U.S. patent application number 11/132222 was filed with the patent office on 2005-10-06 for method and apparatus for production of metal film or the like.
Invention is credited to Coba, Yoshiyuki, Koshiro, Ikumasa, Nishimori, Toshihiko, Ogura, Yuzuru, Sakamoto, Hitoshi, Tonegawa, Hiroshi, Yahata, Naoki.
Application Number | 20050217579 11/132222 |
Document ID | / |
Family ID | 27767766 |
Filed Date | 2005-10-06 |
United States Patent
Application |
20050217579 |
Kind Code |
A1 |
Sakamoto, Hitoshi ; et
al. |
October 6, 2005 |
Method and apparatus for production of metal film or the like
Abstract
In a metal film production apparatus, a copper plate member is
etched with a Cl.sub.2 gas plasma within a chamber to form a
precursor comprising a Cu component and a Cl.sub.2 gas; and the
temperatures of the copper plate member and a substrate and a
difference between their temperatures are controlled as
predetermined, to deposit the Cu component of the precursor on the
substrate, thereby forming a film of Cu. In this apparatus, Cl* is
formed in an excitation chamber of a passage communicating with the
interior of the chamber to flow a Cl.sub.2 gas, and the Cl* is
supplied into the chamber to withdraw a Cl.sub.2 gas from the
precursor adsorbed onto the substrate, thereby promoting a Cu film
formation reaction. The apparatus has a high film formation speed,
can use an inexpensive starting material, and can minimize
impurities remaining in the film.
Inventors: |
Sakamoto, Hitoshi;
(Yokohama-shi, JP) ; Yahata, Naoki; (Takasago-shi,
JP) ; Nishimori, Toshihiko; (Takasago-shi, JP)
; Coba, Yoshiyuki; (Yokohama-shi, JP) ; Tonegawa,
Hiroshi; (Yokohama-shi, JP) ; Koshiro, Ikumasa;
(Takasago-shi, JP) ; Ogura, Yuzuru; (Yokohama-shi,
JP) |
Correspondence
Address: |
BIRCH STEWART KOLASCH & BIRCH
PO BOX 747
FALLS CHURCH
VA
22040-0747
US
|
Family ID: |
27767766 |
Appl. No.: |
11/132222 |
Filed: |
May 19, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
11132222 |
May 19, 2005 |
|
|
|
10384932 |
Mar 7, 2003 |
|
|
|
Current U.S.
Class: |
118/715 |
Current CPC
Class: |
C23C 16/4488 20130101;
H01J 37/32357 20130101; H01L 21/76879 20130101; C23C 16/08
20130101; H01J 37/321 20130101; H01J 2237/3326 20130101; C23C 16/14
20130101; H01L 21/28556 20130101 |
Class at
Publication: |
118/715 |
International
Class: |
H01L 021/44 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 8, 2002 |
JP |
2002-063063 |
Mar 8, 2002 |
JP |
2002-063064 |
Aug 7, 2002 |
JP |
2002-229413 |
Claims
What is claimed is:
1. A metal film production apparatus, comprising: a cylindrical
chamber accommodating a substrate; an etched member formed from a
metal, which forms a high vapor pressure halide, and disposed
within the chamber at a position opposed to the substrate; source
gas supply means for supplying a source gas containing a halogen to
an interior of the chamber between the substrate and the etched
member; film forming plasma generation means which converts the
source gas, which has been supplied to the interior of the chamber,
into a plasma upon supply of a high frequency electric power to
form a source gas plasma within the chamber in order to etch the
etched member; temperature control means for controlling a
temperature of the substrate to a predetermined temperature, which
is lower than a temperature of the etched member, to deposit a
metallic component on the substrate from a precursor comprising the
metallic component and the source gas and obtained as a result of
etching of the etched member by the source gas plasma, thereby
performing predetermined film formation; and source gas radical
replenishment means for replenishing the interior of the chamber
with radicals of the source gas.
2. A metal film production apparatus, comprising: a cylindrical
chamber accommodating a substrate; an etched member formed from a
metal, which forms a high vapor pressure halide, and disposed
within the chamber at a position opposed to the substrate; source
gas plasma supply means for forming a source gas plasma containing
a halogen outside the chamber, and supplying the source gas plasma
to an interior of the chamber between the substrate and the etched
member; temperature control means for controlling a temperature of
the substrate to a predetermined temperature, which is lower than a
temperature of the etched member, to deposit a metallic component
on the substrate from a precursor comprising the metallic component
and the source gas and obtained as a result of etching of the
etched member by the source gas plasma, thereby performing
predetermined film formation; and source gas radical replenishment
means for replenishing the interior of the chamber with radicals of
the source gas.
3. A metal film production apparatus, comprising: a cylindrical
chamber accommodating a substrate; an etched member formed from a
metal, which forms a high vapor pressure halide, and disposed
within the chamber at a position other than a position opposed to
the substrate; a shielding plate disposed within the chamber
between the substrate and the etched member and having a hole
directed toward the substrate; source gas supply means for
supplying a source gas containing a halogen to an interior of the
chamber between the etched member and the shielding plate; film
forming plasma generation means which converts the source gas,
which has been supplied to the interior of the chamber, into a
plasma upon supply of a high frequency electric power to form a
source gas plasma within the chamber in order to etch the etched
member; temperature control means for controlling a temperature of
the substrate to a predetermined temperature, which is lower than a
temperature of the etched member, to deposit a metallic component
on the substrate from a precursor comprising the metallic component
and the source gas and obtained as a result of etching of the
etched member by the source gas plasma, thereby performing
predetermined film formation; and source gas radical replenishment
means for replenishing the interior of the chamber with radicals of
the source gas.
4. The metal film production apparatus according to any one of
claims 1, 2 and 3, wherein the source gas radical replenishment
means supplies a high frequency electric current to a coil wound
round a tubular passage communicating with the interior of the
chamber for flowing the source gas, and converts the source gas
into a plasma by an action of an electric field formed by supply of
the high frequency electric current.
5. The metal film production apparatus according to any one of
claims 1, 2 and 3, wherein the source gas radical replenishment
means has microwave supply means in a tubular passage communicating
with the interior of the chamber for flowing the source gas, and
converts the source gas into a plasma by an action of microwaves
generated by the microwave supply means.
6. The metal film production apparatus according to any one of
claims 1, 2 and 3, wherein the source gas radical replenishment
means has heating means for heating the source gas flowing through
a tubular passage communicating with the interior of the chamber to
dissociate the source gas thermally.
7. The metal film production apparatus according to any one of
claims 1, 2 and 3, wherein the source gas radical replenishment
means has electromagnetic wave generation means for supplying
electromagnetic waves, such as laser light or electron beams, to
the source gas flowing through a tubular passage communicating with
the interior of the chamber to dissociate the source gas.
8. A metal film production apparatus, comprising: a cylindrical
chamber accommodating a substrate; an etched member formed from a
metal, which forms a high vapor pressure halide, and disposed
within the chamber at a position opposed to the substrate; source
gas supply means for supplying a source gas containing a halogen to
an interior of the chamber between the substrate and the etched
member; film forming plasma generation means which converts the
source gas, which has been supplied to the interior of the chamber,
into a plasma upon supply of a high frequency electric power to
form a source gas plasma within the chamber in order to etch the
etched member; temperature control means for controlling a
temperature of the substrate to a predetermined temperature, which
is lower than a temperature of the etched member, to deposit a
metallic component on the substrate from a precursor comprising the
metallic component and the source gas and obtained as a result of
etching of the etched member by the source gas plasma, thereby
performing predetermined film formation; and rare gas supply means
for supplying a rare gas, which has a mass equal to or larger than
a mass of Ne, into the chamber in addition to the source gas.
9. A metal film production apparatus, comprising: a cylindrical
chamber accommodating a substrate; an etched member formed from a
metal, which forms a high vapor pressure halide, and disposed
within the chamber at a position opposed to the substrate; source
gas plasma supply means for forming a source gas plasma containing
a halogen outside the chamber, and supplying the source gas plasma
to an interior of the chamber between the substrate and the etched
member; temperature control means for controlling a temperature of
the substrate to a predetermined temperature, which is lower than a
temperature of the etched member, to deposit a metallic component
on the substrate from a precursor comprising the metallic component
and the source gas and obtained as a result of etching of the
etched member by the source gas plasma, thereby performing
predetermined film formation; and rare gas supply means for
supplying a rare gas, which has a mass equal to or larger than a
mass of Ne, into the chamber in addition to the source gas.
10. A metal film production apparatus, comprising: a cylindrical
chamber accommodating a substrate; an etched member formed from a
metal, which forms a high vapor pressure halide, and disposed
within the chamber at a position other than a position opposed to
the substrate; a shielding plate disposed within the chamber
between the substrate and the etched member and having a hole
directed toward the substrate; source gas supply means for
supplying a source gas containing a halogen to an interior of the
chamber between the etched member and the shielding plate; film
forming plasma generation means which converts the source gas,
which has been supplied to the interior of the chamber, into a
plasma upon supply of a high frequency electric power to form a
source gas plasma within the chamber in order to etch the etched
member; temperature control means for controlling a temperature of
the substrate to a predetermined temperature, which is lower than a
temperature of the etched member, to deposit a metallic component
on the substrate from a precursor comprising the metallic component
and the source gas and obtained as a result of etching of the
etched member by the source gas plasma, thereby performing
predetermined film formation; and rare gas supply means for
supplying a rare gas, which has a mass equal to or larger than a
mass of Ne, into the chamber in addition to the source gas.
11. A metal film production apparatus, comprising: a cylindrical
chamber accommodating a substrate; an etched member formed from a
metal, which forms a high vapor pressure halide, and disposed
within the chamber at a position opposed to the substrate; source
gas supply means for supplying a source gas containing a halogen to
an interior of the chamber between the substrate and the etched
member; film forming plasma generation means which converts the
source gas, which has been supplied to the interior of the chamber,
into a plasma upon supply of a high frequency electric power to
form a source gas plasma within the chamber in order to etch the
etched member; temperature control means for controlling a
temperature of the substrate to a predetermined temperature, which
is lower than a temperature of the etched member, to deposit a
metallic component on the substrate from a precursor comprising the
metallic component and the source gas and obtained as a result of
etching of the etched member by the source gas plasma, thereby
performing predetermined film formation; and electromagnetic wave
generation means for supplying electromagnetic waves into the
chamber to dissociate the source gas generated in accordance with a
film formation reaction.
12. A metal film production apparatus, comprising: a cylindrical
chamber accommodating a substrate; an etched member formed from a
metal, which forms a high vapor pressure halide, and disposed
within the chamber at a position opposed to the substrate; source
gas plasma supply means for forming a source gas plasma containing
a halogen outside the chamber, and supplying the source gas plasma
to an interior of the chamber between the substrate and the etched
member; temperature control means for controlling a temperature of
the substrate to a predetermined temperature, which is lower than a
temperature of the etched member, to deposit a metallic component
on the substrate from a precursor comprising the metallic component
and the source gas and obtained as a result of etching of the
etched member by the source gas plasma, thereby performing
predetermined film formation; and electromagnetic wave generation
means for supplying electromagnetic waves into the chamber to
dissociate the source gas generated in accordance with a film
formation reaction.
13. A metal film production apparatus, comprising: a cylindrical
chamber accommodating a substrate; an etched member formed from a
metal, which forms a high vapor pressure halide, and disposed
within the chamber at a position other than a position opposed to
the substrate; a shielding plate disposed within the chamber
between the substrate and the etched member and having a hole
directed toward the substrate; source gas supply means for
supplying a source gas containing a halogen to an interior of the
chamber between the etched member and the shielding plate; film
forming plasma generation means which converts the source gas,
which has been supplied to the interior of the chamber, into a
plasma upon supply of a high frequency electric power to form a
source gas plasma within the chamber in order to etch the etched
member; temperature control means for controlling a temperature of
the substrate to a predetermined temperature, which is lower than a
temperature of the etched member, to deposit a metallic component
on the substrate from a precursor comprising the metallic component
and the source gas and obtained as a result of etching of the
etched member by the source gas plasma, thereby performing
predetermined film formation; and electromagnetic wave generation
means for supplying electromagnetic waves into the chamber to
dissociate the source gas generated in accordance with a film
formation reaction.
14. A metal film production apparatus, comprising: a cylindrical
chamber accommodating a substrate; an etched member formed from a
composite metal, which comprises a plurality of metallic components
forming high vapor pressure halides, and disposed within the
chamber at a position opposed to the substrate; source gas supply
means for supplying a source gas containing a halogen to an
interior of the chamber between the substrate and the etched
member; film forming plasma generation means which converts the
source gas, which has been supplied to the interior of the chamber,
into a plasma upon supply of a high frequency electric power to
form a source gas plasma within the chamber in order to etch the
etched member; and temperature control means for controlling a
temperature of the substrate to a predetermined temperature, which
is lower than a temperature of the etched member, to deposit the
plurality of metallic components on the substrate from a plurality
of precursors comprising the metallic components and the source gas
and obtained as a result of etching of the etched member by the
source gas plasma, thereby performing predetermined film
formation.
15. A metal film production apparatus, comprising: a cylindrical
chamber accommodating a substrate; an etched member formed from a
composite metal, which comprises a plurality of metallic components
forming high vapor pressure halides, and disposed within the
chamber at a position opposed to the substrate; source gas plasma
supply means for forming a source gas plasma containing a halogen
outside the chamber, and supplying the source gas plasma to an
interior of the chamber between the substrate and the etched
member; and temperature control means for controlling a temperature
of the substrate to a predetermined temperature, which is lower
than a temperature of the etched member, to deposit the plurality
of metallic components on the substrate from a plurality of
precursors comprising the metallic components and a source gas and
obtained as a result of etching of the etched member by the source
gas plasma, thereby performing predetermined film formation.
16. A metal film production apparatus, comprising: a cylindrical
chamber accommodating a substrate; an etched member formed from a
composite metal, which comprises one or more metallic components
and one or more nonmetallic components forming high vapor pressure
halides, and disposed within the chamber at a position opposed to
the substrate; source gas supply means for supplying a source gas
containing a halogen to an interior of the chamber between the
substrate and the etched member; film forming plasma generation
means which converts the source gas, which has been supplied to the
interior of the chamber, into a plasma upon supply of a high
frequency electric power to form a source gas plasma within the
chamber in order to etch the etched member; and temperature control
means for controlling a temperature of the substrate to a
predetermined temperature, which is lower than a temperature of the
etched member, to deposit the metallic components and the
nonmetallic components simultaneously on the substrate from one or
more precursors comprising the metallic components and the source
gas and one or more precursors comprising the nonmetallic
components and the source gas obtained as a result of etching of
the etched member by the source gas plasma, thereby performing
predetermined film formation.
17. A metal film production apparatus, comprising: a cylindrical
chamber accommodating a substrate; an etched member formed from a
composite metal, which comprises one or more metallic components
and one or more nonmetallic components forming high vapor pressure
halides, and disposed within the chamber at a position opposed to
the substrate; source gas plasma supply means for forming a source
gas plasma containing a halogen outside the chamber, and supplying
the source gas plasma to an interior of the chamber between the
substrate and the etched member; and temperature control means for
controlling a temperature of the substrate to a predetermined
temperature, which is lower than a temperature of the etched
member, to deposit the metallic components and the nonmetallic
components simultaneously on the substrate from one or more
precursors comprising the metallic components and a source gas and
one or more precursors comprising the nonmetallic components and
the source gas obtained as a result of etching of the etched member
by the source gas plasma, thereby performing predetermined film
formation.
18. The metal film production apparatus according to any one of
claims 1-3 and 8-13, wherein the etched member formed from the
metal is formed from a composite metal comprising a plurality of
metallic components, and the predetermined film formation is
performed by depositing the plurality of metallic components on the
substrate from a plurality of the precursors comprising the
metallic components and the source gas which have been obtained as
a result of etching of the etched member by the source gas
plasma.
19. The metal film production apparatus according to any one of
claims 1-3 and 8-13, wherein the etched member formed from the
metal is formed from a composite metal comprising one or more
metallic components and one or more nonmetallic components, and the
predetermined film formation is performed by depositing the
metallic components and the nonmetallic components simultaneously
on the substrate from one or more of the precursors comprising the
metallic components and the source gas and one or more of the
precursors comprising the nonmetallic components and the source gas
which have been obtained as a result of etching of the etched
member by the source gas plasma.
20. An interconnection structure forming apparatus for forming a
predetermined interconnection structure in a depression, such as a
trench or a hole, formed in a substrate, by disposing an etched
member, formed from a metal forming a high vapor pressure halide,
in a chamber accommodating the substrate in an interior thereof;
etching the etched member with a source gas plasma containing a
halogen within the chamber to form a precursor comprising a
metallic component and a source gas; and controlling temperatures
of the etched member and the substrate so as to be predetermined
temperatures and so as to provide a predetermined temperature
difference between the temperatures, thereby depositing the
metallic component of the precursor on the substrate to perform
film formation, said apparatus permitting coexistence of a film
formation reaction for forming the film of the metal, and an
etching reaction for etching the metal film, formed by the film
formation reaction, with a plasma of the source gas; and having
control means for exercising control such that a speed of the film
formation reaction is higher than a speed of the etching reaction,
thereby stacking the metal film in the depression sequentially,
starting at a bottom of the depression, to form the predetermined
interconnection structure.
Description
[0001] This application is a Divisional of co-pending application
Ser. No. 10/384,932, filed on Mar. 7, 2003, and for which priority
is claimed under 35 U.S.C. .sctn. 120; and this application claims
priority of Application Nos. 2002-063063, 2002-063064, and
2002-229413 filed in Japan on Mar. 8, 2002; Mar. 8, 2002; and Aug.
7, 2002; respectively, under 35 U.S.C. .sctn. 119; the entire
contents of all are hereby incorporated by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] This invention relates to a method and an apparatus for
production of a metal film or the like. More particularly, the
invention relates to the method and the apparatus useful when
applied in producing a film of a high vapor pressure halide-forming
metal by etching an etched member formed from the metal with a
halogen-containing source gas plasma under predetermined
conditions; and in forming an interconnection structure comprising
the film of the metal.
[0004] The present invention further relates to the method and the
apparatus useful when applied in producing a film of a composite
metal by etching an etched member having a plurality of metals with
a source gas plasma containing a halogen, in particular.
[0005] 2. Description of the Related Art
[0006] In producing a metal film, for example, a thin film of
copper, by vapor phase deposition, it has been common practice to
use an organometallic complex of a liquid, for example,
copper-hexafluoroacetyla- cetonato-trimethylvinylsilane, as a
starting material, dissolve the solid starting material in a
solvent, and vaporize the solution by use of a thermal reaction to
form a film on a substrate.
[0007] High speed semiconductor devices have increasingly used
copper, instead of a conventional aluminum alloy, as a material for
their interconnection in order to increase the speed of switching,
decrease transmission losses, and achieve a high density. In this
case, a predetermined interconnection structure is formed by
performing vapor phase deposition or plating on an insulating
substrate (e.g., SiO.sub.2) having depressions for interconnection,
such as trenches or holes (via holes), on its surface, thereby
adhering copper onto the surface of the substrate, including the
depressions.
[0008] In producing a thin film of copper by vapor phase
deposition, it has been common practice to use an organometallic
complex of a liquid, for example,
copper-hexafluoroacetylacetonato-trimethylvinylsilane, as a
starting material, dissolve the solid starting material in a
solvent, and vaporize the solution by use of a thermal reaction to
form a film on the substrate.
[0009] The damascene method is frequently used in forming a
predetermined copper interconnection structure by burying copper in
the depressions of the substrate. The damascene method is a
technique which cuts trenches in an insulating film, buries copper,
an interconnection material, in the so formed trenches by use of
vapor phase deposition or plating, and removes a surplus thin
copper film outside the trenches by CMP (chemical and mechanical
polishing) to obtain a predetermined interconnection structure.
[0010] With the above-mentioned earlier film formation
technologies, it has been difficult to increase the speed of film
formation, because the film is formed with the use of a thermal
reaction. Moreover, the metal complex as the starting material is
expensive. In addition, hexafluoroacetylacetonato and
trimethylvinylsilane accompanying copper remain as impurities in
the thin film of copper, presenting difficulty in improving the
quality of the film.
[0011] On the other hand, the above-described interconnection
structure obtained by the earlier technologies is formed by
adhesion of a thin copper film on the surface of the substrate,
thus posing the problem that the burial characteristics of copper
are poor. In recent years, the width of the interconnection has
tended to become smaller. In response, the holes need to be
decreased in diameter. As a result, the aspect ratio, the ratio of
the depth to the diameter of the hole, must be minimized. For this
purpose as well, it is an urgent task to improve the burial
characteristics.
[0012] Moreover, the interconnection structure obtained by the
earlier technologies comprises relatively small copper crystal
grains, so that many grain boundaries exist among the grains. Thus,
electromigration is liable to cause a local high-resistance portion
in the grain boundary or the defective site, and in the worst case,
poses the problem that this portion is broken by Joule's heat. At
the same time, stress migration due to residual stress produced
during burial of the copper film in the depression may lead to
physical breakage.
[0013] With the above-mentioned vapor phase deposition method,
moreover, it has been difficult to increase the speed of film
formation, because the film is formed with the use of a thermal
reaction. Besides, the metal complex as the starting material is
expensive. In addition, hexafluoroacetylacetonato and
trimethylvinylsilane accompanying copper remain as impurities in
the thin film of copper, making it difficult to improve the quality
of the film.
[0014] In forming the interconnection by the damascene method,
there is also the problem that the CMP step is absolutely
necessary, requiring a long time for the formation of the
interconnection structure. This is a major drawback with a
multilayer interconnection structure which has tended to be
increasingly used in recent years. The reason is that a
single-layer interconnection structure can be formed by the single
damascene method, while a two-layer interconnection structure can
only be formed by the double damascene method requiring the same
procedure to be performed twice, meaning that as the number of the
layers increases, the number of the CMP steps performed increases
proportionally.
SUMMARY OF THE INVENTION
[0015] The present invention has been accomplished in the light of
the earlier technologies. It is a first object of the invention to
provide a metal film production method and a metal film production
apparatus which have a high film formation speed, which can use an
inexpensive starting material, and which can minimize impurities
remaining in the film.
[0016] A second object of the present invention is to provide an
interconnection structure, and a method and an apparatus for its
formation, which have a high film formation speed, which can use an
inexpensive starting material, which can minimize impurities
remaining in the film, which ensure satisfactory burial in the
depression, which can afford satisfactory electrical
characteristics stable for a long term, and which can minimize the
steps for production of the interconnection structure by a metal
film.
[0017] The present inventors obtained the following findings: A
chlorine gas is supplied into a vacuum chamber accommodating a
substrate. The chlorine gas is converted into a plasma by plasma
generation means, and an etched member comprising a copper plate
disposed within the chamber is etched with the chlorine gas plasma.
By appropriately controlling the relation between the temperatures
of the copper plate and the substrate, the etched copper is
deposited on the substrate, whereby a thin film of copper can be
formed. That is, the thin copper film can be formed on the
substrate by imparting a high temperature (e.g., 300.degree. C. to
400.degree. C.) to the copper plate, the etched member, and
imparting a low temperature (about 200.degree. C.) to the
substrate.
[0018] Hence, the copper plate is disposed so as to face the
chlorine gas plasma forming a relatively high temperature
atmosphere, while the substrate is disposed in a relatively low
temperature atmosphere opposed to the copper plate, with the plasma
atmosphere being interposed between the substrate and the copper
plate. Also, the temperatures of the copper plate and the substrate
are controlled appropriately. By taking these measures, a
production apparatus for a thin Cu film can be easily provided.
[0019] As the etched member, not only Cu, but also a metal forming
a high vapor pressure halide, such as Ta, Ti, W, Zn, In or Cd, can
be used generally. A composite metal containing a plurality of
these metals, such as an alloy of In and Cu, can also be used as
the etched member. Moreover, a composite metal containing a
nonmetallic element, such as S or Se, in addition to the above
metal, for example, an alloy such as CuInSe.sub.2, CdS, or ZnSe,
may also be used as the etched member. As the source gas, any
halogen gas can be used generally, in addition to Cl.sub.2.
[0020] In the above-described production apparatus for the thin Cu
film, the following reactions are assumed to occur:
Dissociation reaction of plasma: Cl.sub.2.fwdarw.2Cl*
Etching reaction: Cu+Cl*.fwdarw.CuCl(g)
Adsorption to substrate: CuCl(g).fwdarw.CuCl(ad)
Film formation reaction: CuCl(ad)+Cl*.fwdarw.Cu+Cl.sub.2.Arrow-up
bold. (1)
[0021] Here, Cl* represents radicals of Cl, (g) represents a
gaseous state, and (ad) represents an adsorbed state.
[0022] In the equation (1), if Cl* exists amply, the reaction
proceeds to the right, whereupon the Cu film can be deposited
satisfactorily. However, Cl.sub.2 and Cl.sup.+ are present mixedly
in the Cl gas plasma, and Cl* does not occur preferentially. Thus,
only the reaction of the equation (1) does not proceed, but a
reaction proceeding to the left occurs at the same time.
Furthermore, the Cu film, once formed, may be etched.
[0023] In addition, Cl.sub.2 cannot be withdrawn sufficiently from
CuCl(ad), so that the following reaction may develop:
CuCl(ad).fwdarw.CuCl(s)
[0024] That is, CuCl in solid form is formed. This CuCl(s) is an
insulator. Thus, the presence of CuCl(s) in the Cu film constitutes
the cause of decreasing the electrical conductivity of the
resulting Cu film, deteriorating the quality of the film.
[0025] Under these circumstances, it is necessary to realize the
metal film production method based on the aforementioned findings
satisfactorily, improve the quality of the film, and increase the
film formation speed at the same time. For these purposes, the
first measure to be taken is to replenish Cl* separately so that
there will be an ample amount of Cl* within the chamber. This can
be done by generating a high density of Cl* in a separate space of
a smaller volume than the chamber, and supplying it into the
chamber. This is because the space of a smaller volume makes it
easy to control plasma conditions so that Cl* will be
generated.
[0026] Another film formation reaction, expressed by the following
equation (2), may be taking place:
2CuCl(ad).fwdarw.2Cu+Cl.sub.2 (2)
[0027] The equation (2) represents a reaction in which CuCl(ad)
receives thermal energy to deposit Cu and release a Cl.sub.2 gas.
This is a reversible reaction which is possible from the aspect of
thermal equilibrium. In the equation (2), if the amount of Cl.sub.2
is decreased, the reaction proceeds rightward. For this purpose,
dissociation of the Cl.sub.2 gas suffices.
[0028] Under these circumstances, a second measure can be taken to
satisfactorily realize the metal film production method based on
the aforementioned findings, further improve the quality of the
film, and further increase the film formation speed at the same
time. The second measure is to increase the dissociation rate of
the Cl.sub.2 gas so that the amount of the Cl.sub.2 gas occurring
in accordance with the film formation reaction will be decreased.
This can be accomplished basically by adjusting the plasma
conditions.
[0029] A first metal film production method according to the
present invention focuses on the film formation reaction of the
aforementioned equation (1), and attains the objects of the
invention by utilizing an etching phenomenon under predetermined
temperature control based on the aforesaid findings, while making
the effects of the invention more remarkable by supplying
separately formed radicals of the source gas. The first metal film
production method is characterized by the following features:
[0030] 1) A metal film production method which comprises disposing
an etched member, formed from a metal forming a high vapor pressure
halide, in a chamber accommodating a substrate in an interior
thereof; etching the etched member with a source gas plasma
containing a halogen within the chamber to form a precursor
comprising a metallic component and a source gas; and controlling
the temperatures of the etched member and the substrate so as to be
predetermined temperatures and so as to provide a predetermined
temperature difference between the temperatures, thereby depositing
the metallic component of the precursor on the substrate to perform
predetermined film formation,
[0031] the metal film production method further comprising:
[0032] separately generating radicals of the source gas; and
[0033] replenishing the interior of the chamber with the source gas
radicals to extract the source gas from the precursor adsorbed onto
the substrate, thereby depositing the metallic component on the
substrate for performing the predetermined film formation.
[0034] Thus, the following basic actions and effects are obtained:
The use of the source gas plasma results in a markedly increased
reaction efficiency and a fast film formation speed. Since the
halogen gas is used as the source gas, moreover, the cost can be
markedly decreased. Furthermore, the desired film formation can be
carried out under temperature control. Thus, the amounts of
impurities, such as chlorine, remaining in the thin metal film can
be decreased, so that a high quality thin metal film can be
produced.
[0035] Besides, film formation can be promoted by the action of
separately formed radicals of the source gas, whereby the film
formation speed can be increased.
[0036] 2) In the metal film production method described in 1), the
radicals of the source gas may be obtained by applying a high
frequency electric field to the source gas flowing through a
tubular passage communicating with the interior of the chamber to
convert the source gas into a plasma. Thus, the effects of the
feature described in 1) can be obtained by a simple apparatus.
[0037] 3) In the metal film production method described in 1), the
radicals of the source gas may be obtained by supplying microwaves
to the source gas flowing through a tubular passage communicating
with the interior of the chamber to convert the source gas into a
plasma. Thus, electromagnetic waves of a higher frequency than in
the feature described in 2) can be used. The source gas radicals
can be obtained with higher density and higher efficiency
accordingly.
[0038] 4) In the metal film production method described in 1), the
radicals of the source gas may be obtained by heating the source
gas flowing through a tubular passage communicating with the
interior of the chamber to dissociate the source gas thermally.
Thus, the effects of the feature described in 1) can be obtained at
the lowest cost.
[0039] 5) In the metal film production method described in 1), the
radicals of the source gas may be obtained by supplying
electromagnetic waves, such as laser light or electron beams, to
the source gas flowing through a tubular passage communicating with
the interior of the chamber to dissociate the source gas. Thus,
desired radicals can be obtained selectively with high efficiency
by selecting and fixing the wavelength of the electromagnetic
waves. Consequently, the effects of the feature described in 1) can
be rendered remarkable.
[0040] A second metal film production method according to the
present invention focuses on the film formation reaction of the
aforementioned equation (2), and attains the objects of the
invention by utilizing an etching phenomenon under predetermined
temperature control based on the aforesaid findings, while making
the effects of the invention more remarkable by increasing the
dissociation rate of the source gas adsorbed onto the substrate.
The second metal film production method is characterized by the
following features:
[0041] 6) A metal film production method which comprises disposing
an etched member, formed from a metal forming a high vapor pressure
halide, in a chamber accommodating a substrate in an interior
thereof; etching the etched member with a source gas plasma
containing a halogen within the chamber to form a precursor
comprising a metallic component and a source gas; and controlling
the temperatures of the etched member and the substrate so as to be
predetermined temperatures and so as to provide a predetermined
temperature difference between the temperatures, thereby depositing
the metallic component of the precursor on the substrate to perform
predetermined film formation,
[0042] the metal film production method further comprising:
[0043] controlling plasma conditions such that the dissociation
rate of the source gas occurring according to a film formation
reaction increases.
[0044] Thus, in addition to the same basic actions and effects as
in the feature described in 1), the increase in the dissociation
rate of the source gas can promote film formation, increasing its
speed.
[0045] 7) In the metal film production method described in 6),
control of the plasma conditions may be realized by decreasing the
amount of the source gas supplied. Thus, the effects of the feature
described in 6) can be achieved most easily.
[0046] 8) In the metal film production method described in 6),
control of the plasma conditions may be realized by increasing the
amount of a high frequency electric power for forming the source
gas plasma. Thus, the effects of the feature described in 6) can be
achieved easily without decreasing the film formation rate.
[0047] 9) In the metal film production method described in 6),
control of the plasma conditions may be realized by supplying a
rare gas, having a mass equal to or larger than the mass of Ne,
into the chamber in addition to the source gas. Thus, the rare gas
functions as a catalyst for increasing the dissociation rate, and
thus can easily increase the dissociability of the source gas.
[0048] 10) In the metal film production method described in 6),
control of the plasma conditions may be realized by supplying
electromagnetic waves into the chamber to dissociate the source gas
supplied into the chamber. Thus, the dissociation of the source gas
can be performed with high efficiency by the energy of
electromagnetic waves.
[0049] A first metal film production apparatus for realizing the
aforementioned first metal film production method is characterized
by the following features:
[0050] 11) A metal film production apparatus, comprising:
[0051] a cylindrical chamber accommodating a substrate;
[0052] an etched member formed from a metal, which forms a high
vapor pressure halide, and disposed within the chamber at a
position opposed to the substrate;
[0053] source gas supply means for supplying a source gas
containing a halogen to an interior of the chamber between the
substrate and the etched member;
[0054] film forming plasma generation means which converts the
source gas, which has been supplied to the interior of the chamber,
into a plasma upon supply of a high frequency electric power to
form a source gas plasma within the chamber in order to etch the
etched member;
[0055] temperature control means for controlling the temperature of
the substrate to a predetermined temperature, which is lower than
the temperature of the etched member, to deposit a metallic
component on the substrate from a precursor comprising the metallic
component and the source gas and obtained as a result of etching of
the etched member by the source gas plasma, thereby performing
predetermined film formation; and
[0056] source gas radical replenishment means for replenishing the
interior of the chamber with radicals of the source gas.
[0057] Thus, the following basic actions and effects are obtained:
The use of the source gas plasma results in a markedly increased
reaction efficiency and a fast film formation speed. Since the
halogen gas is used as the source gas, moreover, the cost can be
markedly decreased. Furthermore, the desired film formation can be
carried out under temperature control. Thus, the amounts of
impurities, such as chlorine, remaining in the thin metal film can
be decreased, so that a high quality thin metal film can be
produced. Moreover, these actions and effects can be obtained by a
so-called inductively coupled apparatus.
[0058] Besides, film formation can be promoted by the action of
separately formed radicals of the source gas, whereby the film
formation speed can be increased.
[0059] 12) A metal film production apparatus, comprising:
[0060] a cylindrical chamber accommodating a substrate;
[0061] an etched member formed from a metal, which forms a high
vapor pressure halide, and disposed within the chamber at a
position opposed to the substrate;
[0062] source gas plasma supply means for forming a source gas
plasma containing a halogen outside the chamber, and supplying the
source gas plasma to an interior of the chamber between the
substrate and the etched member;
[0063] temperature control means for controlling the temperature of
the substrate to a predetermined temperature, which is lower than
the temperature of the etched member, to deposit a metallic
component on the substrate from a precursor comprising the metallic
component and the source gas and obtained as a result of etching of
the etched member by the source gas plasma, thereby performing
predetermined film formation; and
[0064] source gas radical replenishment means for replenishing the
interior of the chamber with radicals of the source gas.
[0065] Thus, the same actions and effects as in the feature
described in 11) can be achieved by a so-called remote plasma
apparatus designed to supply a remotely formed plasma into the
chamber.
[0066] 13) A metal film production apparatus, comprising:
[0067] a cylindrical chamber accommodating a substrate;
[0068] an etched member formed from a metal, which forms a high
vapor pressure halide, and disposed within the chamber at a
position other than a position opposed to the substrate;
[0069] a shielding plate disposed within the chamber between the
substrate and the etched member and having a hole directed toward
the substrate;
[0070] source gas supply means for supplying a source gas
containing a halogen to an interior of the chamber between the
etched member and the shielding plate;
[0071] film forming plasma generation means which converts the
source gas, which has been supplied to the interior of the chamber,
into a plasma upon supply of a high frequency electric power to
form a source gas plasma within the chamber in order to etch the
etched member;
[0072] temperature control means for controlling the temperature of
the substrate to a predetermined temperature, which is lower than
the temperature of the etched member, to deposit a metallic
component on the substrate from a precursor comprising the metallic
component and the source gas and obtained as a result of etching of
the etched member by the source gas plasma, thereby performing
predetermined film formation; and
[0073] source gas radical replenishment means for replenishing the
interior of the chamber with radicals of the source gas.
[0074] Thus, the same effects as in the feature described in 11)
are produced. Furthermore, particles, which are peeled from the
etched member after etching and fall, are prevented from adhering
onto the substrate, and the predetermined precursor can be supplied
to the space above the substrate. The precursor can easily pass
through the hole of the shielding plate, while a low proportion of
the radicals formed in the space between the etched member and the
shielding plate pass through the hole and arrive at the space above
the substrate. In this view, the contribution of replenishment of
the radicals to the promotion of the film formation reaction can be
rendered remarkable.
[0075] 14) In the metal film production apparatus described in any
one of 11), 12) and 13), the source gas radical replenishment means
may supply a high frequency electric current to a coil wound round
a tubular passage communicating with the interior of the chamber
for flowing the source gas, and convert the source gas into a
plasma by the action of an electric field formed by supply of the
high frequency electric current. Thus, the source gas radical
replenishment means of the features described in 11) to 13) can be
accomplished by a simple construction.
[0076] 15) In the metal film production apparatus described in any
one of 11), 12) and 13), the source gas radical replenishment means
may have microwave supply means in a tubular passage communicating
with the interior of the chamber for flowing the source gas, and
convert the source gas into a plasma by the action of microwaves
generated by the microwave supply means. Thus, the source gas
radical replenishment means of the features described in 11) to 13)
can show a higher efficiency than in the feature described in
14).
[0077] 16) In the metal film production apparatus described in any
one of 11), 12) and 13), the source gas radical replenishment means
may have heating means for heating the source gas flowing through a
tubular passage communicating with the interior of the chamber to
dissociate the source gas thermally. Thus, the source gas radical
replenishment means of the features described in 11) to 13) can be
constructed at the lowest cost.
[0078] 17) In the metal film production apparatus described in any
one of 11), 12) and 13), the source gas radical replenishment means
may have electromagnetic wave generation means for supplying
electromagnetic waves, such as laser light or electron beams, to
the source gas flowing through a tubular passage communicating with
the interior of the chamber to dissociate the source gas. Thus, the
source gas radical replenishment means of the features described in
11) to 13) can be constructed as an apparatus capable of forming
desired radicals selectively with high efficiency.
[0079] A second metal film production apparatus for realizing the
aforementioned second metal film production method is characterized
by the following features:
[0080] 18) A metal film production apparatus, comprising:
[0081] a cylindrical chamber accommodating a substrate;
[0082] an etched member formed from a metal, which forms a high
vapor pressure halide, and disposed within the chamber at a
position opposed to the substrate;
[0083] source gas supply means for supplying a source gas
containing a halogen to an interior of the chamber between the
substrate and the etched member;
[0084] film forming plasma generation means which converts the
source gas, which has been supplied to the interior of the chamber,
into a plasma upon supply of a high frequency electric power to
form a source gas plasma within the chamber in order to etch the
etched member;
[0085] temperature control means for controlling the temperature of
the substrate to a predetermined temperature, which is lower than
the temperature of the etched member, to deposit a metallic
component on the substrate from a precursor comprising the metallic
component and the source gas and obtained as a result of etching of
the etched member by the source gas plasma, thereby performing
predetermined film formation; and
[0086] rare gas supply means for supplying a rare gas, which has a
mass equal to or larger than the mass of Ne, into the chamber in
addition to the source gas.
[0087] Thus, in a so-called inductively coupled apparatus, the
catalytic function of the rare gas for the dissociation rate of the
source gas can satisfactorily increase the dissociation rate,
promoting the film formation reaction.
[0088] 19) A metal film production apparatus, comprising:
[0089] a cylindrical chamber accommodating a substrate;
[0090] an etched member formed from a metal, which forms a high
vapor pressure halide, and disposed within the chamber at a
position opposed to the substrate;
[0091] source gas plasma supply means for forming a source gas
plasma containing a halogen outside the chamber, and supplying the
source gas plasma to an interior of the chamber between the
substrate and the etched member;
[0092] temperature control means for controlling the temperature of
the substrate to a predetermined temperature, which is lower than
the temperature of the etched member, to deposit a metallic
component on the substrate from a precursor comprising the metallic
component and the source gas and obtained as a result of etching of
the etched member by the source gas plasma, thereby performing
predetermined film formation; and
[0093] rare gas supply means for supplying a rare gas, which has a
mass equal to or larger than the mass of Ne, into the chamber in
addition to the source gas.
[0094] Thus, in a so-called remote plasma apparatus, the catalytic
function of the rare gas for the dissociation rate of the source
gas can satisfactorily increase the dissociation rate, promoting
the film formation reaction.
[0095] 20) A metal film production apparatus, comprising:
[0096] a cylindrical chamber accommodating a substrate;
[0097] an etched member formed from a metal, which forms a high
vapor pressure halide, and disposed within the chamber at a
position other than a position opposed to the substrate;
[0098] a shielding plate disposed within the chamber between the
substrate and the etched member and having a hole directed toward
the substrate;
[0099] source gas supply means for supplying a source gas
containing a halogen to an interior of the chamber between the
etched member and the shielding plate;
[0100] film forming plasma generation means which converts the
source gas, which has been supplied to the interior of the chamber,
into a plasma upon supply of a high frequency electric power to
form a source gas plasma within the chamber in order to etch the
etched member;
[0101] temperature control means for controlling the temperature of
the substrate to a predetermined temperature, which is lower than
the temperature of the etched member, to deposit a metallic
component on the substrate from a precursor comprising the metallic
component and the source gas and obtained as a result of etching of
the etched member by the source gas plasma, thereby performing
predetermined film formation; and
[0102] rare gas supply means for supplying a rare gas, which has a
mass equal to or larger than the mass of Ne, into the chamber in
addition to the source gas.
[0103] Thus, in the same apparatus as described in 13) designed to
prevent particles of the etched member from falling onto the
substrate, the catalytic function of the rare gas for the
dissociation rate of the source gas can satisfactorily increase the
dissociation rate, promoting the film formation reaction.
[0104] 21) A metal film production apparatus, comprising:
[0105] a cylindrical chamber accommodating a substrate;
[0106] an etched member formed from a metal, which forms a high
vapor pressure halide, and disposed within the chamber at a
position opposed to the substrate;
[0107] source gas supply means for supplying a source gas
containing a halogen to an interior of the chamber between the
substrate and the etched member;
[0108] film forming plasma generation means which converts the
source gas, which has been supplied to the interior of the chamber,
into a plasma upon supply of a high frequency electric power to
form a source gas plasma within the chamber in order to etch the
etched member;
[0109] temperature control means for controlling the temperature of
the substrate to a predetermined temperature, which is lower than
the temperature of the etched member, to deposit a metallic
component on the substrate from a precursor comprising the metallic
component and the source gas and obtained as a result of etching of
the etched member by the source gas plasma, thereby performing
predetermined film formation; and
[0110] electromagnetic wave generation means for supplying
electromagnetic waves into the chamber to dissociate the source gas
generated in accordance with a film formation reaction.
[0111] Thus, in a so-called inductively coupled apparatus, the
source gas occurring in accordance with the film formation reaction
is dissociated by electromagnetic waves, whereby the film formation
reaction can be promoted.
[0112] 22) A metal film production apparatus, comprising:
[0113] a cylindrical chamber accommodating a substrate;
[0114] an etched member formed from a metal, which forms a high
vapor pressure halide, and disposed within the chamber at a
position opposed to the substrate;
[0115] source gas plasma supply means for forming a source gas
plasma containing a halogen outside the chamber, and supplying the
source gas plasma to an interior of the chamber between the
substrate and the etched member;
[0116] temperature control means for controlling the temperature of
the substrate to a predetermined temperature, which is lower than
the temperature of the etched member, to deposit a metallic
component on the substrate from a precursor comprising the metallic
component and the source gas and obtained as a result of etching of
the etched member by the source gas plasma, thereby performing
predetermined film formation; and
[0117] electromagnetic wave generation means for supplying
electromagnetic waves into the chamber to dissociate the source gas
generated in accordance with a film formation reaction.
[0118] Thus, in a so-called remote plasma apparatus, the source gas
occurring in accordance with the film formation reaction is
dissociated by electromagnetic waves, whereby the film formation
reaction can be promoted.
[0119] 23) A metal film production apparatus, comprising:
[0120] a cylindrical chamber accommodating a substrate;
[0121] an etched member formed from a metal, which forms a high
vapor pressure halide, and disposed within the chamber at a
position other than a position opposed to the substrate;
[0122] a shielding plate disposed within the chamber between the
substrate and the etched member and having a hole directed toward
the substrate;
[0123] source gas supply means for supplying a source gas
containing a halogen to an interior of the chamber between the
etched member and the shielding plate;
[0124] film forming plasma generation means which converts the
source gas, which has been supplied to the interior of the chamber,
into a plasma upon supply of a high frequency electric power to
form a source gas plasma within the chamber in order to etch the
etched member;
[0125] temperature control means for controlling the temperature of
the substrate to a predetermined temperature, which is lower than
the temperature of the etched member, to deposit a metallic
component on the substrate from a precursor comprising the metallic
component and the source gas and obtained as a result of etching of
the etched member by the source gas plasma, thereby performing
predetermined film formation; and
[0126] electromagnetic wave generation means for supplying
electromagnetic waves into the chamber to dissociate the source gas
generated in accordance with a film formation reaction.
[0127] Thus, in the same apparatus as described in 13) designed to
prevent particles of the etched member from falling onto the
substrate, the source gas occurring in accordance with the film
formation reaction is dissociated, whereby the film formation
reaction can be promoted.
[0128] A third metal film production method is characterized by the
following feature:
[0129] 24) A metal film production method comprising:
[0130] disposing an etched member, formed from a composite metal
comprising a plurality of metallic components forming high vapor
pressure halides, in a chamber accommodating a substrate in an
interior thereof;
[0131] etching the etched member with a source gas plasma
containing a halogen within the chamber to form a plurality of
precursors comprising the metallic components and a source gas;
and
[0132] controlling the temperatures of the etched member and the
substrate so as to be predetermined temperatures and so as to
provide a predetermined temperature difference between the
temperatures, thereby depositing the metallic components of the
plurality of precursors on the substrate to perform predetermined
film formation.
[0133] Thus, various thin films adapted for applications can be
prepared, and this method can be used as a metal film production
method of great versatility.
[0134] A fourth metal film production method is characterized by
the following feature:
[0135] 25) A metal film production method comprising:
[0136] disposing an etched member, formed from a composite metal
comprising one or more metallic components and one or more
nonmetallic components forming high vapor pressure halides, in a
chamber accommodating a substrate in an interior thereof;
[0137] etching the etched member with a source gas plasma
containing a halogen within the chamber to form one or more
precursors comprising the metallic components and a source gas and
one or more precursors comprising the nonmetallic components and
the source gas; and
[0138] controlling the temperatures of the etched member and the
substrate so as to be predetermined temperatures and so as to
provide a predetermined temperature difference between the
temperatures, thereby depositing the metallic components and the
nonmetallic components simultaneously on the substrate to perform
predetermined film formation.
[0139] Thus, various thin films adapted for applications can be
prepared, and this method can be used as a metal film production
method of great versatility.
[0140] A third metal film production apparatus for realizing the
aforementioned third metal film production method is characterized
by the following features:
[0141] 26) A metal film production apparatus, comprising:
[0142] a cylindrical chamber accommodating a substrate;
[0143] an etched member formed from a composite metal, which
comprises a plurality of metallic components forming high vapor
pressure halides, and disposed within the chamber at a position
opposed to the substrate;
[0144] source gas supply means for supplying a source gas
containing a halogen to an interior of the chamber between the
substrate and the etched member;
[0145] film forming plasma generation means which converts the
source gas, which has been supplied to the interior of the chamber,
into a plasma upon supply of a high frequency electric power to
form a source gas plasma within the chamber in order to etch the
etched member; and
[0146] temperature control means for controlling the temperature of
the substrate to a predetermined temperature, which is lower than
the temperature of the etched member, to deposit the plurality of
metallic components on the substrate from a plurality of precursors
comprising the metallic components and the source gas and obtained
as a result of etching of the etched member by the source gas
plasma, thereby performing predetermined film formation.
[0147] Thus, this apparatus can prepare various thin films adapted
for applications, and can be used as a metal film production
apparatus of great versatility.
[0148] 27) A metal film production apparatus, comprising:
[0149] a cylindrical chamber accommodating a substrate;
[0150] an etched member formed from a composite metal, which
comprises a plurality of metallic components forming high vapor
pressure halides, and disposed within the chamber at a position
opposed to the substrate;
[0151] source gas plasma supply means for forming a source gas
plasma containing a halogen outside the chamber, and supplying the
source gas plasma to an interior of the chamber between the
substrate and the etched member; and
[0152] temperature control means for controlling the temperature of
the substrate to a predetermined temperature, which is lower than
the temperature of the etched member, to deposit the plurality of
metallic components on the substrate from a plurality of precursors
comprising the metallic components and a source gas and obtained as
a result of etching of the etched member by the source gas plasma,
thereby performing predetermined film formation.
[0153] Thus, this apparatus can prepare various thin films adapted
for applications, and can be used as a metal film production
apparatus of great versatility.
[0154] A fourth metal film production apparatus for realizing the
aforementioned fourth metal film production method is characterized
by the following features:
[0155] 28) A metal film production apparatus, comprising:
[0156] a cylindrical chamber accommodating a substrate;
[0157] an etched member formed from a composite metal, which
comprises one or more metallic components and one or more
nonmetallic components forming high vapor pressure halides, and
disposed within the chamber at a position opposed to the
substrate;
[0158] source gas supply means for supplying a source gas
containing a halogen to an interior of the chamber between the
substrate and the etched member;
[0159] film forming plasma generation means which converts the
source gas, which has been supplied to the interior of the chamber,
into a plasma upon supply of a high frequency electric power to
form a source gas plasma within the chamber in order to etch the
etched member; and
[0160] temperature control means for controlling the temperature of
the substrate to a predetermined temperature, which is lower than
the temperature of the etched member, to deposit the metallic
components and the nonmetallic components simultaneously on the
substrate from one or more precursors comprising the metallic
components and the source gas and one or more precursors comprising
the nonmetallic components and the source gas obtained as a result
of etching of the etched member by the source gas plasma, thereby
performing predetermined film formation.
[0161] Thus, this apparatus can prepare various thin films adapted
for applications, and can be used as a metal film production
apparatus of great versatility.
[0162] 29) A metal film production apparatus, comprising:
[0163] a cylindrical chamber accommodating a substrate;
[0164] an etched member formed from a composite metal, which
comprises one or more metallic components and one or more
nonmetallic components forming high vapor pressure halides, and
disposed within the chamber at a position opposed to the
substrate;
[0165] source gas plasma supply means for forming a source gas
plasma containing a halogen outside the chamber, and supplying the
source gas plasma to an interior of the chamber between the
substrate and the etched member; and
[0166] temperature control means for controlling the temperature of
the substrate to a predetermined temperature, which is lower than
the temperature of the etched member, to deposit the metallic
components and the nonmetallic components simultaneously on the
substrate from one or more precursors comprising the metallic
components and a source gas and one or more precursors comprising
the nonmetallic components and the source gas obtained as a result
of etching of the etched member by the source gas plasma, thereby
performing predetermined film formation.
[0167] Thus, this apparatus can prepare various thin films adapted
for applications, and can be used as a metal film production
apparatus of great versatility.
[0168] A fifth metal film production method, which applies the
aforementioned first or second metal film production method to
achieve the production of a thin film of a composite metal, is
characterized by the following feature:
[0169] 30) In the metal film production method described in any one
of 1) to 10),
[0170] the etched member formed from the metal may be formed from a
composite metal comprising a plurality of metallic components,
and
[0171] the predetermined film formation may be performed by
depositing the plurality of metallic components on the substrate
from a plurality of the precursors comprising the metallic
components and the source gas which have been obtained as a result
of etching of the etched member by the source gas plasma.
[0172] Thus, this method can prepare various thin films adapted for
applications, and can be used as a metal film production method of
great versatility.
[0173] A fifth metal film production apparatus for realizing the
aforementioned fifth metal film production method is characterized
by the following feature:
[0174] 31) In the metal film production apparatus described in any
one of 11) to 23),
[0175] the etched member formed from the metal may be formed from a
composite metal comprising a plurality of metallic components,
and
[0176] the predetermined film formation may be performed by
depositing the plurality of metallic components on the substrate
from a plurality of the precursors comprising the metallic
components and the source gas which have been obtained as a result
of etching of the etched member by the source gas plasma.
[0177] Thus, this apparatus can prepare various thin films adapted
for applications, and can be used as a metal film production
apparatus of great versatility.
[0178] A sixth metal film production method, which applies the
aforementioned first or second metal film production method to
achieve the production of a thin film of a composite metal, is
characterized by the following feature:
[0179] 32) In the metal film production method described in any one
of 1) to 10),
[0180] the etched member formed from the metal may be formed from a
composite metal comprising one or more metallic components and one
or more nonmetallic components, and
[0181] the predetermined film formation may be performed by
depositing the metallic components and the nonmetallic components
simultaneously on the substrate from one or more of the precursors
comprising the metallic components and the source gas and one or
more of the precursors comprising the nonmetallic components and
the source gas which have been obtained as a result of etching of
the etched member by the source gas plasma.
[0182] Thus, this method can prepare various thin films adapted for
applications, and can be used as a metal film production method of
great versatility.
[0183] A sixth metal film production apparatus for realizing the
aforementioned sixth metal film production method is characterized
by the following feature:
[0184] 33) In the metal film production apparatus described in any
one of 11) to 23),
[0185] the etched member formed from the metal may be formed from a
composite metal comprising one or more metallic components and one
or more nonmetallic components, and
[0186] the predetermined film formation may be performed by
depositing the metallic components and the nonmetallic components
simultaneously on the substrate from one or more of the precursors
comprising the metallic components and the source gas and one or
more of the precursors comprising the nonmetallic components and
the source gas which have been obtained as a result of etching of
the etched member by the source gas plasma.
[0187] Thus, this apparatus can prepare various thin films adapted
for applications, and can be used as a metal film production
apparatus of great versatility.
[0188] During the film formation reaction shown in the
aforementioned equation (1), as stated earlier, an etching reaction
for the deposited Cu film by means of Cl* simultaneously occurs, in
addition to this film formation reaction. That is, if a proper
amount of Cl* acts on CuCl(ad), the Cu film is deposited by the
film formation reaction shown in the equation (1). In an atmosphere
in which Cl* is present at a high density, the etching of the
deposited Cu film with Cl* is predominant, making growth of the Cu
film impossible. This means that control of the amount of Cl*
enables either the film formation reaction or the etching reaction
to be selected. Thus, if it is possible to create an atmosphere in
which the speed of the film formation reaction is slightly higher
than the speed of the etching reaction, it may be considered to
work out a film formation method in which the Cu film is deposited
by the film formation reaction, and simultaneously the surface of
the Cu film is etched, while the film thickness is gradually
increased. That is, even if the depression of the substrate is a
via hole with a very small diameter, Cu can be sequentially
stacked, starting at its bottom, to form the Cu film. At this time,
the surface of the stacked Cu film is etched with Cl*. Thus,
stacking of the Cu film proceeds, with the intrinsic surface of the
Cu film being always exposed, and with the crystal directions being
unified into a single direction. The Cu film, which is formed in
the depression of the substrate by film formation in this
copresence of the film formation reaction and the etching reaction,
is satisfactory in the adhesion of the film itself. Also, this Cu
film comprises a single crystal, or a crystal composed of large
crystal grains bound together which is regarded as equivalent to a
single crystal (both types of crystals are collectively called a
single crystal-like crystal). Such a single crystal-like crystal
has no grain boundaries, or has several grain boundaries, if any.
Thus, the Cu film is not affected by electromigration or stress
migration, but can be expected to show stable electrical
characteristics for a long period.
[0189] The interconnection structure according to the present
invention, accomplished based on the foregoing findings, is
characterized by the following:
[0190] 34) An interconnection structure formed by burying a metal
film in a depression, such as a trench or a hole, formed in a
substrate,
[0191] the interconnection structure being formed by:
[0192] making a film formation reaction and an etching reaction
coexistent, the film formation reaction being a reaction in which a
precursor comprising a metallic component and a source gas is
adsorbed onto the substrate, and then the metallic component is
deposited to form a metal film of a metal of the metallic
component, and the etching reaction being a reaction in which the
metal film formed by the film formation reaction is etched with a
plasma of the source gas; and
[0193] exercising control such that the speed of the film formation
reaction is higher than the speed of the etching reaction, thereby
stacking the metal film in the depression sequentially, starting at
a bottom of the depression.
[0194] Hence, simultaneously with the deposition of the metal film
by the film formation reaction, the surface of the metal film is
etched, and the film thickness is gradually increased, with the
result that the interconnection structure is formed. That is, even
if the depression of the substrate is a via hole with a very small
diameter, for example, the metal can be sequentially stacked,
starting at its bottom, to form the metal film. At this time, the
surface of the stacked metal film is etched with the source gas
plasma. Thus, stacking of the metal film proceeds, with the
intrinsic surface of the metal film being always exposed, and with
the crystal directions being unified into a single direction.
[0195] Thus, the resulting interconnection structure has by far
better burial characteristics than the interconnection structures
formed by vapor phase deposition and plating according to the
earlier technologies. The metal film itself is satisfactory in
adhesion, and also comprises a single crystal, or a single
crystal-like crystal composed of large crystal grains bound
together which can be regarded as equivalent to a single crystal.
Such a single crystal-like crystal has no grain boundaries, or has
several grain boundaries, if any. Thus, the interconnection
structure is not affected by electromigration or stress migration,
but can maintain stable electrical characteristics for a long
period.
[0196] 35) A multilayer interconnection structure formed by burying
a metal film in a depression, such as a trench or a hole, in
multiple layers formed in a substrate for formation of the
multilayer interconnection structure,
[0197] the multilayer interconnection structure being integrally
formed by:
[0198] making a film formation reaction and an etching reaction
coexistent, the film formation reaction being a reaction in which a
precursor comprising a metallic component and a source gas is
adsorbed onto the substrate, and then the metallic component is
deposited to form a metal film of a metal of the metallic
component, and the etching reaction being a reaction in which the
metal film formed by the film formation reaction is etched with a
plasma of the source gas; and
[0199] exercising control such that the speed of the film formation
reaction is higher than the speed of the etching reaction, thereby
stacking the metal film in the depression sequentially, starting at
a bottom of the depression.
[0200] Thus, the multilayer interconnection structure can be formed
as an integrally continued single crystal-like crystal of the
metal. Consequently, the actions and effects described in 34) above
are even more remarkable than in the earlier technologies.
[0201] 36) In the multilayer interconnection structure described in
35), a barrier metal layer may be formed on the surface of the
depression of the substrate.
[0202] Thus, the multilayer interconnection structure can be formed
as an integrally continued single crystal-like crystal of the
metal, and the barrier metal layer necessarily formed between the
interconnection structures of the respective layers in the earlier
technologies can be removed. Consequently, the metals forming the
interconnection structures of the respective layers are not divided
by the barrier metal layer, and a rise in resistivity at this site
can be eliminated. Thus, the electrical characteristics of the
interconnection structure can be improved accordingly.
[0203] 37) In the multilayer interconnection structure described in
any one of 34) to 36), the metal film may be formed by a metal film
production apparatus, which disposes an etched member, formed from
a metal forming a high vapor pressure halide, in a chamber
accommodating the substrate in an interior thereof; etches the
etched member with a source gas plasma containing a halogen within
the chamber to form the precursor comprising the metallic component
and the source gas; and controls the temperatures of the etched
member and the substrate so as to be predetermined temperatures and
so as to provide a predetermined temperature difference between the
temperatures, thereby depositing the metallic component of the
precursor on the substrate to perform predetermined film
formation.
[0204] Thus, the interconnection structure described in 34) to 36)
can be formed easily and reliably.
[0205] The interconnection structure forming method according the
present invention, based on the aforementioned findings, is
characterized by the following:
[0206] 38) An interconnection structure forming method for forming
an interconnection by burying a metal film in a depression, such as
a trench or a hole, formed in a substrate, comprising: making a
film formation reaction and an etching reaction coexistent, the
film formation reaction being a reaction in which a precursor
comprising a metallic component and a source gas is adsorbed onto
the substrate, and then the metallic component is deposited to form
a metal film of a metal of the metallic component, and the etching
reaction being a reaction in which the metal film formed by the
film formation reaction is etched with a plasma of the source gas;
and exercising control such that the speed of the film formation
reaction is higher than the speed of the etching reaction, thereby
stacking the metal film in the depression sequentially, starting at
a bottom of the depression, to form a predetermined
interconnection.
[0207] Thus, the interconnection structure described in 34) can be
formed easily and reliably. In forming it, the relation between the
film formation speed and the etching speed is controlled, thereby
obviating the CMP step, the essential step in the damascene method
according to the earlier technologies. In this case, the
manufacturing cost and time can be dramatically reduced.
[0208] 39) A multilayer interconnection structure forming method
for forming an interconnection by burying a metal film in a
depression, such as a trench or a hole, in multiple layers formed
in a substrate for formation of the multilayer interconnection
structure, comprising: making a film formation reaction and an
etching reaction coexistent, the film formation reaction being a
reaction in which a precursor comprising a metallic component and a
source gas is adsorbed onto the substrate, and then the metallic
component is deposited to form a metal film of a metal of the
metallic component, and the etching reaction being a reaction in
which the metal film formed by the film formation reaction is
etched with a plasma of the source gas; and exercising control such
that the speed of the film formation reaction is higher than the
speed of the etching reaction, thereby stacking the metal film in
the depression sequentially, starting at a bottom of the
depression, to form the multilayer interconnection structure
integrally.
[0209] Thus, the effects described in 38) can be rendered further
remarkable, because the metal film is stacked and buried at a time
in the depressions continued to each other that are formed in the
multilayer substrate, whereby the desired interconnection structure
can be formed. Also, as the number of the layers increases in the
conventional multilayer structure, the number of the CMP step also
increases. With the present invention, by contrast, these steps can
all be eliminated.
[0210] 40) The multilayer interconnection structure forming method
described in 39) may further comprise forming a barrier metal layer
on a surface of the depression of the substrate prior to formation
of the metal film with electrical conductivity.
[0211] Thus, in addition to the effects of the feature described in
39), the multilayer interconnection structure can be formed as an
integrally continued single crystal-like crystal of the metal, and
the barrier metal layer necessarily formed between the
interconnection structures of the respective layers in the earlier
technologies can be removed. Consequently, the metals forming the
interconnection structures of the respective layers are not divided
by the barrier metal layer, and a rise in resistivity at this site
can be eliminated. Thus, the electrical characteristics of the
interconnection structure can be improved accordingly. Moreover,
the barrier metal layer, which was formed for each of the layers in
the earlier technologies, can be formed at a time. In this respect
as well, the multilayer interconnection structure can provide the
overall decrease in the working steps.
[0212] 41) In the interconnection structure forming method
described in any one of 38) to 40), the metal film may be formed by
a metal film production apparatus, which disposes an etched member,
formed from a metal forming a high vapor pressure halide, in a
chamber accommodating the substrate in an interior thereof; etches
the etched member with a source gas plasma containing a halogen
within the chamber to form the precursor comprising the metallic
component and the source gas; and controls the temperatures of the
etched member and the substrate so as to be predetermined
temperatures and so as to provide a predetermined temperature
difference between the temperatures, thereby depositing the
metallic component of the precursor on the substrate to perform
predetermined film formation.
[0213] Thus, the interconnection structure described in 34) to 37)
can be formed satisfactorily by controlling the amount of the
source gas plasma within the chamber.
[0214] The interconnection structure forming apparatus according to
the present invention, based on the aforementioned findings, is
characterized by the following feature:
[0215] 42) An interconnection structure forming apparatus for
forming a predetermined interconnection structure in a depression,
such as a trench or a hole, formed in a substrate, by disposing an
etched member, formed from a metal forming a high vapor pressure
halide, in a chamber accommodating the substrate in an interior
thereof; etching the etched member with a source gas plasma
containing a halogen within the chamber to form a precursor
comprising a metallic component and a source gas; and controlling
the temperatures of the etched member and the substrate so as to be
predetermined temperatures and so as to provide a predetermined
temperature difference between the temperatures, thereby depositing
the metallic component of the precursor on the substrate to perform
film formation,
[0216] the apparatus permitting the coexistence of a film formation
reaction for forming the film of the metal, and an etching reaction
for etching the metal film, formed by the film formation reaction,
with a plasma of the source gas; and having control means for
exercising control such that the speed of the film formation
reaction is higher than the speed of the etching reaction, thereby
stacking the metal film in the depression sequentially, starting at
a bottom of the depression, to form the predetermined
interconnection structure.
[0217] Thus, the interconnection structure described in 34) to 37)
can be formed satisfactorily by controlling the amount of the
source gas plasma within the chamber.
BRIEF DESCRIPTION OF THE DRAWINGS
[0218] The present invention will become more fully understood from
the detailed description given hereinbelow and the accompanying
drawings which are given by way of illustration only, and thus are
not limitative of the present invention, and wherein:
[0219] FIG. 1 is a schematic side view of a metal film production
apparatus according to a first embodiment of the present
invention;
[0220] FIG. 2 is a schematic side view of a metal film production
apparatus according to a second embodiment of the present
invention;
[0221] FIG. 3 is a view taken along the arrowed line I-I of FIG.
2;
[0222] FIG. 4 is a view taken along the arrowed line II-II of FIG.
3;
[0223] FIG. 5 is a schematic side view of a metal film production
apparatus according to a third embodiment of the present
invention;
[0224] FIG. 6 is a schematic side view of a metal film production
apparatus according to a fourth embodiment of the present
invention;
[0225] FIG. 7 is a schematic side view of a metal film production
apparatus according to a fifth embodiment of the present
invention;
[0226] FIG. 8 is a schematic side view of a metal film production
apparatus according to a sixth embodiment of the present
invention;
[0227] FIG. 9 is a schematic side view of a metal film production
apparatus according to a seventh embodiment of the present
invention;
[0228] FIG. 10 is a view taken along the arrowed line I-I of FIG.
9;
[0229] FIG. 11 is a schematic side view of a metal film production
apparatus according to an eighth embodiment of the present
invention;
[0230] FIG. 12 is a schematic side view of a metal film production
apparatus according to a ninth embodiment of the present
invention;
[0231] FIG. 13 is a schematic side view of an interconnection
structure forming apparatus according to a tenth embodiment of the
present invention;
[0232] FIGS. 14(a) to 14(c) are cross-sectional views showing the
process of formation of an interconnection structure formed by the
apparatus illustrated in FIG. 13, and FIG. 14(d) is a
cross-sectional view showing an interconnection structure formed by
an earlier technology;
[0233] FIG. 15 is a characteristic diagram showing the general
density characteristics of Cl*, relative to the depth direction of
a depression 203a of a substrate 203 in the apparatus illustrated
in FIG. 13, in depth position relationship with the depression 203a
of the substrate 203;
[0234] FIGS. 16(a) and 16(b) are cross-sectional views showing a
multilayer (two-layer in this embodiment) interconnection structure
formed by the apparatus of FIG. 13; and
[0235] FIGS. 17(a) to 17(f) are cross-sectional views showing an
interconnection structure in each of steps for forming a multilayer
interconnection structure by the double damascene method according
to the earlier technology.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0236] Preferred embodiments of the present invention will now be
described in detail with reference to the accompanying drawings,
which in no way limit the invention.
First Embodiment
[0237] FIG. 1 is a schematic side view of a metal film production
apparatus according to a first embodiment of the present invention.
As shown in FIG. 1, a support platform 2 is provided near the
bottom of a cylindrical chamber 1 made of, say, a ceramic (an
insulating material), and a substrate 3 is placed on the support
platform 2. Temperature control means 6 equipped with a heater 4
and refrigerant flow-through means 5 is provided in the support
platform 2 so that the support platform 2 is controlled to a
predetermined temperature (for example, a temperature at which the
substrate 3 is maintained at 100 to 200.degree. C.) by the
temperature control means 6.
[0238] An upper surface of the chamber 1 is an opening, which is
closed with a copper plate member 7, as an etched member made of a
metal. The interior of the chamber 1 closed with the copper plate
member 7 is maintained at a predetermined pressure by a vacuum
device 8.
[0239] A coiled film forming plasma antenna 9 is disposed around a
cylindrical portion of the chamber 1 beside the copper plate member
7 in such a manner as to be wound in the axial direction of the
chamber 1. A matching instrument 10 and a power source 11 are
connected to the film forming plasma antenna 9 to supply power.
Film forming plasma generation means is constituted by the film
forming plasma antenna 9, matching instrument 10 and power source
11.
[0240] Slit-shaped opening portions 23 are formed at positions
obliquely upward of the substrate 3 in the cylindrical portion of
the chamber 1, and one end of a tubular passage 24 is fixed to each
of the opening portions 23. A tubular excitation chamber 25 made of
an insulator is provided halfway through the passage 24, and a
coiled plasma antenna 26 is wound round the excitation chamber 25.
The plasma antenna 26 is connected to a matching instrument 27 and
a power source 28 to receive power. The opening portion 23, and the
associated passage 24 and excitation chamber 25 are at the same
height position of the chamber 1, and a combination of these
members is disposed at each of four locations (only two locations
are shown in the drawing) around the chamber 1. A flow controller
29 is connected to the other end of the passage 24, and a Cl.sub.2
gas for obtaining Cl* is supplied into the passage 24 via the flow
controller 29. The plasma antenna 26, matching instrument 27, power
source 28 and flow controller 29 constitute source gas radical
supply means.
[0241] In the source gas radical supply means, Cl* is formed by
shooting electromagnetic waves from the plasma antenna 26 into the
excitation chamber 25, while supplying a Cl.sub.2 gas into the
excitation chamber 25 via the flow controller 29. On this occasion,
plasma conditions are adjusted so that Cl* can be formed at a high
density within the excitation chamber 25. The so formed Cl* is
supplied into the chamber 1 through the passage 24 at the time of
film formation. This Cl* dissociates a Cl.sub.2 gas from CuCl(ad)
adsorbed onto the substrate 3 to promote the film formation
reaction. That is, the film formation reaction shown in the
equation (1) is promoted.
[0242] Nozzles 12 for supplying a source gas (a Cl.sub.2 gas
diluted with He to a chlorine concentration of <50%, preferably
about 10%), containing chlorine, to the interior of the chamber 1
are connected to the cylindrical portion of the chamber 1 above the
support platform 2. The nozzle 12 is open toward the copper plate
member 7, and the nozzle 12 is fed with the source gas via a flow
controller 13. The source gas is conveyed from beside the substrate
3 toward the copper plate member 7 along the wall surface within
the chamber at the time of film formation.
[0243] Nozzles 30 for supplying a rare gas, such as an Ar gas, into
the chamber 1 are connected to an upper site of the cylindrical
portion of the chamber 1. The rare gas, such as an Ar gas, has its
flow rate controlled by a flow controller 31, and is adapted to
increase the dissociation rate of the Cl.sub.2 gas in the film
formation reaction indicated by the equation (2), thereby promoting
the film formation reaction. Thus, a rare gas having a mass equal
to or larger than that of Ne, with the exception of the He gas
contained as a diluent gas in the source gas, can be used as a gas
for increasing the dissociation rate of the Cl.sub.2 gas to promote
the film formation reaction. However, in consideration of the
function of the rare gas, so to speak, as a catalyst for increasing
the dissociation rate, an Ar gas or a Kr gas is preferred, and an
Ar gas is optimal in terms of the cost.
[0244] A mode of film formation in the foregoing metal film
production apparatus is as described below. For film formation, the
film forming plasma antenna 9, and the plasma antenna 26 are
energized.
[0245] While the source gas is supplied through the nozzles 12 into
the chamber 1, electromagnetic waves are shot from the film forming
plasma antenna 9 into the chamber 1, whereby the Cl.sub.2 gas is
ionized to generate a Cl.sub.2 gas plasma (source gas plasma) 14.
The Cl.sub.2 gas plasma 14 is formed in spaces adjacent to the film
forming plasma antenna 9 in the interior of the chamber 1, namely,
in spaces beside the copper plate member 7 (upper portion) within
the chamber 1.
[0246] The Cl.sub.2 gas plasma 14 causes an etching reaction to the
copper plate member 7, forming a precursor (Cu.sub.xCl.sub.y) 15.
At this time, the copper plate member 7 is maintained by the
Cl.sub.2 gas plasma 14 at a predetermined temperature (e.g., 200 to
400.degree. C.) which is higher than the temperature of the
substrate 3.
[0247] The precursor (Cu.sub.xCl.sub.y) 15 formed within the
chamber 1 is transported to the substrate 3 controlled to a lower
temperature than the temperature of the copper plate member 7. The
precursor (Cu.sub.xCl.sub.y) 15 transported to and adsorbed onto
the substrate 3 deposits Cu on the substrate 3 in accordance with
the reactions of the aforementioned equations (1) and (2)
representing the film formation reaction. As a result, a thin Cu
film 16 is formed on the surface of the substrate 3.
[0248] At this time, Cl* is formed with a high efficiency in the
excitation chamber 25, and supplied into the chamber 1 for
replenishment to dissociate Cl in the equation (1), promoting the
film formation reaction. On the other hand, the Ar gas is supplied
into the chamber 1 through the nozzles 30 to dissociate the
Cl.sub.2 gas in the equation (2), promoting the film formation
reaction.
[0249] Since the metal film production apparatus constructed as
above uses the Cl.sub.2 gas plasma (source gas plasma) 14, the
reaction efficiency is markedly increased, and the speed of film
formation is fast. Since the Cl.sub.2 gas is used as the source
gas, moreover, the cost can be markedly decreased. Furthermore, the
substrate 3 is controlled to a lower temperature than the
temperature of the copper plate member 7 by use of the temperature
control means 6. Thus, the amounts of impurities, such as chlorine,
remaining in the thin Cu film 16 can be decreased, so that a high
quality thin Cu film 16 can be produced.
Second Embodiment
[0250] FIG. 2 is a schematic side view of a metal film production
apparatus according to a second embodiment of the present
invention. As shown in FIG. 2, the metal film production apparatus
according to the present embodiment is different in the
construction of the plasma antenna and in the constructions of the
associated portions, but is of the same construction in many
portions, as compared with the first embodiment shown in FIG. 1.
Thus, the same portions as in FIG. 1 are assigned the same
numerals, and duplicate explanations are omitted.
[0251] As shown in FIG. 2, a chamber 41 is a cylindrical member
made of a metal (for example, aluminum). An upper surface of the
chamber 41 is an opening, which is closed with a disk-shaped
ceiling board 47, an insulating member (for example, made of a
ceramic). An etched member 58 made of copper, which comprises a
ring portion 59 and protrusions 60, is disposed at a position
opposed to a substrate 3 within the chamber 41, and is provided so
as to be divided by the protrusions 60 into a plurality of portions
in the circumferential direction. The protrusions 60, the
respective divisional portions, protrude from the inner peripheral
surface of the chamber 41 toward the center of the chamber 41.
Details of the etched member 58 will be described later on based on
FIG. 3. A film forming plasma antenna 49 is in a spiral form and is
disposed outwardly of the ceiling board 47. The plasma antenna 49
receives an electric current supplied from a power source 51 via a
matching instrument 50 to form an electric field. By the action of
the electric field, a Cl.sub.2 gas, a source gas supplied into the
chamber 41, is converted into a plasma in a space beside the etched
member 58 (upper portion) within the chamber 41 to form a Cl.sub.2
gas plasma 14. That is, the film forming plasma antenna 49,
matching instrument 50 and power source 51 constitute film forming
plasma generation means.
[0252] As illustrated in detail in FIG. 3, a plurality of (12 in
the illustrated embodiment) the protrusions 60, which extend close
to the center in the diametrical direction of the chamber 41 (see
FIG. 2) and have the same width, are provided in the
circumferential direction on the inner periphery of the ring
portion 59 of the etched member 58. The protrusions 60 are
integrally or removably attached to the ring portion 59. Notches
(spaces) 67 formed between the protrusions 60 are present between
the ceiling board 47 (see FIG. 2) and the interior of the chamber
41. The ring portion 59 is earthed, and the plural protrusions 60
are electrically connected together by the ring portion 59, and
maintained at the same potential.
[0253] At the time of film formation in the above-described metal
film production apparatus, the film forming plasma antenna 49 and
the plasma antenna 26 are energized. As a result, electromagnetic
waves are shot from the film forming plasma antenna 49 into the
chamber 41. Consequently, the Cl.sub.2 gas is ionized to generate a
Cl.sub.2 gas plasma (source gas plasma) 14, so that a thin Cu film
16 is formed in the same mode as in the aforementioned first
embodiment.
[0254] However, the mode of formation of a film forming plasma in
the present embodiment is slightly different from that in the metal
film production apparatus shown in FIG. 1. This mode will be
explained based on FIG. 4. As shown in FIG. 4, when the Cl.sub.2
gas plasma 14 (see FIG. 2) is generated below the etched member 58,
the direction A of an electric current in the film forming plasma
antenna 49 crosses the protrusions 60. As a result, an induced
current B flowing in the direction shown in FIG. 4 occurs on the
surface of the protrusion 60 opposed to the film forming plasma
antenna 49. Since the notches (spaces) 67 are present in the etched
member 58, the induced current B flows on the lower surface of each
protrusion 60 in the same direction a as the direction A of the
electric current in the film forming plasma antenna 49. When the
etched member 58 is viewed from the substrate 3, therefore, there
is no electric current in a direction in which the electric current
in the film forming plasma antenna 49 is effectively canceled out,
even when the protrusions 60, electric conductors, are present
below the film forming plasma antenna 49, i.e., on the side of the
substrate 3. Thus, an alternating electric field by the film
forming plasma antenna 49 can be formed below the protrusions 60.
Furthermore, the ring portion 59 is earthed, and the protrusions 60
are maintained at the same potential. Thus, even though the etched
member 58, an electric conductor, exists, electromagnetic waves are
reliably thrown from the film forming plasma antenna 49 into the
chamber 1. Consequently, the Cl.sub.2 gas plasma 14 can be stably
generated below the etched member 58.
[0255] In the present embodiment as well, Cl* is formed with a high
efficiency in the excitation chamber 25, and supplied into the
chamber 41 for replenishment to dissociate Cl in the equation (1),
promoting the film formation reaction. On the other hand, the Ar
gas is supplied into the chamber 41 through the nozzles 30 to
dissociate the Cl.sub.2 gas in the equation (2), promoting the film
formation reaction.
[0256] In the present embodiment, it is also possible to eliminate
instability of the plasma due to a difference in potential by
controlling the supply of the source gas, without connecting the
protrusions 60 to the ring portion 59.
Third Embodiment
[0257] As shown in FIG. 5, the present embodiment is an embodiment
in which the film forming plasma antenna 9 in the first embodiment
of FIG. 1 has been removed, and instead the copper plate member 7,
the etched member, concurrently performs the function of a film
forming plasma antenna. Thus, a high frequency power from the power
source 11 is supplied to the copper plate member 7 via the matching
instrument 10, and the support platform 2, an electrically
conductive member, is grounded. That is, the copper plate member 7
and the support platform 2 serve as both electrodes to generate a
Cl.sub.2 gas plasma 14 therebetween within the chamber 1.
[0258] The other constructions in the metal film production
apparatus according to the present embodiment are the same as in
FIG. 1. Thus, the same portions are assigned the same numerals, and
duplicate explanations are omitted.
[0259] In the present embodiment, while the source gas is supplied
through the nozzles 12 into the chamber 1, electromagnetic waves
are shot from the copper plate member 7 into the chamber 1, whereby
the Cl.sub.2 gas is ionized to generate a Cl.sub.2 gas plasma
(source gas plasma) 14. The Cl.sub.2 gas plasma 14 causes an
etching reaction to the copper plate member 7, forming a precursor
(Cu.sub.xCl.sub.y) 15. At this time, the copper plate member 7 is
maintained by temperature control means 6 at a predetermined
temperature (e.g., 200 to 400.degree. C.) which is higher than the
temperature of the substrate 3. Thus, a thin Cu film 16 is formed
on the surface of the substrate 3 in exactly the same mode as in
the first embodiment.
[0260] In the present embodiment as well, Cl* is formed with a high
efficiency in the excitation chamber 25, and supplied for
replenishment into the chamber 1 to dissociate Cl in the equation
(1), promoting the film formation reaction. On the other hand, the
Ar gas is supplied into the chamber 1 through the nozzles 30 to
dissociate the Cl.sub.2 gas in the equation (2), promoting the film
formation reaction.
Fourth Embodiment
[0261] As shown in FIG. 6, the present embodiment can be positioned
as a modification of the third embodiment shown in FIG. 5. In this
modified embodiment, a copper plate member 72, an etched member, is
disposed at a position which is not a position opposed to the
substrate 3 within a chamber 71. At the same time, a shielding
plate 73 of a ground potential, which serve as a counter electrode,
is disposed. A high frequency power from the power source 11 is
supplied to the copper plate member 72 via the matching instrument
10. Also, a source gas is supplied between the copper plate member
72 and the shielding plate 73 within the chamber 71 through the
nozzles 12. Thus, a plasma of the source gas is generated. Many
holes 73a are formed in the shielding plate 73, and a precursor 15
formed between the copper plate member 72 and the shielding plate
73 passes through the holes 73a, arriving at a space above the
substrate 3 within the chamber 71. The copper plate member 72 is a
hollow member in the shape of a truncated cone, and the shielding
plate 73 is composed of a hollow, truncated conical member similar
in shape to the copper plate member 72. Thus, the surfaces of the
copper plate member 72 and the shielding plate 73 opposed to each
other are parallel, and inclined to the substrate 3. Because of
this arrangement, particles peeled from the etched copper plate
member 72 and falling are prevented from adhering onto the
substrate 3, and the predetermined precursor 15 can be supplied to
the space above the substrate 3. This is because the particles are
blocked by the shielding plate 73 and have a low possibility to
arrive at the space above the substrate 3, while the precursor 15
can easily pass through the holes 73a.
[0262] The other constructions in the metal film production
apparatus according to the present embodiment are the same as in
FIG. 5. Thus, the same portions are assigned the same numerals, and
duplicate explanations are omitted.
[0263] In the present embodiment, while the source gas is supplied
through the nozzles 12 into the chamber 71, electromagnetic waves
are shot from the copper plate member 72 into the chamber 71,
whereby the Cl.sub.2 gas is ionized to generate a Cl.sub.2 gas
plasma (source gas plasma) 14. The Cl.sub.2 gas plasma 14 causes an
etching reaction to the copper plate member 72, forming a precursor
(Cu.sub.xCl.sub.y) 15. The precursor (Cu.sub.xCl.sub.y) 15 arrives
at the space above the substrate 3 within the chamber 71 through
the holes 73a of the shielding plate 73. At this time, the copper
plate member 72 is maintained by temperature control means 6 at a
temperature (e.g., 200 to 400.degree. C.) which is higher than the
temperature of the substrate 3. Thus, a thin Cu film 16 is formed
on the surface of the substrate 3 in exactly the same mode as in
the first embodiment.
[0264] The precursor (Cu.sub.xCl.sub.y) 15 easily passes through
the holes 73a, but only a tiny portion of Cl* formed between the
copper plate member 72 and the shielding plate 73 can pass through
the holes 73a and arrive at the space above the substrate 3. The
reason is that Cl* colliding with the shielding plate 73 combines
with another Cl* colliding with the shielding plate 73 to become a
Cl.sub.2 gas. That is, a reaction expressed by
Cl*+Cl*.fwdarw.Cl.sub.2 occurs, so that Cl* vanishes.
[0265] In the present embodiment as well, Cl* is formed with a high
efficiency in the excitation chamber 25, and supplied for
replenishment into the chamber 71 to dissociate Cl in the equation
(1), promoting the film formation reaction. In the present
embodiment, most of Cl* formed in the space between the copper
plate member 72 and the shielding plate 73 vanishes, as stated
above. In this embodiment at such a disadvantage, the supply of Cl*
for replenishment is more meaningful, and its contribution to the
promotion of the film formation reaction is particularly
remarkable.
[0266] In the present embodiment as well, the Ar gas is supplied
into the chamber 71 through the nozzles 30 to dissociate the
Cl.sub.2 gas in the equation (2), promoting the film formation
reaction.
Fifth Embodiment
[0267] In the respective embodiments, the source gas is supplied
into the chamber 1 or the like, and converted into a plasma.
However, a source gas plasma may be directly supplied into the
chamber. A metal film production apparatus having such a feature
will be described in detail with reference to FIG. 7. As shown in
FIG. 7, the metal film production apparatus according to the
present embodiment is greatly different from the metal film
production apparatus according to the first embodiment, etc. shown
in FIG. 1, etc. in that it does not have the film forming plasma
antenna 9, etc. However, the metal film production apparatus
according to the present embodiment has many constituent elements
in common with the metal film production apparatus according to the
first embodiment, etc. Thus, the same portions as in FIG. 1, etc.
are assigned the same numerals, and duplicate explanations are
omitted.
[0268] As shown in FIG. 7, an upper surface of a cylindrical
chamber 81 made of, for example, a ceramic (an insulating material)
is an opening, and the opening is closed with a ceiling board 100,
for example, made of a ceramic (an insulating material). An etched
member 88 made of a metal (copper, Cu) is provided on a lower
surface of the ceiling board 100, and the etched member 88 is of a
pyramidal shape. Slit-shaped opening portions 89 are formed at four
locations (only two locations are shown in the drawing) in the
periphery of an upper part of the cylindrical portion of the
chamber 81, and one end of a tubular passage 90 is fixed to each of
the opening portions 89. A tubular excitation chamber 95 made of an
insulator is provided halfway through the passage 90, and a coiled
plasma antenna 91 is provided around the excitation chamber 95. The
plasma antenna 91 is connected to a matching instrument 92 and a
power source 93 to receive power. The plasma antenna 91, the
matching instrument 92 and the power source 93 constitute plasma
generation means.
[0269] A flow controller 94 is connected to the other end of the
passage 90, and a source gas containing chlorine as a halogen (a
Cl.sub.2 gas diluted with He to a chlorine concentration of
.ltoreq.50%, preferably about 10%) is supplied into the passage 90
via the flow controller 94. By shooting electromagnetic waves from
the plasma antenna 91 into the excitation chamber 95, the Cl.sub.2
gas is ionized to generate a Cl.sub.2 gas plasma (source gas
plasma) 96. This means the construction of excitation means by
which the source gas containing chlorine is excited in the
excitation chamber 95 isolated from the chamber 81. Because of the
generation of the Cl.sub.2 gas plasma 96, excited chlorine is fed
toward the etched member 88 (upper portion) within the chamber 81
through the opening portions 89, whereupon the etched member 88 is
etched with excited chlorine.
[0270] At the time of film formation in the above-described metal
film production apparatus, the Cl.sub.2 gas plasma 96 is generated
in the excitation chamber 95, and the Cl.sub.2 gas plasma 96 is
introduced through the opening portions 89 into the chamber 81 in
which the temperature conditions for the etched member 88 and the
substrate 3 have been adjusted as predetermined. Thus, the etched
member 88 is etched in the same manner as for the metal film
production apparatus shown in FIG. 1, etc., whereby a thin Cu film
16 can be formed on the substrate 3.
[0271] In the present embodiment as well, Cl* is formed with a high
efficiency in the excitation chamber 25, and supplied for
replenishment into the chamber 81 to dissociate Cl in the equation
(1), promoting the film formation reaction. On the other hand, the
Ar gas is supplied into the chamber 81 through the nozzles 30 to
dissociate the Cl.sub.2 gas in the equation (2), promoting the film
formation reaction.
[0272] Next, an explanation will be offered for a case in which the
etched member is made of a composite metal comprising, for example,
In and Cu, or a composite metal such as CuInSe.sub.2, CdS, or ZnSe,
and a thin film of the composite metal is produced.
[0273] Not only in the above-described production of the thin Cu
film, but also in the production of a thin film of the composite
metal (e.g., a thin InCu film), the following reactions are assumed
to occur:
Dissociation reaction of plasma: Cl.sub.2.fwdarw.2Cl*
Etching reaction: Cu+Cl*.fwdarw.CuCl(g)
In+Cl*.fwdarw.InCl(g)
Adsorption to substrate: CuCl(g).fwdarw.CuCl(ad)
InCl(g).fwdarw.InCl(ad)
Film formation reaction: CuCl(ad)+Cl*.fwdarw.Cu+Cl.sub.2.Arrow-up
bold. (3)
InCl(ad)+Cl*In+Cl.sub.2.Arrow-up bold. (4)
[0274] Here, Cl* represents radicals of Cl, (g) represents a
gaseous state, and (ad) represents an adsorbed state.
[0275] Another film formation reaction as indicated below is
expected to be similarly taking place in correspondence with the
equation (2) predicted for the production of the thin Cu film:
2CuCl(ad).fwdarw.2Cu+Cl.sub.2 (5)
2InCl(ad).fwdarw.2In+Cl.sub.2 (6)
[0276] Besides, in the case of the composite metal, such as
CuInSe.sub.2, CdS, or ZnSe, which contains a nonmetallic element,
the nonmetallic element in the composite metal is assumed to be
chlorinated with Cl*. That is, upon etching with Cl*, the
nonmetallic element, such as Se or S, forms a chloride and becomes
a precursor. The precursor is transported onto the substrate to
turn into a constituent element of the thin film.
Sixth Embodiment
[0277] FIG. 8 is a schematic side view of a metal film production
apparatus according to a sixth embodiment of the present invention.
As shown in FIG. 8, a support platform 2 is provided near the
bottom of a cylindrical chamber 1 made of, say, a ceramic (an
insulating material), and a substrate 3 is placed on the support
platform 2. Temperature control means 6 equipped with a heater 4
and refrigerant flow-through means 5 is provided in the support
platform 2 so that the support platform 2 is controlled to a
predetermined temperature (for example, a temperature at which the
substrate 3 is maintained at 100 to 200.degree. C.) by the
temperature control means 6.
[0278] An upper surface of the chamber 1 is an opening, which is
closed with a composite metal plate member 101, as an etched
member, made of a composite metal consisting of In and Cu. The
composite metal plate member 101 is prepared by mixing In and Cu
uniformly at a ratio of 1:1, and then press molding the mixture
into a plate. According to this method of preparation, the
composite metal plate member 101 can be easily produced.
Alternatively, the composite metal plate member 101 may be formed
as a split type in which its right half is formed from In, and its
left half is formed from Cu. According to this method of
preparation, it is easy to control the composition of the thin film
formed. The interior of the chamber 1 closed with the composite
metal plate member 101 is maintained at a predetermined pressure by
a vacuum device 8.
[0279] A coiled film forming plasma antenna 9 is disposed around a
cylindrical portion of the chamber 1 beside the composite metal
plate member 101 in such a manner as to be wound in the axial
direction of the chamber 1. A matching instrument 10 and a power
source 11 are connected to the film forming plasma antenna 9 to
supply power. Film forming plasma generation means is constituted
by the film forming plasma antenna 9, matching instrument 10 and
power source 11.
[0280] Slit-shaped opening portions 23 are formed at positions
obliquely upward of the substrate 3 in the cylindrical portion of
the chamber 1, and one end of a tubular passage 24 is fixed to each
of the opening portions 23. A tubular excitation chamber 25 made of
an insulator is provided halfway through the passage 24, and a
coiled plasma antenna 26 is wound round the excitation chamber 25.
The plasma antenna 26 is connected to a matching instrument 27 and
a power source 28 to receive power. The opening portion 23, and the
associated passage 24 and excitation chamber 25 are at the same
height position of the chamber 1, and a combination of these
members is disposed at each of four locations (only two locations
are shown in the drawing) around the chamber 1. A flow controller
29 is connected to the other end of the passage 24, and a Cl.sub.2
gas for obtaining Cl* is supplied into the passage 24 via the flow
controller 29. The plasma antenna 26, matching instrument 27, power
source 28 and flow controller 29 constitute source gas radical
supply means.
[0281] In the source gas radical supply means, Cl* is formed by
shooting electromagnetic waves from the plasma antenna 26 into the
excitation chamber 25, while supplying a Cl.sub.2 gas into the
excitation chamber 25 via the flow controller 29. On this occasion,
plasma conditions are adjusted within the excitation chamber 25 so
that Cl* can be formed at a high density within it. The so formed
Cl* is supplied into the chamber 1 through the passage 24 at the
time of film formation. This Cl* dissociates a Cl.sub.2 gas from
metal chlorides (CuCl, InCl) adsorbed onto the substrate 3 to
promote the film formation reaction. That is, the film formation
reaction shown in the equations (3) and (4) is promoted.
[0282] Nozzles 12 for supplying a source gas containing chlorine (a
Cl.sub.2 gas diluted with He to a chlorine concentration of
.ltoreq.50%, preferably about 10%) to the interior of the chamber 1
are connected to the cylindrical portion of the chamber 1 above the
support platform 2. The nozzle 12 is open toward the composite
metal plate member 101, and the nozzle 12 is fed with the source
gas via a flow controller 13. The source gas is conveyed from
beside the substrate 3 toward the composite metal plate member 101
along the wall surface within the chamber 1 at the time of film
formation.
[0283] Nozzles 30 for supplying a rare gas, such as an Ar gas, into
the chamber 1 are connected to an upper site of the cylindrical
portion of the chamber 1. The rare gas, such as an Ar gas, has its
flow rate controlled by a flow controller 31, and is adapted to
increase the dissociation rate of the C.sub.2 gas in the film
formation reaction indicated by the equations (5) and (6), thereby
promoting the film formation reaction. Thus, a rare gas having a
mass equal to or larger than that of Ne, with the exception of the
He gas contained as a diluent gas in the source gas, can be used as
a gas for increasing the dissociation rate of the Cl.sub.2 gas to
promote the film formation reaction. However, in consideration of
the function of the rare gas, so to speak, as a catalyst for
increasing the dissociation rate, an Ar gas or a Kr gas is
preferred, and an Ar gas is optimal in terms of the cost.
[0284] A mode of film formation in the foregoing metal film
production apparatus is as described below. During film formation,
the film forming plasma antenna 9, and the plasma antenna 26 are
energized.
[0285] While the source gas is supplied from the nozzles 12 into
the chamber 1, electromagnetic waves are shot from the film forming
plasma antenna 9 into the chamber 1, whereby the Cl.sub.2 gas is
ionized to generate a Cl.sub.2 gas plasma (source gas plasma) 14.
The Cl.sub.2 gas plasma 14 is formed in spaces adjacent to the film
forming plasma antenna 9 in the interior of the chamber 1, namely,
in spaces beside the composite metal plate member 101 (upper
portion) within the chamber 1.
[0286] The Cl.sub.2 gas plasma 14 causes an etching reaction to the
composite metal plate member 101, forming a precursor 102. At this
time, the composite metal plate member 101 is maintained by the
Cl.sub.2 gas plasma 14 at a predetermined temperature (e.g., 200 to
400.degree. C.) which is higher than the temperature of the
substrate 3. The precursor 102 consists of Cu.sub.x1Cl.sub.y1 and
In.sub.x2Cl.sub.y2.
[0287] The precursor 102 formed within the chamber 1 is transported
to the substrate 3 controlled to a lower temperature than the
temperature of the composite metal plate member 101. The precursor
102 transported to and adsorbed onto the substrate 3 deposits Cu
and In on the substrate 3 in accordance with the reactions of the
aforementioned equations (3) to (6) representing the film formation
reaction. As a result, a thin composite metal film 103 composed of
Cu and In is formed on the surface of the substrate 3.
[0288] At this time, Cl* is formed with a high efficiency in the
excitation chamber 25, and supplied for replenishment into the
chamber 1 to dissociate Cl in the equations (3) and (4), promoting
the film formation reaction. On the other hand, the Ar gas is
supplied into the chamber 1 through the nozzles 30 to dissociate
the Cl.sub.2 gas in the equations (5) and (6), promoting the film
formation reaction.
[0289] Since the metal film production apparatus constructed as
above uses the Cl.sub.2 gas plasma (source gas plasma) 14, the
reaction efficiency is markedly increased, and the speed of film
formation is fast. Since the Cl.sub.2 gas is used as the source
gas, moreover, the cost can be markedly decreased. Furthermore, the
substrate 3 is controlled to a lower temperature than the
temperature of the composite metal plate member 101 by use of the
temperature control means 6. Thus, the amounts of impurities, such
as chlorine, remaining in the thin composite metal film 103 can be
decreased, so that a high quality thin composite metal film 103 can
be produced.
[0290] With the metal film production apparatus according to the
present embodiment, moreover, the composite metal plate member 101
may be produced from a composite metal such as CuInSe.sub.2, CdS or
ZnSe. Thus, a thin film of any of these composite metals can be
prepared.
Seventh Embodiment
[0291] FIG. 9 is a schematic side view of a metal film production
apparatus according to a seventh embodiment of the present
invention. As shown in FIG. 9, the metal film production apparatus
according to the present embodiment is different in the
construction of the plasma antenna and in the constructions of the
associated portions, but is of the same construction in many
portions, as compared with the sixth embodiment shown in FIG. 8.
Thus, the same portions as in FIG. 8 are assigned the same
numerals, and duplicate explanations are omitted.
[0292] As shown in FIG. 9, a chamber 41 is a cylindrical member
made of a metal (for example, aluminum). An upper surface of the
chamber 41 is an opening, which is closed with a disk-shaped
ceiling board 47, an insulating member (for example, made of a
ceramic). A composite metal member 105, which comprises a ring
portion 106 and protrusions 107, is disposed at a position opposed
to a substrate 3 within the chamber 41, and is provided so as to be
divided by the protrusions 107 into a plurality of portions in the
circumferential direction. The protrusions 107, the respective
divisional portions, protrude from the inner peripheral surface of
the chamber 41 toward the center of the chamber 41. Details of the
composite metal member 105 will be described later on based on FIG.
10. A film forming plasma antenna 49 is in a spiral form and is
disposed outwardly of the ceiling board 47. The film forming plasma
antenna 49 receives an electric current supplied from a power
source 51 via a matching instrument 50 to form an electric field.
By the action of the electric field, a Cl.sub.2 gas, a source gas
supplied into the chamber 41, is converted into a plasma in a space
beside the composite metal member 105 (upper portion) within the
chamber 41 to form a Cl.sub.2 gas plasma 14. That is, the film
forming plasma antenna 49, matching instrument 50 and power source
51 constitute film forming plasma generation means.
[0293] As illustrated in detail in FIG. 10, a plurality of (12 in
the illustrated embodiment) protrusions 107a to 1071, which extend
close to the center in the diametrical direction of the chamber 41
(see FIG. 9) and have the same width, are provided in the
circumferential direction on the inner periphery of the ring
portion 106 of the composite metal member 105. The protrusions 107a
to 1071 are integrally or removably attached to the ring portion
106. The protrusions 107a, 107e and 107i are made of Cu (copper),
the protrusions 107c, 107g and 107k are made of In (indium), and
the protrusions 107b, 107d, 107f, 107h, 107j and 1071 are made of
Se (selenium). That is, the respective protrusions are formed in
conformity with the proportions of the elements in the composition
of CuInSe.sub.2. Notches (spaces) 67 formed between the protrusions
107a to 1071 are present between the ceiling board 47 (see FIG. 9)
and the interior of the chamber 41. The ring portion 106 is
earthed, and the plural protrusions 107a to 1071 are electrically
connected together by the ring portion 106, and maintained at the
same potential.
[0294] At the time of film formation in the above-described metal
film production apparatus, the film forming plasma antenna 49 and
the plasma antenna 26 are energized. As a result, electromagnetic
waves are shot from the film forming plasma antenna 49 into the
chamber 41. Consequently, the Cl.sub.2 gas is ionized to generate a
Cl.sub.2 gas plasma (source gas plasma) 14, so that a thin
composite metal film 103 is formed in the same mode as in the
aforementioned sixth embodiment.
[0295] The thin composite metal film 103 in the present embodiment
is a thin film of a composite metal comprising CuInSe.sub.2
containing a nonmetallic element, but is assumed to have been
formed by the same mechanism of action as for the formation of the
composite metal film consisting only of metallic elements that is
shown in the aforementioned sixth embodiment. That is, not only the
metallic elements Cu and In, but also the nonmetallic element Se
may also be chlorinated with Cl* to form a chloride as a precursor.
The precursor may be transported to the substrate, forming a thin
film.
[0296] In the present embodiment as well, Cl* is formed with a high
efficiency in the excitation chamber 25, and supplied for
replenishment into the chamber 41 to dissociate Cl in the equations
(3) and (4), promoting the film formation reaction. Moreover, the
chlorinated Se adsorbed onto the substrate is also assumed to
dissociate Cl, promoting the film formation reaction. On the other
hand, the Ar gas is supplied into the chamber 41 through the
nozzles 30 to dissociate the Cl.sub.2 gas in the equations (5) and
(6), promoting the film formation reaction.
[0297] With the metal film production apparatus according to the
present embodiment, moreover, the composite metal member 105 may be
produced from a composite metal such as CdS, ZnSe or InCu. Thus, a
thin film of any of these composite metals can be prepared.
Eighth Embodiment
[0298] As shown in FIG. 11, the present embodiment is an embodiment
in which the film forming plasma antenna 9 in the sixth embodiment
shown in FIG. 8 has been removed, and instead the composite metal
plate member 101, the etched member, concurrently performs the
function of a film forming plasma antenna. Thus, a high frequency
power from the power source 11 is supplied to the composite metal
plate member 101 via the matching instrument 10, and the support
platform 2, an electrically conductive member, is grounded. That
is, the composite metal plate member 101 and the support platform 2
serve as both electrodes to generate a Cl.sub.2 gas plasma 14
therebetween within the chamber 1. The composite metal plate member
101 is formed from a composite metal consisting of In and Cu.
[0299] The other constructions in the metal film production
apparatus according to the present embodiment are the same as in
FIG. 8. Thus, the same portions are assigned the same numerals, and
duplicate explanations are omitted.
[0300] In the present embodiment, while the source gas is supplied
through the nozzles 12 into the chamber 1, electromagnetic waves
are shot from the composite metal plate member 101 into the chamber
1, whereby the Cl.sub.2 gas is ionized to generate a Cl.sub.2 gas
plasma (source gas plasma) 14. The Cl.sub.2 gas plasma 14 causes an
etching reaction to the composite metal plate member 101, forming a
precursor 102. The precursor 102 comprises Cu.sub.x1Cl.sub.y1 and
In.sub.x2Cl.sub.y2. At this time, the composite metal plate member
101 is maintained by temperature control means 6 at a temperature
(e.g., 200 to 400.degree. C.) which is higher than the temperature
of the substrate 3. Thus, a thin composite metal film 103
comprising Cu and In is formed on the surface of the substrate 3 in
exactly the same mode as in the sixth embodiment.
[0301] In the present embodiment as well, Cl* is formed with a high
efficiency in the excitation chamber 25, and supplied for
replenishment into the chamber 1 to dissociate Cl in the equations
(3) and (4), promoting the film formation reaction. On the other
hand, the Ar gas is supplied into the chamber 1 through the nozzles
30 to dissociate the Cl.sub.2 gas in the equations (5) and (6),
promoting the film formation reaction.
[0302] With the metal film production apparatus according to the
present embodiment, moreover, the composite metal plate member 101
may be produced from a composite metal such as CuInSe.sub.2, CdS or
ZnSe. Thus, a thin film of any of these composite metals can be
prepared.
Ninth Embodiment
[0303] In the above sixth to eighth embodiments, the source gas is
supplied into the chamber 1 or the like, and converted into a
plasma. However, a source gas plasma may be directly supplied into
the chamber. A metal film production apparatus having such a
feature will be described in detail with reference to FIG. 12. As
shown in FIG. 12, the metal film production apparatus according to
the present embodiment is greatly different from the metal film
production apparatus according to the sixth embodiment, etc. shown
in FIG. 8, etc. in that it does not have the film forming plasma
antenna 9, etc. However, the metal film production apparatus
according to the present embodiment has many constituent portions
in common with the metal film production apparatus according to the
sixth embodiment, etc. Thus, the same portions as in FIG. 8, etc.
are assigned the same numerals, and duplicate explanations are
omitted.
[0304] As shown in FIG. 12, an upper surface of a cylindrical
chamber 81 made of, for example, a ceramic (an insulating material)
is an opening, and the opening is closed with a ceiling board 100,
for example, made of a ceramic (an insulating material). A
composite metal plate member 101 is provided on a lower surface of
the ceiling board 100, and the composite metal plate member 101 is
of a pyramidal shape. The composite metal plate member 101 is
formed from a composite metal composed of In and Cu.
[0305] Slit-shaped opening portions 89 are formed at four locations
(only two locations are shown in the drawing) in the periphery of
an upper part of the cylindrical portion of the chamber 81, and one
end of a tubular passage 90 is fixed to each of the opening
portions 89. A tubular excitation chamber 95 made of an insulator
is provided halfway through the passage 90, and a coiled plasma
antenna 91 is provided around the excitation chamber 95. The plasma
antenna 91 is connected to a matching instrument 92 and a power
source 93 to receive power. The plasma antenna 91, the matching
instrument 92 and the power source 93 constitute plasma generation
means.
[0306] A flow controller 94 is connected to the other end of the
passage 90, and a source gas containing chlorine as a halogen (a
Cl.sub.2 gas diluted with He to a chlorine concentration of
.ltoreq.50%, preferably about 10%) is supplied into the passage 90
via the flow controller 94. By shooting electromagnetic waves from
the plasma antenna 91 into the excitation chamber 95, the Cl.sub.2
gas is ionized to generate a Cl.sub.2 gas plasma (source gas
plasma) 96. This means the construction of excitation means by
which the source gas containing chlorine is excited in the
excitation chamber 95 isolated from the chamber 81. Because of the
generation of the Cl.sub.2 gas plasma 96, excited chlorine is fed
toward the composite metal plate member 101 (upper portion) within
the chamber 81 through the opening portions 89, whereupon the
composite metal plate member 101 is etched with excited
chlorine.
[0307] At the time of film formation in the above-described metal
film production apparatus, the Cl.sub.2 gas plasma 96 is generated
in the excitation chamber 95, and the Cl.sub.2 gas plasma 96 is
introduced through the opening portions 89 into the chamber 81 in
which the temperature conditions for the composite metal plate
member 101 and the substrate 3 have been adjusted as predetermined.
Thus, the composite metal plate member 101 is etched in the same
manner as for the metal film production apparatus shown in FIG. 8,
etc., whereby a thin composite metal film 103 consisting of Cu and
In can be formed on the surface of the substrate 3.
[0308] In the present embodiment as well, Cl* is formed with a high
efficiency in the excitation chamber 25, and supplied for
replenishment into the chamber 81 to dissociate Cl in the equations
(3) and (4), promoting the film formation reaction. On the other
hand, the Ar gas is supplied into the chamber 81 through the
nozzles 30 to dissociate the Cl.sub.2 gas in the equations (5) and
(6), promoting the film formation reaction.
[0309] With the metal film production apparatus according to the
present embodiment, moreover, the composite metal plate member 101
may be produced from a composite metal such as CuInSe.sub.2, CdS or
ZnSe. Thus, a thin film of any of these composite metals can be
prepared.
[0310] The source gas radical supply means in each of the
embodiments is the coiled plasma antenna 26 wound round the tubular
excitation chamber 25, Cl* is formed within the excitation chamber
25, and the Cl* is supplied for replenishment into the chamber 1 or
the like. However, the source gas radical supply means is not
limited to this construction. It suffices that radicals (e.g. Cl*)
of the source gas (e.g. Cl.sub.2 gas) can be separately formed, and
supplied for replenishment into the chamber. For example, the
source gas radical supply means of the following constructions can
be conceived:
[0311] 1) A construction which has microwave supply means in the
tubular passage communicating with the interior of the chamber for
flowing the source gas, and which converts the source gas into a
plasma by microwaves generated by the microwave supply means. This
construction can be easily achieved by using, for example, a
magnetron. In this case, a frequency of about 2.45 (GHz) can be
used. Incidentally, the frequency supplied to the plasma antenna 26
in each of the embodiments is 13.56 (MHz). Thus, the use of
microwaves enables source gas radicals of a higher density to be
formed.
[0312] 2) A construction which has heating means for heating the
source gas flowing through the tubular passage communicating with
the interior of the chamber to dissociate the source gas thermally.
A heater formed from a filament can be thought of as the heating
means, and such a heater easily obtains a temperature of
1,500.degree. C. or higher which is necessary for thermal
dissociation. Thus, source gas radical replenishment means can be
constructed most inexpensively.
[0313] 3) A construction which has electromagnetic wave generation
means for supplying electromagnetic waves, such as laser light or
electron beams, to the source gas flowing through the tubular
passage communicating with the interior of the chamber to
dissociate the source gas. The electromagnetic wave generation
means can fix the wavelength of laser light or electron beams at a
specific value, thereby generating the desired radicals (e.g. Cl*)
at a high efficiency, namely selectively generating the desired
radicals at a high efficiency.
[0314] In the respective embodiments, the rare gas supply means is
provided, as means for increasing the dissociation rate of the
Cl.sub.2 gas, in order to promote the film formation reaction
expressed by the equations (2), (5) and (6). Instead, however,
electromagnetic waves may be supplied into the chamber 1 or the
like to dissociate the Cl.sub.2 gas. That is, electromagnetic waves
of such a wavelength as to dissociate the source gas (e.g.,
Cl.sub.2 gas), for example, laser light at 200 nm to 350 nm, may be
supplied above the substrate 3. This feature can be easily achieved
by utilizing a laser oscillator for emitting laser light in the
ultraviolet region, such as an excimer laser or a YAG laser.
[0315] Furthermore, to increase the dissociation rate in an attempt
to promote the film formation reaction expressed by the equations
(2), (5) and (6), it is effective to control the plasma conditions
in the following manner:
[0316] 1) To decrease the amount of the source gas (e.g. Cl.sub.2
gas) supplied. In this case, the amount of its precursor is also
decreased, thus making it necessary to sacrifice the film formation
rate somewhat. However, this type of control is theoretically
possible. If the respective embodiments are taken as examples, a
decrease of about 10% from the standard amount of supply is
appropriate in view of the film formation rate. That is, if the
standard amount of supply of a Cl.sub.2 gas is 50 (sccm), a
decrease to about 45 (ccm) is appropriate.
[0317] 2) To increase the amount of a high frequency power to the
film forming plasma antenna for generating a plasma within the
chamber 1 or the like. If the standard power is 22 (W/cm.sup.2),
for example, it is increased to 30 (W/cm.sup.2).
[0318] The metal film production apparatus according to each of the
embodiments has been described as an apparatus which fulfills both
the requirements for promoting the film formation reaction in the
equations (1), (3) and (4) and the requirements for promoting the
film formation reaction in the equations (2), (5) and (6). Needless
to say, however, it may be constructed as an apparatus for
promoting one of the film formation reactions. Moreover, an Ar gas
is separately supplied in order to increase the dissociation rate
for promoting the film formation reaction according to the
equations (2), (5) and (6). However, if an He gas is used as a
diluent gas for the source gas (e.g. Cl.sub.2 gas), the Ar gas may
replace the He gas. In this case, the Ar gas concurrently serves
the function of a diluent gas for the source gas, and the function
of a film formation promoting gas for increasing the dissociation
rate.
[0319] In the respective embodiments, the source gas has been
described, with the Cl.sub.2 gas diluted with He taken as an
example. However, the Cl.sub.2 gas can be used alone, or an HCl gas
can also be applied. When the HCl gas is applied, an HCl gas plasma
is generated as the source gas plasma. In this case, a precursor
formed by etching of an etched member made of copper is
Cu.sub.xCl.sub.y. In the case of the etched member comprising a
composite metal, on the other hand, the precursor is
Cu.sub.x1Cl.sub.y1, In.sub.x2Cly.sub.2, or a chloride of Se or S.
Thus, the source gas may be any gas containing chlorine, and a gas
mixture of an HCl gas and a Cl.sub.2 gas is also usable. Generally,
chlorine is not restrictive, and any halogen gas can be used as the
source gas in the present invention.
[0320] Moreover, the material for the etched member is not limited
to copper. For example, a metal forming a high vapor pressure
halide, such as Ta, Ti, W, Zn, In or Cd, can be similarly used. In
this case, the precursor is a chloride (halide) of Ta, Ti, W, Zn,
In or Cd, and a thin film formed on the surface of the substrate 3
is that of Ta, Ti, W, Zn, In or Cd.
[0321] Furthermore, a composite metal containing a plurality of
these metals, for example, an alloy of In and Cu, can be used as
the etched member. Besides, a composite metal containing a
nonmetallic element, such as S or Se, in addition to any of the
above metals, for example, an alloy such as CuInSe.sub.2, CdS or
ZnSe, can be used as the etched member. In this case, the resulting
precursor is composed of a metal chloride and a chloride of the
nonmetallic element, and a thin film of the composite metal is
formed on the surface of the substrate 3.
[0322] In all of the embodiments, the supply of source gas radicals
for replenishment has been described. However, radicals of the
source gas need not always be supplied for replenishment depending
on the film formation conditions, etc. Nevertheless, the supply of
separately formed radicals of the source gas can result in an
increased film formation speed and an improved film quality.
Tenth Embodiment
[0323] FIG. 13 is a schematic side view of an interconnection
structure forming apparatus according to a tenth embodiment of the
present invention. As shown in FIG. 13, a support platform 202 is
provided near the bottom of a cylindrical chamber 201 made of, say,
a ceramic (an insulating material), and a substrate 203 is placed
on the support platform 202. Depressions 203a, comprising trenches
or holes, are formed in the substrate 203. A Cu film is stacked in
each of the depressions to form a predetermined interconnection
structure.
[0324] Temperature control means 206 equipped with a heater 204 and
refrigerant flow-through means 205 is provided in the support
platform 202 so that the support platform 202 is controlled to a
predetermined temperature by the temperature control means 206.
[0325] An upper surface of the chamber 201 is an opening, which is
closed with a copper plate member 207, as an etched member made of
a metal. The interior of the chamber 201 closed with the copper
plate member 207 is maintained at a predetermined vacuum pressure
by a vacuum device 208.
[0326] A film forming plasma antenna 209 of a coiled shape is
disposed around a cylindrical portion of the chamber 201 beside the
copper plate member 207 in such a manner as to be wound in the
axial direction of the chamber 201. A matching instrument 210 and a
power source 211 are connected to the film forming plasma antenna
209 to supply power. Film forming plasma generation means is
constituted by the film forming plasma antenna 209, matching
instrument 210 and power source 211.
[0327] Nozzles 212 for supplying a source gas containing chlorine
(a Cl.sub.2 gas diluted with He to a chlorine concentration of
.ltoreq.50%, preferably about 10%) are disposed in the interior of
the chamber 201 above the support platform 202. The nozzle 212 is
open toward the copper plate member 207, and the nozzle 212 is fed
with the source gas via a flow controller 213. The source gas is
conveyed from beside the substrate 203 toward the copper plate
member 207 along the wall surface within the chamber 201 at the
time of film formation. The amount of the Cl.sub.2 gas supplied
into the chamber 201 is controlled by the flow controller 213.
[0328] A mode of film formation in the foregoing interconnection
structure forming apparatus is as described below.
[0329] While the source gas is supplied through the nozzles 212
into the chamber 201, electromagnetic waves are shot from the film
forming plasma antenna 209 into the chamber 201, whereby the
Cl.sub.2 gas is ionized to generate a Cl.sub.2 gas plasma (source
gas plasma) 214. The Cl.sub.2 gas plasma 214 is formed in a space
adjacent to the film forming plasma antenna 209 in the interior of
the chamber 201, namely, in a space beside the copper plate member
207 (upper portion) within the chamber 201. On this occasion, Cl*
also occurs.
[0330] The Cl.sub.2 gas plasma 214 causes an etching reaction to
the copper plate member 207, forming a precursor (Cu.sub.xCl.sub.y)
215. At this time, the copper plate member 207 is maintained by the
Cl.sub.2 gas plasma 214 at a predetermined temperature (e.g., 200
to 400.degree. C.) which is higher than the temperature of the
substrate 203.
[0331] The precursor (Cu.sub.xCl.sub.y) 215 formed within the
chamber 201 is transported to the substrate 203 controlled to a
lower temperature than the temperature of the copper plate member
207. The precursor (Cu.sub.xCl.sub.y) 215 transported to and
adsorbed onto the substrate 203 deposits Cu on the substrate 203 in
accordance with the reaction of the aforementioned equation (1)
representing the film formation reaction. As a result, a thin Cu
film (not shown) is formed on the surface of the substrate 203. The
thin Cu film formed on the surface of the substrate 203 is
simultaneously etched with Cl*. The intensity of this etching
reaction depends on the density of Cl*. In the present embodiment,
therefore, the amount of Cl* is appropriately controlled, thereby
creating an atmosphere in which the speed of the film formation
reaction is slightly higher than the speed of the etching reaction.
By this means, the Cu film is deposited by the film formation
reaction, and simultaneously the surface of the Cu film is etched,
while the film thickness is gradually increased to bury the Cu film
in the depressions 203a. Control of the density of Cl* can be
easily exercised by controlling the flow controller 213 to regulate
the amount of the Cl.sub.2 gas supplied into the chamber 201
through the nozzles 212.
[0332] Consequently, in the interconnection structure formed by the
apparatus according to the present embodiment, even if the
depression 203a of the substrate 203 is a via hole with a very
small diameter, for example, Cu can be sequentially stacked,
starting at its bottom, to form the Cu film. At this time, the
surface of the stacked Cu film is etched with Cl*. Thus, stacking
of the Cu film proceeds, with the intrinsic surface of the Cu film
being always exposed, and with the crystal directions being unified
into a single direction.
[0333] Hence, the Cu film, which is buried in the depressions 203a
by film formation in the copresence of the film formation reaction
and the etching reaction, is satisfactory in the adhesion of the
film itself, and also comprises a single crystal-like crystal. Such
a single crystal-like crystal has no grain boundaries, or has
several grain boundaries, if any. Thus, the Cu film is not affected
by electromigration or stress migration, but can maintain stable
electrical characteristics for a long period.
[0334] As shown in FIGS. 14(a) to 14(c) as cross-sectional views of
the process for formation of the Cu film, this process begins with
the initial state shown in FIG. 14(a). Then, a Cu film 216 is
gradually stacked, staring at the bottom of the depression 203a,
toward an opening (upward), whereby an interconnection structure
comprising the Cu film 216 as the single crystal-like crystal is
formed. FIG. 14(d) is a cross-sectional view schematically showing
an interconnection structure obtained by the earlier technology. As
shown in this drawing, a Cu film 216' comprises small crystal
grains, and thus has many grain boundaries 216'a.
[0335] The film formation conditions in this process are, for
example, as follows: The temperature of the substrate 203 is 160 to
200.degree. C. If the temperature is lower than 160.degree. C., a
Cu film cannot be deposited. At a temperature higher than
200.degree. C., the etching reaction is predominant, and no Cu film
is deposited. The power density supplied to the film forming plasma
antenna 209 is 22 (W/cm.sup.2). The flow rate of the Cl.sub.2 gas
supplied is 50 to 120 (sccm). Control is exercised so that the film
formation reaction speed>the etching reaction speed in view of
the depth of the depression 203.
[0336] As described above, the creation of an atmosphere in which
the speed of the film formation reaction is slightly higher than
the speed of the etching reaction can be easily achieved by
utilizing the following phenomenon which occurs in the apparatus
shown in FIG. 13.
[0337] FIG. 15 is a characteristic diagram showing the general
density characteristics (a curve indicated by a solid line in FIG.
15) of Cl*, relative to the depth direction of the depression 203a
of the substrate 203 in the apparatus illustrated in FIG. 13, in
depth position relationship with the depression 203a of the
substrate 203. As shown in the drawing, the density of Cl*
decreases with increasing depth of the depression 203a toward its
bottom. The reason is that Cl*, which has entered the depression
203a, collides with the surface of the depression 203a and vanishes
by the time when it arrives at the bottom of the depression 203a.
That is, the closer to the bottom of the depression 203a Cl* comes,
the higher the probability that the reaction expressed by
Cl*+Cl*.fwdarw.Cl.sub.2 occurs. Thus, Cl* vanishes accordingly,
making the density of Cl lower. On the other hand, the precursor
(Cu.sub.xCl.sub.y) 215 can easily arrive at the bottom of the
depression 203a. Thus, it can be generally said that the closer to
the bottom the site is, the more predominant the film formation
reaction becomes. That is, if the film formation conditions, such
as the concentration of the Cl.sub.2 gas, are appropriately
controlled, the boundary between the film formation reaction region
and the etching reaction region gradually ascends toward the
opening of the depression 203a. Thus, the Cu film 216 can be
stacked, with the intrinsic surface being always exposed.
[0338] FIGS. 16(a) and 16(b) are cross-sectional views showing a
multilayer (two-layer in this embodiment) interconnection structure
formed by controlling the film formation speed and the etching
speed as described above in the apparatus of FIG. 13. As shown in
FIG. 16(a), this multilayer interconnection structure comprises a
substrate I comprising a substrate 223 of an insulator (e.g.,
SiO.sub.2) having a depression 223a, for example, a via hole,
formed therein, another substrate 224 laminated on the substrate
223, and a depression 224a, a trench for interconnection, formed in
the substrate 224. On the surface of the substrate I, a commonly
used barrier metal layer 225 is formed for satisfactorily ensuring
adhesion to an interconnection material (Cu). The material for the
barrier metal layer 225 is, for example, TaN.
[0339] When the above substrate I is accommodated in the apparatus
shown in FIG. 13 and the apparatus is driven under the
above-mentioned conditions, a Cu film 226 is gradually stacked at
the bottom of a depression 223a shown in FIG. 16(a) under the
conditions such that the film formation reaction speed>the
etching reaction speed. As a result, an interconnection structure
reaching the depression 224a is integrally formed. That is, an
integral interconnection structure as shown in FIG. 16(b) can be
formed. Cu, forming such an interconnection structure, is a single
crystal-like crystal ranging from the depression 223a to the
depression 224a.
[0340] At a time when the depression 224a is completely filled with
the Cu film 226 upon burial, the amount of the Cl.sub.2 gas
supplied is increased to render the etching reaction predominant.
By this means, the CMP step in the damascene method concerned with
the earlier technology can be omitted, because the predominance of
the etching reaction precludes the formation of the Cu film 226 on
the surface of the substrate 224 (to be exact, the surface of the
barrier metal layer 225).
[0341] Such a desired multilayer interconnection structure can be
formed in a very short time with a dramatically decreased number of
the production steps as compared with the conventional method. For
comparison, an explanation will be offered for the steps of forming
the multilayer interconnection structure shown in FIG. 16(b) by the
double damascene method according to the earlier technology.
[0342] 1) Prepare a substrate 233 having a barrier metal layer 235,
as well as a depression 233a, formed therein (see FIG. 17(a)).
[0343] 2) Form a Cu film 236 on the surface of the substrate 233,
including the depression 233a, by vapor phase deposition or plating
(see FIG. 17(b)).
[0344] 3) Remove the Cu film 236, except that in the depression
233a, by CMP (see FIG. 17(c)).
[0345] 4) Form a substrate 234, another insulating layer, and
process it to form a depression 234a such as an interconnection
trench (see FIG. 17(d)).
[0346] 5) Form a barrier metal layer 237 on the surface of the
substrate 234, including the depression 234a (see FIG. 17(e)).
[0347] 6) Form a Cu film 238 on the surface of the substrate 234,
including the depression 234a, by vapor phase deposition or plating
(see FIG. 17(f)).
[0348] 7) Then, remove the Cu film 238, except that in the
depression 234a, by CMP.
[0349] According to the earlier technology, the above-described
many steps 1) to 7) are required. With the aforementioned
embodiment of the present invention, on the other hand, after the
substrate I of the multilayer structure having the barrier metal
layer 225 formed therein, as shown in FIG. 16(a), is formed, the
desired multilayer interconnection structure can be formed in one
step. In this respect alone, the production time can be reduced
dramatically.
[0350] In forming the single-layer interconnection structure by the
single damascene method, the earlier technology requires the steps
1) to 3) of the above-described steps. In other words, the CMP step
needs to be performed once. According to the present embodiment, on
the other hand, even when the single-layer interconnection
structure is to be formed, the CMP step can be omitted as stated
earlier to shorten the production time.
[0351] In the aforementioned multilayer interconnection structure
according to the present embodiment, moreover, the Cu film 226
buried in the depression 223a and the Cu film 226 buried in the
depression 224a are not separated from each other by the barrier
metal layer 225. In the multilayer structure according to the
earlier technology shown in FIGS. 17(a) to 17(f), by contrast, the
barrier metal layer 237 is formed on the upper surface of the Cu
film 236, which has been buried in the depression 233a, by the step
shown in FIG. 17(e). Unless this barrier metal layer 237 is removed
separately, the barrier metal layer 237 exists between the Cu film
236 buried in the depression 233a and the Cu film 238 buried in the
depression 234a. Usually, the barrier metal layer 237 is formed
from a high resistor, such as TaN, having resistivity about two
orders of magnitude greater than Cu. With the conventional
structure, therefore, the low-resistance Cu films 236 and 238 are
connected by the high-resistance barrier metal layer 237. As a
result, the electrical performance of the multilayer
interconnection structure is deteriorated. This problem can be
solved at the same time by the multilayer interconnection structure
according to the present embodiment.
[0352] It goes without saying that the interconnection structure
forming apparatus, which forms the interconnection structure
according to the present invention or finds use in the method for
forming the interconnection structure, is not limited to the
interconnection structure forming apparatus according to the
embodiment shown in FIG. 13. The apparatus may be any apparatus
which etches the etched member formed from a copper plate or the
like with a source gas plasma within the chamber to form a
precursor comprising a metallic element and a source gas, and
controls the temperatures of the etched member and the substrate so
as to be predetermined temperatures and to have a temperature
difference therebetween, thereby depositing the metallic element of
the precursor on the substrate to form a film. The reason is that a
metal film can be stacked in a depression of the substrate,
starting at its bottom, under the conditions such that the film
formation reaction speed>the etching reaction speed. Thus, the
apparatus may be not only an apparatus which supplies the source
gas into the chamber and forms a plasma within the chamber, but
also an apparatus which supplies a separately formed source gas
plasma into the chamber.
[0353] In the respective embodiments, the source gas has been
described, with the Cl.sub.2 gas diluted with He taken as an
example. However, the Cl.sub.2 gas can be used alone, or an HCl gas
can also be applied. When the HCl gas is applied, an HCl gas plasma
is generated as the source gas plasma. In this case, a precursor
formed by etching of the etched member made of copper is
Cu.sub.xCl.sub.y. Thus, the source gas may be any gas containing
chlorine, and a gas mixture of an HCl gas and a Cl.sub.2 gas is
also usable. Generally, chlorine is not restrictive, and any
halogen gas can be used as the source gas in the present
invention.
[0354] Moreover, the material for the etched member is not limited
to copper. For example, a metal forming a high vapor pressure
halide, such as Ta, Ti or W, can be similarly used. In this case,
the precursor is a chloride (halide) of Ta, Ti or W, and a thin
film formed on the surface of the substrate 203 is that of Ta, Ti
or W.
[0355] While the present invention has been described in the
foregoing fashion, it is to be understood that the invention is not
limited thereby, but may be varied in many other ways. Such
variations are not to be regarded as a departure from the spirit
and scope of the invention, and all such modifications as would be
obvious to one skilled in the art are intended to be included
within the scope of the appended claims.
* * * * *