U.S. patent application number 13/361391 was filed with the patent office on 2012-05-24 for resist pattern thickening material and process for forming resist pattern, and semiconductor device and method for manufacturing the same.
This patent application is currently assigned to FUJITSU LIMITED. Invention is credited to Miwa Kozawa, Koji Nozaki.
Application Number | 20120126372 13/361391 |
Document ID | / |
Family ID | 37873101 |
Filed Date | 2012-05-24 |
United States Patent
Application |
20120126372 |
Kind Code |
A1 |
Kozawa; Miwa ; et
al. |
May 24, 2012 |
RESIST PATTERN THICKENING MATERIAL AND PROCESS FOR FORMING RESIST
PATTERN, AND SEMICONDUCTOR DEVICE AND METHOD FOR MANUFACTURING THE
SAME
Abstract
A resist pattern thickening material is disclosed that can
utilize ArF excimer laser light; which, when applied over a resist
pattern such as an ArF resist having a line pattern or the like,
can thicken the resist pattern regardless of the size of the resist
pattern; which has excellent etching resistance; and which is
suited for forming a fine space pattern or the like, exceeding the
exposure limits. Also disclosed is a process for forming a resist
pattern and a method for manufacturing a semiconductor device,
wherein the resist pattern thickening material of the present
invention is suitably utilized.
Inventors: |
Kozawa; Miwa; (Kawasaki,
JP) ; Nozaki; Koji; (Kawasaki, JP) |
Assignee: |
FUJITSU LIMITED
Kawasaki-shi
JP
|
Family ID: |
37873101 |
Appl. No.: |
13/361391 |
Filed: |
January 30, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
11362211 |
Feb 27, 2006 |
8129092 |
|
|
13361391 |
|
|
|
|
Current U.S.
Class: |
257/618 ;
257/E21.259; 257/E29.002; 430/331; 438/694 |
Current CPC
Class: |
H01L 21/76816 20130101;
G03F 7/40 20130101; H01L 21/0273 20130101 |
Class at
Publication: |
257/618 ;
438/694; 430/331; 257/E21.259; 257/E29.002 |
International
Class: |
H01L 21/312 20060101
H01L021/312; G03F 7/26 20060101 G03F007/26; H01L 29/02 20060101
H01L029/02 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 30, 2005 |
JP |
2005-345920 |
Claims
1. A resist pattern thickening material, comprising: a resin; and a
compound represented by the following general formula (1):
##STR00005## where R represents a moiety having a cyclic structure,
X represents a monovalent organic group containing a carboxylic
group, Y represents at least any one of a hydroxyl group, an alkyl
group, an alkoxy group, an amino group, an amino group substituted
with an alkyl group, a carbonyl group and an alkoxycarbonyl group,
m represents an integer of 1 or greater, and n represent an integer
of 0 or greater.
2. The resist pattern thickening material according to claim 1,
wherein R in the general formula (1) represents a moiety having a
cyclic structure containing at least one selected from the group
consisting of aromatic hydrocarbons, heterocyclic compounds and
alicyclic compounds.
3. The resist pattern thickening material according to claim 1,
wherein R in the general formula (1) represents a moiety having a
cyclic structure containing at least one selected from the group
consisting of aromatic rings, cyclohexyl rings, norbornyl and
adamantane.
4. The resist pattern thickening material according to claim 1,
wherein m in the general formula (1) represents 1.
5. The resist pattern thickening material according to claim 1,
wherein the compound represented by the general formula (1)
contains at least one of a hydroxyl group and an amino group.
6. The resist pattern thickening material according to claim 1,
wherein the resin is water soluble or alkali soluble.
7. The resist pattern thickening material according to claim 1,
wherein the resin is at least one selected from the group
consisting of polyvinyl alcohol, polyvinyl acetal, polyvinyl
acetate, polyvinylpyrrolidone, cellulose and tannin.
8. The resist pattern thickening material according to claim 1,
wherein the content of the compound represented by the general
formula (1) in the resist pattern thickening material is 0.01 part
to 50 parts by mass of the total mass of the resist pattern
thickening material.
9. The resist pattern thickening material according to claim 1,
further comprising a surfactant.
10. The resist pattern thickening material according to claim 9,
wherein the surfactant is at least one selected from the group
consisting of nonionic surfactants, cationic surfactants, anionic
surfactants and amphoteric surfactants.
11. The resist pattern thickening material according to claim 9,
wherein the surfactant is selected from the group consisting of
polyoxyethylene-polyoxypropylene condensation products,
polyoxyalkylene alkyl ethers, polyoxyethylene alkyl ethers,
polyoxyethylene derivatives, sorbitan fatty acid esters, glycerine
fatty acid esters, primary alcohol ethoxylates, phenol ethoxylates,
alkoxylate surfactants, fatty acid ester surfactants, amide
surfactants, alcohol surfactants and ethylenediamine surfactants,
alkyl cationic surfactants, amide quaternary cationic surfactants,
ester quaternary cationic surfactants, amineoxide surfactants and
betaine surfactants.
12. The resist pattern thickening material according to claim 9,
wherein the content of the surfactant in the resist pattern
thickening material is 2 parts by mass or less per 100 parts by
mass of the resist pattern thickening material.
13. The resist pattern thickening material according to claim 1,
further comprising an organic solvent.
14. The resist pattern thickening material according to claim 13,
wherein the organic solvent is at least one selected from the group
consisting of alcohol solvents, linear ester solvents, cyclic ester
solvents, ketone solvents, linear ether solvents and cyclic ether
solvents.
15. A method for manufacturing a semiconductor device, comprising:
forming a resist pattern on a surface of a workpiece; applying a
resist pattern thickening material over the resist pattern so as to
cover a surface of the resist pattern to thereby thicken the resist
pattern; and etching the surface of the workpiece using the
thickened resist pattern as a mask so as to pattern the surface of
the workpiece, wherein the resist pattern thickening material
comprises: a resin; and a compound represented by the following
general formula (1): ##STR00006## where R represents a moiety
having a cyclic structure, X represents a monovalent organic group
containing a carboxylic group, Y represents at least any one of a
hydroxyl group, an alkyl group, an alkoxy group, an amino group, an
amino group substituted with an alkyl group, a carbonyl group and
an alkoxycarbonyl group, m represents an integer of 1 or greater,
and n represent an integer of 0 or greater.
16. The method for manufacturing a semiconductor device according
to claim 15, further comprising: applying a nonionic surfactant on
the surface of the resist pattern before application of the resist
pattern thickening material, wherein the nonionic surfactant is at
least one selected from the group consisting of
polyoxyethylene-polyoxypropylene condensation products,
polyoxyalkylene alkyl ethers, polyoxyethylene alkyl ethers,
polyoxyethylene derivatives, sorbitan fatty acid esters, glycerine
fatty acid esters, primary alcohol ethoxylates and phenol
ethoxylates.
17. The method for manufacturing a semiconductor device according
to claim 15, wherein a space pattern formed using the thickened
resist pattern is at least one selected from the group consisting
of a line-and-space space pattern, a hole pattern, and a trench
pattern.
18. A semiconductor device manufactured by a method for
manufacturing a semiconductor device, wherein the method for
manufacturing a semiconductor device comprises: forming a resist
pattern on a surface of a workpiece; applying a resist pattern
thickening material over the resist pattern so as to cover a
surface of the resist pattern to thereby thicken the resist
pattern; and etching the surface of the workpiece using the
thickened resist pattern as a mask so as to pattern the surface of
the workpiece, wherein the resist pattern thickening material
comprises: a resin; and a compound represented by the following
general formula (1): ##STR00007## where R represents a moiety
having a cyclic structure, X represents a monovalent organic group
containing a carboxylic group, Y represents at least any one of a
hydroxyl group, an alkyl group, an alkoxy group, an amino group, an
amino group substituted with an alkyl group, a carbonyl group and
an alkoxycarbonyl group, m represents an integer of 1 or greater,
and n represent an integer of 0 or greater.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional application of U.S. patent
application Ser. No. 11/362,211 filed Feb. 27, 2006, and is based
upon and claims the benefit of priority from Japanese Patent
Application No. 2005-345920 filed on Nov. 30, 2005, the entire
contents of which being incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a resist pattern thickening
material that enables formation of a fine space pattern by
thickening a resist pattern formed upon manufacturing of a
semiconductor device, while exceeding the exposure (resolution)
limits of the light sources of available exposure devices, to a
process for forming a resist pattern, to a semiconductor device,
and to a method for manufacturing the semiconductor device, by
utilizing the resist pattern thickening material.
[0004] 2. Description of the Related Art
[0005] In recent years the increase in the packing density of
semiconductor integrated circuits has put LSIs and VLSIs to
practical use. In keeping with this trend, interconnection patterns
are downsized to as small as 200 nm or less, with the smallest ones
reaching even as small as 100 nm or less. A lithographic technique
is extremely important to achieve formation of fine interconnection
patterns; with this lithographic technique a substrate is coated
with a resist film, selectively exposed to light, and developed to
form a resist pattern. Dry etching is then performed for the
substrate using the resist pattern as a mask, and the resist
pattern is removed to provide a desired pattern (e.g., an
interconnection pattern). The lithographic technique, however,
requires that exposure light (light used for exposure) have a short
wavelength and that high-resolution resist materials tailored to
the characteristics of the exposure light be developed.
[0006] However, reducing the wavelength of exposure light requires
improvement of exposure devices, which requires a great deal of
cost. Further, the development of new resist materials suitable for
exposure light of shorter wavelength is not easy.
[0007] To overcome these problems, a technique has been proposed in
which a fine pattern is formed by using a resist pattern thickening
material (hereinafter referred to as "resist swelling agent" in
some cases) by which a resist pattern made of conventional resist
material is thickened and thus a fine space pattern can be
obtained. For instance, Japanese Patent Application Laid-Open
(JP-A) No. 10-73927 discloses a technique called RELACS. According
to the disclosure, a KrF resist pattern is formed by exposing a KrF
(krypton fluoride) resist film to KrF (krypton fluoride) excimer
laser light of 248 nm wavelength which is deep ultraviolet light.
Thereafter, the KrF resist pattern is covered with a water-soluble
resin composition to form a coated film. The coated film and KrF
resist pattern are then made to interact with each other at their
interface with help of acid remaining in the KrF resist pattern
material, so that the KrF resist pattern is thickened (hereinafter
this process is referred to as "swelling" in some cases). In this
way the distance between adjacent lines of the KrF resist pattern
is shortened, enabling the formation of a fine space pattern.
Subsequently, a desired pattern (e.g. an interconnection pattern)
with the same shape as the space pattern is formed.
[0008] The RELACS technique, however, has the following problems:
The KrF resist to be used is formed of an aromatic resin
composition such as novolac resin and naphthoquinonediazide resin,
and therefore, while aromatic rings contained in the aromatic resin
composition allows KrF excimer laser light (wavelength: 248 nm) to
pass through it, they absorb ArF (argon fluoride) excimer laser
light (wavelength: 193 nm), which has a shorter wavelength than KrF
excimer laser light, thereby preventing it from passing through the
aromatic resin composition. For this reason, when the KrF resist is
used, it is impossible to use ArF excimer laser light as exposure
light and to form, for example, a fine interconnection pattern.
Moreover, the RELACS technique also has a problem that although the
resist swelling material is effective for thickening or swelling of
the KrF resist, it is not suitable for thickening or swelling of
the ArF resist. In addition, the resist swelling agent itself has
poor etching resistance. Thus, if the ArF resist pattern, which has
poor etching resistance, is intended to be thickened (swelled), it
is impossible to form a pattern with the same shape as the swelled
pattern on the substrate. Even when the KrF resist pattern, which
has relatively excellent etching resistance, is intended to be
thickened (swelled), it is impossible to perform precise etching in
a case where, for example, the etching conditions are stringent,
where the substrate is thick, where the KrF resist pattern is fine,
and where a resist film is thin, leading to the problem that a
pattern with the same shape as the swelled pattern cannot be
obtained.
[0009] From the standpoint of forming fine interconnection
patterns, it is desirable to use exposure light of wavelength
shorter than the wavelength of KrF excimer laser light (wavelength
of 248 nm), such as ArF excimer laser light (wavelength of 193 nm).
When x-ray or electron beam having a wavelength shorter than ArF
excimer laser light is used for pattern forming, however, it
results in high cost and low productivity. Thus, the utilization of
ArF excimer laser light is desired.
[0010] Accordingly, the present inventors have proposed a resist
pattern thickening material capable of forming a finer ArF resist
pattern by improving, using a surfactant, its compatibility with an
ArF resist pattern on which the resist swelling agent cannot work
effectively by the RELACS technique (see Japanese Patent
Application Laid-Open (JP-A) No. 2004-126080). The use of this
resist pattern thickening material composition, however, sometimes
causes pattern size reduction to depend on the pattern size before
thickened--the larger the pattern size before thickened, the more
the amount the pattern size decreases by a thickening
treatment.
[0011] Thus, a technology that can use ArF excimer laser light as
exposure light in a patterning process, can sufficiently thicken an
ArF resist pattern or the like to an extent that has never been
achieved by the RELACS technique using the resist swelling agent,
and can achieve easy, low cost formation of a finer space pattern
or interconnection pattern, has yet to be provided.
[0012] It is an object of the present invention to solve the
foregoing problems and to achieve the objects described below.
[0013] An object of the present invention is to provide a resist
pattern thickening material, which can utilize ArF excimer laser
light as exposure light in a patterning process; which, when
applied over a resist pattern such as a line-space pattern, can
uniformly and stably thicken the resist pattern regardless of the
composition or size of the resist material while reducing the
roughness of the surface thereof; which has excellent etching
resistance; and which can achieve easy, efficient, and low cost
formation of fine space patterns, exceeding the exposure
(resolution) limits of the light source of an exposure device.
[0014] Another object of the present invention is to provide a
process for forming a resist pattern, which can utilize ArF excimer
laser light as exposure light in a patterning process; which can
uniformly and stably thicken a resist pattern such as line-space
pattern regardless of the composition or size of the resist
material while reducing the roughness of the surface thereof; and
which can achieve easy, efficient, and low cost formation of fine
space patterns, exceeding the exposure (resolution) limits of the
light source of an exposure device.
[0015] Still another object of the present invention is to provide
a process for manufacturing a semiconductor device, which can
utilize ArF excimer laser light as exposure light in a patterning
process; which can form fine space patterns, exceeding the exposure
(resolution) limits of the light source of an exposure device; and
which can efficiently mass produce high-performance semiconductor
devices having a fine interconnection pattern formed using the
space pattern; and a high-performance semiconductor device having a
fine interconnection, manufactured by the process for manufacturing
a semiconductor device.
SUMMARY OF THE INVENTION
[0016] The means for solving aforesaid problems are described in
attached claims. Specifically, the resist pattern thickening
material of the present invention contains at least a compound
represented by the following general formula (1):
##STR00001##
where R represents a moiety having a structure, X represents a
monovalent organic group containing a carboxylic group, Y
represents at least any one of a hydroxyl group, an alkyl group, an
alkoxy group, an amino group, an amino group substituted with an
alkyl group, a carbonyl group and an alkoxycarbonyl group, m
represents an integer of 1 or greater, and n represent an integer
of 0 or greater.
[0017] When the resist pattern thickening material is applied over
the resist pattern, the resist pattern thickening material
infiltrates the resist pattern at their interface to interact (mix)
with the resist pattern material. At this point the resist pattern
thickening material has excellent compatibility with the resist
pattern and thus results in efficient formation of a surface layer
(mixing layer), a layer in which the resist pattern thickening
material and the resist pattern are mixed, on the surface of the
resist pattern which now serves as an inner layer. In this way the
resist pattern is efficiently thickened by means of the resist
pattern thickening material. The resist pattern thus thickened
(hereinafter referred to as "swelled" in some cases) in this way
has been uniformly thickened by means of the resist pattern
thickening material (hereinafter such a resist pattern may be
referred to as "thickened resist pattern" in some cases). Thus, a
space pattern formed using the thickened resist pattern has a fine
structure, exceeding the exposure (resolution) limits. It should be
noted that the resist pattern thickening material of the present
invention contains a compound which is represented by the general
formula (1) and has a carboxyl group, and thus exhibits an
excellent, uniform resist pattern-thickening effect regardless of
the type of the resist pattern material, resist pattern size or the
like, which means that such an effect is less dependent on the type
of the resist pattern material, resist pattern size or the like. In
addition, compounds represented by the general formula (1) have a
moiety having a cyclic structure, thereby imparting the resist
pattern thickening material of the present invention with excellent
etching resistance. For these reasons, the resist pattern
thickening material of the present invention can be suitably used
for the formation of such resist patterns as line-patterns, which
are adopted in the interconnection layers of LOGIC LSIs provided
with resist patterns of various sizes.
[0018] The process of the present invention for forming a resist
pattern includes: forming a resist pattern; and applying the resist
pattern thickening material of the present invention on the resist
pattern so as to cover the surface thereof.
[0019] In this process for forming a resist pattern a resist
pattern is formed, and the resist pattern thickening material of
the present invention is then applied thereon, whereby the resist
pattern thickening material infiltrates the resist pattern at their
interface to interact (mix) with the resist pattern material,
leading to the formation of a surface layer (mixing layer), a layer
in which the resist pattern thickening material and the resist
pattern are mixed, on the surface of the resist pattern which in
turn serves as an inner layer. In this way the resist pattern is
uniformly thickened by means of the resist pattern thickening
material. Thus, the space pattern formed using the thickened resist
pattern has a fine structure, exceeding the exposure (resolution)
limits. It should be noted that the resist pattern thickening
material of the present invention contains a compound which is
represented by the general formula (1) and has a carboxyl group,
and thus exhibits an excellent, uniform resist pattern-thickening
effect regardless of the type of the resist pattern material,
resist pattern size, or the like, which means that such an effect
is less dependent on the type of the resist pattern material,
resist pattern size or the like. In addition, compounds represented
by the general formula (1) have a moiety having a cyclic structure,
thereby imparting the resist pattern thickening material of the
present invention with excellent etching resistance. For these
reasons, the resist pattern thickening material of the present
invention can be suitably used for the formation of such resist
patterns as line-patterns, which are adopted in the interconnection
layers of LOGIC LSIs provided with not only contact hole patterns,
but also resist patterns of various sizes.
[0020] The method of the present invention for manufacturing a
semiconductor device includes: forming a resist pattern on a
surface of a workpiece; applying the resist pattern thickening
material according to claim 1 of the present invention over the
resist pattern so as to cover a surface of the resist pattern to
thereby thicken the resist pattern; and etching the surface of the
workpiece using the thickened resist pattern as a mask so as to
pattern the surface of the workpiece.
[0021] In this method for manufacturing a semiconductor device a
resist pattern is formed on the surface of the workpiece, where a
pattern such as an interconnection pattern is to be formed, and
then the resist pattern thickening material of the present
invention is applied over the workpiece so as to cover the surface
thereof, whereby the resist pattern thickening material infiltrates
the resist pattern at their interface to interact (mix) with the
resist pattern material, leading to the formation of a surface
layer (mixing layer), a layer in which the resist pattern
thickening material and the resist pattern are mixed, on the
surface of the resist pattern which in turn serves as an inner
layer. In this way the resist pattern is uniformly thickened by
means of the resist pattern thickening material. Thus, the space
pattern formed using the thickened resist pattern has a fine
structure, exceeding the exposure (resolution) limits. It should be
noted that the resist pattern thickening material of the present
invention contains a compound which is represented by the general
formula (1) and has a carboxyl group, and thus exhibits an
excellent, uniform resist pattern-thickening effect regardless of
the type of the resist pattern material, resist pattern size or the
like, which means that such an effect is less dependent on the type
of the resist pattern material, resist pattern size, or the like.
In addition, compounds represented by the general formula (1) have
a moiety having a cyclic structure, thereby imparting the resist
pattern thickening material of the present invention with excellent
etching resistance. For these reasons, the resist pattern
thickening material of the present invention can be suitably used
for the formation of such resist patterns as line-patterns, which
are adopted in the interconnection layers of LOGIC LSIs provided
with not only contact hole patterns, but also resist patterns of
various sizes.
[0022] Subsequently, by etching the surface of the workpiece using
the thickened resist pattern as a mask, the surface of the
workpiece is patterned finely and precisely with accurate
dimension, whereby high-quality, high performance semiconductor
devices having fine, precise interconnection patterns with accurate
dimension can be produced efficiently.
[0023] The semiconductor device of the present invention is
manufactured by the process of the present invention for
manufacturing a semiconductor device. The semiconductor device has
fine, precise patterns including interconnection patterns with
accurate dimension, and is of high quality and performance.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] FIG. 1 is an explanatory diagram of a mechanism by which a
resist pattern is thickened by means of a resist pattern thickening
material of the present invention, showing a state where the resist
pattern thickening material is attached to the resist pattern
surface.
[0025] FIG. 2 is an explanatory diagram of the mechanism by which
the resist pattern is thickened by means of the resist pattern
thickening material of the present invention, showing a state where
the resist pattern thickening material infiltrated the resist
pattern surface.
[0026] FIG. 3 is an explanatory diagram of the mechanism by which
the resist pattern is thickened by means of the resist pattern
thickening material of the present invention, showing a state where
the resist pattern surface is thickened by means of the resist
pattern thickening material.
[0027] FIG. 4 is a schematic diagram for explaining an example of a
process of the present invention for forming a resist pattern,
showing a state where a resist film is formed.
[0028] FIG. 5 is a schematic diagram for explaining the example of
the process of the present invention for forming a resist pattern,
showing a state where a resist pattern is formed by patterning the
resist film.
[0029] FIG. 6 is a schematic diagram for explaining the example of
the process of the present invention for forming a resist pattern,
showing a state where the resist pattern thickening material is
applied over the resist pattern surface.
[0030] FIG. 7 is a schematic diagram for explaining the example of
the process of the present invention for forming a resist pattern,
showing a state where the resist pattern thickening material is
mixed with and infiltrated the resist pattern surface.
[0031] FIG. 8 is a schematic diagram for explaining the example of
the process of the present invention for forming a resist pattern,
showing a state where the thickened resist pattern is
developed.
[0032] FIG. 9 is a schematic diagram for explaining an example of a
method of the present invention for manufacturing a semiconductor
device, showing a state where an interlayer dielectric film is
formed on a silicon substrate.
[0033] FIG. 10 is a schematic diagram for explaining the example of
the method of the present invention for manufacturing a
semiconductor device, showing a state where a titanium film is
formed on the interlayer dielectric film shown in FIG. 9.
[0034] FIG. 11 is a schematic diagram for explaining the example of
the method of the present invention for manufacturing a
semiconductor device, showing a state where a resist film is formed
on the titanium film and a hole pattern is formed in the titanium
film.
[0035] FIG. 12 is a schematic diagram for explaining the example of
the method of the present invention for manufacturing a
semiconductor device, showing a state where a hole pattern is also
formed in the interlayer dielectric film.
[0036] FIG. 13 is a schematic diagram for explaining the example of
the method of the present invention for manufacturing a
semiconductor device, showing a state where a Cu film is formed on
the interlayer dielectric film provided with the hole pattern.
[0037] FIG. 14 is a schematic diagram for explaining the example of
the method of the present invention for manufacturing a
semiconductor device, showing a state where Cu deposited on the
interlayer dielectric film is removed while leaving the hole
pattern filled with it.
[0038] FIG. 15 is a schematic diagram for explaining the example of
the method of the present invention for manufacturing a
semiconductor device, showing a state where another interlayer
dielectric film is formed both on the Cu plug formed in the hole
pattern and the interlayer dielectric film.
[0039] FIG. 16 is a schematic diagram for explaining the example of
the method of the present invention for manufacturing a
semiconductor device, showing a state where a hole pattern is
formed in the interlayer dielectric film serving as a surface layer
and a Cu plug is formed therein.
[0040] FIG. 17 is a schematic diagram for explaining the example of
the method of the present invention for manufacturing a
semiconductor device, showing a state where a three-level
interconnection structure is formed.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
(Resist Pattern Thickening Material)
[0041] The resist pattern thickening material of the present
invention contains at least a resin and a compound represented by
the following general formula (1), and further contains a
surfactant, an organic solvent and/or an additional component on an
as-needed basis, which are appropriately selected.
##STR00002##
where R represents a moiety having a cyclic structure, X represents
a monovalent organic group containing a carboxylic group, Y
represents at least any one of a hydroxyl group, an alkyl group, an
alkoxy group, an amino group, an amino group substituted with an
alkyl group, a carbonyl group and an alkoxycarbonyl group, m
represents an integer of 1 or greater, and n represent an integer
of 0 or greater.
[0042] The resist pattern thickening material of the present
invention is water soluble or alkali soluble; its water solubility
is not particularly limited and can be appropriately set depending
on the intended use. For example, the resist pattern thickening
material preferably has a solubility of at least 0.1 g per 100 g of
25.degree. C. water.
[0043] Meanwhile, the alkali solubility of the resist pattern
thickening material is not particularly limited and can be
appropriately set depending on the intended use. For example, the
resist pattern thickening material preferably has a solubility of
at least 0.1 g per 100 g of 2.38% (by mass) aqueous solution of
tetramethylammoniumhydroxide (TMAH) having a temperature of
25.degree. C.
[0044] The form in which the resist pattern thickening material of
the present invention is present is not particularly limited; it
may be present in the form of an aqueous solution, colloidal
solution or emulsion solution. Preferably, the resist pattern
thickening material is present in the form of aqueous solution.
--Resin--
[0045] The resin is not particularly limited and can be
appropriately selected depending on the intended use. However,
water-soluble resins or alkali-soluble resins are preferably
used.
[0046] For the resin, resins that contain two or more polar groups
are preferable in light of their excellent water solubility or
alkali solubility.
[0047] The polar group is not particularly limited and can be
appropriately selected depending on the intended use; suitable
examples thereof include a hydroxyl group, amino group, sulfonyl
group, carbonyl group, carboxyl group and derivative groups
thereof. These groups may be contained in the resin singly or in
combination.
[0048] If the resin is a water-soluble resin, it preferably has a
solubility of at least 0.1 g per 100 g of 25.degree. C. water.
[0049] Examples of the water-soluble resin include polyvinyl
alcohol, polyvinyl acetal, polyvinyl acetate, polyacrylic acid,
polyvinylpyrrolidone, polyethyleneimine, polyethyleneoxide, a
styrene-maleic acid copolymer, polyvinylamine, polyallylamine,
oxazoline group-containing water-soluble resins, water-soluble
melamine resins, water-soluble urea resins, alkyd resins,
sulfonamide resins, cellulose and tannin.
[0050] If the resin is an alkali-soluble resin, it preferably has a
solubility of at least 0.1 g per 100 g of 2.38% (by mass) aqueous
solution of tetramethylammoniumhydroxide (TMAH) having a
temperature of 25.degree. C.
[0051] Examples of the alkali-soluble resins include novolac
resins, vinylphenol resins, polyacrylic acid, polymethacrylic acid,
poly-p-hydroxyphenylacrylate, poly-p-hydroxyphenylmethacrylate and
copolymers thereof.
[0052] These resins may be used singly or in combination. Among
these, polyvinyl alcohol, polyvinyl acetal, polyvinyl acetate,
polyvinylpyrrolidone, cellulose and tannin are preferably used.
[0053] The content of the resin in the resist pattern thickening
material can be appropriately determined depending on the type,
content, etc. of the compound represented by the general formula
(1), surfactant or the like to be described later.
--Compounds Represented by the General Formula (1)--
[0054] The compounds represented by the general formula (1) are not
particularly limited as long as they have a moiety having a cyclic
structure containing a carboxylic group and are represented by the
following general formula (1); they are selected depending on the
intended use. The fact that these compounds have such a moiety
having a cyclic structure is also advantageous because it is
possible to impart excellent etching resistance to the resist
pattern thickening material.
##STR00003##
where R represents a moiety having a cyclic structure, X represents
a monovalent organic group containing a carboxylic group, Y
represents at least any one of a hydroxyl group, an alkyl group, an
alkoxy group, an amino group, an amino group substituted with an
alkyl group, a carbonyl group and an alkoxycarbonyl group, m
represents an integer of 1 or greater and preferably represents 1
because it is possible to prevent the occurrence of cross-linking
reactions and for easy reaction control, and n represent an integer
of 0 or greater and is preferably in a range of 0 to 2 in light of
water-solubility.
[0055] The R in the general formula (1) is not particularly limited
as long as it has a cyclic structure and can be appropriately
selected depending on the intended use; suitable examples thereof
include cyclic moieties containing at least one selected from the
group consisting of aromatic hydrocarbons, heterocyclic compounds
and alicyclic compounds.
[0056] The cyclic moieties containing the aromatic hydrocarbons are
not particularly limited and can be appropriately selected
depending on the intended use. Such cyclic moieties preferably
contain, for example, an aromatic ring; specific examples of the
aromatic ring include a benzene ring and a naphthalene ring.
[0057] The cyclic moieties containing the heterocyclic compounds
are not particularly limited and can be appropriately selected
depending on the intended use. Such cyclic moieties preferably
contain, for example, pyridine and/or pyrimidine.
[0058] The cyclic moieties containing the alicyclic compounds are
not particularly limited, and can be appropriately selected
depending on the intended use. Such cyclic moieties preferably
contain, for example, a cyclohexyl ring, norbornyl and/or
adamantane.
[0059] The X in the general formula (1) is not particularly limited
as long as it represents a monovalent organic group containing a
carboxylic group, and can be appropriately selected depending on
the intended use. In light of water-solubility, the X preferably
represents an organic group containing two or more of groups
selected from the group consisting of a hydroxyl group, an alkyl
group, an alkoxy group, an amino group, an amino group substituted
with an alkyl group, a carbonyl group and an alkoxycarbonyl group
at the same time; among these, organic groups containing at least
one of a hydroxyl group and an amino group at the same time are
preferably used.
[0060] The Y in the general formula (1) needs to represent at least
one of a hydroxyl group, an alkyl group, an alkoxy group, an amino
group, an amino group substituted with an alkyl group, a carbonyl
group and an alkoxycarbonyl group. Among these, the Y preferably
represents a hydroxyl group or an amino group.
[0061] Specific examples of the compounds represented by the
general formula (1) include mandelic acid, phenylalanine,
phenylglycine, tyrosine, phenyllactic acid, hydroxyphenylpyruvic
acid, hydroxydimethylphenylpropionic acid, aminotetralincarboxylic
acid, aminophenylpropionic acid, phenylglutamic acid,
phenylenedipropionic acid, benzylserine, naphthylalanine,
methylcyclohexanecarboxylic acid, aminocyclohexanecarboxylic acid,
aminobicycloheptanecarboxylic acid and hydroxyadamantanecarboxylic
acid. These compounds may be used singly or in combination. Among
these compounds, phenyllactic acid, phenylalanine and
phenylglycine, in which in the general formula (1) the X contains a
carboxylic group and a hydroxyl group or amino group at the same
time, are preferable because they have high water-solubility and
thus can be dissolved in water in large amounts.
[0062] The content of the compound represented by the general
formula (1) in the resist pattern thickening material is not
particularly limited, and can be appropriately determined depending
on the intended use; the content of such a compound is preferably
0.01 part to 50 parts by mass, more preferably 0.1 part to 10 parts
by mass of the total mass of the resist pattern thickening
material.
[0063] If the content of the compound represented by the general
formula (1) is less than 0.01 part by mass, the resist pattern
thickening material may be less reactive with a resist pattern than
desired. Whereas if the content is greater than 50 parts by mass,
it is highly likely that the compound precipitates during a coating
process, and that defects occur on the pattern formed.
--Surfactant--
[0064] When it is required, for example, to improve compatibility
between a resist pattern thickening material and a resist pattern,
to thicken the resist pattern to a greater extent, to improve
in-plane uniformity of a thickening effect at the interface between
the resist pattern thickening material and the resist pattern, and
to provide anti-foaming properties, the addition of the surfactant
can fulfill the requirements.
[0065] The surfactant is not particularly limited and can be
selected depending on the intended use; examples thereof include
nonionic surfactants, cationic surfactants, anionic surfactants and
amphoteric surfactants. These may be used singly or in combination.
Among these, nonionic surfactants are preferable because they
contain no metallic ion, such as sodium ion and potassium ion.
[0066] Suitable examples of the nonionic surfactants include
alkoxylate surfactants, fatty acid ester surfactants, amide
surfactants, alcohol surfactants and ethylenediamine surfactants;
specific examples thereof include polyoxyethylene-polyoxypropylene
condensation products, polyoxyalkylene alkyl ethers,
polyoxyethylene alkyl ethers, polyoxyethylene derivatives, sorbitan
fatty acid esters, glycerine fatty acid esters, primary alcohol
ethoxylates, phenol ethoxylates, nonylphenol ethoxylates,
octylphenol ethoxylates, lauryl alcohol ethoxylates, oleyl alcohol
ethoxylates, fatty acid esters, amides, natural alcohols,
ethylenediamines and secondary alcohol ethoxylates.
[0067] The cationic surfactants are not particularly limited and
can be selected depending on the intended use; examples thereof
include alkyl cationic surfactants, amide quaternary cationic
surfactants and ester quaternary cationic surfactants.
[0068] The amphoteric surfactants are not particularly limited and
can be appropriately selected depending on the intended use;
examples thereof include amine oxide surfactants and betaine
surfactants.
[0069] The content of the surfactant in the resist pattern
thickening material is not particularly limited, and can be
appropriately determined depending on the type, content, etc. of
the resin, the compound represented by the general formula (1) or
the like; for example, the content of the surfactant is preferably
2 parts by mass or less per 100 parts by mass of the resist pattern
thickening material. If the content of the surfactant exceeds 2
parts by mass, it is highly likely that the surfactant precipitates
during a coating process, and that defects occur on the pattern
formed.
[0070] The resist pattern thickening material of the present
invention does not contain a surfactant as an essential component
because it already has high compatibility with a resist pattern and
can provide a thickening effect without help of such a surfactant.
For this reason, the lower limit of the content of such a
surfactant is not particularly specified; however, the content of
such a surfactant is preferably in a range of 0.08 part to 0.5 part
by mass, inside of which it is certain that the foregoing
surfactant effect can be obtained.
--Organic Solvent--
[0071] The organic solvent can be added to the resist pattern
thickening material of the present invention in order to increase
the solubilities of the resin, the compound represented by the
general formula (1) and the surfactant, which are contained in the
resist pattern thickening material.
[0072] The organic solvent is not particularly limited and can be
appropriately selected depending on the intended use; examples
thereof include alcohol organic solvents, linear ester organic
solvents, cyclic ester organic solvents, ketone organic solvents,
linear ether organic solvents and cyclic ether organic
solvents.
[0073] The organic solvent can be mixed with water for use.
Suitable examples of water are pure water (deionized water).
[0074] Examples of the alcohol organic solvents include methanol,
ethanol, propyl alcohol, isopropyl alcohol and butyl alcohol.
[0075] Examples of the linear ester organic solvents include ethyl
lactate and propylene glycol methyl ether acetate (PGMEA).
[0076] Examples of the cyclic ester organic solvents include
lactone organic solvents such as .gamma.-butyrolactone.
[0077] Examples of the ketone organic solvents include acetone,
cyclohexanone and heptanone.
[0078] Examples of the linear ether organic solvents include
ethyleneglycol dimethylether.
[0079] Examples of the cyclic ether organic solvents include
tetrahydrofuran and dioxane.
[0080] These organic solvents can be used singly or in combination.
Among these organic solvents, those with boiling points from about
80.degree. C. to 200.degree. C. are preferable because it is
possible to achieve precise resist pattern thickening. The content
of the organic solvent in the resist pattern thickening material
can be determined depending on the type, content, etc. of the
resin, the compound represented by the general formula (1), the
surfactant or the like.
--Additional Component--
[0081] The additional component is not particularly limited as long
as it never adversely affects the effects of the present invention,
and can be appropriately selected depending on the intended use;
examples thereof include various types of known additives,
including quenchers such as amines and amides.
[0082] The content of the additional component in the resist
pattern thickening material can be determined depending on the
type, content, etc. of the resin, the compound represented by the
general formula (1), the surfactant or the like.
--Usages--
[0083] The resist pattern thickening material of the present
invention can be used by applying it on a resist pattern.
[0084] Upon application of the resist pattern thickening material
the surfactant may be applied on the resist pattern before coating
the resist pattern with the resist pattern thickening material,
rather than applying the surfactant after mixing it with the resist
pattern thickening material.
[0085] When the resist pattern thickening material is applied onto
the resist pattern and made to interact or mix with it, the resist
pattern thickening material undergoes an interaction with the
resist pattern to form a mixing layer on the surface of the resist
pattern. As a result, the resist pattern is thickened by an amount
corresponding to the mixing layer, and a thickened resist pattern
is formed.
[0086] Since the resist pattern thickening material contains a
compound represented by the general formula (1) at this point, an
excellent and uniform thickening effect can be obtained regardless
of the type, size, etc. of the resist pattern material, which means
that the amount thickened is less dependent on the type and/or size
of the resist pattern material.
[0087] The opening-diameter and/or line-width of a space pattern
formed using the thickened resist pattern is smaller than the
opening-diameter and/or line-width of the one formed using a resist
pattern that is not thickened. In this way a fine space pattern can
be provided, exceeding the exposure or resolution limits of the
light source of an exposure device used for resist pattern
patterning, i.e., the space pattern has an opening-diameter and/or
line-width smaller than the minimum that can be achieved at the
minimum possible wavelength of light applied for the light source.
Thus, when the resist pattern, which has been obtained using ArF
excimer laser beam, is thickened by means of the resist pattern
thickening material of the present invention and the thickened
resist pattern is to be used for the formation of a space pattern,
the resultant space pattern has as fine precise lines and/or holes
as those obtained by using, for example, an electron beam.
[0088] Note that the amount of the resist pattern thickened can be
controlled to fall within a desired range by appropriately
adjusting, for example, the viscosity, coat thickness, baking
temperature, baking time of the resist pattern thickening
material.
--Resist Pattern Material--
[0089] The material for the resist pattern material where the
resist pattern thickening material of the present invention is to
be applied is not particularly limited and can be appropriately
selected from known resist materials depending on the intended use.
In addition, the resist pattern material may be either of negative
or positive type; examples thereof include g-ray resists, i-ray
resists, KrF resists, ArF resists, F.sub.2 resists and
electron-beam resists, which can be patterned using g-ray, i-ray,
KrF excimer laser, ArF excimer laser, F.sub.2 excimer laser,
electron beam and the like. These resists may be of either
chemically amplified or non-chemically amplified type. Among them,
KrF resists, ArF resists, and resists containing acrylic resins are
preferable; furthermore, ArF resists and resists containing acrylic
resins, where the need to improve their resolution limits is
imperative, are more preferable in order to provide finer
patterning and to improve throughput.
[0090] Specific examples of the resist pattern materials include
novolac resists, PHS resists, acrylic resists, cycloolefin-maleic
acid anhydrate (COMA) resists, cycloolefin resists, hybrid resists
such as alicyclic acrylic-COMA copolymers. These resists may be
modified by fluorine.
[0091] The forming process, size, thickness, etc. of the resist
pattern are not particularly limited and can be appropriately set
depending on the intended use. In particular, the thickness
generally ranges from about 0.3 .mu.m to 700 .mu.m, though it can
be appropriately determined depending on the type of the surface of
a workpiece, etching conditions, etc.
[0092] Hereinafter, the process for thickening the resist pattern
by means of the resist pattern thickening material of the present
invention will be described with reference to the drawings.
[0093] After forming a resist pattern 3 on the surface of a
workpiece (base material) 5 as shown in FIG. 1, a resist pattern
thickening material 1 is provided (applied) on the surface of the
resist pattern 3, and is baked (heated and dried) to form a coated
film. At this point, mixing (infiltration) of the resist pattern
thickening material 1 into the resist pattern 3 occurs at the
interface between the resist pattern 3 and the resist pattern
thickening material 1. As shown in FIG. 2, a reaction then occurs
between the mixed (infiltrated) portion of the resist pattern
thickening material 1 and the resist pattern 3 at the interface
between an inner layer resist pattern 10b (the resist pattern 3)
and the resist pattern thickening material 1, resulting in the
formation of a surface layer (mixing layer) 10a. Since the resist
pattern thickening material 1 contains a compound represented by
the general formula (1) at this point, the inner layer resist
pattern 10b (the resist pattern 3) is stably and uniformly
thickened without being affected by its original size.
[0094] Subsequently, as shown in FIG. 3, a development process is
performed to dissolve the resist pattern thickening material 1 to
remove the portion with no interaction (mixing) with the resist
pattern 3 or the portion with less interaction with it, i.e.,
portions with high water-solubility. In this way a thickened resist
pattern 10 is formed (developed), which is a uniformly thickened
resist pattern.
[0095] Note that the development process may be performed either
using a water developer or an alkali developer.
[0096] The thickened resist pattern 10 has, on the surface of the
inner layer resist pattern 10b (the resist pattern 3), the surface
layer (mixing layer) 10a that has resulted from the reaction
between the resist pattern thickening material 1 and the resist
pattern 3. Since the thickened resist pattern 10 is thicker than
the resist pattern 3 by an amount corresponding to the thickness of
the surface layer (mixing layer) 10a, the size of the space
pattern--the distance between adjacent lines of the thickened
resist pattern 10 or the opening diameter of the hole pattern
formed using the thickened resist pattern 10--is smaller than that
of the one formed using the resist pattern 3 that is not thickened.
Thus, it is possible to form a fine space pattern, exceeding the
exposure or resolution limits of the light source of an exposure
device. To be more specific, even when exposure is performed using
ArF excimer laser light, the resultant space pattern has as fine
precise lines and/or holes as those obtained using, for example, an
electron beam. The space pattern formed using the thickened resist
pattern 10 has finer, more precise lines and/or holes than does the
space pattern formed using the resist pattern 3.
[0097] The surface layer (mixing layer) 10a in the thickened resist
pattern 10 is made of the resist pattern material 1, and the
compound represented by the general formula (1) in the resist
pattern thickening material 1 contains a moiety having a cyclic
structure. For this reason, even when the resist pattern 3 (inner
layer resist pattern 10b) is made of material with poor etching
resistance, the resultant thickened resist pattern 10 will have
excellent etching resistance.
[0098] The resist pattern thickening material of the present
invention can be suitably used for thickening a resist pattern, and
miniaturizing the space pattern, exceeding the exposure limits. In
addition, the resist pattern thickening material of the present
invention can be suitably used for the process of the present
invention for forming a resist pattern, the method of the present
invention for manufacturing a semiconductor device, and the
like.
[0099] Moreover, the compound represented by the general formula
(1) in the resist pattern thickening material of the present
invention contains a moiety having a cyclic structure. For this
reason, the resist pattern thickening material of the present
invention can be suitably used to coat or thicken a resist pattern
made of resin or the like, which will be exposed to plasma and the
like and thus require improved etching resistance on its
surface.
(Process for Forming a Resist Pattern)
[0100] The process of the present invention for forming a resist
pattern includes forming a resist pattern, and applying the resist
pattern thickening material of the present invention over the
resist pattern so as to cover the surface of the resist pattern,
and further includes an additional step on an as-needed basis that
are appropriately selected.
[0101] Suitable examples of the resist pattern materials are those
described in the description of the resist pattern thickening
material of the present invention.
[0102] The resist pattern can be formed using known methods.
[0103] The resist pattern can be formed on the surface of a
workpiece (base material). The surface of a workpiece (base
material) is not particularly limited and can be appropriately
selected depending on the intended use. When the resist pattern is
to be formed in a semiconductor device, it is formed on the surface
of a semiconductor substrate. Specifically, the resist pattern is
suitably formed, for example, on the surface of substrates such as
silicon wafers, and various types of oxide films.
[0104] The method for applying the resist pattern thickening
material is not particularly limited and can be selected from known
coating methods depending on the intended use; spin coating is
suitably used. For example, the spin coating is performed under the
following conditions: rotational speed=about 100 rpm to 10,000 rpm,
more preferably 800 rpm to 5,000 rpm; time=about 1 second to 10
minutes, more preferably 1 second to 90 seconds.
[0105] The thickness of the applied resist pattern thickening
material generally ranges from about 100 .ANG. to 10,000 .ANG. (10
nm to 1,000 nm), more preferably ranges from about 1,000 .ANG. to
5,000 .ANG. (100 nm to 500 nm).
[0106] Note that in such a coating process the surfactant may be
applied on the resist pattern before coating it with the resist
pattern thickening material, rather than applying the surfactant
with after mixing it with the resist pattern thickening
material.
[0107] The resist pattern thickening material thus applied is then
pre-baked (heated and dried) either during the coating process or
after that process, thereby allowing the resist pattern-thickening
material to efficiently mix with (or infiltrate) the resist pattern
at their interface.
[0108] Note that the pre-baking (heating and drying) process and
the conditions under which it is performed are not particularly
limited unless a resist pattern is softened, and can be
appropriately selected depending on the intended use. For example,
the pre-baking process may be carried out once, or twice, or more.
When the pre-baking process is to be carried out twice or more, the
pre-baking temperature may be constant or variable throughout each
round of the process. If the pre-baking temperature is constant,
the pre-baking temperature is preferably about 40.degree. C. to
150.degree. C., more preferably 70.degree. C. to 120.degree. C.,
and the pre-baking times is preferably about 10 seconds to 5
minutes, more preferably 40 seconds to 100 seconds.
[0109] After the pre-baking (heating and drying) process, it is
also preferable to perform a reaction baking process for
facilitating the reaction between the applied resist pattern
thickening material and the resist pattern. This is because this
process can efficiently facilitate the reaction of the mixed
(infiltrated) portion occurring at the interface of the resist
pattern and the resist pattern thickening material.
[0110] Note that the reaction baking (heating and drying) process
and the conditions under which it is performed are not particularly
limited, and can be appropriately selected depending on the
intended use. The baking temperature is, however, higher in this
reaction baking process than in the foregoing pre-baking (heating
and drying) process. For example, the baking temperature is about
70.degree. C. to 150.degree. C., more preferably 90.degree. C. to
130.degree. C., and the baking time is 10 seconds to 5 minutes,
more preferably 40 seconds to 100 seconds.
[0111] Moreover, it is preferable to subject the applied resist
pattern thickening material to a development process after the
reaction baking process. This is because it is possible to form
(develop) a thickened resist pattern by dissolving the resist
pattern thickening material to remove the portion with no
interaction (mixing) with the resist pattern, or the portion with
less interaction with it, i.e., portions with high water
solubility.
[0112] Note that this development process is performed in the same
manner as described above.
[0113] Hereinafter, the process of the present invention for
forming a resist pattern will be described with reference to the
drawings.
[0114] After applying a resist pattern material 3a on a work
surface (base material) 5 as shown in FIG. 4, the resist pattern
material 3a is patterned to form a resist pattern 3 as shown in
FIG. 5. Thereafter, a resist pattern thickening material 1 is
applied on the surface of the resist pattern 3, and is baked
(heated and dried) to form a coated film. At this point, mixing
(infiltration) of the resist pattern thickening material 1 into the
resist pattern 3 occurs at the interface between the resist pattern
3 and the resist pattern thickening material 1. As shown in FIG. 7,
a reaction then occurs between the mixed (infiltrated) portion of
the resist pattern thickening material 1 and the resist pattern 3
at the interface between the resist pattern 3 and the resist
pattern thickening material 1. Subsequently, as shown in FIG. 8, a
development process is performed to dissolve the resist pattern
thickening material 1 to remove the portion with no interaction
(mixing) with the resist pattern 3, or the portion with less
interaction with it, i.e., portions with high water solubility. In
this way a thickened resist pattern 10 is formed (developed), where
a surface layer 10a is formed on an inner resist pattern 10b
(resist pattern 3).
[0115] Note that although the development process may be performed
either using a water developer or an alkali developer, a
development process using a water developer is preferable because
it is efficient and features low costs.
[0116] The thickened resist pattern 10 obtained by means of the
resist pattern thickening material 1 has, on the surface of the
inner layer resist pattern 10b (the resist pattern 3), the surface
layer (mixing layer) 10a that has resulted from the reaction
between the resist pattern thickening material 1 and the resist
pattern 3. Since the resist pattern thickening material 1 contains
a compound represented by the general formula (1), the resist
pattern 3 is stably and uniformly thickened to form the thickened
resist pattern 10 regardless of the type or size of the resist
pattern material. Furthermore, since the thickened resist pattern
10 is thicker than the resist pattern 3 (inner resist pattern 10b)
by an amount corresponding to the thickness of the surface layer
10a, the line-width of the space pattern formed using the thickened
resist pattern 10 is smaller than that of the one formed using the
resist pattern 3 (inner layer resist pattern 10b). Thus, a space
pattern formed using the thickened resist pattern 10 is fine.
[0117] The surface layer (mixing layer) 10a in the thickened resist
pattern 10 is formed of the resist pattern material 1, and the
compound represented by the general formula (1) in the resist
pattern thickening material 1 contains a moiety having a cyclic
structure. For this reason, even when the resist pattern 3 (inner
layer resist pattern 10b) is made of material with poor etching
resistance, it is possible to form a thickened resist pattern 10,
the surface of which has a surface layer (mixing layer) 10a with
excellent etching resistance.
[0118] The resist pattern produced by the process of the present
invention for forming a resist pattern (hereinafter referred to as
"thickened resist pattern" in some cases) includes a surface layer
formed as a result of an interaction of the resist pattern
thickening material of the present invention with the surface of
the resist pattern. The resist pattern thickening material contains
a compound represented by the general formula (1) containing a
moiety having a cyclic structure. For this reason, even when the
resist pattern is made of material with poor etching resistance, it
is possible to efficiently produce a thickened resist pattern that
has a surface layer (mixing layer) with excellent etching
resistance on the surface. In addition, since the thickened resist
pattern produced by the process of the present invention for
forming a resist pattern is thickened by an amount corresponding to
the thickness of the surface layer (mixing layer), the size (e.g.,
opening-diameter and/or line-width) of a space pattern formed using
the produced thickened resist pattern 10 is smaller than that of
the one formed using the foregoing resist pattern. Thus, it is
possible to produce a fine space pattern efficiently by the process
of the present invention for forming a resist pattern.
[0119] Whether or not the surface layer (mixing layer) contains the
moiety having a cyclic structure can be determined by analyzing the
IR absorption spectrum of the surface layer (mixing layer), for
example.
[0120] The process of the present invention for forming a resist
pattern can be suitably used for the formation of various spaces
patterns such as a line-and-space pattern, hole pattern (e.g., for
contact holes), and trench pattern. The thickened resist pattern
produced by this process can be suitably used as a mask pattern,
reticle pattern, or the like, can be used, for example, for the
manufacture of functional parts such as metallic plugs,
interconnections, magnetic heads, liquid crystal displays (LCDs),
plasma display panels (PDPs) and surface acoustic wave filters (SAW
filters); optical parts for optical interconnection; fine parts
such as microactuators; and semiconductor devices, and can be
employed in the method of the present invention for manufacturing a
semiconductor device, which will be described later.
(The Method for Manufacturing a Semiconductor Device)
[0121] The method of the present invention for manufacturing a
semiconductor device includes a resist pattern formation step and a
patterning step, and further includes an additional step on an
as-needed basis.
[0122] The resist pattern formation step is a step in which a
resist pattern is formed on the surface of a workpiece and the
resist pattern thickening material of the present invention is
applied thereon in such a way as to cover the resist pattern to
thicken the resist pattern. Through the resist pattern formation
step, a thickened resist pattern is formed on the surface of the
workpiece.
[0123] The details of the resist pattern formation step are similar
to those of the process of the present invention for forming a
resist pattern.
[0124] Examples of the surface of the workpiece include surface
layers of parts of a semiconductor device; among these, substrates
(e.g., silicon wafers) or the surfaces thereof, and various oxide
films are suitable. The resist pattern is formed as described
above, and the coating process is performed as described above,
which is preferably followed by the above-described pre-baking
process, reaction baking process and the like.
[0125] The patterning step is a step in which the workpiece surface
is patterned by etching using the thickened resist pattern formed
in the resist pattern formation step as a mask or the like (i.e.,
as a mask pattern or the like).
[0126] The etching method is not particularly limited and can be
appropriately selected from known methods depending on the intended
use; dry etching is a suitable example. The etching conditions are
not particularly limited and can be set depending on the intended
purpose.
[0127] Suitable examples of the additional step include a
surfactant application step and a development step.
[0128] The surfactant application step is a step for applying the
surfactant on the surface of the resist pattern prior to the resist
pattern formation step.
[0129] The surfactant is not particularly limited and can be
appropriately selected depending on the intended use; suitable
examples thereof include the surfactants listed above, such as
polyoxyethylene-polyoxypropylene condensation products,
polyoxyalkylene alkylethers, polyoxyethylene alkylethers,
polyoxyethylene derivatives, sorbitan fatty acid esters, glycerin
fatty acid esters, primary alcohol ethoxylates, phenol ethoxylates,
nonylphenol ethoxylates, octylphenol ethoxylates, lauryl alcohol
ethoxylates, oleyl alcohol ethoxylates, fatty acid esters, amides,
natural alcohols, ethylene diamines, secondary alcohol ethoxylates,
alkyl cations, amide quaternary cations, ester quaternary cations,
amine oxides and betaines.
[0130] The development step is a step in which the applied resist
pattern thickening material is subjected to a development treatment
between the resist pattern formation step and the patterning step.
Note that the development step is performed as described above.
[0131] With the method of the present invention for manufacturing a
semiconductor device, it is possible to efficiently manufacture
various types of semiconductor devices including flash memories,
DRAMs and FRAMs.
[0132] Although Examples of the present invention will be described
below, the present invention is not limited to these Examples.
EXAMPLE 1
--Preparation of Resist Pattern Thickening Materials--
[0133] Resist pattern thickening materials A to O having
compositions shown in Table 1 were prepared.
[0134] Note in Table 1 that the term "thickening material" means a
resist pattern thickening material and that the letters "A" to "O"
correspond to the resist pattern thickening materials A to O. Out
of the resist pattern thickening materials A to O, the resist
pattern thickening materials M to O were those prepared in
Comparative Example and the resist pattern thickening materials A
to L were those prepared in Examples of the present invention. In
Table 1 the units in parentheses represent "parts by mass (g)."
[0135] Phenylalanine, phenyllactic acid, phenylglycine and
1-methyl-cyclohexylcarboxylic acid, which are listed in the
"Compound Represented by the General Formula (1)" column for the
resist pattern thickening materials A to L, are all compounds
represented by the following general formula (1):
##STR00004##
where R represents a moiety having a cyclic structure, X represents
a monovalent organic group containing a carboxylic group, Y
represents at least any one of a hydroxyl group, an alkyl group, an
alkoxy group, an amino group, an amino group substituted with an
alkyl group, a carbonyl group and an alkoxycarbonyl group, m
represents an integer of 1 or greater, and n represent an integer
of 0 or greater.
[0136] In the "Resin" column "KW-3" represents polyvinyl acetal
resin (manufactured by Sekisui Chemical Co., Ltd.) and "PVA"
represents polyvinyl alcohol resin ("PVA-205C" manufactured by
Kuraray Co., Ltd.). In the "Surfactant" column "PC-6" represents a
nonionic surfactant (a polynuclear phenol surfactant manufactured
by ASAHI DENKA, Co., Ltd.), "TN-80" represents a nonionic
surfactant (a primary alcohol ethoxylate surfactant manufactured by
ASAHI DENKA, Co., Ltd.), and "SO-145" represents a nonionic
surfactant (a secondary alcohol ethoxylate surfactant manufactured
by ASAHI DENKA, Co., Ltd.).
[0137] Mixtures of pure water (deionized water) and
isopropylalcohol, an organic solvent, were prepared as solvents;
for the resist pattern thickening materials A to C and J to O, the
amounts of pure water (deionized water) and isopropylalchol are
98.6 parts by mass (g) and 0.4 part by mass (g), respectively,
while for the resist pattern thickening materials D to I, the
amounts of pure water (deionized water) and isopropylalchol are
98.4 parts by mass (g) and 0.4 part by mass (g), respectively.
TABLE-US-00001 TABLE 1 Resin Compound Surfactant Thickening (Parts
by Represented by Solvent (Parts by Material Mass) General Formula
(1) (Parts by mass) Mass) A KW-3 (16) Phenylalanine (1) PureWater
(98.6) + -- IPA (0.4) B KW-3 (16) Phenyllactic Acid (1) PureWater
(98.6) + -- IPA (0.4) C KW-3 (16) Phenyllactic Acid (1) PureWater
(98.6) + PC-6 (0.25) IPA (0.4) D PVA (4) Phenylglycine (0.5)
PureWater (98.4) + -- IPA (0.4) E PVA (4) Phenylglycine (1)
PureWater (98.4) + -- IPA (0.4) F PVA (4) Phenylalanine (1)
PureWater (98.4) + -- IPA (0.4) G PVA (4) Phenyllactic Acid (0.5)
PureWater (98.4) + -- IPA (0.4) H PVA(4) Phenyllactic Acid (1)
PureWater (98.4) + -- IPA (0.4) I PVA (4) Phenyllactic Acid (3)
PureWater (98.4) + -- IPA (0.4) J PVA (4) Phenyllactic Acid (1)
PureWater (98.6) + TN-80 (0.25) IPA (0.4) K PVA (4) Phenyllactic
Acid (1) PureWater (98.6) + PC-6 (0.25) IPA (0.4) L PVA (4)
1-methyl- PureWater (98.6) + SO-145 (0.1) cyclohexylcarboxylic IPA
(0.4) acid (1) M PVA (4) -- PureWater (98.6) + -- IPA (0.4) N PVA
(4) -- PureWater (98.6) + TN-80 (0.25) IPA (0.4) O PVA (4) Note1
PureWater (98.6) + PC-6 (0.25) IPA (0.4) Note1: 1.35 parts by mass
of tetramethoxymethyl glycouril was added as a crosslinking agent
in place of a compound represented by the general formula (1).
--Resist Pattern Formation--
[0138] By spin coating, the resist pattern thickening materials A
to O thus prepared were applied on different hole patterns, which
have opening diameters shown in the "Space Pattern Size Before
Thickened" column in Table 2 and which had been formed using an
alicyclic ArF resist ("AR1244J" manufactured by JSR Corporation),
under the condition of 1,000 rpm/5 s at early stages and under the
condition of 3,500 rpm/40 s at later stages, followed by a baking
process under the condition of 110.degree. C./60 s. The resist
pattern thickening materials A to O were then rinsed with pure
water for 60 seconds, and subjected to a development process to
remove unreacted portions, or portions with no interaction (mixing)
with the resist patterns, to form thickened resist patterns.
[0139] Table 2 lists the sizes of space patterns formed using these
thickened resist patterns, which correspond to the values in the
"Space Pattern Size After Thickened" column in Table 2, together
with the initial space pattern sizes (i.e., the sizes of space
patterns formed using resist patterns before thickened,
corresponding to the values in the "Space Pattern Size Before
Thickened" column in Table 2). Note in Table 2 that the letters "A"
to "O" correspond to the resist pattern thickening materials A to
O.
TABLE-US-00002 TABLE 2 Space Pattern Size Space Pattern Size
Thickening Before Thickened After Thickened Material (nm) (nm) A
108.5 93.8 B 110.6 93.6 C 107.9 89.3 D 109.8 101.6 E 109.1 96.1 F
109.3 93.5 G 110.0 100.6 H 107.3 96.4 I 107.9 94.6 J 108.6 92.5 K
107.7 92.1 L 106.6 98.3 M 110.2 105.9 N 108.3 107.2 O 108.1
81.9
[0140] From Table 2, it was established that the use of the resist
pattern thickening materials of the present invention for the
formation of a hole pattern can reduce the inner diameters of the
holes created, and that the magnitude of change in inner diameter
is smaller with the resist pattern thickening materials M and N
prepared in Comparative Example, which do not contain compounds
represented by the general formula (1), than with the resist
pattern thickening materials A to L which contain compounds
expressed by general formula (1). Moreover, it was established that
the inner diameter of holes in the hole pattern are significantly
reduced with the resist pattern thickening material O that contains
a crosslinking agent but not a compound represented by the general
formula (1).
[0141] By spin coating, the resist pattern thickening materials K
and O thus prepared were applied onto different trench patterns
which had been formed using an alicyclic ArF resist ("AR1244J"
manufactured by JSR Corporation) and have various trench
sizes--about 100 nm, 200 nm, and 300 nm as shown in the "Space
Pattern Size Before Thickened" column in Table 3, under the
condition of 1,000 rpm/5 s at early stages and under the condition
of 3,500 rpm/40 s at later stages, followed by a baking process
under the condition of 110.degree. C./60 s. The resist pattern
thickening materials K and O were then rinsed with pure water for
60 seconds, and subjected to a development process to remove
unreacted portions, or portions with no interaction (mixing) with
the trench patterns, to form thickened resist patterns.
[0142] Table 3 lists the amounts of reduction (nm) in the size of
the space patterns that were formed using the thickened resist
patterns K and O--the difference between the size of the space
pattern after thickened and the size of the space pattern before
thickened shown in Table 3--together with the initial space pattern
sizes (i.e., the sizes of space patterns formed using resist
patterns before thickened, corresponding to the values in the
"Space Pattern Size Before Thickened" column in Table 3). Note in
Table 3 that the thickening materials "K" and "O" correspond to the
resist pattern thickening materials K and O.
TABLE-US-00003 TABLE 3 The Amount of Reduction Space Pattern Size
in Space Pattern Size Before Thickened (nm) After thickened (nm)
Thickening Thickening Thickening Thickening Material K Material O
Material K Material O 107.7 108.1 15.6 26.2 205.0 204.1 16.7 39.9
300.1 300.3 17.0 52.1
[0143] It was established that the use of the resist pattern
thickening material K can realize formation of a dense, uniform and
fine patterns of trench while minimizing its dependence on the
trench pattern size (see Table 3).
[0144] In addition, it was established that, when the resist
pattern thickening material O in Comparative Example, a
conventional resist pattern thickening material containing a uryl
crosslinking agent, is used for the formation of a trench pattern,
the trench pattern cannot be thickened uniformly because the amount
of reduction in the space pattern size is highly dependent on the
size of the trench pattern before thickened, i.e., the larger the
initial space pattern size, the more the amount of reduction in the
space pattern size after the thickening of the trench pattern.
[0145] Next, the resist pattern thickening materials A, J and K
were applied on the surface of each of resists formed on silicon
substrates to form surface layers of 500 nm thickness. Using an
etching machine (parallel-plain type RIE, manufactured by Fujitsu
Limited), etching was then performed for these layers, as well as
for the KrF resist (UV-6, produced by Shipley Company L.L.C) and
polymethylmethacrylate (PMMA) for comparison; etching was performed
under the following conditions: etching time=3 minutes; P.mu.=200
W; pressure=0.02 Torr; CF.sub.4 gas=80 sccm. These samples were
then evaluated for their etching rate by determining the etched
amounts, with the etching rate of the KrF resist being used as a
reference (=1.00). The results are shown in Table 4.
TABLE-US-00004 TABLE 4 Material Etching Rate (nm/s) Ratio UV-6 52.0
1.00 PMMA 64.2 1.23 A 54.0 1.04 J 51.3 0.99 K 55.4 1.06
[0146] From the result shown in Table 4, it was established that
since the resist pattern thickening materials of the present
invention all contain a compound represented by the general formula
(1), they exhibit more excellent etching resistance than PMMA,
which is as high as that of the KrF resist.
EXAMPLE 2
[0147] As shown in FIG. 9, the interlayer dielectric film 12 was
formed on a silicon substrate 11 and as shown in FIG. 10, a
titanium film 13 was formed on the interlayer dielectric film 12 by
sputtering. Next, as shown in FIG. 11, a resist pattern 14 was
formed by a known photolithographic technique. Using the resist
pattern 14 as a mask, the titanium film 13 was patterned by
reactive ion etching to form an opening 15a. Subsequently, reactive
ion etching was performed to remove the resist pattern 14 and, at
the same time, as shown in FIG. 12, an opening 15b was formed in
the interlayer dielectric film 12 using the titanium film 13 as a
mask.
[0148] Next, the titanium film 13 was removed in a wet processing
and as shown in FIG. 13, a TiN film 16 was formed on the interlayer
dielectric film 12 by sputtering. By electrolytic plating, a Cu
film 17 was then deposited on the TiN film 16. As shown in FIG. 14,
the surface of the silicon substrate 11 was then planarized by
removing the barrier metal and the Cu film (first metallic film)
using CMP, with the grooves corresponding to the opening 15b (shown
in FIG. 12) left filled with them. In this way a first layer
interconnection 17a was formed.
[0149] Next, as shown in FIG. 15, an interlayer dielectric film 18
was formed on the first layer interconnection 17a. Thereafter, as
shown in FIG. 16, a Cu plug (second metallic film) 19 and TiN film
16a, which serve to connect the first layer interconnection 17a to
upper layer interconnections to be formed later, were formed in a
similar manner as those shown in FIGS. 9 to 14.
[0150] By repeating the steps described above, a semiconductor
device with a multilevel-interconnection structure that has the
first layer interconnection 17a, a second layer interconnection 20,
and a third layer interconnection 21 which are sequentially
provided on the silicon substrate 11 was manufactured as shown in
FIG. 17. Note in FIG. 17 that barrier metallic layers formed
beneath each of these layers are not shown.
[0151] In Example 2 the resist pattern 14 is a thickened resist
pattern formed in the same manner described in Examples 1 and 2,
where the resist pattern thickening material of the present
invention is used.
[0152] According to the present invention, it is possible to solve
the foregoing problems and to achieve the foregoing objects.
[0153] According to the present invention, it is possible to
provide a resist pattern thickening material which can utilize ArF
excimer laser light as exposure light in a patterning process;
which, when applied over a resist pattern such as a line-space
pattern formed using an ArF resist or the like, can uniformly and
stably thicken the resist pattern regardless of the composition or
size of the resist material while reducing the roughness of the
surface thereof; which has excellent etching resistance; and which
can achieve easy, efficient, and low cost formation of a fine space
pattern, exceeding the exposure (resolution) limits of the light
source of an exposure device.
[0154] According to the present invention, it is possible to
provide a process for forming a resist pattern, which can utilize
ArF excimer laser light as exposure light in a patterning process;
which can uniformly and stably thicken a resist pattern such as
line-space pattern regardless of the composition or size of the
resist material while reducing the roughness of the surface
thereof; and which can achieve easy, efficient, and low cost
formation of a fine space pattern, exceeding the exposure
(resolution) limits of the light source of an exposure device.
[0155] Moreover, according to the present invention, it is possible
to provide a method for manufacturing a semiconductor device, which
can utilize ArF excimer laser light as exposure light in a
patterning process; which can form a fine space pattern, exceeding
the exposure (resolution) limits of the light source of an exposure
device; and which can efficiently mass produce high-performance
semiconductor devices having fine interconnection patterns formed
using the space pattern; and a high-performance semiconductor
device having fine interconnection patterns, which is manufactured
by the process for manufacturing a semiconductor device.
[0156] The resist pattern thickening material of the present
invention can be suitably used for the process for forming a fine
space pattern, interconnection pattern, etc, by thickening a resist
pattern formed using an ArF resist or the like, exceeding the
exposure limits of exposure light in a patterning process, as well
as for various patterning methods and semiconductor manufacturing
methods. In particular, the resist pattern thickening material of
the present invention can be suitably used for the process of the
present invention for forming a resist pattern, and for the method
of the present invention for manufacturing a semiconductor
device.
[0157] The process of the present invention for forming a resist
pattern can be suitably used for the production of, for example,
functional parts such as a mask pattern, reticle pattern, magnetic
heads, liquid crystal displays (LCDs), plasma display panels (PDPs)
and surface acoustic wave filters (SAW filters); optical parts for
optical interconnection; fine parts such as microactuators; and
semiconductor devices, and can be suitably employed in the method
of the present invention for manufacturing a semiconductor
device.
[0158] The method of the present invention for manufacturing a
semiconductor device can be employed for manufacturing various
semiconductor devices including flash memories, DRAMs, and
FRAMs.
* * * * *