U.S. patent application number 10/996560 was filed with the patent office on 2005-04-28 for acid generator and thin film composition containing the same.
This patent application is currently assigned to KOREA KUMHO PETROCHEMICAL CO., LTD.. Invention is credited to Kim, Seong Ju, Lee, Joung Bum, Park, Joo Hyeon.
Application Number | 20050090605 10/996560 |
Document ID | / |
Family ID | 29208776 |
Filed Date | 2005-04-28 |
United States Patent
Application |
20050090605 |
Kind Code |
A1 |
Park, Joo Hyeon ; et
al. |
April 28, 2005 |
Acid generator and thin film composition containing the same
Abstract
The present invention relates to the compounds generating strong
acids (described hereafter as "acid generators") decomposed by heat
and the composition of thin film containing the same. Provided are
the compounds represented by the structure of formula I and the
composition containing the compounds. 1 wherein X is alkyl or aryl
group and R is hydrogen atom, hydroxy, alkoxy or alkyl group. The
abovementioned acid generators of the present invention generate
acid by heat at relatively low temperatures, preventing the change
in the ratio of the composition due to evaporation of some
components in the composition. Accordingly, it has the advantageous
effect that the ratio of components in the composition is
controlled and the preparation of the thin film with the wanted
properties is simplified.
Inventors: |
Park, Joo Hyeon; (Chonan-si,
KR) ; Lee, Joung Bum; (Asan-si, KR) ; Kim,
Seong Ju; (Asan-si, KR) |
Correspondence
Address: |
SQUIRE, SANDERS & DEMPSEY L.L.P
600 HANSEN WAY
PALO ALTO
CA
94304-1043
US
|
Assignee: |
KOREA KUMHO PETROCHEMICAL CO.,
LTD.
Seoul
KR
|
Family ID: |
29208776 |
Appl. No.: |
10/996560 |
Filed: |
November 23, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10996560 |
Nov 23, 2004 |
|
|
|
10421490 |
Apr 22, 2003 |
|
|
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Current U.S.
Class: |
524/556 ;
525/330.3; 525/333.3 |
Current CPC
Class: |
G03F 7/0382 20130101;
G03F 7/0045 20130101; G03F 7/038 20130101 |
Class at
Publication: |
524/556 ;
525/330.3; 525/333.3 |
International
Class: |
G03C 001/492 |
Foreign Application Data
Date |
Code |
Application Number |
May 2, 2002 |
KR |
10-2002-0024082 |
Claims
1. A composition of a thin film comprising the compound represented
by the structure of the formula I 13wherein X is alkyl or aryl
group and R is hydrogen atom, hydroxy group, alkoxy group or alkyl
group; cross linking agent, resin, additives and solvents.
2. (canceled)
3. (canceled)
4. The composition of the thin film as set forth in claim 1,
wherein the resin is selected more than one from the group of
polyhydroxystyrene, polystyrene and polyacrylate.
5. The composition of the thin film comprising the compounds of
claim 1, cross linking agent, additives and solvents.
6. The composition of the thin film as set forth in claim 1 or
claim 5, wherein the cross linking agents is the polymer
represented by the structure of formula II. 14wherein R1 and R2
both are alkyl group and m/(m+n) is in the range of 0.3 to 0.8.
7. The composition of the thin film as set forth in claim 1 or
claim 5, wherein the cross linking agent is the polymer represented
by the structure of formula III. 15wherein R3 and R4 are all
hydrogen atoms or alkyl groups, R5 is hydrogen atom, alkoxy group,
hydroxyalkyl epoxyalkyl group, alkoxyalkyl group or hydroxy group
and m'/(m'+n') is in the range of 0.2 to 1.0.
8. The composition of the thin film as set forth in claim 1 or
claim 5, wherein the cross linking agent is the polymer represented
by the structure of formula IV. 16wherein R6 and R8 are hydrogen
atom or methyl group, R7 is hydrogen atom, alkoxy group,
hydroxyalkyl epoxyalkyl group, alkoxyalkyl or hydroxy group group,
R9 and R10 are alkyl groups and m"/(m"+n") is in the range of 0.2
to 1.0.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to the compounds generating
strong acids (described hereafter as "acid generators", decomposed
by heat and the composition of thin films containing the same.
Particularly, the present invention relates to the composition
which maintains the thin film notwithstanding the severe condition
because of the cross linking reaction carried out by the generated
acid.
[0003] 2. Description of the Related Arts
[0004] In recent years, great interests are shown on the thin film
as the industrial sectors develop rapidly. The thin film technology
is used in the processes of ultra fine semiconductors as well as in
the household electronic products and furniture. For example, an
organic thin film composition is used in the manufacturing process
of semiconductor to shield the reflection of light from the bottom
layer and to increase the adhesive strength to the substrate. In
case it is not shielded, deformation in the ultra fine pattern
occurs. When the substrate coated by thin film is exposed to the
ArF eximer laser, the light of 193 nm wave length is reflected by
the substrate, making the patterns change. The thin film technology
is utilized also in the manufacturing process of LCD, to protect
the top part of the color filter and the thin film is used as a
means to protect the surface of the household electronic products
and the furniture.
[0005] The technology of making thin films is categorized into two
methods according to the catalyst employed. One method is the
technology using radical initiator. The frequently used resin in
this case is acrylate derivatives. The functional group
participating in the reaction is the unreacted acrylate. The other
method is the technology using cation catalyst in making the thin
films. The resin generally used in the process is the acrylates
derivatives containing epoxy group. The epoxy group easily goes
into cross linking reaction by strong acids.
[0006] The technology using radical initiator to make the thin
films has to be blocked from oxygen in the air, making the process
problematic, while the technology of using cation catalyst has the
advantage of not needing the oxygen blockade.
[0007] The cation catalysts are grouped into the compounds
according to their characteristics whether generation of acid is by
light or by heat. The compounds generating acid by light include
iodonium salts, sulfonium salts, phosphonium salts, diazonium
slats, pyridinium salts and amides. The compound generating acid by
heat includes sec-alkyl-p-toluenesulfonat- e.
[0008] The acid generators by heat or light has to possess both
appropriate stability and the property of decomposing by heat
according to the uses. When the acid generator decomposes easily by
heat or during storage period, it loses the product value, while it
also loses the product value when it is too stable to heat because
it lacks in reactivity.
SUMMARY OF THE INVENTION
[0009] The present invention is to provide novel acid generators
which are stable during the long storage period and under the
intended temperature in consideration of the above needs.
[0010] Other object of the present invention is to provide the
composition containing the abovementioned novel acid
generators.
[0011] These objects of the present invention are accomplished by
the novel acid generators represented by the structure of the
following formula I. 2
[0012] wherein X is alkyl or aryl group and R is hydrogen atom,
hydroxy group, alkoxy group or alkyl group.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] The above and other objects, features and other advantages
of the present invention will be more clearly understood from the
following detailed description taken in conjunction with the
accompanying drawing, in which:
[0014] FIG. 1 is the NMR diagram of the novel acid generator of the
present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0015] In the following is the illustration of the general
properties of the acid generators, exhibited by the compound of the
chemical formula I which is the acid generator of formula I wherein
X is toluene group. 3
[0016] When heat or acid is added to the compound represented by
the chemical formula I, decomposition reaction occurs around
110.degree. C. and the mechanism of decomposition is as in the
following reaction scheme I. 4
[0017] The compound of the chemical formula I is decomposed by heat
into olefin and toluenesulfonic acid. The generated toluenesulfonic
acid having functions as a strong acid in the thin film
composition. The FIG. 1 is NMR (nuclear magnetic resonance) diagram
which identifies the structure of the chemical formula I.
[0018] The conventionally used sec-alkyl-p-toluenesulfonate has the
higher decomposition temperature of 150.degree. C. Because of this
high temperature, it has shortcomings in that the volatile
components of the thin film composition evaporate easily.
[0019] The major constituents of the thin film composition
including the above acid generator are the compounds which have the
functional group reacting in the cross linking reaction(described
hereafter as "cross linking agent"), acid generator, resin, some
additive and the solvent dissolving these materials.
[0020] Cross Linking Agent
[0021] A cross linking agent is a modifier of the original property
of a compound by the reaction with acid, light or radical
initiator. Examples are the compounds represented by the structure
of the general formula II, III and IV. 5
[0022] In the formula II, R1 and R2 both are alkyls and m/(m+n) is
in the range of 0.3 to 0.8.
[0023] In the formula III, R3 and R4 are all hydrogen atoms or
alkyl groups, R5 is hydrogen atom, alkoxy group, hydroxyalkyl
epoxyalkyl group, alkoxyalkyl group or hydroxy group and m'/(m'+n')
is in the range of 0.2 to 1.0.
[0024] In the formula IV, R6 and R8 are hydrogen atom or methyl
group, R7 is hydrogen atom, alkoxy group, hydroxyalkyl epoxyalkyl
group, alkoxyalkyl group or hydroxy group, R9 and R10 are alkyl
groups and m"/(m"+n") is in the range of 0.2 to 1.0.
[0025] The compound represented by the formula II is the resin of
acrolein polymer, part of which is acetalized by alcohol. This
compound produces high molecular compounds by going into cross
linking reaction with alcohol or phenol under the acid
catalyst.
[0026] The compound represented by the formula III is easily
synthesized by usual radical reaction. The compound goes into cross
linking reaction with tetrahydrofurfuryl group. The functional
group proceeds into cross linking reaction by opening the ring
under the strong acid catalysts. The cross linking reaction either
proceeds alone or with alcohols or phenols.
[0027] The compound represented by the formula IV is a modified
acrolein polymer copolymerized with other monomer to improve its
shortcoming of solubility in general solvents. This polymer and the
intermediate have the advantage of good solubility.
[0028] Acid Generator
[0029] The acid generators are grouped into two categories of
generating acid by either heat or light according to molecular
characteristics. The compounds generating acid by light include
onium types such as iodonium salts, sulfonium salts, phosphonium
salts, diazonium slats, pyridinium salts and amides. The other kind
of compound generating acid by heat includes
sec-alkyl-p-toluenesulfonate. Acid generators either by heat or
light are used according to different kinds of thin films. It is
better to use the acid generator by light when there is the chance
of deformation by heat. But the onium type has disadvantage of
being expensive. In some cases, solubility of the composition
decreases.
[0030] The novel acid generators of the present invention,
represented by the following formula I, have appropriate stability
and reactivity under heat. 6
[0031] wherein R is hydrogen atom, hydroxy, alkoxy or alkyl
group.
[0032] The characteristics of the compounds are in that they are
soluble in almost all organic solvents and have easy manufacturing
process, providing low cost thin films. Another advantage is that,
due to the property of norbomene, the compounds generate acid at a
low temperature, compared with other secondary alkyl group (for
example, cyclohexyl, isopropyl and cyclopentyl group). The
temperature of acid generation for usual secondary alky group is at
around 150.degree. C. while that of norbomanyl group is at around
110.degree. C. The temperature of acid generation is important
because at the temperature more that 130.degree. C., the volatile
components such as low molecular additives, evaporate, degrading
the properties of the thin film.
[0033] The acid generators described above are synthesized by
reacting olefin and epoxy compounds with alkyl sulfonic acid or
aryl sulfonic acid. The detailed synthetic method is described in
the examples of synthesis. The schematic reaction route is
illustrated in the following. 7
[0034] The reaction between norbornene and toluenesulfonic acid
proceeds very slowly and the temperature has to be raised to around
70.degree. C. But the reaction with expoxide compound proceeds very
rapidly at around 0.degree. C. Both compounds are used after
recrystalization in usual organic solvent after termination of the
reactions. The thin films are readily manufactured with these
compounds, yet for the specific properties and specific use of the
thin film, small amount of onium types such as iodonium salts,
sulfonium salts, phosphonium salt, diazonium salts, pyridinium
salts and amides are added.
[0035] Resin and Additives
[0036] When the cross linking agent is resin itself, another resin
is not needed according to the use. But for the optimization of the
wanted properties, addition of another resin is required. For
example for the bottom anti-reflective coating in the manufacturing
process of semiconductor, specific compounds or resins absorbing UV
light are used. In order to absorb UV light of 193 nm wave length,
the resins or compounds substituted with aromatic functional groups
are used and for the UV light of 248 nm wave length, anthracene
substituted resins and compounds are used. The resins absorbing UV
light of 193 nm wave length are polyhydroxystyrene, polyacrylate or
polystyrene.
[0037] For additives, utilized are a plasticizer for controlling
the strength of the thin film, polyhydroxy or epoxy compounds for
the effective proceeding of the cross linking reaction, surfactant
for uniformity of the thin film and homogenous mixing of the
solution and light induced acid generator of onium types such as
iodonium salts, sulfonium salts, phosphonium salt, diazonium salts,
pyridinium salts and amides when the composition is used for the
anti-reflective layer.
[0038] For the homogeneous and smooth coating layer by the thin
film composition, solvents with appropriate evaporation velocity
and viscosity are used to make solution. Such solvents include
ethyleneglycol monmethyl ether, ethyleneglycol monoethyl ether,
ethyleneglycol monopropyl ether, methylcellosolve acetate,
ethylcellosolve acetate, propyleneglycol monomethyl ether acetate,
propyleneglycol monoethyl ether acetate, propyleneglycol monopropyl
ether acetate, methyl isopropyl ketone, cyclohexanone, methyl
2-hydroxypropionate, ethyl 2-hydroxypropionate, 2-heptanone, ethyl
lactate or .gamma.-butyrolactone. In some cases, mixtures of more
than two of these compounds are used. The amount of solvents are
controlled appropriately to have homogeneity of the solution in
consideration of the evaporation and viscosity of the solvent.
[0039] The following examples are a detailed description of the
present invention. The examples are presented for illustrative
purposes only and are not intended as a restriction on the scope of
the present invention.
[0040] Synthesis 1--Synthesis of the Acid Generator Represented by
the Structure of Formula I 8
[0041] 100 g of norbornene and 100 g of toluenesulfonic acid were
added into 1 liter flask and dissolved in 500 ml of chloroform. The
solution was heated to 70.degree. C. and stirred for 5 hours. The
solution was cooled down to room temperature and washed with
aqueous Na2CO3 solution. The washed organic layer was washed more
than 2 times with distilled water and the solvent was completely
eliminated. The reaction mixture without the solvent was dissolved
in hexane and cooled down to 10.degree. C. to obtain white solids.
The solids were filtered and obtained 130 g of the compound
represented by formula I.
[0042] Synthesis 2--Synthesis of the Polymer Represented by the
Structure of Formula II 9
[0043] 50 g of acrolein and 100 ml of ethyl acetate were added into
250 ml flask and 6 g of AIBN was added and dissolved. The solution
was heated to 70.degree. C. and stirred for 12 hours. The solution
was cooled down to room temperature and the produced solids were
filtered and dried. The dried solids were put into 500 ml flask and
200 ml of methanol and 0.2 g of sulfuric acid were added and
stirred at 60.degree. C. for 15 hours. The solution was cooled down
to room temperature and neutralized with 0.5 ml of triethylamine.
The neutralized solution was slowly dropped into excess distilled
water to obtain while solids. The solids were filtered and dried to
obtain 58 g of the polymer of the formula II with m value around
0.6.
[0044] Synthesis 3--Synthesis of the Polymer Represented by the
Structure of Formula III 10
[0045] 16 g of tetrahydrofurfuryl methacrylate and 5 g of acrotein
were dissolved in 60 ml of isopropyl alcohol. 0.8 g of AIBN was
added and heated to 70.degree. C. The solution was stirred for 8
hour at this temperature and cooled to room temperature. The
solution was dropped slowly into excess distilled water. The
produced solids were dried and obtained 18 g of the polymer of the
formula III with m' value around 0.7.
[0046] Synthesis 4--Synthesis of the Polymer Rpresented by the
Structure of Formula IV 11
[0047] 100 g of methylacrylate, 100 g of acrolein and 10 g AIBN
were dissolved in 400 g of dioxane and the reaction temperature was
raised to 70.degree. C. After stirring at this temperature for 15
hours, the unreacted monomer and the solvent, dioxane, were
eliminated by vacuum distillation. Into the reactor, 400 g of
methanol and 1 g of sulfuric acid were added and reacted for 8 hour
at the same temperature. The reactants were cooled down to room
temperature and was dropped slowly into excess amount of distilled
water. The produced solids were dried and obtained 210 g of the
polymer of the formula IV with m" value of 0.4.
[0048] Synthesis 5--Synthesis of the Polymer Represented by the
Structure of Formula V 12
[0049] 50 ml of tetrahydrofurfuryl methacrylate and 33 g of methyl
methacrylate were dissolved in 100 ml of acetone. After adding 6 g
or AIBN, heated to 65.degree. C. and stirred for 6 hours. The
reactants were cooled down to room temperature, additional 300 ml
of acetone was added to dissolve and the solution was dropped
slowly into excess amount of distilled water. The produced solids
were dried and obtained 76 g of the polymer of the formula V with
m' value of 0.6.
EXAMPLE 1
[0050] 0.6 g of the polymer obtained in synthesis 2, 0.1 g of the
acid generator obtained in synthesis 1 and 0.4 g of
polyhydroxystyrene were dissolved in 45 g of propyleneglycol
methylether acetate and filtered with 0.2 .mu.m membrane filter to
make the composition for the thin film. The composition was spin
coated on the substrate and heated at 190.degree. C. for 90 seconds
to form the thin film (the anti-reflective film of blocking the
light of 193 nm wave length). On the thin film ArF resist was spin
coated and heated 90 seconds at 110.degree. C. in order to form
multi-layered thin film. The substrate was exposed to light using
the ArF eximer laser exposure apparatus and heat treated at
130.degree. C. for 90 seconds. The substrate is cooled down and
developed for 40 seconds and washed with 2.38 wt % of aqueous
tetraammonium hydroxide solution and dried to form a resist
pattern. The produced resist pattern had very good adhesive
property and obtained very excellent pattern profile at the
resolution of 0.13 .mu.m.
Comparison Example 1
[0051] ArF was spin coated on the substrate without the thin film
composition and heated at 110.degree. C. for 90 seconds to make
thin film. The substrate was exposed to light using the ArF eximer
laser exposure apparatus and heat treated at 130.degree. C. for 90
seconds. The substrate is cooled down and developed for 40 seconds
and washed with 2.38 wt % of aqueous tetraammonium hydroxide
solution and dried to form a resist pattern. The completed pattern
had low adhesive property. At less than 0.15 .mu.m pattern, the
phenomenon of the patterns being detached is observed and at 0.18
.mu.m resolution, side surface of the pattern profile is observed
to be not uniform.
EXAMPLE 2
[0052] Carried out the same experiment as described In the Example
1, except using 0.6 g of polymer synthesized in the Synthesis 3
instead of Synthesis 2. The result showed excellent adhesive
property of the resist pattern and excellent vertical pattern
profile at 0.13 .mu.m resolution.
EXAMPLE 3
[0053] Carried out the same experiment as described In the Example
1, except using 0.6 g of polymer synthesized in the Synthesis 4
instead of Synthesis 2. The result showed excellent adhesive
property of the resist pattern and excellent vertical pattern
profile at the resolution of 0.12 .mu.m.
EXAMPLE 4
[0054] Carried out the same experiment as described In the Example
1, except using 0.6 g of polymer synthesized in the Synthesis 5
instead of Synthesis 2. The result showed excellent adhesive
property of the resist pattern and excellent vertical pattern
profile at the resolution of 0.1 .mu.m.
EXAMPLE 5
[0055] Carried out the same experiment as described In the Example
4, except using additionally 50 ppm of fluorinated ether type
surfactant. The result showed excellent adhesive property of the
resist pattern and excellent vertical pattern profile at the
resolution of 0.11 .mu.m.
EXAMPLE 6
[0056] 2 g of polymer obtained in Synthesis 5 and 0.001 g of the
acid generator obtained in Synthesis 1 were dissolved in 50 g of
propyleneglycol methylether acetate and filtered by 0.2 .mu.m
membrane filter to formulate a thin film composition. The
composition was spin coated on a glass substrate and heated at
190.degree. C. for 90 seconds to make the thin film. The completed
thin film was homogeneous and formed a coated layer which was not
dissolved in usual organic solvents.
EXAMPLE 7
[0057] Carried out the same experiment as described In the Example
6, except using additionally 0.2 g of glycerol. The result showed
that the completed thin film was homogeneous and it formed a coated
layer which was not dissolved in usual organic solvents.
[0058] The abovementioned acid generator of the present invention
generates acid by heat at a relatively low temperature, preventing
the change in the ratio of the composition due to evaporation of
some components in the composition. Accordingly it has the
advantageous effect that the ratio of components in the composition
is controlled and the preparation of the thin film with the wanted
properties is simplified.
* * * * *