U.S. patent application number 14/112125 was filed with the patent office on 2014-05-22 for method for manufacturing molybdenum oxide-containing thin film, starting material for forming molybdenum oxide-containing thin film, and molybdenum amide compound.
The applicant listed for this patent is Hiroki Sato, Junji Ueyama. Invention is credited to Hiroki Sato, Junji Ueyama.
Application Number | 20140141165 14/112125 |
Document ID | / |
Family ID | 47258988 |
Filed Date | 2014-05-22 |
United States Patent
Application |
20140141165 |
Kind Code |
A1 |
Sato; Hiroki ; et
al. |
May 22, 2014 |
METHOD FOR MANUFACTURING MOLYBDENUM OXIDE-CONTAINING THIN FILM,
STARTING MATERIAL FOR FORMING MOLYBDENUM OXIDE-CONTAINING THIN
FILM, AND MOLYBDENUM AMIDE COMPOUND
Abstract
Disclosed is a method for manufacturing a molybdenum
oxide-containing thin film, involving vaporizing a starting
material for forming a thin film containing a compound represented
by the following general formula (I) to give vapor containing a
molybdenum amide compound, introducing the obtained vapor onto a
substrate, and further introducing an oxidizing gas to cause
decomposition and/or a chemical reaction to form a thin film on the
substrate. In the formula, R.sup.1 and R.sup.2 each represents a
straight or branched alkyl group having 1 to 4 carbon atom(s),
R.sup.3 represents a t-butyl group or a t-amyl group, y represents
0 or 2, x is 4 when y is 0, or x is 2 when y is 2, wherein R.sup.1
and R.sup.2 that are plurally present may be the same or different.
##STR00001##
Inventors: |
Sato; Hiroki; (Tokyo,
JP) ; Ueyama; Junji; (Tokyo, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Sato; Hiroki
Ueyama; Junji |
Tokyo
Tokyo |
|
JP
JP |
|
|
Family ID: |
47258988 |
Appl. No.: |
14/112125 |
Filed: |
May 11, 2012 |
PCT Filed: |
May 11, 2012 |
PCT NO: |
PCT/JP2012/062199 |
371 Date: |
October 16, 2013 |
Current U.S.
Class: |
427/255.31 ;
556/57 |
Current CPC
Class: |
C23C 16/40 20130101;
C23C 16/405 20130101; C07F 11/005 20130101; H01L 29/4966 20130101;
H01L 29/517 20130101; C23C 16/45553 20130101; Y02P 70/521 20151101;
H01L 21/28194 20130101; H01L 21/28556 20130101; H01L 21/76841
20130101; Y02P 70/50 20151101; Y02E 10/541 20130101 |
Class at
Publication: |
427/255.31 ;
556/57 |
International
Class: |
C23C 16/40 20060101
C23C016/40 |
Foreign Application Data
Date |
Code |
Application Number |
May 27, 2011 |
JP |
2011-118760 |
Claims
1. A method for manufacturing a molybdenum oxide-containing thin
film, comprising, vaporizing a starting material for forming a thin
film containing a compound represented by the following general
formula (I) to give vapor containing a molybdenum amide compound,
introducing the obtained vapor onto a substrate, and further
introducing an oxidizing gas to cause decomposition and/or a
chemical reaction to form a thin film on the substrate:
##STR00018## wherein R.sup.1 and R.sup.2 each represents a straight
or branched alkyl group having 1 to 4 carbon atom(s), R.sup.3
represents a t-butyl group or a t-amyl group, y represents 0 or 2,
and x is 4 when y is 0, or x is 2 when y is 2, wherein R.sup.1 and
R.sup.2 that are plurally present may be the same or different.
2. The method for manufacturing a molybdenum oxide-containing thin
film according to claim 1, wherein the oxidizing gas is a gas
containing ozone, oxygen or water.
3. A starting material for forming a molybdenum oxide-containing
thin film, which contains the compound represented by the following
general formula (I) used for the method for the manufacture of a
thin film according to claim 1: ##STR00019## wherein R.sup.1 and
R.sup.2 each represents a straight or branched alkyl group having 1
to 4 carbon atom(s), R.sup.3 represents a t-butyl group or a t-amyl
group, y represents 0 or 2, and x is 4 when y is 0, or x is 2 when
y is 2, wherein R.sup.1 and R.sup.2 that are plurally present may
be the same or different.
4. A compound represented by the following general formula (II):
##STR00020## wherein R.sup.4 and R.sup.5 each represents a straight
or branched alkyl group having 1 to 4 carbon atom(s).
5. A starting material for forming a molybdenum oxide-containing
thin film, which contains the compound represented by the following
general formula (I) used for the method for the manufacture of a
thin film according to claim 2: ##STR00021## wherein R.sup.1 and
R.sup.2 each represents a straight or branched alkyl group having 1
to 4 carbon atom(s), R.sup.3 represents a t-butyl group or a t-amyl
group, y represents 0 or 2, and x is 4 when y is 0, or x is 2 when
y is 2, wherein R.sup.1 and R.sup.2 that are plurally present may
be the same or different.
Description
TECHNICAL FIELD
[0001] The present invention relates to a method for manufacturing
a molybdenum oxide-containing thin film using vapor formed by
vaporizing a molybdenum amide compound having a specific ligand, a
molybdenum oxide-containing thin film manufactured by the
manufacture method, a starting material for forming a molybdenum
oxide-containing thin film used for the manufacture method, and a
novel molybdenum amide compound having a t-amylimide group as a
ligand.
BACKGROUND ART
[0002] Molybdenum oxide-containing thin films can be used for
organic light-emitting diodes, liquid crystal displays, plasma
display panels, field emission displays, thin film solar batteries,
low resistance ohmics, and other electronic devices and
semiconductor devices, and are mainly used as elements for
electronic parts such as barrier films.
[0003] Examples of a method for manufacturing the above-mentioned
thin film may include a flame deposition process, a sputtering
process, an ion plating process, MOD processes such as a
coating-pyrolysis process and a sol-gel process, a chemical vapor
deposition process, and the like, and a chemical vapor deposition
(hereinafter sometimes simply referred to as CVD) process including
an ALD (Atomic Layer Deposition) process is an appropriate
manufacture process, because of the many advantages of the process
including excellent properties in composition control and step
coverage, suitability for mass manufacture, capability of providing
hybrid integration, and the like.
[0004] As starting materials for the chemical vapor phase
deposition process for the manufacture of a molybdenum
oxide-containing thin film, organic molybdenum compounds such as
molybdenum carbonyl [Mo(CO).sub.6], molybdenum acetylacetonate,
molybdenum chloride (MoCl.sub.3 or MoCl.sub.5), molybdenum fluoride
(MoF.sub.6) and MoO.sub.2
(2,2,6,6-tetramethylheptane-3,5-dione).sub.2, and molybdenum
oxychloride (MoO.sub.2Cl.sub.2 or MoOCl.sub.4) are reported in
Patent Literature 1. Furthermore, a molybdenum amide imide compound
is reported as a starting material for the formation of a
molybdenum nitride thin film by ALD in Non-patent Literature 1.
[0005] In a method for manufacturing a molybdenum oxide-containing
thin film including introducing vapor obtained by vaporizing a
starting material for forming a thin film into a substrate, and
further decomposing and/or chemically reacting the vapor by
introducing oxidizing gas to form a thin film on the substrate,
there is no report about the method for manufacturing a thin film
using a molybdenum amide compound according to the present
invention.
CITATION LIST
Patent Literature
[0006] Patent Literature 1: U.S. Pat. No. 6,416,890
Non-Patent Literature
[0006] [0007] Non-patent Literature 1: Chem. Vap. Deposition 2008,
14, 71-77
SUMMARY OF INVENTION
Technical Problem
[0008] In the manufacture of a molybdenum oxide-containing thin
film by a CVD process, it was not necessarily able to be considered
that the molybdenum compounds that had been suggested in the past
had sufficient properties. The properties required for a compound
(precursor) that is suitable for a starting material for forming a
thin film by vaporizing a compound in a CVD process and the like
are that the compound has a low melting point; the compound has a
temperature difference between the melting point and boiling point
such that a liquid state can be stably retained during the
manufacture of a molybdenum oxide-containing thin film, and thus
the compound can be stably transported in a liquid state; and the
compound has a high vapor pressure and thus is easily vaporized.
The compounds that had been used as conventional molybdenum sources
were solids or had a small temperature difference between the
melting point and boiling point, and thus had problems of poor
precursor transportation property and a low vapor pressure in a CVD
process. Furthermore, when a molybdenum compound containing a
fluorine atom was used as a molybdenum source for the manufacture
of a molybdenum oxide-containing thin film by a CVD process, there
was a problem that hydrogen fluoride sometimes generated as a
reaction by-product during the manufacture of the thin film and
caused a device to corrode.
Solution to Problem
[0009] The present inventors did various studies, and consequently
found that a method for manufacturing a molybdenum oxide-containing
thin film by a CVD process using a specific molybdenum amide
compound as a precursor can resolve the above-mentioned problems,
and attained the present invention.
[0010] The present invention provides a method for manufacturing a
molybdenum oxide-containing thin film, comprising,
[0011] vaporizing a starting material for forming a thin film
containing a compound represented by the following general formula
(I) to give vapor containing a molybdenum amide compound,
introducing the obtained vapor onto a substrate, and further
introducing an oxidizing gas to cause decomposition and/or a
chemical reaction to form a thin film on the substrate.
##STR00002##
wherein R.sup.1 and R.sup.2 each represents a straight or branched
alkyl group having 1 to 4 carbon atom(s), R.sup.3 represents a
t-butyl group or a t-amyl group, y represents 0 or 2, and x is 4
when y is 0, or x is 2 when y is 2, wherein R.sup.1 and R.sup.2
that are plurally present may be the same or different.
[0012] Furthermore, the present invention provides a starting
material for forming a molybdenum oxide-containing thin film,
containing the compound represented by the above-mentioned general
formula (I) used for the above-mentioned method for manufacturing a
thin film.
[0013] Furthermore, the present invention provides a novel compound
represented by the following general formula (II).
##STR00003##
wherein R.sup.4 and R.sup.5 each represents a straight or branched
alkyl group having 1 to 4 carbon atom(s).
Advantageous Effects of Invention
[0014] According to the present invention, since the molybdenum
amide compound according to the present invention is a low melting
point compound that becomes a liquid at an ordinary temperature or
by slight warming, has a significant temperature difference between
the melting point and boiling point, and has a high vapor pressure,
the precursor-transport property is excellent, and the supply
amount to the substrate is easily controlled and stable supplying
is possible in the manufacture of a molybdenum oxide-containing
thin film by a CVD process, and thus a molybdenum oxide-containing
thin film having a fine quantity manufacture property and a fine
quality can be manufactured.
BRIEF DESCRIPTION OF DRAWINGS
[0015] FIG. 1 is a schematic drawing showing an example of an
apparatus for chemical vapor deposition, which is used for the
method for manufacturing a molybdenum oxide-containing thin film of
the present invention.
[0016] FIG. 2 is a schematic drawing showing another example of an
apparatus for chemical vapor deposition, which is used for the
method for manufacturing a molybdenum oxide-containing thin film of
the present invention.
[0017] FIG. 3 is a schematic drawing showing still another example
of an apparatus for chemical vapor deposition, which is used for
the method for manufacturing a molybdenum oxide-containing thin
film of the present invention.
DESCRIPTION OF EMBODIMENTS
[0018] Hereinafter the method for manufacturing a molybdenum
oxide-containing thin film of the present invention will be
explained in detail with referring to preferable exemplary
embodiments thereof.
[0019] In the above-mentioned general formula (I) representing the
molybdenum amide compound of the present invention, examples of the
straight or branched alkyl group having 1 to 4 carbon atom(s)
represented by R.sup.1 and R.sup.2 may include methyl, ethyl,
propyl, isopropyl, butyl, s-butyl, t-butyl and isobutyl, examples
of R.sup.3 may include t-butyl or t-amyl, y represents 0 or 2, x is
4 when y is 0, or x is 2 when y is 2, wherein R.sup.1 and R.sup.2
that are plurally present may be the same or different. Specific
examples of the molybdenum amide compound, which is a ligand
compound having such groups, may include compounds No. 1 to 81
shown below. However, the present invention is not construed to be
limited at all by the following exemplary compounds.
##STR00004## ##STR00005## ##STR00006## ##STR00007## ##STR00008##
##STR00009## ##STR00010## ##STR00011## ##STR00012## ##STR00013##
##STR00014## ##STR00015##
[0020] In the molybdenum amide compound used for the method for
manufacturing a molybdenum oxide-containing thin film of the
present invention, R.sup.1 to R.sup.3 in the above-mentioned
general formula (I) are preferably groups such that the compound is
a liquid and has a high vapor pressure, and specifically, when x
and y are 2, R.sup.1 and R.sup.2 are each preferably a methyl group
or an ethyl group, and R.sup.3 is a t-butyl group or a t-amyl
group. Compounds wherein R.sup.3 is a t-butyl group are
specifically preferable since they give a high vapor pressure. When
x is 4 and y is 0, R.sup.1 and R.sup.2 are each preferably a methyl
group or an ethyl group.
[0021] The starting material for forming a thin film of the present
invention contains the molybdenum amide compound explained above as
a precursor for the manufacture of a molybdenum oxide-containing
thin film, and differs in form depending on the process. The
molybdenum amide compound according to the present invention is
specifically useful as a starting material for a chemical vapor
deposition process for its physical properties.
[0022] In the case when the starting material for forming a thin
film of the present invention is a starting material for a chemical
vapor deposition process, the form thereof is suitably selected
depending on techniques such as transport and supply method used in
the chemical vapor deposition process.
[0023] As the above-mentioned transport and supply method, there
are a gas carrier process involving vaporizing a starting material
for chemical vapor deposition by heating and/or reducing pressure
in a starting material container, and introducing the resulting
vapor, if necessary, together with carrier gas such as argon,
nitrogen and helium, into a deposition reaction unit; and a liquid
carrier process involving transporting a starting material for
chemical vapor deposition in a liquid or solution state to a
vaporization chamber, vaporizing the starting material by heating
and/or reducing pressure in the vaporization chamber, and
introducing the obtained vapor into a deposition reaction unit. In
the case of the gas carrier process, the molybdenum amide compound
itself represented by the above-mentioned general formula (I) is a
starting material for chemical vapor deposition, and in the case of
the liquid carrier process, the molybdenum amide compound itself
represented by the above-mentioned general formula (I) or a
solution in which the compound is dissolved in an organic solvent
is a starting material for chemical vapor deposition.
[0024] In a chemical vapor deposition process of a multi-component
system, there are a method involving vaporizing and supplying
independently each component of starting materials for chemical
vapor deposition (hereinafter also referred to as a single source
process) and a method involving vaporizing and supplying a mixed
starting material that is prepared by mixing multi-component
starting materials at a desired composition in advance (hereinafter
also referred to as a cocktail source process). In the case of the
cocktail source process, a mixture or mixed solution of the
molybdenum amide compound according to the present invention and
the other precursor is the starting material for chemical vapor
deposition.
[0025] The organic solvent used for the above-mentioned starting
material for chemical vapor deposition is not specifically limited,
and general organic solvents that are well-known can be used.
Examples of the organic solvents may include acetate esters such as
ethyl acetate, butyl acetate and methoxyethyl acetate; ether
alcohols such as ethylene glycol monomethyl ether, ethylene glycol
mono ethyl ether, ethylene glycol monobutyl ether and diethylene
glycol monomethyl ether; ethers such as tetrahydrofuran,
tetrahydropyran, ethylene glycol dimethyl ether, diethylene glycol
dimethyl ether, triethylene glycol dimethyl ether, dibutyl ether
and dioxane; ketones such as methyl butyl ketone, methyl isobutyl
ketone, ethyl butyl ketone, dipropyl ketone, diisobutyl ketone,
methyl amyl ketone, cyclohexanone and methylcyclohexanone;
hydrocarbons such as hexane, cyclohexane, methylcyclohexane,
dimethylcyclohexane, ethylcyclohexane, heptane, octane, toluene and
xylene; hydrocarbons having a cyano group such as 1-cyanopropane,
1-cyanobutane, 1-cyanohexane, cyanocyclohexane, cyanobenzene,
1,3-dicyanopropane, 1,4-dicyanobutane, 1,6-dicyanohexane,
1,4-dicyanocyclohexane and 1,4-dicyanobenzene; pyridine and
lutidine, and these are used alone or as a mixed solvent of two or
more depending on the solubility of the solute, the relationship of
the use temperature, boiling point and ignition point, and the
like. In the case when these organic solvents are used, these are
preferably used in such a manner that the total amount of the
molybdenum amide compound according to the present invention and
the other precursor in the organic solvent becomes 0.01 to 2.0
mol/liter, specifically 0.05 to 1.0 mol/liter.
[0026] Furthermore, the other precursor that is used together with
the molybdenum amide compound according to the present invention in
the case of the starting material for chemical vapor deposition of
a multi-component system is not specifically limited, and general
well-known precursors that are used in starting materials for
chemical vapor deposition can be used.
[0027] Examples of the above-mentioned other precursors may include
compounds of one or two or more of organic coordinated compound(s)
such as alcohol compounds, glycol compounds, .beta.-diketone
compounds, cyclopentadiene compounds and organic amine compounds
with silicon or metals. Examples of the metal species for the
precursors may include lithium, sodium, potassium, magnesium,
calcium, strontium, barium, titanium, zirconium, hafnium, vanadium,
niobium, tantalum, molybdenum, manganese, iron, ruthenium, cobalt,
rhodium, iridium, nickel, palladium, platinum, copper, silver,
gold, zinc, aluminum, gallium, indium, germanium, tin, lead,
antimony, bismuth, yttrium, lantern, cerium, praseodymium,
neodymium, promethium, samarium, europium, gadolinium, terbium,
dysprosium, holmium, erbium, thulium and ytterbium.
[0028] Examples of the alcohol compounds used as the
above-mentioned organic ligands may include alkyl alcohols such as
methanol, ethanol, propanol, isopropanol, butanol, 2-butanol,
isobutanol, t-butanol, amyl alcohol, isoamyl alcohol and t-amyl
alcohol; ether alcohols such as 2-methoxyethanol, 2-ethoxyethanol,
2-butoxyethanol, 2-(2-methoxyethoxy)ethanol,
2-methoxy-1-methylethanol, 2-methoxy-1,1-dimethylethanol,
2-ethoxy-1,1-dimethylethanol, 2-isopropoxy-1,1-dimethyl ethanol,
2-butoxy-1,1-dimethylethanol,
2-(2-methoxyethoxy)-1,1-dimethylethanol,
2-propoxy-1,1-diethylethanol, 2-s-butoxy-1,1-diethylethanol and
3-methoxy-1,1-dimethylpropanol.
[0029] Examples of the glycol compounds used as the above-mentioned
organic ligands may include 1,2-ethanediol, 1,2-propanediol,
1,3-propanediol, 2,4-hexanediol, 2,2-dimethyl-1,3-propanediol,
2,2-diethyl-1,3-propanediol, 1,3-butanediol, 2,4-butanediol,
2,2-diethyl-1,3-butanediol, 2-ethyl-2-butyl-1,3-propanediol,
2,4-pentanediol, 2-methyl-1,3-propanediol,
2-methyl-2,4-pentanediol, 2,4-hexanediol and
2,4-dimethyl-2,4-pentanediol.
[0030] Examples of the .beta.-diketone compounds used as the
above-mentioned organic ligands may include alkyl-substituted
.beta.-diketones such as acetylacetone, hexane-2,4-dione,
5-methylhexane-2,4-dione, heptane-2,4-dione,
2-methylheptane-3,5-dione, 5-methylheptane-2,4-dione,
6-methylheptane-2,4-dione, 2,2-dimethylheptane-3,5-dione,
2,6-dimethylheptane-3,5-dione, 2,2,6-trimethylheptane-3,5-dione,
2,2,6,6-tetramethylheptane-3,5-dione, octane-2,4-dione,
2,2,6-trimethyloctane-3,5-dione, 2,6-dimethyloctane-3,5-dione,
2,9-dimethylnonane-4,6-dione 2-methyl-6-ethyldecane-3,5-dione and
2,2-dimethyl-6-ethyldecane-3,5-dione; fluorine-substituted alkyl
.beta.-diketones such as 1,1,1-trifluoropentane-2,4-dione,
1,1,1-trifluoro-5,5-dimethylhexane-2,4-dione,
1,1,1,5,5,5-hexafluoropentane-2,4-dione and
1,3-diperfluorohexylpropane-1,3-dione; ether-substituted
.beta.-diketones such as
1,1,5,5-tetramethyl-1-methoxyhexane-2,4-dione,
2,2,6,6-tetramethyl-1-methoxyheptane-3,5-dione and
2,2,6,6-tetramethyl-1-(2-methoxyethoxy)heptane-3,5-dione.
[0031] Examples of the cyclopentadiene compounds used as the
above-mentioned organic ligands may include cyclopentadiene,
methylcyclopentadiene, ethylcyclopentadiene, propylcyclopentadiene,
isopropylcyclopentadiene, butylcyclopentadiene,
s-butylcyclopentadiene, isobutylcyclopentadiene,
t-butylcyclopentadiene, dimethylcyclopentadiene,
tetramethylcyclopentadiene and the like; and examples of the
organic amine compounds used as the organic ligands may include
methylamine, ethylamine, propylamine, isopropylamine, butylamine,
s-butylamine, t-butylamine, isobutylamine, dimethylamine,
diethylamine, dipropylamine, diisopropylamine, ethylmethylamine,
propylmethylamine, isopropylmethylamine and the like.
[0032] As the above-mentioned other precursors, a compound having
similar thermal and/or chemical decomposition behaviors is
preferable for the single source process, and a compound causing no
chemical alteration during mixing in addition to having similar
thermal and/or chemical decomposition behaviors is preferable for
the cocktail source process.
[0033] The starting material for the chemical vapor deposition of
the present invention is designed to reduce the components of
impurity metal elements, impurity halogen such as impurity
chlorine, and organic impurities, except for components
constituting the material to a minimum. The amount of the impurity
metal elements is preferably 100 ppb or less per element and more
preferably 10 ppb or less, and the total amount of the impurity
metal elements is preferably 1 ppm or less and more preferably 100
ppb or less. For use as a gate insulating film, a gate film or a
barrier film of LSIs, the amounts of alkali metal elements,
alkaline earth metal elements and family elements (chromium or
tungsten), which have an effect on the electrical properties of the
resulting thin film, are required to be minimized. The amount of
the impurity halogen is preferably 100 ppm or less, more preferably
10 ppm or less, and still more preferably 1 ppm or less. The total
amount of the organic impurities is preferably 500 ppm or less,
more preferably 50 ppm or less, and still more preferably 10 ppm or
less. Furthermore, since moisture causes generation of particles in
the starting material for the chemical vapor deposition or
generation of particles in the course of the formation of the thin
film, moisture is desirably removed from the metal compounds,
organic solvents, and nucleophilic reagents to reduce the moisture
content of each material as much as possible before use. The
moisture content in each of the metal compounds, organic solvents,
and nucleophilic reagents is preferably 10 ppm or less, and more
preferably 1 ppm or less.
[0034] Further, in order to reduce or prevent particle
contamination in a thin film manufactured, it is preferable to
decrease particles to a minimum in the starting material for the
chemical vapor deposition of the present invention. Specifically,
as measured with a light scattering type liquid-borne particle
sensor in a liquid phase, it is preferable that the number of
particles having a diameter of 0.3 .mu.m or larger is 100 or less
per 1 ml of the liquid phase, it is more preferable that the number
of particles having a diameter of 0.2 .mu.m or larger is 1,000 or
less per 1 ml of the liquid phase, and it is even more preferable
that the number of particles having a diameter of 0.2 .mu.m or
larger is 100 or less per 1 ml of the liquid phase.
[0035] The method for manufacturing a molybdenum oxide-containing
thin film according to the present invention is a chemical vapor
deposition process involving introducing a gas containing a
molybdenum amide compound formed by vaporizing the compound
represented by the above-mentioned formula (I), and a gas obtained
by vaporizing other precursor used as necessary and an oxidative
gas onto a substrate, and decomposing and/or chemically reacting
the molybdenum amide compound and the other precursor used as
necessary on the substrate to form a thin film on the substrate.
There are no particular limitations on transport and supply methods
of the starting material, deposition methods, manufacture
conditions, manufacture apparatus and the like, and generally
well-known methods and conditions can be used.
[0036] Examples of the oxidizing gas used in the method for
manufacturing a molybdenum oxide-containing thin film according to
the present invention may include oxygen, singlet oxygen, ozone,
carbon dioxide, nitrogen monoxide, nitrogen dioxide, water,
hydrogen peroxide, formic acid, acetic acid, acetic anhydride and
the like, and one or two or more of these can be used. The
above-mentioned oxidizing gas containing ozone, oxygen or water is
preferably used since the residual carbon in the film can further
be decreased.
[0037] Examples of the above-mentioned transport and supply methods
may include the gas carrier methods, liquid carrier methods, single
source processes, cocktail source processes described above, and
the like.
[0038] The above-mentioned deposition methods include a thermal CVD
process in which the molybdenum amide compound (and the other
precursor gas) and reactive gas are reacted only by heat in order
to deposit a thin film, a plasma CVD process in which heat and
plasma are used, a photo CVD process in which heat and light are
used, a photo-plasma CVD process in which heat, light and plasma
are used, and an ALD process in which a deposition reaction in a
CVD process is separated into elementary steps and deposition is
carried out step by step in a molecular level.
[0039] The above-mentioned manufacture conditions include a
reaction temperature (substrate temperature), a reaction pressure,
a deposition rate and the like. The reaction temperature is
preferably 100.degree. C. or more at which the molybdenum amide
compound according to the present invention is sufficiently
reacted, and is more preferably 100.degree. C. to 300.degree. C.
The reaction pressure is preferably 0.01 Pa to 300 Pa for the
thermal CVD process, photo CVD process and plasma CVD process. The
deposition rate may be controlled by the supply conditions
(vaporization temperature and vaporization pressure) of the
starting material and the reaction temperature and pressure. When
the deposition rate is high, the resulting thin film possibly has
poor properties, whereas when the deposition rate is low, there may
be a problem with the productivity; thus, the deposition rate is
preferably 0.2 to 40.0 nm/min and more preferably 4.0 to 25.0
nm/min. In the case of the ALD process, a desired thickness is
obtained by controlling the number of cycles.
[0040] For example, in the case when a molybdenum oxide thin film
is formed by the ALD process, a precursor thin film is formed on
the substrate by the molybdenum amide compound that has been
introduced in the deposition reaction unit, after the step of
introducing the starting material explained above (a step of
forming a precursor thin film). At this time, heat may be applied
by heating the substrate or heating the deposition reaction unit.
The precursor thin film formed in this step is a molybdenum amide
thin film, or a thin film formed by the decomposition and/or
reaction of a part of the molybdenum amide compound, and has a
different composition from that of the intended molybdenum oxide
thin film. The temperature at which this step is conducted is
preferably room temperature to 500.degree. C., more preferably 100
to 300.degree. C.
[0041] Next, the unreacted molybdenum amide compound gas and
by-produced gas are discharged from the deposition reaction unit (a
step of discharging gases). Although it is ideal that the unreacted
molybdenum amide compound gas and by-produced gas are completely
discharged from the deposition reaction unit, they do not have to
be completely discharged. Examples of the method for discharging
gases may include a method involving purging the inside of the
system with inert gas such as helium and argon, a method for
discharging gases by reducing the pressure in the system, a method
involving these methods in combination, and the like. The degree of
pressure reduction in the case when the pressure is reduced is
preferably 0.01 to 300 Pa, more preferably 0.1 to 100 Pa.
[0042] Next, oxidizing gas is introduced into the deposition
reaction unit, and a molybdenum oxide thin film is formed from the
precursor thin film obtained in the previous step of forming the
precursor thin film by the action of the oxidizing gas, or the
oxidizing gas and heat (a step of forming a molybdenum oxide thin
film). The temperature during the action of heat in this step is
preferably room temperature to 500.degree. C., more preferably 100
to 300.degree. C. The molybdenum amide compound according to the
present invention has fine reactivity with oxidizing gas, and thus
a molybdenum oxide thin film can be obtained.
[0043] Setting the deposition of the thin film by a series of
operations consisting of the steps of introducing the starting
material, the step of forming the precursor thin film, the step of
discharging gases, and the step of forming the molybdenum oxide
thin film mentioned above as one cycle, the cycle may be repeated
plural times until a thin film having a necessary film thickness is
obtained. In this case, it is preferable to conduct one cycle, then
conduct the above-mentioned step of discharging gases in a similar
manner to thereby discharge the unreacted molybdenum amide compound
gas and oxidizing gas, and by-produced gas from the deposition
reaction unit, and conduct the next one cycle.
[0044] Furthermore, in the formation of the molybdenum oxide thin
film by the ALD process, energies such as plasma, light and voltage
may be applied. The time for applying these energies is not
specifically limited, and may be, for example, the time when the
molybdenum amide compound gas is introduced in the step of
introducing the starting material, the time of warming in the step
of forming the molybdenum oxide thin film or the step of forming
the molybdenum oxide thin film, the time when the gases in the
system are discharged in the step of discharging gases, or the time
when the oxidizing gas is introduced in the step of forming the
molybdenum oxide thin film, or may be between the above-mentioned
respective steps.
[0045] In the method for the manufacture of the thin film of the
present invention, an annealing treatment may be conducted under an
inert atmosphere, an oxidizing gas or a reductive gas atmosphere
after the deposition of the thin film so as to obtain a better film
quality, and in the case when embedding of steps is necessary, a
reflow step may be provided. The temperature in such case is 400 to
1,200.degree. C., specifically preferably 500 to 800.degree. C.
[0046] As the apparatus used for the method for forming the thin
film of the present invention, a well-known apparatus for a
chemical vapor deposition process can be used. Specific examples of
the apparatus may include a non-shower head type apparatus as shown
in FIG. 1, an apparatus that can conduct a precursor by supplying
bubbling as shown in FIG. 2, and an apparatus having a vaporizing
chamber as shown in FIG. 3. Furthermore, not only the single wafer
apparatuses as shown in FIG. 1, FIG. 2 and FIG. 3, but an apparatus
using a batch furnace, which can treat plural wafers at the same
time, can also be used.
[0047] Examples of the molybdenum oxide-containing thin film formed
and manufactured by using the starting material for chemical vapor
deposition of the present invention may include molybdenum dioxide,
molybdenum trioxide, molybdenum-sodium-based composite oxides,
molybdenum-calcium-based composite oxides, molybdenum-bismuth-based
composite oxides, molybdenum-niobium-based composite oxides,
molybdenum-zinc-based composite oxides, molybdenum-silicon-based
composite oxides and molybdenum-cerium-based composite oxides, and
examples of the purposes of use of these may include electronic
parts and elements such as electrodes and barrier films, catalysts,
starting materials for catalysts, starting materials for metals,
metal surface-treating agents, additives for ceramics, additives
for sintered metals, flame retarders, smoke suppressants, starting
materials for antifreeze liquids, color developers for inorganic
pigments, dye mordants for basic dyes, starting materials for
anticorrosives, trace-element fertilizers for agriculture, and
sub-starting materials for ceramic engineering.
[0048] The molybdenum amide compound according to the present
invention is not specifically limited by the manufacture method
therefor, and is manufactured by applying a well-known reaction. As
the manufacture method, a well-known general synthesis method using
a corresponding amide compound may be applied. Examples may include
a method involving obtaining a reactive intermediate by a method
for reacting a sodium acid salt of molybdenum, an amine and
trimethylchlorosilane in 1,2-dimethoxyethane, and reacting the
reactive intermediate with a dialkylamine.
[0049] Examples of the above-mentioned reactive intermediate may
include an imide compound of molybdenum represented by the
following general formula (III).
##STR00016##
wherein R.sup.6 represents a t-butyl group or t-amyl group.
[0050] In the synthesis example of the above-mentioned molybdenum
amide compound, the molybdenum amide compound of the present
invention represented by the following general formula (II), which
can be obtained by reacting a reactive medium wherein R.sup.6 is a
t-amyl group among the compounds represented by the above-mentioned
general formula (III) with a dialkylamine, is useful as a starting
material for a chemical vapor deposition process, since the
compound does not have halogen atoms such as fluorine in the
structure and is a liquid having a high vapor pressure or a low
melting point compound that becomes a liquid by slight warming, the
device is not eroded by the reaction by-product in the manufacture
of the molybdenum oxide-containing thin film by a chemical vapor
deposition process, and the vaporizing property and the
precursor-carrying performance are excellent.
##STR00017##
wherein R.sup.4 and R.sup.5 each represents a straight or branched
alkyl group having 1 to 4 carbon atom(s).
EXAMPLES
[0051] The present invention will be further described in detail
with reference to the following examples, evaluation examples and
comparative examples. However, the present invention is in no way
limited to the following examples and the like.
Manufacture Example 1
Manufacture of Compound No. 37
[0052] Under a dry argon gas atmosphere, 0.12 mol of sodium
molybdate, 2.52 mol of 1,2-dimethoxyethane, 0.252 mol of
t-amylamine, 0.48 mol of triethylamine and 0.96 mol of
trimethylchlorosilane were charged in a 500 mL reaction flask, the
temperature in the system was controlled to 80 to 82.degree. C.,
and stirring was conducted for 12 hours. The solid content was
filtered off by a 0.2 .mu.m filter from the reaction solution, and
the reaction solution was concentrated by removing the solvent by
distillation under a reduced pressure to give a dark green
slurry-like reactive intermediate at a yield of 95%. Subsequently,
0.114 mol of the reactive intermediate and 1.12 mol of dehydrated
toluene were added to a reaction flask and dissolved, the solution
was cooled to -20.degree. C. by dry ice-isopropanol, 0.48 mol of
dimethylamine gas was blown into the solution, and 140 mL of a 1.6
mol/L hexane solution of n-butyl lithium was added dropwise thereto
and reacted. The reaction solution was gradually returned to room
temperature and subsequently reacted by stirring for 2 hours. The
solid substance was filtered off from the reaction solution by a
0.2 .mu.m filter, the reaction solution was concentrated by
distilling off the solvent under a reduced pressure, and the
fraction at 195 Pa and a column top temperature of 103 to
104.degree. C. was further separated from the reaction solution by
distillation under a reduced pressure to give the intended product,
compound No. 37. The collection rate by this purification was 60%.
For the obtained yellowish orange liquid, the following analyses
were conducted.
(Analytical Values)
[0053] (1) Elemental analysis (metal analysis: ICP-AES, chlorine
analysis: TOX)
[0054] Molybdenum; 26.89 mass % (theoretical value 27.07%), Na;
lower than 1 ppm, Cl; lower than 5 ppm
(2) .sup.1H-NMR (solvent: deuterated benzene) (chemical shift:
multiplicity: number of H)
[0055] (1.06: t: 3) (1.35: s: 6) (1.62: q: 2) (3.46: s: 6)
(3) TG-DTA
[0056] (Ar 100 ml/min, temperature rise 10.degree. C./min, sample
amount 8.836 mg) Temperature at 50 mass % loss 190.degree. C.
Manufacture Example 2
Manufacture of Compound No. 38
[0057] Under a dry argon gas atmosphere, 0.12 mol of sodium
molybdate, 2.52 mol of 1,2-dimethoxyethane, 0.252 mol of
t-amylamine, 0.48 mol of triethylamine and 0.96 mol of
trimethylchlorosilane were charged in a 500 mL reaction flask, the
temperature in the system was controlled to 80 to 82.degree. C.,
and stirring was conducted for 12 hours. The solid content was
filtered off by a 0.2 .mu.m filter from the reaction solution, and
the reaction solution was concentrated by removing the solvent by
distillation under a reduced pressure to give a dark green
slurry-like reactive intermediate at a yield of 95%. Subsequently,
0.114 mol of the reactive intermediate and 1.12 mol of dehydrated
toluene were added to a reaction flask and dissolved, the solution
was cooled to -20.degree. C. by dry ice-isopropanol, 0.48 mol of
dimethylamine gas was blown into the solution, and 140 mL of a 1.6
mol/L hexane solution of n-butyl lithium was added dropwise thereto
and reacted. The reaction solution was gradually returned to room
temperature and subsequently reacted by stirring for 2 hours. The
solid substance was filtered off from the reaction solution by a
0.2 .mu.m filter, the reaction solution was concentrated by
distilling off the solvent under a reduced pressure, and the
fraction at 40 Pa and a column top temperature of 98 to 101.degree.
C. was further separated from the reaction solution by distillation
under a reduced pressure to give the intended product, compound No.
38. The collection rate by this purification was 60%. For the
obtained yellowish orange liquid, the following analyses were
conducted.
(Analytical Values)
[0058] (1) Elemental analysis (metal analysis: ICP-AES, chlorine
analysis: TOX)
[0059] Molybdenum; 25.31 mass % (theoretical value 25.09%), Na;
lower than 1 ppm, Cl; lower than 5 ppm
(2).sup.1H-NMR (solvent: deuterated benzene) (chemical shift:
multiplicity: number of H)
[0060] (1.02: t: 2) (1.30: s: 9) (1.59: q: 3) (3.47: s: 3) (3.67:
q: 2)
(3) TG-DTA
[0061] (Ar 100 ml/min, temperature rise 10.degree. C./min, sample
amount 12.009 mg) Temperature at 50 mass % loss 209.degree. C.
Evaluation Examples 1 to 7 and Comparative Examples 1-1 and 1-2
Evaluation of Physical Properties of Molybdenum Compounds
[0062] For the novel compounds Nos. 37 and 38 obtained by the
above-mentioned Manufacture Examples, compounds Nos. 1, 2, 9, 73
and 74, which are known compounds, and comparative compounds 1 and
2 shown below, the state of each compound at an ordinary
temperature under an ordinary pressure was visually observed, and
for the solid compounds, the melting point was measured by using a
micro melting point measuring apparatus, and the boiling point of
each compound was measured. The results are shown in Table 1.
Comparative Compound 1
MoF.sub.6
Comparative Compound 2
Mo(CO).sub.6
TABLE-US-00001 [0063] TABLE 1 Melting Compound State point Boiling
point Comparative Comparative Liquid 17.degree. C. 37.degree. C.
Example 1-1 Compound 1 Comparative Comparative Solid 150.degree. C.
156.degree. C. Example 1-2 Compound 2 Evaluation Compound Liquid --
62.degree. C./53 Pa Example 1 No. 1 Evaluation Compound Liquid --
76.degree. C./57 Pa Example 2 No. 2 Evaluation Compound Liquid --
86.degree. C./61 Pa Example 3 No. 9 Evaluation Compound Liquid --
104.degree. C./195 Pa Example 4 No. 37 Evaluation Compound Liquid
-- 99.degree. C./40 Pa Example 5 No. 38 Evaluation Compound Solid
~50.degree. C.*.sup.1 40-70.degree. C./1 Pa Example 6 No. 73
Evaluation Compound Liquid -- 65-90.degree. C./0.1 Pa Example 7 No.
74 *.sup.1Although a clear melting point was not able to be
measured, the compound was a solid at 25.degree. C. and was a
liquid at 50.degree. C.
[0064] It was able to be confirmed from the above-mentioned Table 1
that Comparative Example 1-2 was a solid, whereas Evaluation
Examples 1 to 7 were low melting point compounds, which are liquids
or become liquids by slight warming. Furthermore, it was able to be
confirmed that Comparative Examples 1-1 and 1-2, and Evaluation
Examples 1 to 5 had low boiling points. Although comparative
compounds 1 and 2 has low boiling points, comparative compound 1
has a small difference between the melting point and boiling point
and thus is difficult to stably supply a starting material in a
liquid state, and further has a problem that the compound erodes a
device during film formation due to generation of hydrogen fluoride
as a reaction byproduct, and comparative compound 2 has a smaller
difference between the melting point and boiling point than that of
comparative compound 1 and thus is difficult to stably supply a
starting material in a liquid state stable; therefore, these
compounds are not suitable as starting materials for chemical vapor
deposition. It was able to be confirmed that the molybdenum amide
compound according to the present invention is suitable as a
starting material for chemical vapor deposition in that the
compound does not contain halogen atoms such as a fluorine atom in
the structure, and that the compound has a significant temperature
difference between the melting point and boiling point and thus can
stably retain its liquid state.
Evaluation Examples 8 to 11
Evaluation of Ozone Reactivity of Molybdenum Amide Compound
[0065] For comparative compound 2, compound No. 2, and compounds
Nos. 37 and 38, a TG-DTA measurement was conducted under an ozone
atmosphere. The measurement was conducted under conditions of
oxygen with addition of 4% of ozone of 2,000 ml/min and temperature
rise of 10.degree. C./min. The presence or absence of the
reactivity between the molybdenum compound and ozone was confirmed
by the presence or absence of an exothermic peak accompanying with
weight loss generated by the oxidative decomposition of the
molybdenum compound by the ozone, and the residual amount at
300.degree. C., at which the reaction is considered to have been
sufficiently completed, was confirmed. The amounts of the samples
were 3.275 mg to 8.447 mg. The results are shown in Table 2.
TABLE-US-00002 TABLE 2 Ozone reactivity Residual amount (Reaction
at 300.degree. C. Compound temperature) (cal.*.sup.1) Evaluation
Comparative .largecircle. (115.degree. C.) 30.6% Example 8 compound
2 (45.5%) Evaluation Compound No. 2 .largecircle. (130.degree. C.)
50.4% Example 9 (59.3%) Evaluation Compound No. 37 .largecircle.
(145.degree. C.) 50.5% Example 10 (59.3%) Evaluation Compound No.
38 .largecircle. (100.degree. C.) 50.3% Example 11 (60.9%) *A
calculated value of the residual amount when the residual component
is considered as MoO.sub.3.
[0066] From Table 2, it was found that, when the molybdenum amide
compound according to the present invention has similar ozone
reactivity to that of comparative compound 2, and the residual
amount at 300.degree. C. and the calculated value of the residual
component in the case when the residual component is considered as
MoO.sub.3 were compared, the molybdenum amide compound according to
the present invention had a smaller difference from the calculated
value than that of comparative compound 2. Therefore, it was able
to be confirmed that the molybdenum amide compound according to the
present invention is converted to molybdenum oxide at a better
yield ratio than that of comparative compound 2, and thus the
molybdenum amide compound according to the present invention is
useful as a starting material for producing a molybdenum
oxide-containing thin film by a chemical vapor deposition
process.
Example 1
Manufacture of Molybdenum Oxide Thin Film by ALD Process
[0067] Using compound No. 2 as a starting material for chemical
vapor deposition, a molybdenum oxide thin film was manufactured on
a silicon wafer by using the apparatus shown in FIG. 1 by an ALD
process under the following conditions and involving the following
steps. For the obtained thin film, the film thickness was measured
by fluorescent X-ray, the composition ratio was analyzed by an
X-ray photoelectron spectroscopy, and the composition was analyzed
by X-ray diffraction were conducted. The results are shown in Table
3.
(Conditions)
[0068] Reaction temperature (substrate temperature); 240.degree.
C., reactive gas; ozone gas
(Steps)
[0069] A series of steps consisting of the following (1) to (4) was
set as one cycle, 50 cycles were repeated.
(1) Vapor of a starting material for chemical vapor deposition
formed by vaporizing under conditions of a vaporizing chamber
temperature of 70.degree. C. and a vaporizing chamber pressure of
70 Pa is introduced and deposited under a system pressure of 100 Pa
for 20 seconds. (2) The unreacted starting material is removed by
purging with argon for 15 seconds. (3) Reactive gas is introduced,
and a reaction is conducted under a system pressure of 80 Pa for 20
seconds. (4) The unreacted starting material is removed by purging
with argon for 15 seconds.
TABLE-US-00003 TABLE 3 Number of Film Composition cycles thickness
ratio (Mo:O) Composition Example 1 50 times 2.1 nm 1.0:2.4
MoO.sub.3
[0070] It was found from the results in the above-mentioned Example
1 that, by using the molybdenum amide compound according to the
present invention as a starting material for chemical vapor
deposition, the compound is excellent in precursor carrying
property and supplying property since the compound is a low melting
point compound that is a liquid at an ordinary temperature under an
ordinary pressure or becomes a liquid by slight warming, and thus a
molybdenum oxide thin film having a fine film quality can be
manufactured at high producibility.
* * * * *