U.S. patent application number 11/373199 was filed with the patent office on 2006-10-19 for bottom resist layer composition and patterning process using the same.
This patent application is currently assigned to SHIN-ETSU CHEMICAL CO., LTD.. Invention is credited to Jun Hatakeyama.
Application Number | 20060234158 11/373199 |
Document ID | / |
Family ID | 37108875 |
Filed Date | 2006-10-19 |
United States Patent
Application |
20060234158 |
Kind Code |
A1 |
Hatakeyama; Jun |
October 19, 2006 |
Bottom resist layer composition and patterning process using the
same
Abstract
There is disclosed a bottom resist layer composition for a
multilayer-resist film used in lithography which comprises, at
least, a polymer having a repeating unit represented by the
following general formula (1). Thereby, there can be provided a
bottom resist layer composition which shows an antireflection
effect against an exposure light by combining with an intermediate
resist layer having an antireflection effect if necessary, has a
higher etching resistance during etching a substrate than
polyhydroxy styrene, cresol novolac resin, etc., has a high
poisoning-resistant effect, and is suitable for using in a
multilayer-resist process like a bilayer resist process or a
trilayer resist process. ##STR1##
Inventors: |
Hatakeyama; Jun; (Niigata,
JP) |
Correspondence
Address: |
OLIFF & BERRIDGE, PLC
P.O. BOX 19928
ALEXANDRIA
VA
22320
US
|
Assignee: |
SHIN-ETSU CHEMICAL CO.,
LTD.
Tokyo
JP
|
Family ID: |
37108875 |
Appl. No.: |
11/373199 |
Filed: |
March 13, 2006 |
Current U.S.
Class: |
430/270.1 ;
430/271.1; 430/272.1; 430/313 |
Current CPC
Class: |
G03F 7/094 20130101;
G03F 7/0752 20130101 |
Class at
Publication: |
430/270.1 ;
430/313 |
International
Class: |
G03F 7/26 20060101
G03F007/26; G03C 1/00 20060101 G03C001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 14, 2005 |
JP |
2005-116897 |
Claims
1. A bottom resist layer composition for a multilayer-resist film
used in lithography which comprises, at least, a polymer having a
repeating unit represented by the following general formula (1),
##STR30## ,wherein R.sup.1 represents any one of a hydrogen atom, a
linear, branched or cyclic alkyl group having 1-10 carbon atoms, an
aryl group having 6-10 carbon atoms, a linear, branched or cyclic
alkenyl group having 2-10 carbon atoms, and a halogen atom, R.sup.2
and R.sup.12 independently represent any one of a hydrogen atom, a
linear, branched or cyclic alkyl group having 1-6 carbon atoms, a
linear, branched or cyclic alkenyl group having 2-6 carbon atoms,
an aryl group having 6-10 carbon atoms, an acyl group or an alkoxy
carbonyl group having 1-10 carbon atoms, a group forming an acetal
group with an oxygen atom bonded with R.sup.2 or R.sup.12 in the
above general formula (1), and a glycidyl group, R.sup.3 and
R.sup.13 independently represent any one of a hydrogen atom, a
linear, branched or cyclic alkyl group having 1-10 carbon atoms,
and an aryl group having 6-10 carbon atoms, a and b satisfy
0<a<1, 0<b<1, and 0<a+b.ltoreq.1, and Z represents
fused polycyclichydrocarbon which may have hetero atoms.
2. The bottom resist layer composition according to claim 1 wherein
the multilayer-resist film is a trilayer resist film comprising a
bottom resist layer formed on a substrate, an intermediate resist
layer containing silicon atoms formed on the bottom resist layer,
and a top resist layer of a photoresist composition formed on the
intermediate resist layer.
3. The bottom resist layer composition according to claim 1 wherein
the bottom resist layer composition further contains any one of or
more of a cross-linker, an acid generator and an organic
solvent.
4. The bottom resist layer composition according to claim 2 wherein
the bottom resist layer composition further contains any one of or
more of a cross-linker, an acid generator and an organic
solvent.
5. A patterning process on a substrate with lithography wherein, at
least, a bottom resist layer is formed on a substrate with the
bottom resist layer composition according to claim 1, an
intermediate resist layer containing silicon atoms is formed on the
bottom resist layer, a top resist layer of a photoresist
composition is formed on the intermediate resist layer, to form a
trilayer resist film, a pattern circuit area of the trilayer resist
film is exposed and developed with a developer to form a resist
pattern on the top resist layer, the intermediate resist layer is
etched using as a mask the top resist layer on which the pattern is
formed, the bottom resist layer is etched using as a mask at least
the intermediate resist layer on which the pattern is formed, and
then the substrate is etched using as a mask at least the bottom
resist layer on which the pattern is formed, to form the pattern on
the substrate.
6. A patterning process on a substrate with lithography wherein, at
least, a bottom resist layer is formed on a substrate with the
bottom resist layer composition according to claim 2, an
intermediate resist layer containing silicon atoms is formed on the
bottom resist layer, a top resist layer of a photoresist
composition is formed on the intermediate resist layer, to form a
trilayer resist film, a pattern circuit area of the trilayer resist
film is exposed and developed with a developer to form a resist
pattern on the top resist layer, the intermediate resist layer is
etched using as a mask the top resist layer on which the pattern is
formed, the bottom resist layer is etched using as a mask at least
the intermediate resist layer on which the pattern is formed, and
then the substrate is etched using as a mask at least the bottom
resist layer on which the pattern is formed, to form the pattern on
the substrate.
7. A patterning process on a substrate with lithography wherein, at
least, a bottom resist layer is formed on a substrate with the
bottom resist layer composition according to claim 3, an
intermediate resist layer containing silicon atoms is formed on the
bottom resist layer, a top resist layer of a photoresist
composition is formed on the intermediate resist layer, to form a
trilayer resist film, a pattern circuit area of the trilayer resist
film is exposed and developed with a developer to form a resist
pattern on the top resist layer, the intermediate resist layer is
etched using as a mask the top resist layer on which the pattern is
formed, the bottom resist layer is etched using as a mask at least
the intermediate resist layer on which the pattern is formed, and
then the substrate is etched using as a mask at least the bottom
resist layer on which the pattern is formed, to form the pattern on
the substrate.
8. A patterning process on a substrate with lithography wherein, at
least, a bottom resist layer is formed on a substrate with the
bottom resist layer composition according to claim 4, an
intermediate resist layer containing silicon atoms is formed on the
bottom resist layer, a top resist layer of a photoresist
composition is formed on the intermediate resist layer, to form a
trilayer resist film, a pattern circuit area of the trilayer resist
film is exposed and developed with a developer to form a resist
pattern on the top resist layer, the intermediate resist layer is
etched using as a mask the top resist layer on which the pattern is
formed, the bottom resist layer is etched using as a mask at least
the intermediate resist layer on which the pattern is formed, and
then the substrate is etched using as a mask at least the bottom
resist layer on which the pattern is formed, to form the pattern on
the substrate.
9. The patterning process according to claim 5 wherein the top
resist layer does not contain silicon atoms, and the etching of the
bottom resist layer using the intermediate resist layer as a mask
is carried out with dry etching using a gas mainly containing
oxygen gas.
10. The patterning process according to claim 6 wherein the top
resist layer does not contain silicon atoms, and the etching of the
bottom resist layer using the intermediate resist layer as a mask
is carried out with dry etching using a gas mainly containing
oxygen gas.
11. The patterning process according to claim 7 wherein the top
resist layer does not contain silicon atoms, and the etching of the
bottom resist layer using the intermediate resist layer as a mask
is carried out with dry etching using a gas mainly containing
oxygen gas.
12. The patterning process according to claim 8 wherein the top
resist layer does not contain silicon atoms, and the etching of the
bottom resist layer using the intermediate resist layer as a mask
is carried out with dry etching using a gas mainly containing
oxygen gas.
13. The patterning process according to claim 5 wherein the pattern
circuit area is exposed with ArF excimer laser at a wavelength of
193 nm or KrF excimer laser at a wavelength of 248 nm.
14. The patterning process according to claim 6 wherein the pattern
circuit area is exposed with ArF excimer laser at a wavelength of
193 nm or KrF excimer laser at a wavelength of 248 nm.
15. The patterning process according to claim 7 wherein the pattern
circuit area is exposed with ArF excimer laser at a wavelength of
193 nm or KrF excimer laser at a wavelength of 248 nm.
16. The patterning process according to claim 8 wherein the pattern
circuit area is exposed with ArF excimer laser at a wavelength of
193 nm or KrF excimer laser at a wavelength of 248 nm.
17. The patterning process according to claim 9 wherein the pattern
circuit area is exposed with ArF excimer laser at a wavelength of
193 nm or KrF excimer laser at a wavelength of 248 nm.
18. The patterning process according to claim 10 wherein the
pattern circuit area is exposed with ArF excimer laser at a
wavelength of 193 nm or KrF excimer laser at a wavelength of 248
nm.
19. The patterning process according to claim 11 wherein the
pattern circuit area is exposed with ArF excimer laser at a
wavelength of 193 nm or KrF excimer laser at a wavelength of 248
nm.
20. The patterning process according to claim 12 wherein the
pattern circuit area is exposed with ArF excimer laser at a
wavelength of 193 nm or KrF excimer laser at a wavelength of 248
nm.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a bottom resist layer
composition useful for a multilayer-resist process used for
micropatterning in production process of semiconductor devices etc,
and especially to a bottom resist layer composition of a trilayer
resist film suitable for exposure with far ultraviolet rays at a
wavelength of 300 nm or less like KrF excimer laser light (248 nm)
and ArF excimer laser light (193 nm). Furthermore, the present
invention also relates to a patterning process for forming a
pattern on a substrate with lithography using the composition.
[0003] 2. Description of the Related Art
[0004] It has been needed to make a finer pattern rule along with a
tendency in which integration and speed of LSI have become higher
in recent years. And in lithography using optical exposure which is
used as a general technique at present, resolution has almost
reached the inherent limit derived from a wavelength of a light
source.
[0005] Optical exposure has been widely used using g line (436 nm)
or i line (365 nm) of a mercury-vapor lamp as a light source for
lithography when a resist pattern is formed. It has been considered
that a method of using an exposure light with a shorter wavelength
is effective as a means for achieving a further finer pattern. For
this reason, for example, KrF excimer laser at a shorter wavelength
of 248 nm has been used as an exposure light source instead of i
line (365 nm), for mass-production process of a 64 M bit DRAM
processing method. However, a light source at far shorter
wavelength is needed for manufacture of DRAM with an integration of
1 G or more which needs a still finer processing technique (for
example, a processing dimension is 0.13 .mu.m or less), and
lithography using ArF excimer laser (193 nm) has been especially
examined.
[0006] On the other hand, it has been known so far that a
multilayer-resist process such as a bilayer resist process or a
trilayer resist process is excellent in order to form a pattern
with a high aspect ratio on a nonplanar substrate.
[0007] Especially, it is supposed that it is preferable to use a
high-molecular silicone compound having a hydrophilic group, such
as a hydroxy group, a carboxyl group, etc. as a base resin of a top
resist layer composition, in order to develop a bilayer resist film
with a general alkaline developer in a bilayer resist process.
[0008] As the high-molecular silicone compound, there have been
proposed for KrF excimer lasers a silicone chemically amplified
positive-resist composition in which polyhydroxy benzyl
silsesquioxane, which is a stable alkali-soluble silicone polymer,
in which some phenolic hydroxyl groups are protected by a t-Boc
group is used as a base resin, and which is combined with an acid
generator (for example, see Japanese Patent Application Laid-open
(KOKAI) No. 6-118651 and SPIE vol. 1925 (1993) p377). Moreover,
there have been proposed for ArF excimer lasers a positive resist
in which silsesquioxane that a cyclohexyl carboxylic acid is
substituted with an acid labile group is used as a base resin (for
example, see Japanese Patent Application Laid-open (KOKAI) No.
10-324748, Japanese Patent Application Laid-open (KOKAI) No.
11-302382, and SPIE vol. 3333 (1998) p62). Furthermore, there has
been proposed for F.sub.2 laser a positive resist in which
silsesquioxane having a hexafluoro isopropanol as a soluble group
is used as a base resin (for example, see Japanese Patent
Application Laid-open (KOKAI) No. 2002-55456).
[0009] These high-molecular silicone compounds contain poly
silsesquioxane containing a ladder structure formed by the
condensation polymerization of a trialkoxy silane or a tri
halogenated silane in a main chain.
[0010] As a base polymer for resist in which silicon is suspended
from a side chain, (meth)acrylate polymer containing silicon is
proposed (for example, see Japanese Patent Application Laid-open
(KOKAI) No. 9-110938 and J. Photopolymer Sci. and Technol. Vol. 9
No. 3(1996) p435-446).
[0011] Examples of a bottom resist layer used for a bilayer-resist
process may preferably include a hydrocarbon compound which can be
etched with oxygen gas. It is also desirable for the bottom resist
layer to have a high etching resistance, since the layer is further
used as a mask in the case of etching a substrate under the layer.
When etching of the bottom resist layer using a top resist layer as
a mask is conducted according to oxygen gas etching, it is
preferable that the bottom resist layer consists of only
hydrocarbons which do not contain a silicon atom. Moreover, in
order to improve a line width controllability of the top resist
layer containing silicon atoms and to reduce irregularity on a
pattern side wall and collapse of a pattern due to a stationary
wave, it is preferable that the bottom resist layer also has a
function as an antireflection film. Specifically, it is desirable
that a reflectivity from the bottom resist layer to the top resist
layer can be suppressed to 1% or less.
[0012] Then, the reflectivity can be suppressed to 1% or less by
applying a composition having an optimal refractive index n value
which is a real part of refractive index, and an optimal extinction
coefficient k value which is an imaginary part of refractive index
with a suitable thickness.
[0013] Here results of calculation of reflectivity of a substrate
while a thickness of a bottom resist layer was changed in a range
of 0-500 nm are shown in the FIG. 1 and FIG. 2. It was premised
that an exposure wavelength was 193 nm, n value of a top resist
layer was 1.74 and k value of that was 0.02.
[0014] FIG. 1 is a graph which shows a fluctuation of reflectivity
of a substrate while k value of a bottom resist layer was fixed at
0.3, a vertical axis signifies n value of that, a horizontal axis
signifies a thickness of the bottom resist layer, the n value was
changed in a range of 1.0-2.0, and the thickness was changed in a
range of 0-500 nm. In FIG. 1, in the case of assuming a bottom
resist layer with a thickness of 300 nm or more for a bilayer
resist process, it is found that an optimum value to suppress
reflectivity to 1% or less exists in a range of 1.6-1.9 of a
refractive index (n value) which is as much as or a little higher
than that of a top resist layer.
[0015] FIG. 2 is a graph which shows a fluctuation of reflectivity
of a substrate while n value of a bottom resist layer was fixed at
1.5, a vertical axis signifies k value of that, a horizontal axis
signifies a thickness of the layer, the k value was changed in a
range of 0-0.8, and the thickness was changed in a range of 0-500
nm. In FIG. 2, in the case of assuming a bottom resist layer with a
thickness of 300 nm or more for a bilayer resist process, it is
found that reflectivity can be suppressed to 1% or less when k
value is in a range of 0.24-0.15. On the other hand, an optimum k
value of antireflection film used with a thin thickness of about 40
nm for a single layer resist process is 0.4-0.5, which is different
from an optimum k value of a bottom resist layer with a thickness
of 300 nm or more for a bilayer resist process. As described above,
it has been revealed that a bottom resist layer with lower k value,
namely, with higher transparency is needed in a bilayer resist
process.
[0016] Then, a copolymer of a polyhydroxy styrene and an acrylate
has been examined as a bottom resist layer composition for a
wavelength of 193 nm (for example, see SPIE Vol. 4345 (2001) p50).
Polyhydroxy styrene has a very strong absorption at a wavelength of
193 nm, and the k value of itself is high of about 0.6. Then, the k
value is adjusted to about 0.25 by carrying out copolymerization
with acrylate of which k value is almost 0.
[0017] However, etching resistance of acrylate is low during
etching of a substrate, compared with that of polyhydoroxystyrene,
and it is indispensable to copolymerize acrylate at a significant
ratio in order to lower the k value. As a result, etching
resistance during etching of a substrate is significantly lowered.
The etching resistance influences not only an etch rate but
generation of surface roughness after etching. The increase of
surface roughness after etching becomes serious due to
copolymerization of acrylate.
[0018] Then, it has been proposed to use a naphthalene ring which
is one of those having a higher transparency at a wavelength of 193
nm than a benzene ring and high etching resistance. For example,
there has been proposed a bottom resist layer which has a
naphthalene ring or an anthracene ring (for example, see Japanese
Patent Application Laid-open (KOKAI) No. 2002-14474). However, k
value of a naphthol copolycondensation novolac resin and a
polyvinyl naphthalene resin is between 0.3 and 0.4, and does not
reach a desired transparency of 0.1 to 0.3, and thus it is
necessary to raise a transparency further in order to obtain a
desired antireflection effect. Moreover, n value at a wavelength of
193 nm of a naphthol copolycondensation novolac resin and a
polyvinyl naphthalene resin is low, and it is 1.4 in a naphthol
copolycondensation novolac resin, and is 1.2 in a polyvinyl
naphthalene resin according to measurement by the present
inventors, and which do not reach the desired range. Furthermore,
although an acenaphthylene polymer is proposed (for example, see
Japanese Patent Application Laid-open (KOKAI) No. 2001-40293 and
Japanese Patent Application Laid-open (KOKAI) No. 2002-214777), n
value at a wavelength of 193 nm is lower than that at a wavelength
of 248 nm, k value is high, and neither n nor k reaches the desired
values.
[0019] As described above, a bottom resist layer which has high n
value, low k value, high transparency, and a high etching
resistance is needed in a bilayer resist process.
[0020] On the other hand, a trilayer resist process stacking a top
resist layer of a single layer resist without containing silicon,
an intermediate resist layer containing silicon atoms under the top
layer, and a bottom resist layer of an organic layer under the
intermediate layer (for example, see J. Vac. Sci. Technol., 16(6),
November/December 1979).
[0021] In general, a single layer resist which is a top resist
layer of a trilayer resist process and does not contain silicon is
superior in resolution to a silicon-containing resist which is a
top resist layer of a bilayer resist process. Therefore, a single
layer resist with high resolution can be used as an exposure
imaging layer in a trilayer resist process.
[0022] Moreover, a Spin On Glass (SOG) film is used as an
intermediate resist layer, and many SOG films have been
suggested.
[0023] Here an optimum optical constant (n value, k value) to
suppress reflection from a substrate in a trilayer resist process
is different from that in a bilayer resist process. The purpose to
suppress reflection from a substrate as much as possible, in
particular, to suppress a reflectivity of a substrate to 1% or less
is the same in both a bilayer resist process and a trilayer resist
process. However, antireflection effect is given only to a bottom
resist layer in a bilayer resist process, it can be given to either
an intermediate resist layer or a bottom resist layer, or to both
of them in a trilayer resist process.
[0024] For example, an intermediate resist layer containing silicon
with antireflection effect has been suggested (for example, see
U.S. Pat. No. 6,506,497 specification and U.S. Pat. No. 6,420,088
specification).
[0025] In general, antireflection effect is higher in a multi-layer
antireflection film than in a single-layer antireflection film.
Therefore, the multi-layer antireflection film has been widely and
industrially used as an antireflection film for optical materials.
And, high antireflection effect can be obtained by giving
antireflection effect to both an intermediate resist layer and a
bottom resist layer in a trilayer resist process. Namely, if an
intermediate resist layer containing silicon atoms functions as an
antireflection layer in a trilayer resist process, it is not
particularly necessary for a bottom resist layer to function as a
superior antireflection layer. A high etching resistance during
process of a substrate is rather necessary for a bottom resist
layer in a trilayer resist process than antireflection effect.
[0026] Here FIG. 3 is a graph which shows a fluctuation of
reflectivity of a substrate while n value of a bottom resist layer
was fixed at 1.5, k value thereof was fixed at 0.6, a thickness
thereof was fixed at 500 nm, n value of an intermediate resist
layer was fixed at 1.5, k value thereof was changed in a range of
0-0.4, and a thickness thereof was changed in a range of 0-400
nm.
[0027] In FIG. 3, it is found that a sufficient antireflection
effect to suppress reflectivity of a substrate to 1% or less can be
obtained by setting k value of an intermediate resist layer to be
low of 0.2 or less and a thickness thereof properly. k value of an
intermediate resist layer as an antireflection layer with a
thickness of 100 nm or less is generally necessary to be 0.2 or
more in order to suppress a reflectivity of a substrate to 1% or
less (see FIG. 2). However, because a bottom resist layer can
suppress reflection to some extent in a trilayer structure, k value
of an intermediate resist layer is optimum in a range of 0.2 or
less.
[0028] Next, FIG. 4 and FIG. 5 are graphs which show a fluctuation
of reflectivity of a substrate while k value of a bottom resist
layer was fixed at 0.2 and 0.6 respectively, and a thickness of an
intermediate resist layer and a thickness of a bottom resist layer
were changed. The bottom resist layer with k value of 0.2 simulates
a bottom resist layer optimized for a bilayer resist process, and
the bottom resist layer with k value of 0.6 simulates novolac resin
or polyhydroxy styrene exposed to a light at a wavelength of 193
nm. Although a thickness of a bottom resist layer fluctuates
depending on topography of a substrate, a thickness of an
intermediate resist layer is considered not to fluctuate and the
intermediate layer can be applied with a prescribed thickness.
[0029] Here, when k value of a bottom resist layer is high (k value
is 0.6), a reflectivity of a substrate can be suppressed to 1% or
less with a thinner thickness of the bottom layer by selecting an
optimum thickness of an intermediate resist layer like 50 nm, 110
nm and 170 nm. When k value of a bottom resist layer is 0.2, a
thickness of an intermediate resist layer is hardly limited to
suppress a reflectivity of a substrate to 1% or less at 250 nm
thickness of the bottom layer. From a standpoint of expanding a
selective range of a thickness of an intermediate resist layer
suppressing reflection from a substrate, 0.2 is preferable to 0.6
as k value of a bottom resist layer. However, as to an etching
resistance during etching a substrate of compositions of which k
values at a wavelength of 193 nm are 0.2 and 0.6 respectively, the
composition with k value of 0.6 is generally higher. Furthermore, a
bottom resist layer with k value of 0.6 can suppress a reflectivity
of a substrate to 1% or less with an optimum thickness of an
intermediate resist layer even when a thickness of the bottom
resist layer is thin of 100 nm or less. And a thinner thickness of
a resist layer can be realized because of its high etching
resistance.
[0030] As described above, a bottom resist layer which has a higher
etching resistance during etching a substrate and proper k value to
be able to suppress a reflectivity of a substrate even when a
thickness of an intermediate resist layer is thin is needed in a
trilayer resist process.
[0031] Furthermore, when a processed layer to be an underlayer of
resist layers is a low dielectric constant insulator film
comprising porous silica, there is a problem called poisoning that
footing profile occurs or scum is generated in a space portion. The
poisoning is considered to occur as follows: porous silica adsorbs
ammonia in cleaning process of a substrate in which ammonia is
used, ammonia is liberated in a resist process, and the ammonia
neutralizes acid in resist generated in an exposed area.
[0032] Against such a problem, a bottom resist layer that has a
high poisoning-resistant effect in a porous silica insulator film
after cleaning of a substrate is needed.
SUMMARY OF THE INVENTION
[0033] The present invention has been made in order to solve such
problems. The object of the present invention is to provide a
bottom resist layer composition which has a higher etching
resistance during etching a substrate than polyhydroxy styrene,
cresol novolac resin, etc., shows an antireflection effect against
an exposure light by combining with an intermediate resist layer
having an antireflection effect if necessary, has a high
poisoning-resistant effect, and is suitable for using in a
multilayer-resist process like a bilayer resist process or a
trilayer resist process.
[0034] To achieve the above mentioned object, the present invention
provides a bottom resist layer composition for a multilayer-resist
film used in lithography which comprises, at least, a polymer
having a repeating unit represented by the following general
formula (1), ##STR2##
[0035] wherein R.sup.1 represents any one of a hydrogen atom, a
linear, branched or cyclic alkyl group having 1-10 carbon atoms, an
aryl group having 6-10 carbon atoms, a linear, branched or cyclic
alkenyl group having 2-10 carbon atoms, and a halogen atom, R.sup.2
and R.sup.12 independently represent any one of a hydrogen atom, a
linear, branched or cyclic alkyl group having 1-6 carbon atoms, a
linear, branched or cyclic alkenyl group having 2-6 carbon atoms,
an aryl group having 6-10 carbon atoms, an acyl group or an alkoxy
carbonyl group having 1-10 carbon atoms, a group forming an acetal
group with an oxygen atom bonded with R.sup.2 or R.sup.12 in the
above general formula (1), and a glycidyl group, R.sup.3 and
R.sup.13 independently represent any one of a hydrogen atom, a
linear, branched or cyclic alkyl group having 1-10 carbon atoms,
and an aryl group having 6-10 carbon atoms, a and b satisfy
0<a<1, 0<b<1, and 0<a+b.ltoreq.1, and Z represents
fused polycyclichydrocarbon which may have hetero atoms.
[0036] The bottom resist layer composition which comprises, at
least, a polymer having a repeating unit represented by the above
general formula (1) has a high etching resistance during etching a
substrate and has a high poisoning-resistant effect.
[0037] And, an excellent resist pattern profile after development
can be obtained by using such a bottom resist layer
composition.
[0038] In this case, it is preferable that the multilayer-resist
film is a trilayer resist film comprising a bottom resist layer
formed on a substrate, an intermediate resist layer containing
silicon atoms formed on the bottom resist layer, and a top resist
layer of a photoresist composition formed on the intermediate
resist layer.
[0039] If the bottom resist layer composition of the present
invention is used in a trilayer resist process, an excellent
antireflection effect against an exposure light can be obtained by
combining with an intermediate resist layer having an
antireflection effect, thereby pattern with higher resolution can
be formed.
[0040] And, it is preferable that the bottom resist layer
composition of the present invention further contains any one of or
more of a cross-linker, an acid generator and an organic
solvent.
[0041] As mentioned above, if the bottom resist layer composition
of the present invention further contains any one of or more of a
cross-linker, an acid generator and an organic solvent, cross
linking reaction in a bottom resist layer can be promoted by baking
after application to a substrate etc., and an application property
to a substrate etc. can be improved. Therefore, a bottom resist
layer made of such a composition has an excellent uniformity. And
there is little possibility to intermix with a top resist layer or
an intermediate resist layer, and low molecular components hardly
diffuse to the top resist layer etc.
[0042] Furthermore, the present invention provides a patterning
process on a substrate with lithography wherein, at least, a bottom
resist layer is formed on a substrate with the bottom resist layer
composition according to the present invention, an intermediate
resist layer containing silicon atoms is formed on the bottom
resist layer, a top resist layer of a photoresist composition is
formed on the intermediate resist layer, to form a trilayer resist
film, a pattern circuit area of the trilayer resist film is exposed
and developed with a developer to form a resist pattern on the top
resist layer, the intermediate resist layer is etched using as a
mask the top resist layer on which the pattern is formed, the
bottom resist layer is etched using as a mask at least the
intermediate resist layer on which the pattern is formed, and then
the substrate is etched using as a mask at least the bottom resist
layer on which the pattern is formed, to form the pattern on the
substrate.
[0043] As mentioned above, the bottom resist layer formed by using
the bottom resist layer composition of the present invention has a
particularly excellent etching resistance during etching a
substrate, brings an excellent antireflection effect by combining
with an intermediate resist layer having an antireflection effect
if necessary, and has a high poisoning-resistant effect. Therefore,
if it is used as a bottom resist layer of a trilayer resist
process, a pattern can be formed on a substrate with higher
precision.
[0044] In this case, it is possible that the top resist layer does
not contain silicon atoms, and the etching of the bottom resist
layer using the intermediate resist layer as a mask is carried out
with dry etching using a gas mainly containing oxygen gas.
[0045] A top resist layer without containing silicon atoms has the
benefit of being more excellent in resolution than a top resist
layer containing silicon atoms. Therefore, a pattern transferred to
an intermediate resist layer and even a pattern transferred to a
bottom resist layer with dry etching using a gas mainly containing
oxygen gas using the intermediate resist layer as a mask can be
excellent in precision. Accordingly, a substrate is etched using as
a mask the bottom resist layer on which the pattern is transferred
to form a pattern on the substrate, thereby a pattern can be formed
on the substrate with higher precision.
[0046] It is possible that the pattern circuit area is exposed with
ArF excimer laser at a wavelength of 193 nm or KrF excimer laser at
a wavelength of 248 nm.
[0047] The bottom resist layer composition of the present invention
can be suitably used for a patterning process in which the pattern
circuit area is exposed with ArF excimer laser at a wavelength of
193 nm or KrF excimer laser at a wavelength of 248 nm, thereby a
pattern can be formed with higher precision.
[0048] As mentioned above, according to the present invention, a
bottom resist layer composition having those characteristics as
follows can be obtained. An etching rate during etching with
CF.sub.4/CHF.sub.3 gas, Cl.sub.2/BCl.sub.3 gas, etc. used for
processing a substrate is slower than that of polyhydroxy styrene,
cresol novolac resin, etc., namely, the composition has an
excellent etching resistance during etching a substrate. And the
composition brings an excellent antireflection effect against an
exposure light by combining with an intermediate resist layer
having an antireflection effect if necessary. Furthermore an
excellent resist pattern profile after development can be also
obtained. The composition has a high poisoning-resistant effect,
and is suitable for using in a multilayer-resist process, in
particular, a trilayer resist process.
BRIEF DESCRIPTION OF THE DRAWINGS
[0049] FIG. 1 is a graph which shows the relation between a
thickness of a bottom resist layer and reflectivity of a substrate
in a bilayer-resist process when refractive index k value of the
bottom resist layer is fixed at 0.3, and a refractive index n value
of the bottom resist layer is changed in a range of 1.0 to 2.0
(exposure wavelength is 193 nm, the n value of a top resist layer
is 1.74, and the k value thereof is 0.02).
[0050] FIG. 2 is a graph which shows the relation between a
thickness of a bottom resist layer and reflectivity of a substrate
in a bilayer-resist process when a refractive index n value of the
bottom resist layer is fixed at 1.5, and the k value of the bottom
resist layer is changed in a range of 0 to 0.8 (exposure wavelength
is 193 nm, the n value of a top resist layer is 1.74, and the k
value thereof is 0.02).
[0051] FIG. 3 is a graph which shows fluctuation of reflectivity of
a substrate in a trilayer-resist process when a refractive index n
value of a bottom resist layer is fixed at 1.5, k value of the
bottom resist layer is fixed at 0.6, a thickness of the bottom
resist layer is fixed at 500 nm, a refractive index n value of an
intermediate resist layer is fixed at 1.5, k value of the
intermediate resist layer is changed in a range of 0 to 0.4, and a
thickness of the intermediate resist layer is changed in a range of
0 to 400 nm.
[0052] FIG. 4 is a graph which shows fluctuation of reflectivity of
a substrate in a trilayer-resist process when a refractive index n
value of a bottom resist layer is fixed at 1.5, k value of the
bottom resist layer is fixed at 0.2, a refractive index n value of
an intermediate resist layer is fixed at 1.5, k value of the
intermediate resist layer is fixed at 0.1, and a thickness of the
bottom resist layer and the intermediate resist layer is
changed.
[0053] FIG. 5 is a graph which shows fluctuation of reflectivity of
a substrate in a trilayer-resist process when a refractive index n
value of a bottom resist layer is fixed at 1.5, k value of the
bottom resist layer is fixed at 0.6, a refractive index n value of
an intermediate resist layer is fixed at 1.5, k value of the
intermediate resist layer is fixed at 0.1, and a thickness of the
bottom resist layer and the intermediate resist layer is
changed.
[0054] FIG. 6 is an explanatory view of an example of a patterning
process of the present invention in a trilayer resist process.
DESCRIPTION OF THE INVENTION AND A PREFERRED EMBODIMENT
[0055] Hereafter, a preferred embodiment of the present invention
will be explained. However, the present invention is not limited
thereto.
[0056] As mentioned above, in particular, in a bottom resist layer
of a trilayer resist process, a high etching resistance during
etching a substrate is needed rather than an effect as an anti
reflection film. Therefore, it is preferable to use novolac resin
that has a high etching resistance and many aromatic groups as a
bottom resist layer of a trilayer resist process. For example,
novolac resins obtained from condensed hydrocarbon like naphthol,
hydroxy anthracene, etc. has been suggested (for example, see
Japanese Patent Application Laid-open (KOKAI) No. 2002-14474). In
addition, a patterning process of a trilayer resist process using a
bottom resist layer like polyarylene resin, naphthol novolac,
hydroxy anthracene novolac, etc. whose carbon ratio is 80 wt % or
more has been suggested (for example, see Japanese Patent
Application Laid-open (KOKAI) No. 2002-305187).
[0057] As mentioned above, an etching resistance can be improved by
using novolac resins obtained from condensed hydrocarbon like
naphthol, hydroxy anthracene, etc. that has high carbon density and
a high etching resistance as a bottom resist layer composition.
However, according to investigations by the present inventors,
molecular weight of a novolac resin consisting of only 1-naphthol
is low. And, a mass average molecular weight thereof measured with
gel permeation chromatography relative to polystyrene standards is
about 1,000, and a large amount of low molecular compounds like
monomer, oligomer, etc. that did not react are existing. When it
comes to condensed polycyclic hydrocarbon having more carbon atoms
than 1-hydroxy anthracene, polymerization reaction hardly
progresses with the hydrocarbon alone. As mentioned above, when a
large amount of low molecular compounds remain in a bottom resist
layer composition, it has been found that there is problems in
which the compounds volatilize during baking after spin-coating to
contaminate coatercup, or uniformity of a film thickness is
deteriorated.
[0058] The inventors of the present invention have investigated
further, and have found that condensed hydrocarbon with a hydroxyl
group can increase molecular weight thereof by condensation
polymerization with phenols, and thus-obtained polymer can be
preferably used as a bottom resist layer. Thus, they accomplished
the present invention. As mentioned above, a rate of reaction in
which condensed hydrocarbon becomes a novolac resin can be faster
by condensation polymerization with phenols, and a bottom resist
layer composition that can form a bottom resist layer with a high
uniformity by spin-coating having a high etching resistance and
excellent embedding characteristics in a nonplanar substrate, a via
hole, etc. can be obtained.
[0059] Namely, the present invention provides a bottom resist layer
composition for a multilayer-resist film used in lithography which
comprises, at least, a polymer having a repeating unit represented
by the following general formula (1), ##STR3##
[0060] ,wherein R.sup.1 represents any one of a hydrogen atom, a
linear, branched or cyclic alkyl group having 1-10 carbon atoms, an
aryl group having 6-10 carbon atoms, a linear, branched or cyclic
alkenyl group having 2-10 carbon atoms, and a halogen atom, R.sup.2
and R.sup.12 independently represent any one of a hydrogen atom, a
linear, branched or cyclic alkyl group having 1-6 carbon atoms, a
linear, branched or cyclic alkenyl group having 2-6 carbon atoms,
an aryl group having 6-10 carbon atoms, an acyl group or an alkoxy
carbonyl group having 1-10 carbon atoms, a group forming an acetal
group with an oxygen atom bonded with R.sup.2 or R.sup.12 in the
above general formula (1), and a glycidyl group, R.sup.3 and
R.sup.13 independently represent any one of a hydrogen atom, a
linear, branched or cyclic alkyl group having 1-10 carbon atoms,
and an aryl group having 6-10 carbon atoms, a and b satisfy
0<a<1, 0<b<1, and 0<a+b.ltoreq.1, and Z represents
fused polycyclichydrocarbon which may have hetero atoms like a
sulfur atom.
[0061] The polymer according to the present invention comprising
repeating units a and b in the above general formula (1) may
comprise one type of a and b respectively, or may comprise two or
more types of a and/or b.
[0062] By using such a bottom resist layer composition, a bottom
resist layer which has high carbon density and an extremely high
dry etching resistance during processing a substrate can be
obtained.
[0063] In addition, such a bottom resist layer composition can be
used for a multilayer-resist process like a bilayer resist process
or a trilayer resist process, in particular, preferably for a
trilayer resist process. In a trilayer resist process a
reflectivity of a substrate can be suppressed to 1% or less by
combining a bottom resist layer with an intermediate resist layer
having an antireflection effect if necessary.
[0064] And, a bottom resist layer formed with such a bottom resist
layer composition is excellent in film denseness and ammonia gas
can be shielded sufficiently, thereby generation of poisoning can
be prevented.
[0065] Furthermore, such a bottom resist layer can be preferably
used for exposure with a high energy beam particularly at a
wavelength of 300 nm or less, in particular, excimer laser light of
248 nm or 193 nm, etc.
[0066] A synthetic process of a bottom resist layer composition of
the present invention is not limited. However, for example, as
described above, it can be obtained by condensation polymerization
of condensed hydrocarbon having a hydroxyl group with phenols.
[0067] Examples of the phenols used in this condensation
polymerization may include: phenol, o-cresol, m-cresol, p-cresol,
2,3-dimethylphenol, 2,5-dimethylphenol, 3,4-dimethylphenol,
3,5-dimethylphenol, 2,4-dimethylphenol, 2,6-dimethylphenol,
2,3,5-trimethyl phenol, 3,4,5-trimethyl phenol, 2-t-butyl-phenol,
3-t-butyl-phenol, 4-t-butyl-phenol, 2-phenyl-phenol,
3-phenyl-phenol, 4-phenyl-phenol, 3,5-diphenyl-phenol,
2-naphthylphenol, 3-naphthylphenol, 4-naphthylphenol,
4-tritylphenol, 4-vinylphenol, 4-propynylphenol, 4-allylphenol,
4-ethinylphenol, resorcinol, 2-methyl resorcinol, 4-methyl
resorcinol, 5-methyl resorcinol, catechol, 4-t-butyl-catechol,
2-methoxy phenol, 3-methoxy phenol, 2-propyl phenol, 3-propyl
phenol, 4-propyl phenol, 2-isopropyl phenol, 3-isopropyl phenol,
4-isopropyl phenol, 2-cyclohexylphenol, 3-cyclohexylphenol,
4-cyclohexylphenol, 2-methoxy-5-methyl phenol, 2-t-butyl-5-methyl
phenol, pyrogallol, thymol, isothymol, etc.
[0068] In addition, condensed hydrocarbon having a hydroxyl group
used in the above condensation polymerization may include:
1-naphthol, 2-naphthol, 2-methyl-1-naphthol, 4-methoxy-1-naphthol,
7-methoxy-2-naphthol and dihydroxy naphthalene such as
1,5-dihydroxy naphthalene, 1,7-dihydroxy naphthalene, 2,6-dihydroxy
naphthalene, etc., hydroxy indene, hydroxy benzothiophene, hydroxy
anthracene, hydroxy acenaphthylene, hydroxy pyrene, hydroxy
fluorene, hydroxy phenanthrene, hydroxy azulene, hydroxy heptalene,
hydroxy biphenylene, hydroxy indacene, hydroxy fluoracene, hydroxy
naphthacene, hydroxy aceanthrylene, hydroxy perylene, etc.
[0069] In the above general formula (1), a polymer with R.sup.2 and
R.sup.12 of a glycidyl group can be obtained by turning a phenolic
hydroxyl group of novolac according to the above general formula
(1) into a glycidyl group according to a conventional method using
epichlorohydrin. In addition, a polymer with R.sup.2 and R.sup.12
forming an acetal group with an oxygen atom bonded with R.sup.2 or
R.sup.12 can be obtained by reacting a phenolic hydroxyl group of
novolac according to the above general formula (1) with alkenyl
ether compounds in the presence of acid catalyst, or by using
halogenated alkyl ether compounds to protect a phenolic hydroxyl
group by an alkoxy alkyl group in the presence of base. And, a
polymer with R.sup.2 and R.sup.12 of an acyl group can be obtained
by reacting a phenolic hydroxyl group of novolac according to the
above general formula (1) with alkyl carbonyl chloride.
Furthermore, a polymer with R.sup.2 and R.sup.12 of an alkoxy
carbonyl group can be obtained by reacting a phenolic hydroxyl
group of novolac according to the above general formula (1) with
dialkyl dicarbonate or alkoxy carbonyl alkyl halide.
[0070] In synthetic reaction of novolac resin, condensation
reaction is carried out with adding aldehyde to above-mentioned
condensed hydrocarbon and phenols. Aldehydes used in the synthetic
reaction of novolac resin may include: formaldehyde, trioxane,
paraformaldehyde, benzaldehyde, acetaldehyde, propylaldehyde,
phenylacetaldehyde, .alpha.-phenylpropylaldehyde,
.beta.-phenylpropylaldehyde, o-hydroxybenzaldehyde,
m-hydroxybenzaldehyde, p-hydroxybenzaldehyde, o-chlorobenzaldehyde,
m-chlorobenzaldehyde, p-chlorobenzaldehyde, o-nitrobenzaldehyde,
m-nitrobenzaldehyde, p-nitrobenzaldehyde, o-methylbenzaldehyde,
m-methylbenzaldehyde, p-methylbenzaldehyde, p-ethylbenzaldehyde,
p-n-butylbenzaldehyde, furfural, etc. Among these, in particular,
formaldehyde can be preferably used.
[0071] These aldehydes may be used alone or in admixture.
[0072] An amount of the aldehyde to be used is preferably 0.2 to 5
moles per 1 mole of above-mentioned condensed hydrocarbon and
phenols, more preferably 0.5 to 2 moles.
[0073] In addition, catalyst can be used in the above-mentioned
synthetic reaction of novolac resin.
[0074] For example, the catalyst may include: acid catalyst like
hydrochloric acid, nitric acid, sulfuric acid, formic acid, oxalic
acid, acetic acid, methansulfonic acid, camphor sulfonic acid,
tosyl acid, trifluoromethane sulfonic acid, etc.
[0075] An amount of the acid catalyst to be used is
1.times.10.sup.-5 to 5.times.10.sup.-1 moles per 1 mole of
above-mentioned condensed hydrocarbon and phenols.
[0076] A reaction solvent in such a condensation polymerization may
include: water, methanol, ethanol, propanol, butanol,
tetrahydrofuran, dioxane, admixture thereof, etc. These solvents
can be preferably used, for example, in a range of 0 to 2000 parts
by mass per 100 parts by mass of reaction materials.
[0077] Although reaction temperature can be selected properly
according to reactivity of reaction materials, it is generally in a
range of 10 to 20.degree. C.
[0078] In addition, in a process of condensation polymerization,
for example, the above-mentioned condensed hydrocarbon, phenols,
aldehydes and catalyst may be added at a time, or the
above-mentioned condensed hydrocarbon, phenols and aldehydes may be
added dropwise in the presence of catalyst.
[0079] After termination of the above-mentioned condensation
polymerization reaction, in order to remove unreacted materials,
catalyst, etc. in a sytem, temperature of a reactor can be elevated
to 130 to 230.degree. C. to remove devolatilize at about 1 to 50
mmHg.
[0080] In addition, in the above-mentioned condensation
polymerization reaction, one type of condensed hydrocarbon having a
hydroxyl group may be reacted with one type of phenol, or condensed
hydrocarbon and/or phenol may be two types or more.
[0081] Copolymerization ratio of a polymer represented in the above
general formula (1) is 0<a<1 and 0<b<1, preferably
0.2.ltoreq.a.ltoreq.0.99, 0.01.ltoreq.b.ltoreq.0.7, more preferably
0.3.ltoreq.a.ltoreq.0.98, 0.02.ltoreq.b.ltoreq.0.6.
[0082] As for molecular weight of the polymer of the present
invention relative to polystyrene standards, mass
average-molecular-weight (Mw) is preferably 1,000 to 30,000, in
particular, 2,000 to 20,000. Molecular-weight distribution thereof
is preferably in a range of 1.2 to 7. And, if monomer, oligomer or
low-molecular components with molecular weight (Mw) of 1,000 or
less is removed, to narrow molecular-weight distribution,
efficiency of crosslink increases, and contamination around bakecup
can be prevented by suppressing volatile components during
baking.
[0083] In addition, hydrogenation can be carried out in order to
raise a transparency of a polymer having a repeating unit
represented by the general formula (1) of the present invention at
a wavelength of 193 nm. A desirable ratio of hydrogenation is 80
mole % or less of an aromatic group, in particular, 60 mole % or
less.
[0084] Furthermore, other polymers can be blended with the polymer
of the present invention. Blend polymers are mixed with the polymer
of the general formula (1) to play a role to improve film
deposition characteristics in spin coating and embedding
characteristics in a nonplanar substrate. As a blend polymer,
materials with high carbon density and high etching resistance is
selected. For example, such a material may include: phenol,
o-cresol, m-cresol, p-cresol, 2,3-dimethylphenol,
2,5-dimethylphenol, 3,4-dimethylphenol, 3,5-dimethylphenol,
2,4-dimethylphenol, 2,6-dimethylphenol, 2,3,5-trimethyl phenol,
3,4,5-trimethyl phenol, 2-t-butyl-phenol, 3-t-butyl-phenol,
4-t-butyl-phenol, 2-phenyl-phenol, 3-phenyl-phenol,
4-phenyl-phenol, 3,5-diphenyl-phenol, 2-naphthylphenol,
3-naphthylphenol, 4-naphthylphenol, 4-tritylphenol, resorcinol,
2-methyl resorcinol, 4-methyl resorcinol, 5-methyl resorcinol,
catechol, 4-t-butyl-catechol, 2-methoxy phenol, 3-methoxy phenol,
2-propyl phenol, 3-propyl phenol, 4-propyl phenol, 2-isopropyl
phenol, 3-isopropyl phenol, 4-isopropyl phenol, 2-methoxy-5-methyl
phenol, 2-t-butyl-5-methyl phenol, pyrogallol, thymol, isothymol,
4,4'-(9H-fluorene-9-ylidene)bisphenol,
2,2'-dimethyl-4,4'-(9H-fluorene-9-ylidene)bisphenol,
2,2'-diallyl-4,4'-(9H-fluorene-9-ylidene)bisphenol,
2,2'-difluoro-4,4'-(9H-fluorene-9-ylidene)bisphenol,
2,2'-diphenyl-4,4'-(9H-fluorene-9-ylidene)bisphenol,
2,2'-dimethoxy-4,4'-(9H-fluorene-9-ylidene)bisphenol,
2,3,2',3'-tetrahydro-(1,1')-spirobiindene-6,6'-diol,
3,3,3',3'-tetramethyl-2,3,2',3'-tetrahydro-(1,1')-spirobiindene-6,6'-diol-
,
3,3,3',3',4,4'-hexamethyl-2,3,2',3'-tetrahydro-(1,1')-spirobiindene-6,6'-
-diol, 2,3,2',3'-tetrahydro-(1,1')-spirobiindene-5,5'-diol,
5,5'-dimethyl-3,3,3',3'-tetramethyl-2,3,2',3'-tetrahydro-(1,1')-spirobiin-
dene-6,6'-diol, 1-naphthol, 2-naphthol, 2-methyl-1-naphthol,
4-methoxy-1-naphthol, 7-methoxy-2-naphthol, dihydroxy naphthalene
such as 1,5-dihydroxy naphthalene, 1,7-dihydroxy naphthalene,
2,6-dihydroxy naphthalene, etc., a novolac resin of
3-hydroxy-naphthalene-2-methyl carboxylate, indene, hydroxy indene,
benzofuran, hydroxy anthracene, acenaphthylene, biphenyl,
bisphenol, tris phenol, dicyclopentadiene, tetrahydro indene,
4-vinyl cyclohexene, norbornadiene, 5-vinyl-norborna-2-en,
.alpha.-pinene, .beta.-pinene, limonene, etc., polyhydroxy styrene,
polystyrene, polyvinyl naphthalene, polyvinyl anthracene, polyvinyl
carbazole, polyindene, poly acenaphthylene, poly norbornene, poly
cyclodecene, poly tetracyclododecene, polynortricyclene,
poly(meth)acrylate, and copolymer thereof.
[0085] An amount of the blend polymers to be added is 0 to 1,000
parts by mass per 100 parts by mass of a polymer represented by the
general formula (1), preferably 0 to 500 parts by mass.
[0086] One of the properties required for bottom layers including
antireflection layers is that the layer does not intermix with an
upper layer, for example, an intermediate layer containing silicon
and a resist layer, and low molecular components hardly diffuse to
the upper layer from the bottom layer [See Proc. SPIE Vol. 2195, p
225-229(1994)]. In order to prevent intermixing and diffusing, a
method to carry out thermal crosslinking by baking after an
antireflection layer is spin-coated is generally adopted.
Therefore, when a cross-linker can be added as a component of an
antireflection layer composition, a substituent which can carry out
crosslinking can be introduced into a polymer. Even in the case of
not adding a cross-linker particularly, if R.sup.2 or R.sup.12
represents a hydrogen atom in the above general formula (1), the
polymer can be cross-linked by heating of 300.degree. C. or more to
induce condensation reaction of hydroxyl groups.
[0087] If the bottom resist layer composition explained above
further contains a cross-linker, an acid generator, an organic
solvent, etc., an application property of the composition to a
substrate etc. can be improved, and cross linking reaction in a
bottom resist layer can be promoted by baking etc. after
application of the composition. Therefore, such a bottom resist
layer has an excellent uniformity. And there is little possibility
to intermix with a top resist layer, and low molecular components
hardly diffuse to the top resist layer. And, the bottom resist
layer has an excellent rigidity and solvent-resistant property.
[0088] Hereafter, these compounds are detailed.
[0089] Examples of the cross-linker which can be used according to
the present invention may include: a melamine compound, a guanamine
compound, a glycol uryl compound or an urea compound substituted
with at least one group chosen from a methylol group, an alkoxy
methyl group and an acyloxy methyl group, an epoxy compound, an
isocyanate compound, an azide compound, a compound including a
double bond such as an alkenyl ether group, etc. Although they may
be used as an additive, they can be introduced into a polymer side
chain as a pendant group. Moreover, a compound containing a hydroxy
group can also be used as a cross-linker.
[0090] Examples of the epoxy compound among the above-mentioned
specific examples of the cross-linker may include:
tris(2,3-epoxypropyl)isocyanurate, trimethylol methanetriglycidyl
ether, trimethylol propane triglycidyl ether, triethylol
ethanetriglycidyl ether, etc. Examples of the melamine compound may
include: hexamethylol melamine, hexamethoxy methyl melamine, a
compound in which 1-6 methylol groups of hexamethylol melamine are
methoxy methylated or a mixture thereof, hexamethoxy ethyl
melamine, hexaacyloxy methyl melamine, a compound in which 1-6
methylol groups of hexamethylol melamine are acyloxy methylated or
a mixture thereof, etc. Examples of a guanamine compound may
include: tetramethylol guanamine, tetra methoxy methyl guanamine, a
compound in which 1-4 methylol groups of tetramethylol guanamine
are methoxy-methylated and a mixture thereof, tetramethoxy ethyl
guanamine, tetraacyloxy guanamine, a compound in which 1-4 methylol
groups of tetramethylol guanamine are acyloxy-methylated and a
mixture thereof, etc. Examples of a glycol uryl compound may
include: tetramethylol glycol uryl, tetramethoxy glycol uryl,
tetramethoxy methyl-glycol uryl, a compound in which 1-4 methylol
groups of tetramethylol glycol uryl are methoxy methylated or a
mixture thereof, and a compound in which 1-4 methylol group of
tetramethylol glycol uryl are acyloxy methylated or a mixture
thereof, etc. Examples of a urea compound may include: tetra
methylol urea, tetra methoxy methyl urea, a compound in which 1-4
methylol groups of tetra methylol urea are methoxy-methylated or a
mixture thereof, and tetra methoxy ethyl urea, etc.
[0091] Examples of the isocyanate compound may include: tolylene
diisocyanate, diphenyl methane diisocyanate, hexamethylene
diisocyanate, cyclohexane diisocyanate, etc. Examples of the azide
compound may include: 1,1'-biphenyl-4,4'-bisazide, 4,4'-methylidene
bisazide, and 4,4'-oxy-bisazide, etc.
[0092] Examples of the compound containing an alkenyl ether group
may include: ethylene glycol divinyl ether, triethylene-glycol
divinyl ether, 1,2-propanediol divinyl ether, 1,4-butanediol
divinyl ether, tetramethylene-glycol divinyl ether, neo pentyl
glycol divinyl ether, trimethylol-propane trivinyl ether, hexane
diol divinyl ether, 1,4-cyclohexane diol divinyl ether,
pentaerythritol trivinyl ether, pentaerythritol tetra vinyl ether,
sorbitol tetra vinyl ether, sorbitol penta vinyl ether, and
trimethylol-propane trivinyl ether, etc.
[0093] A compound in which a hydroxy group of an
alcoholic-group-containing compound is turned into a glycidyl ether
group by epichlorohydrin can be used as a cross-linker. The
alcoholic-group-containing compound may include: naphthol novolac,
m- and p-cresol novolac, naphthol dicyclopentadiene novolac, m- and
p-cresol dicyclopentadiene novolac, 4,8-bis(hydroxymethyl)tricyclo
[5.2.1.0.sup.2,6] -decane, pentaerythritol, 1,2,6-hexanetriol,
4,4',4''-methylidene tris cyclohexanol, 4,4'-[1-[4-[1-(4-hydroxy
cyclohexyl)-1-methylethyl]phenyl]ethylidene]biscyclohexanol,
[1,1'-bicyclohexyl]-4,4'-diol, methylene biscyclohexanol, decahydro
naphthalene-2,6-diol, and
[1,1'-bicyclohexyl]-3,3',4,4'-tetrahydroxy, etc. And a compound in
which a hydroxy group of a pheonl containing less benzene nuclei is
turned into a glycidyl ether group by epichlorohydrin can be used
as a cross-linker. The pheonl containing less benzene nuclei may
include: bisphenol, methylene bisphenol, 2,2'-methylene bis
[4-methyl phenol], 4,4'-methylidene-bis[2,6-dimethylphenol],
4,4'-(1-methyl-ethylidene)bis[2-methyl phenol],
4,4'-cyclohexylidene bisphenol, 4,4'-(1,3-dimethyl
butylidene)bisphenol, 4,4'-(1-methyl-ethylidene)bis[2,6-dimethyl
phenol], 4,4'-oxybisphenol, 4,4'-methylene bisphenol,
bis(4-hydroxyphenyl)methanone, 4,4'-methylene bis[2-methylphenol],
4,4'-[1,4-phenylene bis(1-methyl ethylidene)]bisphenol,
4,4'-(1,2-ethane-di-yl)bisphenol, 4,4'-(diethyl silylene)bisphenol,
4,4'-[2,2,2-trifluoro-1-(trifluoromethyl)ethylidene]bisphenol,
4,4',4''-methylidene trisphenol,
4,4'-[1-(4-hydroxyphenyl)-1-methylethyl]phenyl]ethylidene]bisphenol,
2,6-bis[(2-hydroxy-5-methylphenyl)methyl]-4-methyl phenol,
4,4',4''-ethylidyne tris[2-methyl phenol], 4,4',4''-ethylidyne
trisphenol, 4,6-bis[(4-hydroxy phenyl)methyl]1,3-benzene diol,
4,4'-[(3,4-dihydroxy phenyl)methylene]bis[2-methylphenol],
4,4',4'',4'''-(1,2-ethanediylidene)tetrakisphenol,
4,4',4,4'',4'''-ethanediylidene tetrakis[2-methylphenol],
2,2'-methylene bis
[6-[(2-hydroxy-5-methylphenyl)methyl]-4-methylphenol],
4,4',4'',4'''-(1,4-phenylene dimethylidyne)tetrakisphenol,
2,4,6-tris(4-hydroxy phenylmethyl)-1,3-benzenediol,
2,4',4''-methylidene trisphenol,
4,4',4'''-(3-methyl-1-propanyl-3-ylidene)trisphenol,
2,6-bis[(4-hydroxy-3-phlorophenyl)methyl]-4-fluorophenol,
2,6-bis[4-hydroxy-3-fluorophenyl]methyl]-4-fluorophenol,
3,6-bis[(3,5-dimethyl-4-hydroxyphenyl)methyl]1,2-benzenediol,
4,6-bis[(3,5-dimethyl-4-hydroxy phenyl)methyl]1,3-benzenediol,
p-methylcalics[4]allene, 2,2'-methylene
bis[6-[(2,5/3,6-dimethyl-4/2-hydroxyphenyl)methyl]-4-methylphenol,
2,2'-methylene
bis[6-[(3,5-dimethyl-4-hydroxyphenyl)methyl]-4-methyl phenol,
4,4',4'',4'''-tetrakis[(1-methyl
ethylidene)bis(1,4-cyclohexylidene)]-phenol, 6,6'-methylene
bis[4-(4-hydroxy phenyl methyl)-1,2,3-benzentriol, and
3,3',5,5'-tetrakis[(5-methyl-2-hydroxyphenyl)methyl]-[(1,1'-biphenyl)-4,4-
'-diol], etc.
[0094] The amount of the cross-linker to be blended in the bottom
resist layer composition of the present invention is preferably 0
to 50 parts (it means parts by mass hereafter), especially 0 to 40
parts per 100 parts of the base polymer (total resin). If it is 3
parts or more, there is little possibility that a bottom resist
layer intermixes with a top resist layer or an intermediate resist
layer. And if it is 50 parts or less, there is little possiblity
that antireflection effect may be deteriorated, a crack may be
generated in the film after crosslinking, or etching resistance may
be deteriorated due to low carbon density.
[0095] In a bottom resist layer composition of the present
invention, an acid generator for promoting a crosslinking reaction
by heat etc. can be further added. There are an acid generator
which generates an acid by pyrolysis and an acid generator which
generates an acid by optical irradiation, and either of the acid
generator can be added.
[0096] Examples of the acid generator used in the bottom resist
layer composition of the present invention are as follows:
[0097] i) an onium salt represented by the following general
formulae (P1a-1), (P1a-2), (P1a-3) or (P1b),
[0098] ii) a diazomethane derivative represented by the following
general formula (P2),
[0099] iii) a glyoxime derivative represented by the following
general formula (P3),
[0100] iv) a bis sulfone derivative represented by the following
general formula (P4),
[0101] v) a sulfonate of an N-hydroxy imide compound represented by
the following general formula (P5),
[0102] vi) a .beta.-keto sulfonic-acid derivative,
[0103] vii) a disulfone derivative,
[0104] viii) a nitro benzyl sulfonate derivative, and
[0105] ix) a sulfonate derivative, etc. ##STR4##
[0106] (In the formulae, R.sup.101a, R.sup.101b, and R.sup.101c
independently represent a linear, branched or cyclic alkyl group,
alkenyl group, oxoalkyl group or oxoalkenyl group each having 1-12
carbon atoms, an aryl group having 6-20 carbon atoms, an aralkyl
group or an aryl oxoalkyl group having 7-12 carbon atoms. Some or
all of hydrogen atoms of these groups may be substituted with an
alkoxy group etc. R.sup.101b and R.sup.101c may constitute a ring.
In the case that they constitute a ring, R.sup.101b and R.sup.101c
represent an alkylene group having 1-6 carbon atoms respectively.
K.sup.- represents a non-nucleophilic counter ion. R.sup.101d,
R.sup.101e, R.sup.101f and R.sup.101g are represented by adding a
hydrogen atom to R.sup.101a, R.sup.101b, and R.sup.101c. R.sup.101d
and R.sup.101e, and R.sup.101d, R.sup.101e and R.sup.101f can form
a ring respectively. When they form a ring, R.sup.101d and
R.sup.101e, and R.sup.101d, R.sup.101e, and R.sup.101f, represent
an alkylene group having 3-10 carbon atoms or a heteroaromatic ring
having the nitrogen atom in the formula in the ring.)
[0107] The above-mentioned R.sup.101a, R.sup.101b, R.sup.101c,
R.sup.101d, R.sup.101e, R.sup.101f, and R.sup.101g may be the same
or different. Examples thereof as an alkyl group may include: a
methyl group, an ethyl group, a propyl group, an isopropyl group,
n-butyl group, sec-butyl group, tert-butyl group, a pentyl group, a
hexyl group, a heptyl group, an octyl group, a cyclopentyl group, a
cyclohexyl group, a cycloheptyl group, a cyclopropyl methyl group,
4-methyl cyclohexyl group, a cyclohexyl methyl group, a norbornyl
group, and an adamantyl group, etc. Examples of an alkenyl group
may include: a vinyl group, an allyl group, a propenyl group, a
butenyl group, a hexenyl group, and a cyclohexenyl group, etc.
Examples of an oxo alkyl group may include: 2-oxocyclopentyl group,
2-oxocyclohexyl group, 2-oxopropyl group, 2-cyclopentyl-2-oxoethyl
group, 2-cyclohexyl-2-oxoethyl group,
2-(4-methylcyclohexyl)-2-oxoethyl group, etc. Examples of an
oxoalkenyl group may include: 2-oxo-4-cyclohexenyl group,
2-oxo-4-propenyl group, etc. Examples of an aryl group may include:
a phenyl group, a naphthyl group, etc., and an alkoxy phenyl group
such as p-methoxyphenyl group, m-methoxyphenyl group,
o-methoxyphenyl group, an ethoxyphenyl group, p-tert-butoxyphenyl
group and m-tert-butoxy phenyl group, an alkyl phenyl group such as
2-methylphenyl group, 3-methylphenyl group, 4-methylphenyl group,
an ethylphenyl group, 4-tert-butylphenyl group, 4-butylphenyl
group, a dimethyl phenyl group, etc., an alkyl naphthyl group such
as a methylnaphthyl group, an ethyl naphthyl group, etc., an alkoxy
naphthyl group such as a methoxy naphthyl group, an ethoxy naphthyl
group, etc., a dialkyl naphthyl group such as a dimethyl naphthyl
group, a diethyl naphthyl group, etc., a dialkoxy naphthyl group
such as a dimethoxy naphthyl group, a diethoxy naphthyl group, etc.
Examples of the aralkyl group may include a benzyl group, a
phenylethyl group, a phenethyl group, etc. Examples of an aryl
oxoalkyl group may include: 2-aryl-2-oxoethyl group such as
2-phenyl-2-oxoethyl group, 2-(1-naphthyl)-2-oxoethyl group,
2-(2-naphthyl)-2-oxoethyl group, etc. Examples of a
non-nucleophilic counter ion as K.sup.- may include: a halide ion
such as a chloride ion, a bromide ion, etc., a fluoro alkyl
sulfonate such as triflate, 1,1,1-trifluoro ethanesulfonate,
nonafluoro butane sulfonate, etc., an aryl sulfonate such as
tosylate, benzene sulfonate, 4-fluorobenzene sulfonate,
1,2,3,4,5-pentafluoro benzene sulfonate, etc., and an alkyl
sulfonate such as mesylate, butane sulfonate, etc.
[0108] In addition, examples of a heteroaromatic ring that R101d,
R.sup.101e, R.sup.101f and R.sup.101g have the nitrogen atom in the
formula in the ring may include: an imidazole derivative (for
example, imidazole, 4-methyl imidazole, 4-methyl-2-phenyl
imidazole, etc.), a pyrazole derivative, a furazan derivative, a
pyrroline derivative (for example, pyrroline, 2-methyl-1-pyrroline,
etc.), a pyrrolidine derivative (for example, pyrrolidine, N-methyl
pyrrolidine, pyrrolidinone, N-methyl pyrolidone, etc.), an
imidazoline derivative, an imidazolidine derivative, a pyridine
derivative (for example, pyridine, methyl pyridine, ethyl pyridine,
propyl pyridine, butyl pyridine, 4-(1-butyl pentyl)pyridine,
dimethyl pyridine, trimethyl pyridine, triethyl pyridine, phenyl
pyridine, 3-methyl-2-phenyl pyridine, 4-tert-butyl pyridine,
diphenyl pyridine, benzyl pyridine, methoxy pyridine, butoxy
pyridine, dimethoxy pyridine, 1-methyl-2-pyridone, 4-pyrrolidino
pyridine, 1-methyl-4-phenyl pyridine, 2-(1-ethylpropyl)pyridine,
amino pyridine, dimethyl amino pyridine, etc.), a pyridazine
derivative, a pyrimidine derivative, a pyrazine derivative, a
pyrazoline derivative, a pyrazolidine derivative, a piperidine
derivative, a piperazine derivative, a morpholine derivative, an
indole derivative, an isoindole derivative, a 1H-indazole
derivative, an indoline derivative, a quinoline derivative (for
example, quinoline, 3-quinoline carbonitrile, etc.), an
isoquinoline derivative, a cinnoline derivative, a quinazoline
derivative, a quinoxaline derivative, a phthalazine derivative, a
purine derivative, a pteridine derivative, a carbazole derivative,
a phenanthridine derivative, an acridine derivative, a phenazine
derivative, 1,10-phenanthroline derivative, an adenine derivative,
an adenosine derivative, a guanine derivative, a guanosine
derivative, an uracil derivative, an uridine derivative, etc.
[0109] Although (P1a-1) and (P1a-2) have both effects of a photo
acid-generator and a thermal acid generator, (P1a-3) acts as a
thermal acid generator. ##STR5##
[0110] (In the formula, R.sup.102a and R.sup.102b each represents a
linear, branched or cyclic alkyl group having 1-8 carbon atoms.
R.sup.103 represents a linear, branched or cyclic alkylene group
having 1-10 carbon atoms. R.sup.104a and R.sup.104b each represents
a 2-oxoalkyl group having 3-7 carbon atoms. K.sup.- represents a
non-nucleophilic counter ion.)
[0111] Examples of the above-mentioned R.sup.102a and R.sup.102b
may include: a methyl group, an ethyl group, a propyl group, an
isopropyl group, n-butyl group, sec-butyl group, tert-butyl group,
a pentyl group, a hexyl group, a heptyl group, an octyl group, a
cyclopentyl group, a cyclohexyl group, a cyclopropylmethyl group,
4-methylcyclohexyl group, a cyclohexyl methyl group, etc. Examples
of R.sup.103 may include: a methylene group, an ethylene group, a
propylene group, a butylene group, a pentylene group, a hexylene
group, a heptylene group, an octylene group, a nonylene group,
1,4-cyclohexylene group, 1,2-cyclohexylene group,
1,3-cyclopentylene group, 1,4-cyclooctylene group, 1,4-cyclohexane
dimethylene group, etc. Examples of R.sup.104a and R.sup.104b may
include: 2-oxopropyl group, 2-oxocyclopentyl group, 2-oxocyclohexyl
group, 2-oxocycloheptyl group, etc. As K.sup.-, the same as
mentioned in the formulae (P1a-1), (P1a-2) and (P1a-3) can be
exemplified. ##STR6##
[0112] (In the formula, R.sup.105 and R.sup.106 represent a linear,
branched or cyclic alkyl group or a halogenated alkyl group having
1-12 carbon atoms, an aryl group or a halogenated aryl group having
6-20 carbon atoms, or an aralkyl group having 7-12 carbon
atoms.)
[0113] Examples of an alkyl group as R.sup.105 and R.sup.106 may
include: a methyl group, an ethyl group, a propyl group, an
isopropyl group, n-butyl group, sec-butyl group, tert-butyl group,
a pentyl group, a hexyl group, a heptyl group, an octyl group, an
amyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl
group, a norbornyl group, an adamantyl group, etc. Examples of a
halogenated alkyl group may include: trifluoromethyl group,
1,1,1-trifluoroethyl group, 1,1,1-trichloroethyl group, a
nonafluoro butyl group, etc. Examples of an aryl group may include:
a phenyl group, an alkoxyphenyl group such as p-methoxyphenyl
group, m-methoxyphenyl group, o-methoxyphenyl group, an
ethoxyphenyl group, p-tert-butoxyphenyl group, m-tert-butoxyphenyl
group, etc. and an alkylphenyl group such as 2-methylphenyl group,
3-methylphenyl group; 4-methylphenyl group, an ethylphenyl group,
4-tert-butylphenyl group, 4-butylphenyl group, a dimethylphenyl
group, etc. Examples of a halogenated aryl group may include: a
fluorophenyl group, a chlorophenyl group, 1,2,3,4,5-pentafluoro
phenyl group, etc. Examples of an aralkyl group may include: a
benzyl group, a phenethyl group, etc. ##STR7##
[0114] (In the formula, R.sup.107, R.sup.108 and R.sup.109
represent a linear, branched, cyclic alkyl group or halogenated
alkyl group having 1-12 carbon atoms, an aryl group or a
halogenated aryl group having 6-20 carbon atoms, or an aralkyl
group having 7-12 carbon atoms. R.sup.108 and R.sup.109 may be
bonded each other and form a cyclic structure. When they form a
cyclic structure, R.sup.108 and R.sup.109 each represents a linear
or branched alkylene group having 1-6 carbon atoms. R.sup.105
represents the same group as that in the formula P2.)
[0115] Examples of the alkyl group, the halogenated alkyl group,
the aryl group, the halogenated aryl group, and the aralkyl group
as R.sup.107, R.sup.108 and R.sup.109 may be the same as
exemplified for R.sup.105 and R.sup.106. In addition, as an
alkylene group for R.sup.108 and R.sup.109, a methylene group, an
ethylene group, a propylene group, a butylene group, a hexylene
group, etc. may be exemplified. ##STR8## (In the formula,
R.sup.101a and R.sup.101b are the same as explained above.)
##STR9##
[0116] (In the formula, R.sup.110 represents an arylene group
having 6-10 carbon atoms, an alkylene group having 1-6 carbon atoms
or an alkenylene group having 2-6 carbon atoms. Some or all of
hydrogen atoms of these groups may be further substituted with a
linear or branched alkyl group or an alkoxy group having 1-4 carbon
atoms, a nitro group, an acetyl group, or a phenyl group. R.sup.111
represents a linear, branched or substituted alkyl group, alkenyl
group or alkoxy alkyl group having 1-8 carbon atoms, a phenyl group
or a naphthyl group. Some or all of hydrogen atoms of these groups
may be substituted with an alkyl group or an alkoxy group having
1-4 carbon atoms; a phenyl group which may be substituted with an
alkyl group or an alkoxy group having 1-4 carbon atoms, a nitro
group or an acetyl group; a hetero aromatic group having 3-5 carbon
atoms; or a chlorine atom or a fluorine atom.)
[0117] Examples of the arylene group as R.sup.110 may include:
1,2-phenylene group, 1,8-naphtylene group, etc. Examples of the
alkylene group may include: a methylene group, an ethylene group, a
trimethylene group, a tetramethylene group, a phenylethylene group,
a norbornane-2,3-di-yl group, etc. Examples of the alkenylene group
may include: 1,2-vinylene group, 1-phenyl-1,2-vinylene group,
5-norbornene-2,3-di-yl group, etc. Examples of the alkyl group as
R.sup.111 may be the same as exemplified for R.sup.101a-R.sup.101c.
Examples of the alkenyl group as R.sup.111 may include: a vinyl
group, a 1-propenyl group, an allyl group, a 1-butenyl group, a
3-butenyl group, an isoprenyl group, a 1-pentenyl group, a
3-pentenyl group, a 4-pentenyl group, a dimethyl allyl group, a
1-hexenyl group, a 3-hexenyl group, a 5-hexenyl group, a 1-heptenyl
group, a 3-heptenyl group, a 6-heptenyl group, a 7-octenyl group,
etc. Examples of the alkoxy alkyl group may include: a methoxy
methyl group, an ethoxy methyl group, a propoxy methyl group, a
butoxy methyl group, a pentyloxy methyl group, a hexyloxy methyl
group, a heptyloxy methyl group, a methoxy ethyl group, an ethoxy
ethyl group, a propoxy ethyl group, a butoxy ethyl group, a
pentyloxy ethyl group, a hexyloxy ethyl group, a methoxy propyl
group, an ethoxy propyl group, a propoxy propyl group, a butoxy
propyl group, a methoxy butyl group, an ethoxy butyl group, a
propoxy butyl group, a methoxy pentyl group, an ethoxy pentyl
group, a methoxy hexyl group, a methoxy heptyl group, etc.
[0118] In addition, examples of the alkyl group having 1-4 carbon
atoms which may be further substituted may include: a methyl group,
an ethyl group, a propyl group, an isopropyl group, an n-butyl
group, an isobutyl group, a tert-butyl group, etc. Examples of the
alkoxy group having 1-4 carbon atoms may include: a methoxy group,
an ethoxy group, a propoxy group, an isopropoxy group, an n-butoxy
group, an isobutoxy group, a tert-butoxy group, etc. Examples of
the phenyl group which may be substituted with an alkyl group and
an alkoxy group having 1-4 carbon atoms, a nitro group or an acetyl
group may include: a phenyl group, a tolyl group, a p-tert-butoxy
phenyl group, a p-acetyl phenyl group, a p-nitrophenyl group, etc.
Examples of a hetero aromatic group having 3-5 carbon atoms may
include: a pyridyl group, a furil group, etc.
[0119] Examples of an acid generator may include: an onium salt
such as tetramethyl ammonium trifluoromethane sulfonate,
tetramethyl ammonium nonafluoro butane sulfonate, triethyl ammonium
nonafluoro butane sulfonate, pyridinium nonafluoro butane
sulfonate, triethyl ammonium camphor sulfonate, pyridinium camphor
sulfonate, tetra n-butyl-ammonium nonafluoro butane sulfonate,
tetraphenyl ammonium nonafluoro butane sulfonate, tetramethyl
ammonium p-toluene sulfonate, diphenyl iodinium trifluoromethane
sulfonate, (p-tert-butoxy phenyl)phenyl iodinium trifluoromethane
sulfonate, diphenyl iodinium p-toluene sulfonate, (p-tert-butoxy
phenyl)phenyl iodinium p-toluene sulfonate, triphenyl sulfonium
trifluoromethane sulfonate, (p-tert-butoxy phenyl)diphenyl
sulfonium trifluoromethane sulfonate, bis(p-tert-butoxy
phenyl)phenyl sulfonium trifluoromethane sulfonate,
tris(p-tert-butoxy phenyl)sulfonium trifluoromethane sulfonate,
triphenyl sulfonium p-toluene sulfonate, (p-tert-butoxy
phenyl)diphenyl sulfonium p-toluene sulfonate, bis(p-tert-butoxy
phenyl)phenyl sulfonium p-toluene sulfonate, tris(p-tert-butoxy
phenyl)sulfonium p-toluene sulfonate, triphenyl sulfonium
nonafluoro butane sulfonate, triphenyl sulfonium butane sulfonate,
trimethyl sulfonium trifluoromethane sulfonate, trimethyl sulfonium
p-toluene sulfonate, cyclohexyl methyl(2-oxocyclohexyl)sulfonium
trifluoromethane sulfonate, cyclohexyl methyl(2-oxo
cyclohexyl)sulfonium p-toluene sulfonate, dimethyl phenyl sulfonium
trifluoromethane sulfonate, dimethyl phenyl sulfonium p-toluene
sulfonate, dicyclohexyl phenyl sulfonium trifluoromethane
sulfonate, dicyclohexyl phenyl sulfonium p-toluene sulfonate,
trinaphthylsulfonium trifluoromethane sulfonate,
(2-norbonyl)methyl(2-oxocyclohexyl)sulfonium trifluoromethane
sulfonate, ethylene bis[methyl(2-oxocyclopentyl)sulfonium
trifluoromethane sulfonate], 1,2'-naphthyl carbonyl
methyl-tetrahydro thiophenium triflate, etc.
[0120] Examples of a diazomethane derivative may include:
bis(benzene sulfonyl)diazomethane, bis(p-toluene
sulfonyl)diazomethane, bis(xylene sulfonyl)diazomethane,
bis(cyclohexyl sulfonyl)diazomethane, bis(cyclopentyl
sulfonyl)diazomethane, bis(n-butylsulfonyl)diazomethane,
bis(isobutyl sulfonyl)diazomethane,
bis(sec-butylsulfonyl)diazomethane,
bis(n-propylsulfonyl)diazomethane, bis(isopropyl
sulfonyl)diazomethane, bis(tert-butyl-sulfonyl)diazomethane,
bis(n-amylsulfonyl)diazomethane, bis(isoamylsulfonyl)diazomethane,
bis(sec-amylsulfonyl)diazomethane,
bis(tert-amylsulfonyl)diazomethane,
1-cyclohexylsulfonyl-1-(tert-butyl-sulfonyl)diazomethane,
1-cyclohexyl sulfonyl-1-(tert-amyl sulfonyl)diazomethane,
1-tert-amyl sulfonyl-1-(tert-butyl-sulfonyl)diazomethane, etc.
[0121] Examples of a glyoxime derivative may include:
bis-O-(p-toluene sulfonyl)-.alpha.-dimethylglyoxime,
bis-O-(p-toluene sulfonyl)-.alpha.-diphenyl glyoxime,
bis-O-(p-toluene sulfonyl)-.alpha.-dicyclohexyl glyoxime,
bis-O-(p-toluene sulfonyl)-2,3-pentanedione glyoxime,
bis-O-(p-toluene sulfonyl)-2-methyl-3,4-pentanedione glyoxime,
bis-O-(n-butane sulfonyl)-.alpha.-dimethylglyoxime, bis-O-(n-butane
sulfonyl)-.alpha.-diphenyl glyoxime, bis-O-(n-butane
sulfonyl)-.alpha.-dicyclohexyl glyoxime, bis-O-(n-butane
sulfonyl)-2,3-pentanedione glyoxime, bis-O-(n-butane
sulfonyl)-2-methyl-3,4-pentanedione glyoxime, bis-O-(methane
sulfonyl)-.alpha.-dimethylglyoxime, bis-O-(trifluoromethane
sulfonyl)-.alpha.-dimethylglyoxime, bis-O-(1,1,1-trifluoro ethane
sulfonyl)-.alpha.-dimethylglyoxime, bis-O-(tert-butane
sulfonyl)-.alpha.-dimethylglyoxime, bis-O-(perfluoro octane
sulfonyl)-.alpha.-dimethylglyoxime, bis-O-(cyclohexane
sulfonyl)-.alpha.-dimethylglyoxime, bis-O-(benzene
sulfonyl)-.alpha.-dimethylglyoxime, bis-O-(p-fluorobenzene
sulfonyl)-.alpha.-dimethylglyoxime, bis-O-(p-tert-butylbenzene
sulfonyl)-.alpha.-dimethylglyoxime, bis-O-(xylene
sulfonyl)-.alpha.-dimethylglyoxime, bis-O-(camphor
sulfonyl)-.alpha.-dimethylglyoxime, etc.
[0122] Examples of a bissulfone derivative may include: bis
naphthyl sulfonyl methane, bis-trifluoro methyl sulfonyl methane,
bis methyl sulfonyl methane, bis ethyl sulfonyl methane, bis propyl
sulfonyl methane, bis isopropyl sulfonyl methane, bis-p-toluene
sulfonyl methane, bis benzene sulfonyl methane, etc.
[0123] Examples of the .beta.-ketosulfone derivative may include:
2-cyclohexyl carbonyl-2-(p-toluene sulfonyl)propane, 2-isopropyl
carbonyl-2-(p-toluene sulfonyl)propane, etc.
[0124] Examples of the disulfone derivative may include: a diphenyl
disulfone derivative, a diyclohexyl disulfone derivative, etc.
[0125] Examples of the nitro benzyl sulfonate derivative may
include: 2,6-dinitro benzyl p-toluenesulfonate, 2,4-dinitro benzyl
p-toluenesulfonate, etc.
[0126] Examples of the sulfonate derivative may include:
1,2,3-tris(methane sulfonyloxy)benzene, 1,2,3-tris(trifluoromethane
sulfonyloxy)benzene, 1,2,3-tris(p-toluene sulfonyloxy)benzene,
etc.
[0127] Examples of the sulfonate derivative of N-hydroxy imide
compound may include: N-hydroxy succinimide methane sulfonate,
N-hydroxy succinimide trifluoromethane sulfonate, N-hydroxy
succinimide ethane sulfonate, N-hydroxy succinimide 1-propane
sulfonate, N-hydroxy succinimide 2-propane sulfonate, N-hydroxy
succinimide 1-pentane sulfonate, N-hydroxy succinimide 1-octane
sulfonate, N-hydroxy succinimide p-toluenesulfonate, N-hydroxy
succinimide p-methoxybenzene sulfonate, N-hydroxy succinimide
2-chloroethane sulfonate, N-hydroxy succinimide benzenesulfonate,
N-hydroxy succinimide-2,4,6-trimethyl benzene sulfonate, N-hydroxy
succinimide 1-naphthalene sulfonate, N-hydroxy succinimide
2-naphthalene sulfonate, N-hydroxy-2-phenyl succinimide methane
sulfonate, N-hydroxy maleimide methane sulfonate, N-hydroxy
maleimide ethane sulfonate, N-hydroxy-2-phenyl maleimide methane
sulfonate, N-hydroxy glutarimide methane sulfonate, N-hydroxy
glutarimide benzenesulfonate, N-hydroxy phthalimide methane
sulfonate, N-hydroxy phthalimide benzenesulfonate, N-hydroxy
phthalimide trifluoromethane sulfonate, N-hydroxy phthalimide
p-toluenesulfonate, N-hydroxy naphthalimide methane sulfonate,
N-hydroxy naphthalimide benzenesulfonate,
N-hydroxy-5-norbornene-2,3-dicarboxyimide methane sulfonate,
N-hydroxy-5-norbornene-2,3-dicarboxyimide trifluoromethane
sulfonate, N-hydroxy-5-norbornene-2,3-dicarboxyimide
p-toluenesulfonate, etc.
[0128] Preferable examples thereof may include: an onium salt such
as triphenyl sulfonium trifluoromethane sulfonate, (p-tert-butoxy
phenyl)diphenyl sulfonium trifluoromethane sulfonate,
tris(p-tert-butoxy phenyl)sulfonium trifluoromethane sulfonate,
triphenyl sulfonium p-toluene sulfonate, (p-tert-butoxy
phenyl)diphenyl sulfonium p-toluene sulfonate, tris(p-tert-butoxy
phenyl)sulfonium p-toluene sulfonate, trinaphthylsulfonium
trifluoromethane sulfonate, cyclohexyl
methyl(2-oxocyclohexyl)sulfonium trifluoromethane sulfonate,
(2-norbonyl)methyl(2-oxocyclohexyl)sulfonium trifluoromethane
sulfonate, 1,2'-naphthyl carbonylmethyl tetrahydrothiophenium
triflate, etc.;
[0129] a diazomethane derivative such as bis(benzene
sulfonyl)diazomethane, bis(p-toluene sulfonyl)diazomethane,
bis(cyclohexyl sulfonyl)diazomethane,
bis(n-butylsulfonyl)diazomethane, bis(isobutyl
sulfonyl)diazomethane, bis(sec-butylsulfonyl)diazomethane,
bis(n-propyl sulfonyl)diazomethane, bis(isopropyl
sulfonyl)diazomethane, bis(tert-butylsulfonyl)diazomethane,
etc.;
[0130] a glyoxime derivative, such as bis-O-(p-toluene
sulfonyl)-.alpha.-dimethylglyoxime, bis-O-(n-butane
sulfonyl)-.alpha.-dimethylglyoxime, etc.;
[0131] a bissulfone derivative, such as bisnaphthyl sulfonyl
methane;
[0132] a sulfonate derivative of N-hydroxyimide compounds, such as
N-hydroxy succinimide methane sulfonate, N-hydroxy succinimide
trifluoromethane sulfonate, N-hydroxy succinimide 1-propane
sulfonate, N-hydroxy succinimide 2-propane sulfonate, N-hydroxy
succinimide 1-pentane sulfonate, N-hydroxy succinimide p-toluene
sulfonate, N-hydroxy naphthalimide methane sulfonate, N-hydroxy
naphthalimide benzene sulfonate, etc.
[0133] The above-mentioned acid generator may be used alone or in
admixture.
[0134] An amount of the acid generator to be added is preferably 0
to 50 parts, more preferably 0.1 to 40 parts per 100 parts of a
base polymer. Acid generator is not indispensable. However, if 0.1
parts or more of acid generator is added, sufficient amount of acid
is generated and a crosslinking reaction is induced sufficiently.
If 50 parts or less of acid generator is added, there is little
possibility that intermixing phenomenon in which acid migrates to a
top resist layer or an intermediate resist layer.
[0135] Furthermore, a basic compound for improving preservation
stability can be blended with a bottom resist layer composition of
the present invention.
[0136] A compound which plays a role of a quencher to an acid to
prevent an acid generated in a minute amount by an acid generator
from promoting a crosslinking reaction is suitable as the basic
compound.
[0137] Examples of such a basic compound may include: a primary,
secondary and tertiary aliphatic amines, a mixed amine, an aromatic
amine, a heterocyclic amine, a compound containing nitrogen which
has a carboxy group, a compound containing nitrogen which has a
sulfonyl group, a compound containing nitrogen which has a hydroxyl
group, a compound containing nitrogen which has a hydroxy phenyl
group, an alcoholic compound containing nitrogen, an amide
derivative, an imide derivative, etc.
[0138] Examples of the primary aliphatic amine may include:
ammonia, methylamine, ethylamine, n-propylamine, isopropylamine,
n-butylamine, isobutyl amine, sec-butyl-amine, tert-butylamine,
pentylamine, tert-amylamine, cyclopentyl amine, hexylamine,
cyclohexyl amine, heptylamine, octylamine, nonylamine, decyl amine,
dodecylamine, cetylamine, methylene diamine, ethylenediamine,
tetraethylene pentamine and the like. Examples of the secondary
aliphatic amine may include: dimethylamine, diethylamine,
di-n-propylamine, diisopropyl amine, di-n-butylamine, diisobutyl
amine, di-sec-butylamine, dipentylamine, dicyclopentyl amine,
dihexyl amine, dicyclohexyl amine, diheptylamine, dioctylamine,
dinonylamine, didecylamine, didodecylamine, dicetylamine,
N,N-dimethyl methylenediamine, N,N-dimethyl ethylenediamine,
N,N-dimethyl tetraethylene pentamine, etc. Examples of the tertiary
aliphatic amine may include: trimethylamine, triethylamine,
tri-n-propylamine, triisopropyl amine, tri-n-butyl amine,
triisobutyl amine, tri-sec-butyl amine, tripentyl amine,
tricyclopentyl amine, trihexyl amine, tricyclohexyl amine,
triheptyl amine, trioctyl amine, trinonyl amine, tridecyl amine,
tridodecyl amine, tricetyl amine, N,N,N',N'-tetra methyl methylene
diamine, N,N,N',N'-tetramethyl ethylenediamine,
N,N,N',N'-tetramethyl tetraethylene pentamine, etc.
[0139] Moreover, examples of the mixed amines may include: a
dimethyl ethylamine, methyl ethyl propyl amine, benzylamine,
phenethyl amine, benzyl dimethylamine, etc.
[0140] Examples of the aromatic amines and the heterocyclic amines
may include: an aniline derivative (for example, aniline, N-methyl
aniline, N-ethyl aniline, N-propyl aniline, N,N-dimethylaniline,
2-methyl aniline, 3-methyl aniline, 4-methyl aniline, ethyl
aniline, propyl aniline, trimethyl aniline, 2-nitroaniline,
3-nitroaniline, 4-nitroaniline, 2,4-dinitro aniline, 2,6-dinitro
aniline, 3,5-dinitro aniline, N,N-dimethyl toluidine, etc.),
diphenyl(p-tolyl)amine, methyl diphenylamine, triphenylamine,
phenylenediamine, naphthylamine, diamino naphthalene, a pyrrole
derivative (for example, pyrrole, 2H-pyrrole, 1-methyl pyrrole,
2,4-dimethyl pyrrole, 2,5-dimethyl pyrrole, N-methyl pyrrole,
etc.), an oxazole derivative (for example, oxazole, isoxazole,
etc.), a thiazole derivative (for example, thiazole, isothiazole,
etc.), an imidazole derivative (for example, imidazole, 4-methyl
imidazole, 4-methyl-2-phenyl imidazole, etc.), a pyrazole
derivative, a furazan derivative, a pyrroline derivative (for
example, pyrroline, 2-methyl-1-pyrroline, etc.), a pyrrolidine
derivative (for example, pyrrolidine, N-methyl pyrrolidine,
pyrrolidinone, N-methyl pyrolidone, etc.), an imidazoline
derivative, an imidazolidine derivative, a pyridine derivative (for
example, pyridine, methyl pyridine, ethyl pyridine, propyl
pyridine, butyl pyridine, 4-(1-butyl pentyl) pyridine, dimethyl
pyridine, trimethyl pyridine, triethyl pyridine, phenyl pyridine,
3-methyl-2-phenyl pyridine, 4-tert-butyl pyridine, diphenyl
pyridine, benzyl pyridine, methoxy pyridine, butoxy pyridine,
dimethoxy pyridine, 1-methyl-2-pyridone, 4-pyrrolidino pyridine,
1-methyl-4-phenyl pyridine, 2-(1-ethylpropyl)pyridine, amino
pyridine, dimethyl amino pyridine, etc.), a pyridazine derivative,
a pyrimidine derivative, a pyrazine derivative, a pyrazoline
derivative, a pyrazolidine derivative, a piperidine derivative, a
piperazine derivative, a morpholine derivative, an indole
derivative, an isoindole derivative, a 1H-indazole derivative, an
indoline derivative, a quinoline derivative (for example,
quinoline, 3-quinoline carbonitrile, etc.), an isoquinoline
derivative, a cinnoline derivative, a quinazoline derivative, a
quinoxaline derivative, a phthalazine derivative, a purine
derivative, a pteridine derivative, a carbazole derivative, a
phenanthridine derivative, an acridine derivative, a phenazine
derivative, a 1,10-phenanthroline derivative, an adenine
derivative, an adenosine derivative, a guanine derivative, a
guanosine derivative, an uracil derivative, an uridine derivative,
etc.
[0141] Furthermore, examples of a compound containing nitrogen
which has a carboxy group may include: aminobenzoic acid, indole
carboxylic acid, an amino acid derivative (for example, nicotinic
acid, alanine, arginine, aspartic acid, glutamic acid, glycine,
histidine, isoleucine, glycyl leucine, leucine, methionine,
phenylalanine, threonine, lysine, 3-aminopyrazine-2-carboxylic
acid, methoxy alanine), etc. Examples of a compound containing
nitrogen which has a sulfonyl group may include: 3-pyridine
sulfonic acid, pyridinium p-toluenesulfonate, etc. Examples of a
compound containing nitrogen which has a hydroxyl group, a compound
containing nitrogen which has a hydroxy phenyl group, and an
alcoholic compound containing nitrogen may include: 2-hydroxy
pyridine, amino cresol, 2,4-quinoline diol, 3-indole methanol
hydrate, monoethanolamine, diethanolamine, triethanolamine, N-ethyl
diethanolamine, N,N-diethyl ethanolamine, triisopropanol amine,
2,2'-iminodiethanol, 2-amino ethanol, 3-amino-1-propanol,
4-amino-1-butanol, 4-(2-hydroxyethyl)morpholine,
2-(2-hydroxyethyl)pyridine, 1-(2-hydroxyethyl)piperazine,
1-[2-(2-hydroxyethoxy)ethyl]piperazine, piperidine ethanol,
1-(2-hydroxy ethyl)pyrrolidine, 1-(2-hydroxyethyl)-2-pyrrolidinone,
3-piperidino-1,2-propanediol, 3-pyrrolidino-1,2-propanediol,
8-hydroxyjulolidine, 3-quinuclidinol, 3-tropanol,
1-methyl-2-pyrrolidine ethanol, 1-aziridine ethanol,
N-(2-hydroxyethyl)phthalimide, N-(2-hydroxyethyl)isonicotinamide,
etc.
[0142] Examples of an amide derivative may include: formamide,
N-methyl formamide, N,N-dimethylformamide, acetamide, N-methyl
acetamide, N,N-dimethylacetamide, propione amide, benzamide,
etc.
[0143] Examples of an imide derivative may include: phthalimide,
succinimide, maleimide, etc.
[0144] An amount of the basic compound to be blended is preferably
0.001 to 2 parts, especially 0.01 to 1 parts per 100 parts of a
total base polymer. If the amount is 0.001 parts or more, an effect
of the blending is sufficiently obtained. If it is 2 parts or less,
there is little possibility that all the acids generated by heat
may be trapped, and a crosslinking may not be induced.
[0145] An organic solvent which can be used in a bottom resist
layer composition of the present invention is not limited, as far
as the polymer having a repeating unit represented by the general
formula (1), an acid generator, a cross-linker, other additives,
etc. can be dissolved. Examples thereof may include: ketones such
as cyclohexanone, methyl-2-amyl ketone, etc.; alcohols such as
3-methoxy butanol, 3-methyl-3-methoxy butanol,
1-methoxy-2-propanol, 1-ethoxy-2-propanol, etc.; ethers, such as
propylene glycol monomethyl ether, ethylene glycol monomethyl
ether, propylene-glycol monoethyl ether, ethylene glycol monoethyl
ether, propylene-glycol dimethyl ether, diethylene-glycol dimethyl
ether, etc.; esters, such as propylene-glycol-monomethyl-ether
acetate, propylene-glycol monoethyl ether acetate, ethyl lactate,
ethyl pyruvate, butyl acetate, methyl 3-methoxypropionate, ethyl
3-ethoxypropionate, tert-butyl acetate, tert-butyl propionate,
propylene-glycol-monomethyl-ether acetate, propylene-glycol
mono-tert-butyl-ether acetate, etc. They can be used alone or in
admixture. However, they are not limited thereto.
[0146] Among the above-mentioned organic solvents,
diethylene-glycol dimethyl ether, 1-ethoxy-2-propanol, ethyl
lactate, propylene-glycol-monomethyl-ether acetate,
propylene-glycol-monomethyl-ether and a mixed solvent thereof are
preferably used for the bottom resist layer composition of the
present invention.
[0147] An amount of the organic solvent to be blended is preferably
200 to 10,000 parts, especially 300 to 5,000 parts per 100 parts of
the total base polymer.
[0148] Furthermore, the present invention provides a patterning
process on a substrate with lithography wherein, at least, a bottom
resist layer is formed on a substrate with the bottom resist layer
composition according to the present invention, an intermediate
resist layer containing silicon atoms is formed on the bottom
resist layer, a top resist layer of a photoresist composition is
formed on the intermediate resist layer, to form a trilayer resist
film, a pattern circuit area of the trilayer resist film is exposed
and developed with a developer to form a resist pattern on the top
resist layer, the intermediate resist layer is etched using as a
mask the top resist layer on which the pattern is formed, the
bottom resist layer is etched using as a mask at least the
intermediate resist layer-on which the pattern is formed, and then
the substrate is etched using as a mask at least the bottom resist
layer on which the pattern is formed, to form the pattern on the
substrate.
[0149] Such a trilayer resist process will be explained with
reference to FIG. 6.
[0150] A bottom resist layer 22 of the present invention can be
formed on a substrate 21 by a spin-coating etc. as in a method of
forming a photoresist film. After forming the bottom resist layer
22 by spin-coating etc., it is preferable that an organic solvent
is evaporated, and baking is carried out in order to promote a
crosslinking reaction to prevent intermixing with an intermediate
resist layer 24. The baking is preferably carried out at a
temperature in a range of 80 to 300.degree. C., for 10 to 300
seconds. Although a thickness of the bottom resist layer 22 is
selected appropriately, it is preferably 30 to 20,000 nm, and
especially 50 to 15,000 nm.
[0151] Next, in the case of a trilayer resist process, an
intermediate resist layer 24 containing silicon is formed on the
bottom layer, furthermore, thereon single resist layer without
silicon (a top resist layer 23) is formed (see FIG. 6(a)).
[0152] In this case, a known photoresist composition can be used to
form the top resist layer. Namely, the top resist layer 23 in a
trilayer resist process may be a positive type or a negative type,
and usual single resist layer compositions can be used as the
photoresist composition.
[0153] On the other hand, a composition based on polysilsesquioxane
can be preferably used to form the intermediate resist layer 24
containing silicon for a trilayer resist process. Reflection from a
substrate can be suppressed by giving an antireflection effect to
the intermediate resist layer 24. In particular, if a composition
containing a large amount of aromatic groups and having a high
etching resistance during etching a substrate is used to form a
bottom resist layer for exposure to light at a wavelength of 193
nm, k value becomes high and a reflectivity of a substrate becomes
high. However, a reflectivity of a substrate can be suppressed to
0.5% or less by suppressing reflection with an intermediate resist
layer. As an intermediate resist layer with an antireflection
effect, polysilsesquioxane having a phenyl group or an absorption
group having an Si-Si bond as a pendant group that crosslinks with
acid or heat is preferably used for exposure to light at a
wavelength of 193 nm. SiON etc. are also known as an intermediate
resist layer with an antireflection effect.
[0154] When the intermediate resist layer 24 and the top resist
layer 23 are formed, sping-coating is preferably used as in the
case of forming the above-mentioned bottom resist layer. In
addition, an intermediate resist layer formed with Chemical Vapor
Deposition (CVD) method can also be used. The spin-coating is
easier than the CVD method and has advantage of cost to form an
intermediate resist layer.
[0155] After the top resist layer 23 is formed with spin-coating
etc., pre-baking is carried out, preferably at a temperature of 80
to 180.degree. C. for 10 to 300 seconds. In addition, a thickness
of the top resist layer 23 is not limited, however, 30 to 500 nm,
in particular, 50 to 400 nm is preferable.
[0156] Then, according to a conventional method, a pattern circuit
area 25 of a trilayer resist film is exposed (see FIG. 6(b)), and
post exposure baking (PEB) and development are carried out to
obtain a resist pattern on the top resist layer (see FIG.
6(c)).
[0157] As an exposure light, high energy beams at a wavelength of
300 nm or less can be used. Examples thereof may include: excimer
lasers at a wavelength of 248 nm, 193 nm, and 157 nm, soft X-ray at
a wavelength of 3 to 20 nm, electron beam, X-ray, etc. Among these,
laser beam of KrF excimer laser at a wavelength of 248 nm and laser
beam of ArF excimer laser at a wavelength of 193 nm are preferably
used.
[0158] The development is carried out with a puddle method, a dip
method, etc. using an alkaline solution. Preferably, the puddle
method using a 2.38% by mass aqueous solution of tetramethyl
ammonium hydroxide is used, and it is carried out at a room
temperature for 10 to 300 seconds. Then, it is rinsed with pure
water, and is dried by a spin dry, a nitrogen blow, etc.
[0159] Then, etching is carried out using obtained resist pattern
as a mask.
[0160] Etching of the intermediate resist layer 24 in a trilayer
resist process is carried out with a gas mainly containing
fluocarbon gas etc. using the resist pattern as a mask (see FIG.
6(d)). Next, etching of the bottom resist layer 22 is carried out
by dry etching etc. with a gas mainly containing oxygen gas using
the resist pattern transferred to the intermediate resist layer 24
as a mask (see FIG. 6(e)). In the case of the dry etching with a
gas mainly containing oxygen gas, it is also possible to add an
inert gas such as He, Ar, etc. and CO, CO.sub.2, NH.sub.3,
SO.sub.2, N.sub.2, NO.sub.2 and H.sub.2 gas in addition to oxygen
gas. In addition, the etching can be carried out with just CO,
CO.sub.2, NH.sub.3, SO.sub.2, N.sub.2, NO.sub.2 and H.sub.2 gas.
Especially the latter gases are used for protection of a side wall
to prevent undercut of a side wall of a pattern.
[0161] Next, etching of the substrate 21 can also be carried out by
a conventional method. For example, etching with a gas mainly
containing fluocarbon gas is carried out in the case that the
substrate is SiO.sub.2, SiN or silica-type low-dielectric-constant
insulator film. Etching with a gas mainly containing a chlorine gas
or a bromine gas is carried out in the case that the substrate is
poly silicon (p-Si), Al or W (see FIG. 6(f)).
[0162] In the case of etching the substrate with a gas mainly
containing fluorocarbon gas, the intermediate resist layer 24
containing silicon in a trilayer resist process is removed during
etching of the substrate.
[0163] In the case of etching the substrate with a gas mainly
containing a chlorine gas or a bromine gas, it is necessary to
remove the intermediate resist layer 24 containing silicon by
carrying out dry etching with a gas mainly containing fluorocarbon
gas separately from etching the substrate.
[0164] The bottom resist layer of the present invention is
characterized by having an excellent etching resistance during
etching a substrate.
[0165] In addition, as shown in FIG. 6, the substrate 21 may
consist of a processed layer 21b and a base layer 21a. The base
layer 21a of the substrate 21 is not limited and may be Si, an
amorphous silicon (.alpha.-Si), p-Si, SiO.sub.2, SiN, SiON, W, TiN,
Al, etc. And a different material from a processed layer 21b may be
used. As the processed layer 21b, Si, SiO.sub.2, SiON, SiN, p-Si,
.alpha.-Si, W, W-Si, Al, Cu, Al-Si, etc., various low dielectric
constant films, and an etching stopper film thereof may be used,
and it may be formed generally at a thickness of 50 to 10,000 nm,
especially at a thickness of 100 to 5,000 nm.
EXAMPLES
[0166] Hereafter the present invention will be explained in detail
with reference to Synthetic Examples, Examples and Comparative
Examples. However, the present invention is not limited
thereto.
[0167] In addition, as for measurement of molecular weight, mass
average molecular weight (Mw) and number average molecular weight
(Mn) relative to polystyrene standards were determined by gel
permeation chromatography (GPC), and molecular-weight distribution
(Mw/Mn) was determined.
Synthetic Example 1
[0168] To a 300 mL flask 160 g of m-cresol, 50 g of 1-naphthol, 75
g of 37% formalin solution and 5 g of oxalic acid were added, and
the contents were stirred at 100.degree. C. for 24 hours. After the
reaction, the contents were dissolved into 500 mL of methyl
isobutyl ketone. Then, a catalyst and metallic impurities were
removed by sufficient washing with water, and the solvent was
removed under a reduced pressure. And the solution was subjected to
a condition of at a temperature of 150.degree. C. and at a reduced
pressure of 2 mmHg, and water and unreacted monomer were removed to
yield 188 g of the following polymer 1.
[0169] Molecular weight (Mw) and distribution (Mw/Mn) of polymer 1
were determined by GPC, and a ratio of repeating units in polymer 1
was determined as follows by .sup.1H-NMR analysis.
[0170] polymer 1; a1:b1 (mole ratio)=0.8:0.2
[0171] Molecular weight (Mw)=12,000
[0172] Molecular-weight distribution (Mw/Mn)=4.60 ##STR10##
Synthetic Example 2
[0173] To a 300 mL flask 160 g of m-cresol, 70 g of 1-hydroxy
pyrene, 75 g of 37% formalin solution and 5 g of oxalic acid were
added, and the contents were stirred at 100.degree. C. for 24
hours. After the reaction, the contents were dissolved into 500 mL
of methyl isobutyl ketone. Then, a catalyst and metallic impurities
were removed by sufficient washing with water, and the solvent was
removed under a reduced pressure. And the solution was subjected to
a condition of at a temperature of 150.degree. C. and at a reduced
pressure of 2 mmHg, and water and unreacted monomer were removed to
yield 193 g of the following polymer 2.
[0174] Molecular weight (Mw) and molecular-weight distribution
(Mw/Mn) of polymer 2 were determined by GPC, and a ratio of
repeating units in polymer 2 was determined as follows by
.sup.1H-NMR analysis.
[0175] polymer 2; a1:b2 (mole ratio)=0.83:0.17
[0176] Molecular weight (Mw)=12,700
[0177] Molecular-weight distribution (Mw/Mn)=4.80 ##STR11##
Synthetic Example 3
[0178] To a 300 mL flask 160 g of m-cresol, 60 g of 2-hydroxy
fluorene, 75 g of 37% formalin solution and 5 g of oxalic acid were
added, and the contents were stirred at 100.degree. C. for 24
hours. After the reaction, the contents were dissolved into 500 mL
of methyl isobutyl ketone. Then, a catalyst and metallic impurities
were removed by sufficient washing with water, and the solvent was
removed under a reduced pressure. And the solution was subjected to
a condition of at a temperature of 150.degree. C. and at a reduced
pressure of 2 mmHg, and water and unreacted monomer were removed to
yield 190 g of the following polymer 3.
[0179] Molecular weight (Mw) and a molecular-weight distribution
(Mw/Mn) of polymer 3 were determined by GPC, and a ratio of
repeating units in polymer 3 was determined as follows by
.sup.1H-NMR analysis.
[0180] polymer 3; a1:b3 (mole ratio)=0.75:0.25
[0181] Molecular weight (Mw)=10,800
[0182] Molecular-weight distribution (Mw/Mn)=4.30 ##STR12##
Synthetic Example 4
[0183] To a 300 mL flask 160 g of m-cresol, 50 g of 6-hydroxy
indene, 75 g of 37% formalin solution and 5 g of oxalic acid were
added, and the contents were stirred at 100.degree. C. for 24
hours. After the reaction, the contents were dissolved into 500 mL
of methyl isobutyl ketone. Then, a catalyst and metallic impurities
were removed by sufficient washing with water, and the solvent was
removed under a reduced pressure. And the solution was subjected to
a condition of at a temperature of 150.degree. C. and at a reduced
pressure of 2 mmHg, and water and unreacted monomer were removed to
yield 175 g of the following polymer 4.
[0184] Molecular weight (Mw) and molecular-weight distribution
(Mw/Mn) of polymer 4 were determined by GPC, and a ratio of
repeating units in polymer 4 was determined as follows by
.sup.1H-NMR analysis.
[0185] polymer 4; a1:b4 (mole-ratio)=0.68:0.32
[0186] Molecular weight (Mw)=9,800
[0187] Molecular-weight distribution (Mw/Mn)=5.30 ##STR13##
Synthetic Example 5
[0188] To a 1 L flask 125 g of polymer 1 (m-cresol-1-naphthol
resin) obtained in the above Synthetic Example 1 and 300 g of
epichlorohydrin were added and dissolved. The temperature of the
contents was elevated to 80.degree. C., and 220 g of 20% sodium
hydroxide was added dropwise for 3 hours with stirring the
contents. After stirring for aging of 1 hour, brine of underlayer
was isolated, and unreacted epichlorohydrin was removed with
distillation with heating at 150.degree. C. Next, after 300 g of
MIBK (methyl isobutyl ketone) was added and the contents were
dissolved, the lower aqueous layer was removed by repeating
separation by washing with water three times, followed by drying
and filtration. And then MIBK as the solvent was removed by heating
at 150.degree. C., to yield 140 g of the following polymer 5.
[0189] Molecular weight (Mw) and molecular-weight distribution
(Mw/Mn) of polymer 5 were determined by GPC, and a ratio of
repeating units in polymer 5 was determined as follows by
.sup.1H-NMR analysis.
[0190] polymer 5; a2:b5:a1:b1 (mole ratio)=0.4:0.06:0.4:0.14
[0191] Molecular weight (Mw)=12,800
[0192] Molecular-weight distribution (Mw/Mn)=4.60 ##STR14##
Synthetic Example 6
[0193] In a 2 L flask 125 g of polymer 1 (m-cresol-1-naphthol
resin) obtained in the above Synthetic Example 1 was dissolved in
1000 mL of pyridine, and 56 g of di-tert-butyl dicarbonate was
added with stirring at 45.degree. C. After reacting for 1 hour, the
reaction solution was dropped into 3 L of water to obtain white
solid. The solid was filtrated, dissolved into 400 mL of acetone,
dropped into 10 L of water, and filtration and vacuum drying were
carried out to yield the following polymer 6.
[0194] Molecular weight (Mw) and molecular-weight distribution
(Mw/Mn) of polymer 6 were determined by GPC, and a ratio of
repeating units in polymer 6 was determined as follows by
.sup.1H-NMR analysis.
[0195] polymer 6; a3:b6:a1:b1 (mole ratio)=0.2:0.04:0.6:0.16
[0196] Molecular weight (Mw)=12,600
[0197] Molecular-weight distribution (Mw/Mn)=4.60 ##STR15##
Synthetic Example 7
[0198] To a 300 mL flask 220 g of m-phenyl-phenol, 50 g of
1-naphthol, 75 g of 37% formalin solution and 5 g of oxalic acid
were added, and the contents were stirred at 100.degree. C. for 24
hours. After the reaction, the contents were dissolved into 500 mL
of methyl isobutyl ketone. Then, a catalyst and a metallic
impurities were removed by sufficient washing with water, and the
solvent was removed under a reduced pressure. And the solution was
subjected to a condition of at a temperature of 150.degree. C. and
at a reduced pressure of 2 mmHg, and water and unreacted monomer
were removed to yield 168 g of the following polymer 7.
[0199] Molecular weight (Mw) and molecular-weight distribution
(Mw/Mn) of polymer 7 were determined by GPC, and a ratio of
repeating units in polymer 7 was determined as follows by
.sup.1H-NMR analysis.
[0200] polymer 7; a4:b1 (mole ratio)=0.8:0.2
[0201] Molecular weight (Mw)=6,000
[0202] Molecular-weight distribution (Mw/Mn)=4.70 ##STR16##
Comparative Synthetic Example 1
[0203] To a 300 mL flask 200 g of m-cresol, 75 g of 37% formalin
solution and 5 g of oxalic acid were added, and the contents were
stirred at 100.degree. C. for 24 hours. After the reaction, the
contents were dissolved into 500 mL of methyl isobutyl ketone.
Then, a catalyst and metallic impurities were removed by sufficient
washing with water, and the solvent was removed under a reduced
pressure. And the solution was subjected to a condition of at a
temperature of 150.degree. C. and at a reduced pressure of 2 mmHg,
and water and unreacted monomer were removed to yield 193 g of the
following comparative polymer 1.
[0204] Molecular weight (Mw) and molecular-weight distribution
(Mw/Mn) of comparative polymer 1 were determined by GPC, and a
ratio of repeating units in comparative polymer 1 was determined as
follows by .sup.1H-NMR analysis.
[0205] comparative polymer 1; a1=1.0
[0206] Molecular weight (Mw)=18,000
[0207] Molecular-weight distribution (Mw/Mn)=4.80 ##STR17##
Comparative Synthetic Example 2
[0208] To a 300 mL flask 200 g of 1-naphthol, 75 g of 37% formalin
solution and 5 g of oxalic acid were added, and the contents were
stirred at 100.degree. C. for 24 hours. After the reaction, the
contents were dissolved into 500 mL of methyl isobutyl ketone.
Then, a catalyst and metallic impurities were removed by sufficient
washing with water, and the solvent was removed under a reduced
pressure. And the solution was subjected to a condition of at a
temperature of 150.degree. C. and at a reduced pressure of 2 mmHg,
and water and unreacted monomer were removed to yield 85 g of the
following comparative polymer 2.
[0209] Molecular weight (Mw) and molecular-weight distribution
(Mw/Mn) of comparative polymer 2 were determined by GPC, and a
ratio of repeating units in comparative polymer 2 was determined as
follows by .sup.1H-NMR analysis.
[0210] comparative polymer 2; b1=1.0
[0211] Molecular weight (Mw)=1,100
[0212] Molecular-weight distribution (Mw/Mn)=3.40 ##STR18##
Comparative Synthetic Example 3
[0213] To a 300 mL flask 200 g of 1-hydroxy pyrene, 75 g of 37%
formalin solution and 5 g of oxalic acid were added, and the
contents were stirred at 100.degree. C. for 24 hours. After the
reaction, the contents were dissolved into 500 mL of methyl
isobutyl ketone. Then, a catalyst and metallic impurities were
removed by sufficient washing with water, and the solvent was
removed under a reduced pressure. And the solution was subjected to
a condition of at a temperature of 150.degree. C. and at a reduced
pressure of 2 mmHg, and water was removed. However, polymer was not
obtained.
Blend polymer Synthetic Example 1
[0214] As a base polymer for blending, 1-naphthol-dicyclo
pentadiene novolac resin was synthesized by copolycondensation with
oxalic acid to yield the following blend polymer 1.
[0215] blend polymer 1; c:d (mole ratio)=0.6:0.4
[0216] Molecular weight (Mw)=1,300
[0217] Molecular-weight distribution (Mw/Mn)=3.6 ##STR19##
Blend polymer Synthetic Example 2
[0218] As a base polymer for blending, acenaphthylene-hydroxy
styrene was synthesized by cationic polymerization to yield the
following blend polymer 2.
[0219] blend polymer 2; e:f (mole ratio)=0.8:0.2
[0220] Molecular weight (Mw)=3,200
[0221] Molecular-weight distribution (Mw/Mn)=1.55 ##STR20##
Blend polymer Synthetic Example 3
[0222] As a base polymer for blending,
4,4'-(9H-fluorene-9-ylidene)bisphenol was turned into a novolac
resin by using formalin to yield the following blend polymer 3.
[0223] blend polymer 3; Molecular weight (Mw)=8,800
[0224] Molecular-weight distribution=4.50 ##STR21##
Examples, Comparative Examples
[0225] [Preparation of Bottom Resist Layer Compositions and
Intermediate Resist Layer Compositions]
[0226] Solutions of bottom resist layer compositions (Examples
1-15, and Comparative Examples 1 and 2) and solutions of
intermediate resist layer compositions (SOG 1 and SOG 2) were
prepared respectively by dissolving the polymers of the Synthetic
Examples 1-7, the Comparative Synthetic Examples 1 and 2 and the
Blend polymer Synthetic Examples 1-3, silicon containing
intermediate layer polymers shown below as silicon containing KrF
intermediate layer polymer 1 and silicon containing ArF
intermediate layer polymer 1, acid generators shown below as AG1
and AG2 and cross-linkers shown below as CR 1 and CR 2 at a ratio
shown in Table 1 in an organic solvent containing 0.1% by mass of
FC-430 (manufactured by Sumitomo 3M), and filtering them with a 0.1
.mu.m filter made of fluoroplastics.
[0227] Each of the compositions in Table 1 is as follows.
[0228] Polymer 1-7: obtained in the Synthetic Example 1-7
[0229] Blend polymer 1-3: obtained in the Blend polymer Synthetic
Example 1-3
[0230] Comparative polymer 1-2: obtained in the Comparative Example
1-2
[0231] silicon containing intermediate layer polymer: silicon
containing ArF intermediate layer polymer 1 [mole ratio
(o:p:q)=0.2:0.5:0.3, Molecular weight (Mw)=3,400], silicon
containing KrF intermediate layer polymer 1 [mole ratio (m:n)
=0.3:0.7, Molecular weight (Mw)=2,500], (see the following
structural formulae) ##STR22## ##STR23##
[0232] Acid generator: AG1 and AG2 (see the following structural
formulae) ##STR24##
[0233] Cross-linker: CR1 and CR2 (see the following structural
formulae) ##STR25##
[0234] Organic solvent: PGMEA (propylene glycol monomethyl ether
acetate)
[0235] The bottom resist layer compositions (Examples 1-15,
Comparative Examples 1 and 2) prepared above were applied on a
silicon substrate 8 inches (about 200 mm) across, and baked for 60
seconds at 300.degree. C. in the Examples 1-3, baked for 60 seconds
at 200.degree. C. in the Examples 4-15 and the Comparative Examples
1 and 2 to form bottom resist layers with a thickness of 300 nm. In
addition, as intermediate resist layers, the solutions of the
intermediate resist layer compositions (SOG 1 and SOG 2) prepared
above were applied by spin-coating, and baked for 60 seconds at
200.degree. C. to form silicon containing intermediate resist
layers with a thickness of 100 nm, respectively.
[0236] After formation of the bottom resist layers and the
intermediate resist layers, the refractive index (n, k) of the
bottom resist layers and the intermediate resist layers at a
wavelength of 193 nm and 248 nm were measured using an incident
light angle variable spectroscopic ellipsometer (VASE) manufactured
by J.A. Woollam Co., Inc. The results were shown in Table 1.
[0237] In addition, layer-thickness of the whole plane of wafers 8
inches across was determined using an a film thickness measurement
system Lambda Ace manufactured by Dainippon Screen Mfg. Co., Ltd.,
and difference of the maximum valume and the minimum value of the
layer-thickness was calculated. The results were shown in Table 1
as "uniformity of layer". TABLE-US-00001 TABLE 1 cross- organic
refractive refractive bottom resist linker acid solvent index index
layer (parts generator (parts uniformity (193 nm) (248 nm)
composition polymer by (parts by by of layer n k n k etc. (parts by
mass) mass) mass) mass) (nm) value value value value Example 1
polymer 1 -- -- PGMEA 3 1.48 0.55 1.95 0.28 (20) (100) Example 2
polymer 2 -- -- PGMEA 3 1.46 0.57 2.06 0.17 (20) (100) Example 3
polymer 3 -- -- PGMEA 3 1.49 0.53 1.86 0.15 (20) (100) Example 4
polymer 1 CR1 AG1 PGMEA 1 1.49 0.53 1.96 0.21 (20) (2.0) (0.1)
(100) Example 5 polymer 2 CR1 AG1 PGMEA 1 1.48 0.55 2.03 0.15 (20)
(2.0) (0.1) (100) Example 6 polymer 3 CR1 AG1 PGMEA 1 1.50 0.51
1.88 0.12 (20) (2.0) (0.1) (100) Example 7 polymer 4 CR1 AG1 PGMEA
1 1.48 0.52 1.83 0.03 (20) (2.0) (0.1) (100) Example 8 polymer 5 --
AG1 PGMEA 3 1.49 0.53 1.94 0.22 (20) (0.1) (100) Example 9 polymer
6 -- AG1 PGMEA 3 1.49 0.52 1.98 0.21 (20) (0.1) (100) Example 10
polymer 7 -- AG1 PGMEA 3 1.40 0.55 1.85 0.20 (20) (0.1) (100)
Example 11 polymer 1 CR2 AG1 PGMEA 2 1.44 0.55 1.98 0.22 (20) (2.0)
(0.1) (100) Example 12 polymer 1 CR1 AG2 PGMEA 1 1.46 0.33 1.92
0.21 (20) (2.0) (0.1) (100) Example 13 blend polymer 1 CR2 AG1
PGMEA 3 1.52 0.40 1.78 0.28 (10) (2.0) (0.1) (100) polymer 1 (10)
Example 14 blend polymer 2 CR1 AG2 PGMEA 2 1.43 0.45 1.96 0.12 (10)
(2.0) (0.1) (100) polymer 1 (10) Example 15 blend polymer 3 CR1 AG1
PGMEA 2 1.37 0.58 2.05 0.28 (10) (2.0) (0.1) (100) polymer 1 (10)
SOG 1 silicon containing -- AG1 PGMEA 1 1.66 0.15 1.60 0.01 ArF
intermediate (1) (1000) layer polymer 1 (20) SOG 2 silicon
containing -- AG1 PGMEA 1 1.53 0.28 1.78 0.15 KrF intermediate (1)
(1000) layer polymer 1 (20) Comparative comparative CR1 AG1 PGMEA 8
1.30 0.63 1.96 0.06 Example 1 polymer1 (2.0) (1) (100) (28.0)
Comparative comparative CR1 AG1 PGMEA 30 1.32 0.32 2.10 0.36
Example 2 polymer2 (2.0) (1) (100) (28.0)
[0238] As shown in Table 1, the bottom resist layers in the
Examples 1-15 has excellent uniformity of layer after application,
has appropriate refractive index (n, k) at a wavelength of 193 nm,
namely k value is in a range of 0.2 to 0.8, has also appropriate
refractive index (n, k) at a wavelength of 248 nm, and a sufficient
antireflection effect can be obtained by combining with an
intermediate resist layer if necessary.
[Preparation of Top Resist Layer Compositions]
[0239] The following polymers (KrF single layer resist polymer 1
and ArF single layer resist polymer 1) were prepared as base resins
of top resist layers. ##STR26##
[0240] KrF single layer resist polymer 1 consists of the repeating
units r, s and t shown above. A copolymerization mole ratio and
molecular weight (Mw) of the polymer are shown below.
[0241] Copolymerization mole ratio; r:s:t=0.70:0.10:0.20
[0242] Molecular weight (Mw)=9,300 ##STR27##
[0243] ArF single layer resist polymer 1 consists of the repeating
units u, v and w shown above. A copolymerization mole ratio and
molecular weight (Mw) of this polymer are shown below.
[0244] Copolymerization mole ratio; u:v:w=0.40:0.30:0.30
[0245] Molecular weight (Mw)=7,800
[0246] Solution of KrF top resist layer composition and Solution of
ArF top resist layer composition were prepared by dissolving the
polymers prepared above (KrF single layer resist polymer 1 and ArF
single layer resist polymer 1), an acid generator (PAG1) and a
basic compound (TMMEA) at a ratio shown in Table 2 in an organic
solvent containing 0.1% by mass of FC-430 (manufactured by Sumitomo
3M), and filtering them with a 0.1 .mu.m filter made of
fluoroplastics.
[0247] Each of the compositions in Table 2 is as follows.
[0248] Acid generator: PAG1 (see the following structural formula)
##STR28##
[0249] basic compound: TMMEA (see the following structural formula)
##STR29##
[0250] Organic solvent: PGMEA (propylene glycol monomethyl ether
acetate) TABLE-US-00002 TABLE 2 top resist layer polymer acid
generator basic compound organic solvent composition (parts by
mass) (parts by mass) (parts by mass) (parts by mass) KrF top
resist layer KrF single layer resist polymer 1 PAG1 TMMEA PGMEA
composition (100) (4.0) (0.3) (1,200) ArF top resist layer ArF
single layer resist polymer 1 PAG1 TMMEA PGMEA composition (100)
(2.2) (0.3) (1,200)
[Observation of a Pattern Profile] (1) Observation of a Resist
Pattern Profile 1) Exposure to KrF
[0251] The solutions of the bottom resist layer compositions
(Examples 1, 4, 8-15) prepared above were applied on a substrate
having an SO.sub.2 film with a thickness of 300 nm, baked for 60
seconds at 300.degree. C. in the Example 1, and baked for 60
seconds at 200.degree. C. in the Examples 4, 8-15, to form bottom
resist layers with a thickness of 400 nm. Next, thereon the
solution of the intermediate resist layer composition (SOG 2)
prepared above was applied, and baked for 60 seconds at 200.degree.
C., to form an intermediate resist layer with a thickness of 80 nm.
Next, the solution of the KrF top resist layer composition prepared
above was applied, and baked for 60 seconds at 120.degree. C., to
form a top resist layer with a thickness of 150 nm. Subsequently,
it was exposed by the KrF exposure system (S203B, NA0.68,
.sigma.0.7, 2/3 annular illumination, an attenuated phase shifting
mask with a transmission of 6%, manufactured by Nikon Corporation),
baked (PEB) for 60 seconds at 110.degree. C., and developed in
2.38% by mass aqueous solution of tetra methyl ammonium hydroxide
(TMAH), to obtain a positive resist pattern. The results of
observation of the pattern profile of 0.14 .mu.m L/S with an
electron microscope manufactured by Hitachi Ltd. (S-4700) were
shown in Table 3.
2) Exposure to ArF
[0252] The solutions of the bottom resist layer compositions
(Examples 1-15, Comparative Examples 1-2) prepared above were
applied on a substrate having an SiO.sub.2 film with a thickness of
300 nm, baked for 60 seconds at 300.degree. C. in the Examples 1-3,
and baked for 60 seconds at 200.degree. C. in the Examples 4-15 and
Comparative Examples 1-2, to form bottom resist layers with a
thickness of 200 nm. Next, thereon the solution of the intermediate
resist layer composition (SOG 1) was applied, and baked for 60
seconds at 200.degree. C., to form an intermediate resist layer
with a thickness of 70 nm. Next, the solution of the ArF top resist
layer composition prepared above was applied, and baked for 60
seconds at 130.degree. C., to form a top resist layer with a
thickness of 150 nm. Subsequently, it was exposed by the ArF
exposure system (S307E, NA0.85, a0.93, 4/5 annular illumination, an
attenuated phase shifting mask with a transmission of 6%,
manufactured by Nikon Corporation), baked (PEB) for 60 seconds at
110.degree. C., and developed in 2.38% by mass aqueous solution of
tetra methyl ammonium hydroxide (TMAH), to obtain a positive resist
pattern. The results of observation of the pattern profile of 0.08
.mu.m L/S with an electron microscope (S-4700) manufactured by
Hitachi Ltd. were shown in Table 4.
(2) Observation of a Pattern Profile Transferred to an Intermediate
Resist Layer
[0253] Next, after a resist pattern was formed using the same
compositions and method as those used in the above-mentioned
"Observation of a resist pattern profile", thus-obtained resist
pattern was transferred to an intermediate resist layer under the
following conditions.
[0254] The etching conditions were as follows.
[0255] Chamber pressure: 40.0 Pa
[0256] RF power: 1,000 W
[0257] Gap: 9 mm
[0258] CHF.sub.3 gas flow rate: 20 ml/min
[0259] CF.sub.4 gas flow rate: 60 ml/min
[0260] Ar gas flow rate: 200 ml/min
[0261] Time: 30 sec
[0262] The results of observation of thus-obtained pattern profile
with an electron microscope (S-4700) manufactured by Hitachi Ltd.
were shown in Table 3 and 4.
(3) Observation of a Pattern Profile Transferred to a Bottom Resist
Layer
[0263] Next, after a resist pattern was transferred to an
intermediate resist layer using the same compositions and method as
those used in the above-mentioned "Observation of a pattern profile
transferred to an intermediate resist layer", thus-obtained resist
pattern was transferred to a bottom resist layer by etching with a
gas mainly containing oxygen gas.
[0264] The etching conditions were as follows.
[0265] Chamber pressure: 450 mTorr (60.0 Pa)
[0266] RF power: 600 W
[0267] Ar gas flow rate: 40 sccm
[0268] O.sub.2 gas flow rate: 60 sccm
[0269] Gap: 9 mm
[0270] Time: 20 sec
[0271] The results of observation of thus-obtained pattern profile
with an electron microscope (S-4700) manufactured by Hitachi Ltd.
were shown in Table 3 and 4.
(4) Observation of a Pattern Profile Formed on a Substrate
[0272] Next, a pattern was formed on a bottom resist layer using
the same compositions and method as those used in the
above-mentioned "Observation of a pattern profile transferred to a
bottom resist layer", the bottom resist layer was used as a mask
and a substrate was etched with a gas mainly containing
CF.sub.4/CHF.sub.3 gas using a dry-etching-system TE-8500P
manufactured by Tokyo Electron, Ltd.
[0273] The etching conditions were as follows.
[0274] Chamber pressure: 40.0 Pa
[0275] RF power: 1,300 W
[0276] gap: 9 mm
[0277] CHF.sub.3 gas flow rate: 30 ml/min
[0278] CF.sub.4 gas flow rate: 30 ml/min
[0279] Ar gas flow rate: 100 ml/min
[0280] Time: 60 sec
[0281] The results of observation of thus-obtained pattern profile
with an electron microscope (S-4700) manufactured by Hitachi Ltd.
were shown in Table 3 and 4. TABLE-US-00003 TABLE 3 bottom pattern
pattern profile after pattern profile after pattern profile resist
layer top resist layer profile after transfer-etching
transfer-etching after transfer- composition composition
development intermediate resist layer bottom resist layer etching
substrate Example 1 KrF top resist rectangle rectangle rectangle
rectangle layer composition Example 4 KrF top resist rectangle
rectangle rectangle rectangle layer composition Example 8 KrF top
resist rectangle rectangle rectangle rectangle layer composition
Example 9 KrF top resist rectangle rectangle rectangle rectangle
layer composition Example 10 KrF top resist rectangle rectangle
rectangle rectangle layer composition Example 11 KrF top resist
rectangle rectangle rectangle rectangle layer composition Example
12 KrF top resist rectangle rectangle rectangle rectangle layer
composition Example 13 KrF top resist rectangle rectangle rectangle
rectangle layer composition Example 14 KrF top resist rectangle
rectangle rectangle rectangle layer composition Example 15 KrF top
resist rectangle rectangle rectangle rectangle layer
composition
[0282] TABLE-US-00004 TABLE 4 bottom pattern pattern profile after
pattern profile after pattern profile resist layer top resist layer
profile after transfer-etching transfer-etching bottom after
transfer- composition composition development intermediate resist
layer resist layer etching substrate Example 1 ArF top resist layer
rectangle rectangle rectangle rectangle composition Example 2 ArF
top resist layer rectangle rectangle rectangle rectangle
composition Example 3 ArF top resist layer rectangle rectangle
rectangle rectangle composition Example 4 ArF top resist layer
rectangle rectangle rectangle rectangle composition Example 5 ArF
top resist layer rectangle rectangle rectangle rectangle
composition Example 6 ArF top resist layer rectangle rectangle
rectangle rectangle composition Example 7 ArF top resist layer
rectangle rectangle rectangle rectangle composition Example 8 ArF
top resist layer rectangle rectangle rectangle rectangle
composition Example 9 ArF top resist layer rectangle rectangle
rectangle rectangle composition Example 10 ArF top resist layer
rectangle rectangle rectangle rectangle composition Example 11 ArF
top resist layer rectangle rectangle rectangle rectangle
composition Example 12 ArF top resist layer rectangle rectangle
rectangle rectangle composition Example 13 ArF top resist layer
rectangle rectangle rectangle rectangle composition Example 14 ArF
top resist layer rectangle rectangle rectangle rectangle
composition Example 15 ArF top resist layer rectangle rectangle
rectangle rectangle composition Comparative ArF top resist layer
rectangle rectangle rectangle taper and film Example 1 composition
loss Comparative ArF top resist layer rectangle rectangle rectangle
rectangle Example 2 composition
[0283] As shown in Table 3, it was found that, in the case of using
the bottom resist layer compositions of Examples 1, 4, 8-15, both a
resist pattern profile after development on exposure to KrF, a
pattern profile transferred to an intermediate resist layer, a
pattern profile transferred to a bottom resist layer, and a pattern
profile transferred to a substrate were excellent, and a pattern
with a high aspect ratio could be formed.
[0284] In addition, as shown in Table 4, it was found that, in the
case of using the bottom resist layer compositions of Examples
1-15, both a resist pattern profile after development on exposure
to ArF, a pattern profile transferred to an intermediate resist
layer, a pattern profile transferred to a bottom resist layer, and
a pattern profile transferred to a substrate were excellent, and a
pattern with a high aspect ratio could be formed.
[Evaluation of Dry Etching Resistance]
[0285] In a test of dry etching resistance, the solutions of the
bottom resist layer compositions (Examples 1-15, Comparative
Examples 1-2) prepared above were applied on a Si substrate 8
inches (about 200 mm) across, baked for 60 seconds at 300.degree.
C. in the Examples 1-3, and baked for 60 seconds at 200.degree. C.
in the Examples 4-15 and in the Comparative Examples 1-2, to form
bottom resist layers with a thickness of 300 nm. They were
evaluated under the two types of the following conditions.
1) Etching Test with CF.sub.4/CHF.sub.3 Gas
[0286] A difference in a thickness of bottom resist layers before
and after etching was determined using dry-etching-system TE-8500P
manufactured by Tokyo Electron, Ltd.
[0287] Etching conditions were the same as those of observation of
a pattern profile formed on a substrate.
[0288] The results were shown in Table 5. TABLE-US-00005 TABLE 5 a
gas etching rate with CF.sub.4/CHF.sub.3 gas bottom resist layer
composition (nm/min) Example1 98 Example2 92 Example3 95 Example4
100 Example5 99 Example6 97 Example7 102 Example8 97 Example9 98
Example10 88 Example11 96 Example12 98 Example13 96 Example14 82
Example15 91 Comparative Example1 120 Comparative Example2 95
2) Etching Test with Cl.sub.2/BCl.sub.3 Gas
[0289] The difference in a thickness of a bottom resist layer
before and after etching was determined using dry-etching-system
L-507D-L manufactured by Nichiden ANELVA Corporation.
[0290] Etching conditions are shown below. TABLE-US-00006 Chamber
pressure 40.0 Pa RF power 300 W Gap 9 mm Cl.sub.2 gas flow rate 30
ml/min BCl.sub.3 gas flow rate 30 ml/min CHF.sub.3 gas flow rate
100 ml/min O.sub.2 gas flow rate 2 ml/min Time 60 sec
[0291] The results were shown in Table 6. TABLE-US-00007 TABLE 6 a
gas etching rate with Cl.sub.2/BCl.sub.3 gas bottom resist layer
composition (nm/min) Example1 105 Example2 100 Example3 98 Example4
108 Example5 102 Example6 100 Example7 108 Example8 106 Example9
105 Example10 98 Example11 104 Example12 108 Example13 103
Example14 92 Example15 100 Comparative Example1 133 Comparative
Example2 102
[0292] As shown in Tables 5 and 6, an etching rate of the Examples
1-15 in CF.sub.4/CHF.sub.3 gas etching and Cl.sub.2/BCl.sub.3 gas
etching was lower than that of the Comparative Example 1 (m-cresol
novolac resin). Therefore, it was found that the bottom resist
layers of the Examples 1-15 had an extremely high etching
resistance during etching a substrate.
[0293] The present invention is not limited to the above-described
embodiment. The above-described embodiment is a mere example, and
those having the substantially same structure as that described in
the appended claims and providing the similar action and effects
are included in the scope of the present invention.
* * * * *