U.S. patent application number 09/912504 was filed with the patent office on 2002-01-03 for film forming apparatus and method for producing tungsten nitride film.
Invention is credited to Harada, Masamichi.
Application Number | 20020000199 09/912504 |
Document ID | / |
Family ID | 11843083 |
Filed Date | 2002-01-03 |
United States Patent
Application |
20020000199 |
Kind Code |
A1 |
Harada, Masamichi |
January 3, 2002 |
Film forming apparatus and method for producing tungsten nitride
film
Abstract
A technique for forming a tungsten nitride film having a high
growth speed without causing any dusting. The film forming
apparatus 2 according to the present invention has a constitution
where an adhesion preventive container 8 is placed in a reactor 11
and a object on which a film is to be formed 20 is located in the
adhesion preventive container 8. In a first gas inlet equipment, a
first feedstock gas is jetted from a shower nozzle 12. In a second
gas inlet equipment, a second feedstock gas is jetted around the
object on which a film is to be formed 20 between the shower nozzle
12 and the material 20. Owing to this constitution, the first
feedstock gas and the second feedstock gas attain the surface of
the object on which a film is to be formed without being mixed
together, which enables the efficient performance of the reaction.
Since the adhesion preventive container is heated to 150 to
250.degree. C., neither WF.sub.6.4NH.sub.3 nor W.sub.xN is formed
and thus no dusting is caused.
Inventors: |
Harada, Masamichi;
(Chigasaki-shi, JP) |
Correspondence
Address: |
ARMSTRONG,WESTERMAN, HATTORI,
MCLELAND & NAUGHTON, LLP
1725 K STREET, NW, SUITE 1000
WASHINGTON
DC
20006
US
|
Family ID: |
11843083 |
Appl. No.: |
09/912504 |
Filed: |
July 26, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
09912504 |
Jul 26, 2001 |
|
|
|
09489338 |
Jan 21, 2000 |
|
|
|
Current U.S.
Class: |
118/715 ;
427/255.394 |
Current CPC
Class: |
C23C 16/45514 20130101;
C23C 16/4401 20130101; C23C 16/4558 20130101; C23C 16/45565
20130101; C23C 16/34 20130101 |
Class at
Publication: |
118/715 ;
427/255.394 |
International
Class: |
C23C 016/34 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 22, 1999 |
JP |
11-13791 |
Claims
What is claimed is:
1. A film forming apparatus comprising: an evacuatable reactor; an
adhesion preventive container placed in said reactor; a holder
whereby a material on which the film is to be formed is located in
said adhesion preventive container; a first gas inlet equipment
which faces to said holder and constructed so that it can jet a gas
into said adhesion preventive container; and a second gas inlet
equipment which is constructed so that it can jet a gas between
said first gas inlet equipment and said holder.
2. The film forming apparatus as claimed in claim 1, which is
constructed so that, in said adhesion preventive container, at
least the part around said material on which the film is to be
formed is maintained at a temperature of 150 to 300.degree. C.
3. The film forming apparatus as claimed in claim 1, wherein said
first gas inlet equipment comprises a shower nozzle provided with a
number of gas jet orifices formed on the almost same plane.
4. The film forming apparatus as claimed in claim 2, wherein said f
irst gas inlet equipment comprises a shower nozzle provided with a
number of gas jet orifices formed on the almost same plane.
5. The film forming apparatus as claimed in claim 1, wherein said
second gas inlet equipment comprises a nozzle made of a hollow pipe
shaped into a ring and a number of gas jet orifices are formed in
said hollow pipe.
6. The film forming apparatus as claimed in claim 2, wherein said
second gas inlet equipment comprises a nozzle made of a hollow pipe
shaped into a ring and a number of gas jet orifices are formed in
said hollow pipe.
7. The film forming apparatus as claimed in claim 3, wherein said
second gas inlet equipment comprises a nozzle made of a hollow pipe
shaped into a ring and a number of gas jet orifices are formed in
said hollow pipe.
8. The film forming apparatus as claimed in claim 4, wherein said
second gas inlet equipment comprises a nozzle made of a hollow pipe
shaped into a ring and a number of gas jet orifices are formed in
said hollow pipe.
9. A method for producing a tungsten f ilm which comprises jetting
a first feedstock gas comprising a nitrogen atom in its chemical
structure and a second feedstock gas comprising a tungsten atom in
its chemical structure into a reactor and reacting said first
feedstock gas with said second feedstock gas so as to form a
tungsten nitride film on the surface of a material on which the
film is to be formed; wherein the distance between the position
from which said first feedstock gas is jetted and the surface of
said material on which the film is to be formed is different from
the distance between the position from which said second feedstock
gas is jetted and the surface of said material on which the film is
to be formed.
10. The method for producing a tungsten film as claimed in claim 9
which comprises: providing an adhesion preventive container in said
reactor and placing said object on which a film is to be formed in
the adhesion preventive container; heating, in said adhesion
preventive container, at least the part around said material on
which the film is to be formed to a temperature of 150 to
250.degree. C.; and jetting said first feedstock gas and second
feedstock gas into said adhesion preventive container.
11. The method for producing a tungsten film as claimed in claim 9,
wherein one of said first feedstock gas and second feedstock gas is
jetted downward in the vertical direction toward the surface of
said object on which a film is to be formed.
12. The method for producing a tungsten film as claimed in claim
10, wherein one of said first feedstock gas and second feedstock
gas is jetted downward in the vertical direction toward the surface
of said object onwhicha film is to be formed.
13. The method for producing a tungsten film as claimed in claim 9,
wherein, between said first feedstock gas and second feedstock gas,
the one gas jetted from the lower position is jetted sideways
toward center of said object on which a film is to be formed.
14. The method for producing a tungsten film as claimed in claim
10, wherein, between said first feedstock gas and second feedstock
gas, the one gas jetted from the lower position is jetted sideways
toward center of said object on which a film is to be formed.
15. The method for producing a tungsten film as claimed in claim
11, wherein, between said first feedstock gas and second feedstock
gas, the one gas jetted from the lower position is jetted sideways
toward center of said object on which a film is to be formed.
16. The method for producing a tungsten film as claimed in claim
12, wherein, between said first feedstock gas and second feedstock
gas, the one gas jetted from the lower position is jetted sideways
toward center of said object on which a film is to be formed.
Description
FIELD OF THE INVENTION
[0001] This invention relates to the technical field of forming
metal nitrides. More particularly, it provides a technique adequate
for forming tungsten nitride films.
BACKGROUND OF THE INVENTION
[0002] In recent years, aluminum has been replaced by copper as the
material mainly employed in metal interconnecting films for
semiconductor devices. In the case of aluminum films, titanium
nitride films are formed as barrier films at the interface between
the aluminum films and silicon substrates. However, these titanium
nitride films are poor in the ability to prevent the diffusion of
copper. Thus, W.sub.xN films (tungsten nitride films) have
attracted attention as barrier films against copper films.
[0003] It has been a practice to produce W.sub.xN films at a high
temperature (i.e., 500.degree. C. or above) under high pressure
(i.e., film-forming pressure: several thousand Pa) . However, a
large-scaled apparatus should be employed to sustain such a high
pressure and, moreover, troublesome operations are needed for the
maintenance thereof. In a pretreatment apparatus for forming
W.sub.xN films and a film forming apparatus for forming copper film
on the W.sub.xN films, substrates should be treated in vacuum.
Thus, there arises an additional problem that these apparatuses are
poor in the connection properties with a W.sub.xN film forming
apparatus and thus the substrates cannot be treated
continuously.
[0004] Accordingly, it has been required to develop a film forming
apparatus by which W.sub.xN films can be produced in vacuum (under
reduced pressure). In FIG. 5(a), a substrate 120, on which a
W.sub.xN film and a copper film are to be formed, consists of a
silicon substrate 150, a silicon oxide film 152 formed on the
silicon substrate 150 and a pore 160 formed in the silicon oxide
film 152.
[0005] When a W.sub.xN film is to be formed on the substrate 120 by
using a CVD apparatus 102 of the prior art as shown in FIG. 6, a
reactor 111 is first evacuated. Then the substrate 120 is carried
thereinto and placed on a holder 114 provided in the bottom side of
the reactor 111.
[0006] A shower nozzle 112 is provided in the ceiling side of the
reactor 111. After heating the substrate 120 to a prescribed
temperature with a heater contained in the holder 114, two types of
feedstock gases (for example, WF.sub.6 gas and NH.sub.3 gas) are
jetted from the shower nozzle 112 toward the substrate 120 as shown
by arrows 151, thereby inducing the following chemical
reaction:
4WF.sub.6+8NH.sub.3 b .fwdarw.2W.sub.2N+24HF+3N.sub.2.
[0007] Thus, a W.sub.xN film 153 is formed on the surface of the
substrate 120 as shown in FIG. 5(b), wherein X is referred
tentatively as to 2.
[0008] When a prescribed thickness of the W.sub.xN film is
achieved, the substrate 120 is taken out from the reactor 111. Then
a copper film 154 is formed on the W.sub.xN film 153 as shown in
FIG. 5(c) and followed by the transportation to the subsequent
stage, i.e., the patterning of the copper film 154, etc.
[0009] When the W.sub.xN film 153 and the copper film 154 are
formed in vacuum as described above, the substrate 120 can be
continuously treated without exposing to the atmosphere by
connecting a apparatus for forming a tungsten film and a apparatus
for forming a copper film to a multi-chamber type apparatus.
[0010] However, a CVD apparatus of the prior art as described above
suffers from the problem of serious dusting. This is because the
reaction between WF.sub.6 and NH.sub.3 proceeds even at room
temperature and not W.sub.xN but WF.sub.6.4NH.sub.3 etc. are formed
at room temperature, different from the above reaction formula, and
adhere to the inner wall of the reactor 111.
[0011] When the wall of the reactor 111 is heated to a temperature
close to the temperature of the substrate 120, at least the
formation of WF.sub.6.4NH.sub.3 can be prevented. In this case,
however, W.sub.xN is deposited on the inner wall of the reactor 111
on the contrary and causes dusting.
[0012] In addition, the above-described reactor 111 of the prior
art suffers from another problem of a low growth speed of the
W.sub.xN film. Thus, it has been required to clarify the cause of
this phenomenon and to establish a countermeasure effective
therefor.
SUMMARY OF THE INVENTION
[0013] The present invention, which has been made to overcome the
above-described problems encountering in the prior art, aims at
providing a technique for forming a tungsten nitride film without
causing dusting, and a technique for forming a tungsten nitride
film showing a high growth speed.
[0014] To achieve these objects, the present invention relates to a
film forming apparatus providedwith an evacuatable reactor, an
adhesion preventive container placed in said reactor, a holder
whereby a object on which the film is to be formed is located in
said adhesion preventive container, a first gas inlet equipment
which faces to said holder and constructed so that it can jet a gas
into said adhesion preventive container, and a second gas inlet
equipment which is constructed so that it can jet a gas between
said first gas inlet equipment and said holder.
[0015] The present invention relates to the film forming apparatus,
which is constructed so that, in said adhesion preventive
container, at least the part around said material on which the film
is to be formed is maintained at a temperature of 150 to
300.degree. C.
[0016] The present invention relates to the film forming apparatus
wherein said first gas inlet equipment has a shower nozzle provided
with a number of gas jet orifices formed on the almost same
plane.
[0017] The invention relates to the film forming apparatus wherein
said second gas inlet equipment has a nozzle made of a hollow pipe
shaped into a ring and a number of gas jet orifices are formed in
said hollow pipe.
[0018] The present invention relates to a method for producing a
tungsten film which comprises jetting a first feedstock gas having
a nitrogen atom in its chemical structure and a second feedstock
gas having a tungsten atom in its chemical structure into a reactor
and reacting said first feedstock gas with said second feedstock
gas so as to form a tungsten nitride film on the surface of a
material on which the film is to be formed, wherein the distance
between the position from which said first feedstock gas is jetted
and the surface of said material on which the film is to be formed
is different from the distance between the position from which said
second feedstock gas is jetted and the surface of said material on
which the film is to be formed.
[0019] The present invention relates to the method for producing a
tungsten film which comprises providing an adhesion preventive
container in said reactor and placing said object on which a film
is to be formed in the adhesion preventive container; heating, in
said adhesion preventive container, at least the part around said
material on which the film is to be formed to a temperature of 150
to 250.degree. C.; and jetting said first feedstock gas and second
feedstock gas into said adhesion preventive container.
[0020] The present invention relates to the method for producing a
tungsten film, wherein one of said first feedstock gas and second
feedstock gas is jetted downward in the vertical direction toward
the surface of said object on which a film is to be formed.
[0021] The present invention relates to the method for producing a
tungsten film, wherein, between said first feedstock gas and second
feedstock gas, the one gas jetted from the lower position is jetted
sideways toward center of said object on which a film is to be
formed.
[0022] Many other features, advantages and additional objects of
the present invention will become manifest to those versed in the
art upon making reference to the detailed description which follows
and the accompanying sheet of drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] FIG. 1 is a drawing which shows an example of the film
forming apparatus according to the present invention.
[0024] FIG. 2 is a drawing which illustrates the adhesion
preventive container of the film forming apparatus.
[0025] FIG. 3(a) is a perspective view of the nozzle shaped into a
ring; FIG. 3(b) is an enlarged partial view thereof; and FIG. 3(c)
is a perspective view of a nozzle in another shape.
[0026] FIG. 4(a) is a plan view of an example of the shower nozzle
of the present invention; and FIG. 4(b) is aplan view of a shower
nozzle of the prior art.
[0027] FIG. 5(a)-(c) are drawings which show the steps of forming a
tungsten nitride film and a copper film.
[0028] FIG. 6 is a drawing which shows a apparatus for forming a
tungsten nitride film of the prior art.
DETAILED DESCRIPTION OF THE INVENTION
[0029] The film forming apparatus according to the present
invention, which has the constitution as described above, has an
adhesion preventive container placed in the reactor. In this
adhesion preventive container, a holder is provided so that a
object on which a film is to be formed (i.e., the substrate) can be
hold in the adhesion preventive container.
[0030] This film forming apparatus is provided with a first gas
inlet equipment and a second gas inlet equipment through which
feedstock gases are respectively jetted into the adhesion
preventive container. The second gas inlet equipment is located at
such a position that it can jet the gas between the jetting
position of the first gas inlet equipment and the holder.
[0031] By locating the gas jetting positions of the first and
second gas inlet equipment at different heights on the surface of
the object on which a film is to be formed and jetting the
feedstock gases into the adhesion preventive container, the first
and second feedstock gases respectively jetted from the gas inlet
equipment can attain the surface of the object on which a film is
to be formed located on the holder without mixing with each other
even under a pressure within the viscous flow region (i.e., 1.0 to
100 Pa).
[0032] When the first feedstock gas having a nitrogen atom in its
chemical structure and the second feedstock gas having a tungsten
atom in its chemical structure are supplied respectively from the
first gas inlet equipment and the second gas inlet equipment,
therefore, these gases react with each other not in the space but
on the surface of the object on which a film is to be formed and
thus a tungsten nitride film can be efficiently formed.
[0033] A tungsten film having a good film thickness distribution
can be formed on the surface of the object on which a film is to be
formed by providing the first gas inlet equipment with a shower
nozzle and thus jetting downward the feedstock gas toward the
object on which a film is to be formed. FIG. 4(a) 71 shows the
surface of the shower nozzle. On this shower nozzle which has a
number of jet orifices 72, the same feedstock gas is jetted.
[0034] In the shower nozzle 171 of the prior art shown in FIG.
4(b), two types of gas jet orifices 173 and 174 are formed. From
one type 173 of these orifices, a feedstock gas containing nitrogen
atom is jetted, while another feedstock gas containing tungsten
atom is jetted from the remainders 174. In this case, these gases
are mixed together and react with each other before attaining the
surface of the object on which a film is to be formed, which
supposedly results in the low film formation (deposition) rate
achieved by the prior art.
[0035] In the present invention, a nozzle shaped into a ring is
further provided in the second gas inlet equipment. This nozzle has
a number of gas jet orifices from which a gas is jetted toward the
center of the ring, optionally somewhat shifting toward the object
on which a film is to be formed. Thus, the feedstock gas supplied
from the second gas inlet equipment can uniformly attain the
surface of the object on which a film is to be formed.
[0036] In this case, the feedstock gas supplied from the first gas
inlet equipment attains the surface of the object on which a film
is to be formed via the center of the ring of the nozzle.
Therefore, the gases supplied respectively from the first and
second gas inlet equipment can attain the surface of the object on
which a film is to be formed, without being mixed together and thus
the reaction can efficiently proceed on the surface of the object
on which a film is to be formed.
[0037] When a feedstock gas containing nitrogen in its chemical
structure (for example, NH.sub.3 gas) and another feedstock gas
containing tungsten in its chemical structure (for example,
WF.sub.6 gas) are separately introduced into the adhesion
preventive container in particular under a pressure of from 1.0 to
100 Pa, WF.sub.6.4NH.sub.3 is formed at a temperature less than
150.degree. C. while a W.sub.xN (i.e., a tungsten nitride film) is
formed at a temperature exceeding 300.degree. C.
[0038] In the present invention, the adhesion preventive container
is maintained at a temperature of from 150 to 250 .degree. C.
(preferably around 200.degree. C.). As a result, neither
WF.sub.6.4NH.sub.3 nor W.sub.xN is formed on the surface of the
adhesion preventive container, thereby causing no dusting.
[0039] These and other objects of the invention will become more
apparent in the detailed description and examples which follow.
[0040] Now, the present invention will be described by reference to
the attached drawings.
[0041] In FIG. 1, sign 2 shows an example of the film forming
apparatus according to the present invention which has a reactor
11. A cavity adhesion preventive container 8 is placed in this
reactor 11.
[0042] As FIG. 2 shows, this adhesion preventive container 8 is
provided with a bottom plate 31, a rectifier plate 32 and a top
plate 33, each in a circular shape, and a cylindrical wall plate
30.
[0043] Circular holes 36 to 38 are formed at the center of the
bottom plate 31, the rectifier plate 32 and the top plate 33
respectively.
[0044] The bottom plate 30 is located at the bottom of the wall
plate 30, while the rectifier plate 32 is located above the bottom
plate 31 and surrounded by the wall plate 30. The top plate 33 is
located at the opening of the wall plate 30 above the rectifier
plate 32.
[0045] The bottom plate 31, the rectifier plate 32 and the top
plate 33 are arranged in parallel at definite intervals and each
fixed to the wall plate 30.
[0046] The holes 36 to 38 formed respectively on the bottomplate
31, the rectifier plate 32 and the top plate 33 are each arranged
in such a manner that the center thereof is located on the center
axis of the wall plate 30.
[0047] The adhesion preventive container 8 having the
above-described constitution is placed as such on the bottom of the
reactor 11.
[0048] The reactor 11 is provided with a holder 14 on the bottom
thereof and the adhesion preventive container 8 is placed so that
the holder 14 is located in the hole 36 of the bottom plate 31 and
the hole 37 of the rectifier plate 32. The surface of the holder 14
is located between the rectifier plate 31 and the top plate 33.
[0049] A first gas source 45 and a second gas source 46, each
consisting of a gas cylinder, a mass flow controller, valves,
pipes, etc., are provided outside the reactor 11.
[0050] In FIG. 1, 61.sub.1 to 61.sub.4 are mass flow controller,
and 62.sub.1 to 62.sub.1 are valves.
[0051] The first gas source 45 is connected to a shower nozzle 12
as a first gas inlet equipment. A first gas inlet system consists
of this first gas source 45 and the shower nozzle 12 which is a
first gas inlet equipment.
[0052] The shower nozzle 12 has a cavity structure and a number of
orifices are formed on the bottom 18 thereof. Thus, a gas is
supplied from the first gas source 45 into the cavity part of
shower nozzle 12 is jetted from the orifices on the bottom.
[0053] The shower nozzle 12 is located above the hole 38 of the top
plate 33 and attached to the top part of the reactor 11 so that the
bottom 18 of the shower nozzle 12 faces to the surface of the
holder 14.
[0054] The hole 38 of the top plate 33 is larger than the bottom 18
of the shower nozzle 12. The bottom 18 of the shower nozzle 12 is
located almost at the same height as the top plate 33 but the
bottom 18 is located lower than the hole 38 of the top plate
33.
[0055] Due to this construction, the gas jetted form the shower
nozzle 12 is introduced directly into the adhesion preventive
container 8 and blown to the surface of the holder 14.
[0056] The second gas source 46 is connected to a gas jet member 4
as a second gas inlet equipment. A second gas inlet system 42
consists of the second gas source 46 and the gas jet member 4 which
is a second gas inlet equipment.
[0057] This gas jet member 4, which is roughly shaped into a ring,
is arranged between the holder 14 and the shower nozzle 12 in the
adhesion preventive container 8 in parallel to the surface of the
holder 14. Namely, the gas jet member 4 is located between the
rectifier plate 32 and the top plate 33 and in parallel to the
rectifier plate 32 and the top plate 33.
[0058] FIG. 3(a) is a perspective view of the gas jet member 4.
[0059] This gas jet member 4 consists of a ring nozzle 21, a
support 22 supporting this nozzle 21, and a pipe 23 with which the
support 22 is connected to the gas inlet system 42 which is located
outside of the reactor 11.
[0060] The nozzle 21, the support 22 and the pipe 23 are each made
up of a hollow pipe. When a gas is introduced from the second gas
source 46 into the gas jet member 4, the gas passes through the
pipe 23 and the support 22 and attains the nozzle 21.
[0061] The gas nozzle 21 shaped into a ring is provided a number of
holes 25 on the inner face. FIG. 3(b) is an enlarged view of the
holes 25. These holes 25 are arranged on somewhat lower part of the
surface of the ring gas nozzle 21 at almost constant intervals so
that the gas flown into the nozzle 21 is regularly discharged from
these holes 25 somewhat downward toward the center.
[0062] Next, a method for forming a tungsten film by using the
above-described film forming apparatus 2 will be illustrated.
[0063] In this case, the first gas source 45 is provided with a gas
cylinder containing the first feedstock gas comprising a nitrogen
atom in its chemical structure (NH.sub.s in this case), while the
second gas source 46 is provided with another gas cylinder
containing the second feedstock gas comprising a tungsten atom in
its chemical structure (WF.sub.6 in this case), thus allowing the
introduction of these gases respectively from the first and second
gas inlet systems 41 and 42 into the reactor 11.
[0064] First, the reactor 11 is evacuated into vacuum atmosphere
with the evacuation system 48 connected to the reactor 11. The
substrate holder 17 is comprised operable to lift up and down. Then
the substrate 20 is carried into the reactor 11 while lifting up
the substrate holder 17 and placed on the holder 14. This substrate
20 is arranged in parallel to the bottom 18 of the shower nozzle
12. Next, the substrate holder 17 is taken down and the substrate
20 is adhered to the holder 14 followed by heating by switching on
the heater 15.
[0065] When another inner heater provided within the adhesion
preventive container 8 is also switched on, the adhesion preventive
container 8 is heated with the inner heater as well as the heat
radiated from the holder 14. In this step, the electricity supplied
to the inner heater is controlled so as to maintain the temperature
of the adhesion preventive container 8 to 200.degree. C.
[0066] When temperature of the substrate 20 is elevated and attains
to 300.degree. C. or higher, the gas sources 45 and 46 are
manipulated so that the first feedstock gas (NH.sub.3) is jetted
from the shower nozzle 12 toward the substrate 20 and, at the same
time, the second feedstock gas (WF.sub.6) is jetted from the nozzle
21 of the gas jet member 4. Thus, the first and second feedstock
gases (i.e., the NH.sub.3 and WF.sub.6 gases) are blown onto the
substrate 20.
[0067] In this case, two different feedstock gases (i.e., the
NH.sub.3 and WF.sub.6 gases) are separately jetted respectively
from the shower nozzle 12 and the gas jet member 4, as described
above. By controlling the supply rates of the gases by manipulating
the first gas source 41 and second gas source 42, the pressure in
the adhesion preventive container 8 can be maintained within the
viscous flow region (i.e., 1.0 to 100 Pa) and the first feedstock
gas and the second feedstock gas can separately attain the surface
of the substrate 20 without being mixed together. As a result, the
reaction of forming thin W.sub.xN proceeds on the surface of the
substrate 20 and thus a thin W.sub.xN film is obtained.
[0068] When the thin W.sub.xN film having a prescribed film
thickness is formed, the substrate 20 is taken out from the reactor
11 and transported into a copper film forming apparatus. At the
same time, another untreated substrate is carried into the reactor
11 and subjected to the formation of a thin W.sub.xN film. Thus,
thin W.sub.xN films can be continuously formed.
[0069] In the above-described film forming apparatus 2, the
adhesion preventive container 8 is filled up with the first
feedstock gas and the second feedstock gas different from each
other (i.e., the NH.sub.3 and WF.sub.6 gases), which protects the
inner wall of the reactor 11 from the deposition of
WF.sub.6.4NH.sub.3 or W.sub.xN thereon. Thus, no dust evolves from
the reactor 11 and a defect-free W.sub.xN film can be produced.
[0070] Since the temperature of the adhesion preventive container 8
is controlled within a range of from 200 to 300.degree. C., neither
WF.sub.6.4NH.sub.3, which is liable to be formed at lower
temperatures, nor W.sub.xN, which is liable to be formed at higher
temperatures, is formed. Thus, W.sub.xN can be formed in dust-free
environment. Because of being removable, moreover, the adhesion
preventive container 8 can be easily cleaned.
[0071] As described above, by using the thin film forming apparatus
2 according to the present invention, different feedstock gases are
not mixed together but can separately attain a substrate and the
reaction efficiently proceeds on the substrate surface. Thus, a
thin film made of the reaction product (for example, a W.sub.xN
film) can grow quickly without causing dusting and a W.sub.xN film
with excellent qualities can be formed.
[0072] Although a number of holes 25 are formed in the inner side
of the gas jet member 4 in the above case, other constitutions may
be employed therefor so long as the feedstock gas can uniformly
jetted from two ormore positions toward the substrate 20. For
example, it is alsopossible that a tip 24 of the support 22 is bent
toward the central axis of the substrate located below and the
feedstock gas is jetted from the hole 26 formed on the tip 24, as
FIG. 3(c) shows.
[0073] Although W.sub.xN is formed in vacuum (under reduced
pressure) of 1.0 to 100 Pa in the above example, it can be formed
under higher pressure, i.e., atmospheric pressure or more.
[0074] By using the present invention, different feedstock gases
are not mixed together but can separately attain the surface of a
object on which a film is to be formed. Thus, the film-formation
speed can be elevated and a uniform film thickness can be
obtained.
[0075] Also, no reaction occurs on the surface of the adhesion
preventive container and thus no dusting arises. In addition, the
feedstock gases are not consumed on the surface of the adhesion
preventive container. Therefore, the reaction can efficiently
proceed on the surface of the object on which a film is to be
formed and no dust adheres to the surface of the adhesion
preventive container.
* * * * *