11 wherein R.sup.11 is a C.sub.1-20 alkyl group
optionally comprising one or more heteroatoms, each of which can be
present in a substituent or replacing a carbon atom in the alkyl
group framework. In some embodiments, R.sup.3 and R.sup.4 are
hydrogen.
[0023] In the photoacid-generating compound structure, Q is
##STR00021##
wherein R.sup.5 and R.sup.6 are each independently hydrogen;
fluorine; cyano; trifluoromethyl; C.sub.1-6 alkyl; C.sub.6-20
hydrocarbyl comprising a lactone group; or --OR.sup.12 wherein
R.sup.12 is C.sub.1-20 alkyl (including C.sub.1-6 alkyl and
C.sub.6-20 polycyclic alkyl) or C.sub.6-20 hydrocarbyl comprising a
lactone group. R.sup.7, R.sup.8, R.sup.9, and R.sup.10 are each
independently hydrogen; hydroxyl; --OR.sup.13 wherein R.sup.13 is a
C.sub.1-20 hydrocarbyl group optionally comprising one or more
heteroatoms; --SR.sup.13 wherein R.sup.13 is defined above;
--OC(O)R.sup.13 wherein R.sup.13 is defined above;
--N(R.sup.14)C(O)R.sup.13 wherein R.sup.13 is defined above and
R.sup.14 is hydrogen or a C.sub.1-20 hydrocarbyl group optionally
comprising one or more heteroatoms;
--[OC(O)C(R.sup.a).dbd.CH.sub.2] wherein R.sup.a is hydrogen or
fluoro or cyano or C.sub.1-10 alkyl or C.sub.1-10 fluoroalkyl;
--[O--(CH.sub.2).sub.n--Y--SO.sub.3.sup.-Z.sup.+] wherein n, Y, and
Z.sup.+ are defined above,
--[S--(CH.sub.2).sub.n--Y--SO.sub.3.sup.-Z.sup.+] wherein n, Y, and
Z.sup.+ are defined above, or
--[O--C(O)--(CH.sub.2).sub.n--Y--SO.sub.3.sup.-Z.sup.+] wherein n,
Y, and Z.sup.+ are defined above. In some embodiments in which
R.sup.13 comprises a heteroatom, it comprises a lactone group. In
some embodiments in which R.sup.13 comprises a heteroatom, it does
not comprise a hydroxyl group.
[0024] In the photoacid-generating compound structure, X is
--CH.sub.2--, --O--, --C(O)--, --S(O)--, or --S(O).sub.2--. In some
embodiments, X is --CH.sub.2--.
[0025] There are certain limitations on the structure of the
photoacid-generating compound. First, the photoacid-generating
compound comprises exactly one occurrence of
--[(CH.sub.2).sub.n--Y--SO.sub.3.sup.-Z.sup.+]. This includes
occurrences in which the
--[(CH.sub.2).sub.n--Y--SO.sub.3.sup.-Z.sup.+] group is linked to
the polycyclic nucleus via --O-- or --S-- or --OC(O)--. Second, the
photoacid-generating compound comprises 1 or 2 occurrences of the
C.sub.6-20 polycyclic hydrocarbyl group comprising a hydroxyl
group, a lactone group, or a combination thereof. Third, the
photoacid-generating compound comprises 1, 2, or 3 total
occurrences of hydroxyl groups and lactone groups, which any
hydroxyl or lactone group in the molecule. Fourth, when Q is
##STR00022##
and R.sup.5, R.sup.6, R.sup.7, R.sup.8, R.sup.9, and R.sup.10 are
hydrogen, and R.sup.2 is
--[(CH.sub.2).sub.n--Y--SO.sub.3.sup.-Z.sup.+], then R.sup.1
excludes --C(O)O-- groups and --S(O).sub.2-- groups.
[0026] In a specific embodiment of the photoacid-generating
compound, Q is
##STR00023##
wherein R.sup.5 and R.sup.6 are hydrogen; and R.sup.2 is
--[(CH.sub.2).sub.n--Y--SO.sub.3.sup.-Z.sup.+],
wherein n is 0, 1, or 2; Y is a C.sub.1-4 alkylene group comprising
at least one fluorine atom, provided that when n is 0, Y is a
C.sub.2-4 alkylene group comprising at least one fluorine atom; and
Z.sup.+ is an organic cation.
[0027] In another specific embodiment of the photoacid-generating
compound, Q is
##STR00024##
wherein one of R.sup.7 and R.sup.8 is hydroxyl and the other of
R.sup.7 and R.sup.8 is hydrogen; one of R.sup.9 and R.sup.10 is
--[O--(CH.sub.2).sub.n--Y--SO.sub.3.sup.-Z.sup.+],
--[OC(O)--(CH.sub.2).sub.n--Y--SO.sub.3.sup.-Z.sup.+], or
--[S--(CH.sub.2).sub.n--Y--SO.sub.3.sup.-Z.sup.+], and the other of
R.sup.9 and R.sup.10 is hydrogen; and R.sup.2 is a C.sub.8-12
polycyclic hydrocarbyl group comprising a hydroxyl group, a lactone
group, or a combination thereof.
[0028] In another specific embodiment of the photoacid-generating
compound, Q is
##STR00025##
wherein R.sup.7 and R.sup.9 are hydrogen; wherein one of R.sup.8
and R.sup.10 is --[O--(CH.sub.2).sub.n--Y--SO.sub.3.sup.-Z.sup.+]
or --[S--(CH.sub.2).sub.n--Y--SO.sub.3.sup.-Z.sup.+] or
--[O--C(O)--(CH.sub.2).sub.n--Y--SO.sub.3.sup.-Z.sup.+] wherein n
is 0, 1, or 2, Y is a C.sub.1-4 alkylene group comprising at least
one fluorine atom, and Z.sup.+ is an organic cation, and the other
of R.sup.8 and R.sup.10 is hydrogen; and R.sup.2 is a C.sub.8-12
polycyclic hydrocarbyl group comprising a hydroxyl group, a lactone
group, or a combination thereof.
[0029] In another specific embodiment of the photoacid-generating
compound, Q is
##STR00026##
and R.sup.2 is
[0030] --[(CH.sub.2).sub.n--Y--SO.sub.3.sup.-Z.sup.+],
wherein n is 0, 1, or 2; Y is a C.sub.1-4 alkylene group comprising
at least one fluorine atom, provided that when n is 0, Y is a
C.sub.2-4 alkylene group comprising at least one fluorine atom; and
Z.sup.+ is an organic cation.
[0031] In some embodiments, the photoacid-generating compound is
selected from the group consisting of
##STR00027## ##STR00028##
wherein Z.sup.+ is an organic cation.
[0032] In some embodiments, the photoacid-generating compound
comprises a polymerizable group and can be used as a monomer to
form photoresist copolymers. For example, in some embodiments, Q
is
##STR00029##
wherein one of R.sup.7 and R.sup.9 is hydrogen or hydroxyl and the
other of R.sup.7 and R.sup.9 is hydrogen; wherein one of R.sup.8
and R.sup.10 is --[OC(O)C(R.sup.a).dbd.CH.sub.2] wherein R.sup.a is
hydrogen, fluoro, cyano, C.sub.1-10 alkyl, or C.sub.1-10
fluoroalkyl, and the other of R.sup.8 and R.sup.10 is hydrogen; and
wherein R.sup.2 is
--[(CH.sub.2).sub.n--Y--SO.sub.3.sup.-Z.sup.+],
wherein n is 0, 1, or 2; Y is a C.sub.1-4 alkylene group comprising
at least one fluorine atom, provided that when n is 0, Y is a
C.sub.2-4 alkylene group comprising at least one fluorine atom; and
Z.sup.+ is an organic cation.
[0033] Another embodiment is a polymer comprising repeat units
derived from the photoacid-generating compound comprising a
polymerizable group, such as, for example, the photoacid-generating
compound of the previous paragraph. In addition to repeat units
derived from the photoacid-generating compound comprising a
polymerizable group, the polymer can, optionally, further comprise
one or more of acid-labile monomers (including monomer comprising
tertiary ester groups, acetal groups, or ketal groups), base-labile
monomers (including monomers comprising lactone groups), and
base-ionizable monomers (including monomers comprising
1,1,1,3,3,3-hexafluoro-2-hydroxy-2-propyl groups,
--NHSO.sub.2CH.sub.3 groups, and --NHSO.sub.2CF.sub.3 groups).
[0034] Another embodiment is a photoresist composition comprising
the polymer of the previous paragraph.
[0035] Another embodiment is a photoresist composition comprising
the photoacid-generating compound, in any of its above-described
variations.
[0036] In addition to the photoacid-generating compound or a
polymer comprising the residue of the polymerizable
photoacid-generating compound, the photoresist composition can
further comprise one or more additional components, such as
photoinitiators, surfactants, quenchers, solvents, and combinations
thereof.
[0037] Photoinitiators are used in the photoresist composition for
initiating polymerization of the cross-linking agents by generation
of free-radicals. Suitable free radical photoinitiators include,
for example, azo compounds, sulfur containing compounds, metallic
salts and complexes, oximes, amines, polynuclear compounds, organic
carbonyl compounds and mixtures thereof as described in U.S. Pat.
No. 4,343,885, column 13, line 26 to column 17, line 18; and
9,10-anthraquinone; 1-chloroanthraquinone; 2-chloroanthraquinone;
2-methylanthraquinone; 2-ethylanthraquinone;
2-tert-butylanthraquinone; octamethylanthraquinone;
1,4-naphthoquinone; 9,10-phenanthrenequinone;
1,2-benzanthraquinone; 2,3-benzanthraquinone;
2-methyl-1,4-naphthoquinone; 2,3-dichloronaphthoquinone;
1,4-dimethylanthraquinone; 2,3-dimethylanthraquinone;
2-phenylanthraquinone; 2,3-diphenylanthraquinone;
3-chloro-2-methylanthraquinone; retenequinone;
7,8,9,10-tetrahydronaphthalenequinone; and
1,2,3,4-tetrahydrobenz(a)anthracene-7,12-dione. Other
photoinitiators are described in U.S. Pat. No. 2,760,863 and
include vicinal ketaldonyl alcohols, such as benzoin, pivaloin,
acyloin ethers, e.g., benzoin methyl and ethyl ethers; and
alpha-hydrocarbon-substituted aromatic acyloins, including
alpha-methylbenzoin, alpha-allylbenzoin, and alpha-phenylbenzoin.
Photoreducible dyes and reducing agents disclosed in U.S. Pat. Nos.
2,850,445; 2,875,047; and 3,097,096 as well as dyes of the
phenazine, oxazine, and quinone classes; benzophenone,
2,4,5-triphenylimidazolyl dimers with hydrogen donors, and mixtures
thereof as described in U.S. Pat. Nos. 3,427,161; 3,479,185; and
3,549,367 can be also used as photoinitiators.
[0038] Illustrative surfactants include fluorinated and
non-fluorinated surfactants, and are preferably non-ionic.
Exemplary fluorinated non-ionic surfactants include perfluoro
C.sub.4 surfactants such as FC-4430 and FC-4432 surfactants,
available from 3M Corporation; and fluorodiols such as POLYFOX
PF-636, PF-6320, PF-656, and PF-6520 fluorosurfactants from
Omnova.
[0039] Suitable quenchers include, for example, those based on
hydroxides, carboxylates, amines, imines and amides. Such quenchers
include C.sub.1-30 organic amines, imines or amides, C.sub.1-30
quaternary ammonium salts of strong bases (e.g., a hydroxide or
alkoxide) or a weak base (e.g., a carboxylate). In some
embodiments, the photoresist composition further comprises a
quencher selected from the group consisting of C.sub.1-30 amines,
C.sub.1-30 amides, and combinations thereof. Exemplary quenchers
include amines such as Troger's base; hindered amines such as
diazabicycloundecene (DBU), diazabicyclononene (DBN), and
tetrahydroxy isopropyl diamine and
tert-butyl-4-hydroxy-1-piperidiene carboxylate; ionic quenchers
including quaternary alkyl ammonium salts such as
tetrabutylammonium hydroxide (TBAH), tetramethylammonium
2-hydroxybenzoic acid (TMA OHBA), and tetrabutylammonium lactate.
Suitable quenchers are further described in U.S. Pat. No. 8,431,325
to Hashimoto et al.
[0040] The photoresist composition components are typically
dissolved in a solvent for dispensing and coating. Exemplary
solvents include anisole; alcohols including 1-methoxy-2-propanol,
and 1-ethoxy-2-propanol; esters including n-butyl acetate, ethyl
lactate, 1-methoxy-2-propyl acetate, methoxyethoxy propionate, and
ethoxyethoxy propionate; ketones including cyclohexanone and
2-heptanone; and combinations thereof. The solvent amount can be,
for example, 70 to 99 weight percent, specifically 85 to 98 weight
percent, based on the total weight of the photoresist
composition.
[0041] The invention further includes a method of forming a
photoresist relief image, comprising: (a) applying a layer of the
photoresist composition on a substrate to form a photoresist layer;
(b) pattern-wise exposing the photoresist layer to activating
radiation to form an exposed photoresist layer; and (c) developing
the exposed photoresist layer to provide a photoresist relief
image. The method can, optionally, further include (d) etching the
resist relief pattern into the underlying substrate. In this
embodiment, the photoresist composition can be the photoresist
composition incorporating the photoacid-generating compound, or
incorporating a polymer comprising a repeat unit derived from a
polymerizable embodiment of the photoacid-generating compound. In
some embodiments, the pattern-wise exposing comprises exposing with
radiation at 193 or 248 nanometers. In other embodiments, the
pattern-wise exposing comprises exposing with electron beam or
extreme ultraviolet radiation.
[0042] All ranges disclosed herein are inclusive of the endpoints,
and the endpoints are independently combinable with each other.
Each range disclosed herein constitutes a disclosure of any point
or sub-range lying within the disclosed range.
[0043] The invention is further illustrated by the following
non-limiting examples.
EXAMPLE 1
Synthesis of Photoacid Generator Compound TPS NB-AdOH-DFES
[0044] FIG. 1 presents a chemical scheme for the synthesis of the
photoacid generator compound referred to as TPS NB-AdOH-DFES. The
synthesis process was as follows. To a suspension of
5-norbornene-2,3-dicarboxylicanhydride (20 grams, 122 millimoles)
and 3-(hydroxymethyDadamantan-1-ol (22.2 grams, 121.8 millimoles)
in acetonitrile (150 milliliters) was added
N,N-dimethylaminopyridine (1.5 grams, 12.27 millimoles) and the
reaction mixture was stirred at 65.degree. C. for 18 hours. The
mixture was cooled to room temperature and concentrated aqueous
hydrochloric acid was added until the pH was reduced to 2. The
crude product was filtered and dried, before being suspended in
ethyl acetate (150 milliliters) and stirred for 30 minutes at room
temperature. Filtration produced 28 grams (yield: 66%) of pure
product (1) as a white solid. .sup.1H NMR (acetone-d6) .delta.:
6.22 (m, 1H), 6.17 (m 1H), 3.69 (d, 2H), 3.53 (d, 2H), 3.40 (m,
2H), 3.14 (m, 2H), 2.17 (s, 2H), 1.41-1.67(m, 15H).
[0045] Compound 1 (20 grams, 57.7 millimoles) was dissolved in 100
milliliters pyridine, and 1,1'-carbonyldiimidazole (CDI, 9.36
grams, 57.7 millimoles) was added to the solution. The mixture was
stirred at room temperature for 2 hours and then warmed to
90.degree. C. Then, 25.0 grams of salt 3 (triphenylsulfonium
1,1-difluoro-2-hydroxyethanesulfonate or TPS OHDFES, synthesized
according to reported procedure in U.S. Patent Application
Publication No. US 2009/0202943 A1) and 4-dimethylaminopyridine
(DMAP. 7.0 grams, 57.3 millimoles) were added, and the mixture was
stirred at 100.degree. C. for 24 hours. The reaction mixture was
cooled to room temperature and poured into 3 Normal aqueous
hydrochloric acid (200 milliliters) and crushed ice (200 grams),
and the resulting sticky solid was isolated by decanting the
liquids. The sticky residue was dissolved in dichloromethane (100
milliliters) and the solution was washed twice with 100 milliliters
0.1 Normal aqueous hydrochloric acid, once with 100 milliliters 0.1
Normal aqueous sodium hydroxide, and then five times with deionized
water. The organic phase was concentrated under reduced pressure
and the concentrated solution was poured slowly into methyl-t-butyl
ether (20 volumes) to produce the product as white solid. The
product was dried under vacuum. Yield: 19.0 g (44%). .sup.1H NMR
(acetone-d6 .delta.): 7.98-7.88 (m, 15H), 6.33 (m, 1H), 6.11 (m,
1H), 3.70 (s, 2H), 3.32-3.45 (m, 4H), 2.91 (m, 2H), 2.18 (s, 2H),
1.41-1.67 (m, 15H). .sup.19F NMR (acetone-d6) .delta.: -115.71 (s,
2F).
EXAMPLE 2
Acid Diffusion Length Evaluation
[0046] Acid diffusion length was determined as follows. An acid
detector layer formulation was prepared by combining Polymer A1
(2-adamantyl-2-propyl methacrylate/alpha-(gamma-butyrolactone)
methacrylate/1-hydroxyadamantyl-3-methacrylate terpolymer, 30/50/20
molar ratio, Mw=10,000 grams/mole) shown below (5.981 weight
percent of total formulation), and
tent-butyl-4-hydroxypiperdine-1-carboxylate as a quencher (0.019
weight percent of total formulation) in a 50/50 (w/w) mixture of
propylene glycol methyl ether acetate (PGMEA) and methyl
2-hydroxyisobutyrate (HBM).
##STR00030##
Separately, an acid source layer formulation was prepared by
combining a tent-butyl acrylate/methacrylic acid copolymer (70/30
molar ratio, respectively; 0.891% w/w solution) and photoacid
generator compound PAG (inventive or comparative) (153.40
micromoles/gram based on the total formulation) in an 80/20
(weight/weight) mixture of 2-methyl-1-butanol and decane. The acid
detector layer formulation and acid source layer solutions were
each filtered separately using a 0.2 micrometer
polytetrafluoroethylene (PTFE) syringe filter.
[0047] The substrate (Si wafer, 200 millimeter diameter) was coated
with AR.TM.77 antireflective coating (Rohm and Haas Electronic
Materials, Marlborough, Mass.) and baked at 205.degree. C. for 60
seconds to form an antireflective layer of 84 nanometer thickness.
A 120 nanometer thickness of the acid detector layer formulation
was coated on the antireflective layer and baked at 110.degree. C.
for 60 seconds. The acid source layer formulation was then coated
on the acid detector layer and baked at 90.degree. C. for 60
seconds. All coating processes were carried out on a TEL ACT 8
coating track manufactured by Tokyo Electron.
[0048] The coated wafer was then open-frame exposed over 100 dose
increments (separate doses) starting from an initial dose of 1
millijoule/centimeter.sup.2 (mJ/cm.sup.2) at increments of 0.2
mJ/cm.sup.2 using a 193 nanometer exposure tool (ASML 1100 Stepper)
and annular illumination. The wafer was post-exposure baked (PEB)
at 100.degree. C. for 60 seconds or 110.degree. C. for 60 seconds.
During the PEB step the acid released during exposure in the acid
source layer diffused into the acid detector layer causing
deprotection of the acid labile group of the polymer of the acid
detector layer. After PEB, the pattern was developed using 0.26
Normal aqueous tetramethylammonium hydroxide (TMAH) solution. The
film thickness difference between the unexposed regions and exposed
regions of the pattern is the total film thickness loss (.DELTA.L).
The greater the film thickness loss in the exposed region, the
greater the acid diffusion.
[0049] The diffusivity of the PAG, D, is defined by Fick's law of
diffusion (equation 1):
D=(.DELTA.L/2 * erfc E.sub.th/E).sup.2/t.sub.PER (equation 1)
where .DELTA.L is the difference in thickness between the exposed
and unexposed areas (also referred to herein as the film thickness
loss), t.sub.PEB is the PEB time, erfc is the error function
complement, E.sub.th is the exposure dose (in mJ/cm.sup.2) at which
film thickness loss was observed for the first time, and E is the
exposure dose (in mJ/cm.sup.2). Once the diffusivity was
determined, the diffusion length, DL, was then calculated using
equation 2:
DL=2*(D*t.sub.PEB).sup.1/2 (equation 2)
The diffusion length data for PAG in accordance with the invention
and comparative PAGs are summarized below in Table 1. Chemical
structures of the comparative PAGs are shown below the table.
TABLE-US-00001 TABLE 1 Comparative Comparative Comparative TPS NB-
PAG 1 PAG 2 PAG 3 AdOH-DFES DL (nm) at 10.9 8.1 5.1 2.6 PEB
100.degree. C. DL (nm) at 37.4 21.9 19.4 18.2 PEB 110.degree. C.
##STR00031## ##STR00032## ##STR00033##
[0050] As can be seen in Table 1, the acid diffusion measurements
indicate shorter acid diffusion length for acid generated from PAG
according to the invention in comparison with the comparative
PAGs.
EXAMPLE 3
Lithographic Evaluation
[0051] Lithographic evaluation of the exemplary PAG was carried out
according to the following procedure. Photoresists were formulated
using the components and proportions shown in Table 2. The
photoresist polymer ("Polymer A2") used in all examples was a
pentapolymer incorporating monomers M1, M2, M3, M4 and M5 having
the chemical structures shown below, where the mole percentage of
M1/M2/M3/M4/M5 is 20/20/30/20/10 for a total of 100 mole percent of
monomers. The weight average molecular weight of the polymer was
8,000 grams/mole.
##STR00034##
The PAG (see Table 2), base (t-butyloxycarbonyl-4-hydroxypyridine
(TBOC-4HP), and surface leveling agent (PF 656 surfactant,
available from Omnova), are given as weight percent based on 100%
solids content, with the balance of the solids being the polymer.
Propylene glycol monomethyl ether acetate (51) and
methyl-2-hydroxyisobutyrate (55) were used as the solvents. The
weight ratio of solvent S1:S5 in the final formulation was 1:1. The
final percent solids in each of the Comparative Examples 1 and 2,
and in the Example, was 4 weight percent (wt %).
[0052] Photoresist formulation compositions for Comparative
Examples A1 and A2 and Example B are shown in Table 2 below.
TABLE-US-00002 TABLE 2 PAG PAG wt % Base wt % SLA wt % C. Ex. A1
Triphenylsulfonium 9.59 1.03 0.1 perfluorobutane-sulfonate C. Ex.
A2 Comparative PAG 3 10.27 1.03 0.1 Ex. B TPS NB-AdOH-DFES 12.83
1.03 0.1
[0053] The Table 2 photoresists were lithographically processed as
follows. The photoresist was spin coated onto a 200 millimeter
diameter silicon wafer having an 84 nanometer thickness of an
organic antireflective coating (AR.TM.77, Dow Electronic Materials)
and baked at 110.degree. C. for 60 seconds, to form a resist film
100 nanometers in thickness. The photoresist was exposed with ArF
excimer laser (193 nanometers) through a mask pattern targeting a
line and space pattern (L/S pattern) having a line width of 90
nanometers and a pitch of 180 nanometers, using an ArF exposure
apparatus ASML-1100 (manufactured by ASML), NA (numerical
aperture)=0.75 under annular illumination with outer/inner sigma of
0.89/0.64 with focus offset/step of 0.10/0.05. The wafers were post
exposure baked (PEB) at 100.degree. C. for 60 seconds followed by
developing with 0.26 Normal aqueous tetramethylammonium hydroxide
(TMAH) developer and subsequent water wash.
[0054] In each example, a line/space pattern having a line width of
90 nanometers and a pitch of 180 nanometers was formed. Line Width
Roughness (LWR) was determined by processing the image captured by
top-down scanning electron microscopy (SEM) using a Hitachi 9380
CD-SEM, operating at an accelerating voltage of 800 volts (V),
probe current of 8.0 picoamperes (pA), and 200 K.times.
magnification. The Clearing Dose, E.sub.0 (mJ/cm.sup.2), is the
amount of exposure energy required to clear the resist. E.sub.0 is
determined from the resist contrast curve, which is a plot of the
film thickness of resist remaining after exposure and development
as a function of exposure energy. The exposure at which the film
clears completely is the clearing dose. The Dose-To-Size,
E.sub.size (mJ/cm.sup.2), is the amount of the exposure energy
required to produce a line/space pattern having a line width of 90
nanometers and a pitch of 180 nanometers.
[0055] The results from the lithographic evaluation of the above
photoresist formulations are shown in Table 3.
TABLE-US-00003 TABLE 3 C. Ex. A1 C. Ex. A2 Ex. B E.sub.0
(mJ/cm.sup.2) 5.2 9.6 10.2 E.sub.size (mJ/cm.sup.2) 22.5 44.8 48.1
LWR 3.sigma. (nm) 12.8 12.4 12.0
[0056] As seen in Table 3, inventive Example B, which includes the
PAG designated TPS NB-AdOH-DFES, showed improved (reduced) Line
Width Roughness relative to the comparative examples.
EXAMPLE 4
Solubility Test
[0057] The photoacid generators were evaluated for solubility in a
selection of organic solvents useful as formulation solvents or as
negative tone photoresist developers. Solubility of each of the
compounds was obtained for attempts to completely dissolve the
compound at 2 weight percent at room temperature (23.degree. C.).
The results for the solubility tests are shown in Table 4. Clearly,
the PAG from the invention TPS NB-AdOH-DFES has better solubility
in formulation solvents such as propyleneglycol monomethyl ether
acetate and propyleneglycol monomethyl ether, as well as in
solvents that can be used as negative tone organic developers, such
as 2-hepanone and n-butyl acetate.
TABLE-US-00004 TABLE 4 PAG Comparative TPS Solvent PAG 3
NB-AdOH-DFES Propyleneglycol monomethyl ether X .largecircle.
acetate Ethyl lactate .largecircle. .largecircle. Propyleneglycol
monomethyl ether X .largecircle. Methyl-2-hydroxyisobutyrate
.largecircle. .largecircle. 2-heptanone X .largecircle. n-butyl
acetate X .largecircle. .largecircle.: compound soluble at 2 wt %
X: compound is insoluble at 1%
* * * * *