U.S. patent application number 09/904868 was filed with the patent office on 2002-01-31 for semiconductor device and semiconductor device manufacturing method.
This patent application is currently assigned to CANON SALES CO., INC.. Invention is credited to Aoki, Junichi, Koromokawa, Takashi, Maeda, Kazuo, Oku, Taizo, Yamamoto, Youichi.
Application Number | 20020013066 09/904868 |
Document ID | / |
Family ID | 26596473 |
Filed Date | 2002-01-31 |
United States Patent
Application |
20020013066 |
Kind Code |
A1 |
Oku, Taizo ; et al. |
January 31, 2002 |
Semiconductor device and semiconductor device manufacturing
method
Abstract
The present invention relates to a semiconductor device
manufacturing method for forming an interlayer insulating film
containing a coating insulating film having a low dielectric
constant. In construction, there are provided the steps of
preparing a substrate 20 on a surface of which a coating insulating
film 26 is formed by coating a coating liquid containing any one
selected from a group consisting of silicon-containing inorganic
compound and silicon-containing organic compound, and forming a
protection layer 27 for covering the coating insulating film 26 by
plasmanizing a first film forming gas to react, wherein the first
film forming gas consists of any one selected from a group
consisting of alkoxy compound having Si--H bonds and siloxane
having Si--H bonds and any one oxygen-containing gas selected from
a group consisting of O.sub.2, N.sub.2O, NO.sub.2, CO, CO.sub.2,
and H.sub.2O.
Inventors: |
Oku, Taizo; (Tokyo, JP)
; Aoki, Junichi; (Tokyo, JP) ; Yamamoto,
Youichi; (Tokyo, JP) ; Koromokawa, Takashi;
(Tokyo, JP) ; Maeda, Kazuo; (Tokyo, JP) |
Correspondence
Address: |
George A. Loud, Esquire
LORUSSO & LOUD
3137 Mount Vernon Avenue
Alexandria
VA
22305
US
|
Assignee: |
CANON SALES CO., INC.
|
Family ID: |
26596473 |
Appl. No.: |
09/904868 |
Filed: |
July 16, 2001 |
Current U.S.
Class: |
438/778 ;
257/E21.261; 257/E21.279; 257/E21.576; 438/976 |
Current CPC
Class: |
H01L 21/02126 20130101;
C23C 16/509 20130101; H01L 21/02274 20130101; H01L 21/76829
20130101; H01L 21/02164 20130101; H01L 21/31612 20130101; H01L
21/02214 20130101; H01L 21/02282 20130101; H01L 21/3122 20130101;
H01L 21/76834 20130101; H01L 21/02216 20130101; H01L 21/022
20130101; C23C 16/401 20130101; H01L 21/76831 20130101 |
Class at
Publication: |
438/778 ;
438/976 |
International
Class: |
H01L 021/31; H01L
021/469 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 21, 2000 |
JP |
2000-221380 |
Sep 18, 2000 |
JP |
2000-281263 |
Claims
What is claimed is:
1. A semiconductor device manufacturing method comprising the steps
of: preparing a substrate on a surface of which a coating
insulating film is formed by coating a coating liquid containing
any one selected from a group consisting of silicon-containing
inorganic compound and silicon-containing organic compound; and
forming a protection layer for covering the coating insulating film
by plasmanizing a first film forming gas to react, wherein the
first film forming gas includes any one selected from a group
consisting of alkoxy compound having Si--H bonds and siloxane
having Si--H bonds and any one oxygen-containing gas selected from
a group consisting of O.sub.2, N.sub.2O, NO.sub.2, CO, CO.sub.2,
and H.sub.2O.
2. A semiconductor device manufacturing method according to claim
1, wherein the first film forming gas further includes any one
selected from a group consisting of N.sub.2 and H.sub.2.
3. A semiconductor device manufacturing method according to claim
1, wherein the alkoxy compound having Si--H bonds constituting the
first film forming gas is formed of trimethoxysilane
(TMS:SiH(OCH.sub.3).sub.3)- .
4. A semiconductor device manufacturing method according to claim
1, wherein the siloxane having Si--H bonds constituting the first
film forming gas is formed of tetramethyldisiloxane
(TMDSO:(CH.sub.3).sub.2HSi --O--SiH(CH.sub.3).sub.2).
5. A semiconductor device manufacturing method according to claim
1, wherein a first electrode and a second electrode of a
parallel-plate type are provided as means for plasmanizing the film
forming gas, and, when a film is formed, a high frequency power
having a frequency of 1 MHz or more is applied to the first
electrode and a low frequency power having a frequency of 100 kHz
to 1 MHz is applied to the second electrode which the substrate is
loaded.
6. A semiconductor device manufacturing method according to claim
1, wherein the substrate has a first wiring, and a protection layer
for covering the first wiring, that is formed by plasmanizing a
second film forming gas to react, wherein the second film forming
gas includes any one selected from a group consisting of alkoxy
compound having Si--H bonds and siloxane having Si--H bonds and any
one oxygen-containing gas selected from a group consisting of
O.sub.2, N.sub.2O, NO.sub.2, CO, CO.sub.2, and H.sub.2O.
7. A semiconductor device manufacturing method according to claim
6, wherein the second film forming gas includes any one selected
from a group consisting of N.sub.2 and H.sub.2.
8. A semiconductor device manufacturing method according to claim
6, wherein the alkoxy compound having Si--H bonds constituting the
second film forming gas is formed of trimethoxysilane
(TMS:SiH(OCH.sub.3).sub.3)- .
9. A semiconductor device manufacturing method according to claim
6, wherein the siloxane having Si--H bonds constituting the second
film forming gas is formed of tetramethyldisiloxane
(TMDSO:(CH.sub.3).sub.2HSi- --O--SiH(CH.sub.3).sub.2).
10. A semiconductor device manufacturing method according to claim
6, wherein a first electrode and a second electrode of a
parallel-plate type are provided as means for plasmanizing the film
forming gas, and, when a film is formed, a high frequency power
having a frequency of 1 MHz or more is applied to the first
electrode and a low frequency power having a frequency of 100 kHz
to 1 MHz is applied to the second electrode which the substrate is
loaded.
11. A semiconductor device manufacturing method according to claim
6, after the step of forming the protection layer for covering the
coating insulating film, further comprising the steps of: forming
an opening portion in the protection layer for covering the coating
insulating film, the coating insulating film, and the protection
layer for covering the first wiring; and forming a second wiring to
connect the first wiring via the opening portion.
12. A semiconductor device manufacturing method according to claim
11, after the step of forming the second wiring, further comprising
the step of: forming a protection layer for covering the second
wiring by plasmanizing a third film forming gas to react, wherein
the third film forming gas includes any one selected from a group
consisting of alkoxy compound having Si--H bonds and siloxane
having Si--H bonds and any one oxygen-containing gas selected from
a group consisting of O.sub.2, N.sub.2O, NO.sub.2, CO, CO.sub.2,
and H.sub.2O.
13. A semiconductor device manufacturing method according to claim
12, wherein the third film forming gas further includes any one
selected from a group consisting of N.sub.2 and H.sub.2.
14. A semiconductor device manufacturing method according to claim
12, wherein the alkoxy compound having Si--H bonds constituting the
third film forming gas is formed of trimethoxysilane
(TMS:SiH(OCH.sub.3).sub.3)- .
15. A semiconductor device manufacturing method according to claim
12, wherein the siloxane having Si--H bonds constituting the third
film forming gas is formed of tetramethyldisiloxane
(TMDSO:(CH.sub.3).sub.2HSi- --O--SiH(CH.sub.3).sub.2).
16. A semiconductor device manufacturing method according to claim
12, wherein a first electrode and a second electrode of a
parallel-plate type are provided as means for plasmanizing the film
forming gas, and, when a film is formed, a high frequency power
having a frequency of 1 MHz or more is applied to the first
electrode and a low frequency power having a frequency of 100 kHz
to 1 MHz is applied to the second electrode which the substrate is
loaded.
17. A semiconductor device comprising: (i) a substrate having (a) a
coating insulating film containing at least any one selected from
the group consisting of a silicon-containing organic compound and a
silicon-containing inorganic compound in a surface of the
substrate; and (ii) a protection layer for covering the coating
insulating film to contact the coating insulating film, wherein the
protection layer for covering the coating insulating film is a
silicon-containing insulating film which has a peak of an
absorption intensity of an infrared rays in a range of a wave
number 2270 to 2350 cm.sup.-1, a film density in a range of 2.25 to
2.40 g/cm.sup.3, and a relative dielectric constant in a range of
3.3 to 4.3.
18. A semiconductor device according to claim 17, further
comprising a first wiring and a protection layer for covering the
first wiring to contact the first wiring, that are provided on a
surface of the substrate, wherein the protection layer for covering
the first wiring is a silicon-containing insulating film which has
a peak of an absorption intensity of an infrared rays in a range of
a wave number 2270 to 2350 cm.sup.-1, a film density in a range of
2.25 to 2.40 g/cm.sup.3, and a relative dielectric constant in a
range of 3.3 to 4.3.
19. A semiconductor device according to claim 18, further
comprising a second wiring on an interlayer insulating film which
consists of the protection layer for covering the first wiring, the
coating insulating film on the protection layer for covering the
first wiring, and the protection layer for covering the coating
insulating film.
20. A semiconductor device according to claim 19, further
comprising an opening portion formed in the interlayer insulating
film and a sidewall protection layer on a sidewall of the opening
portion, wherein the second wiring contacts the first wiring
through the opening portion, and the sidewall protection layer is a
silicon-containing insulating film which has a peak of an
absorption intensity of an infrared rays in a range of a wave
number 2270 to 2350 cm.sup.-1, a film density in a range of 2.25 to
2.40 g/cm.sup.3, and a relative dielectric constant in a range of
3.3 to 4.3.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a semiconductor device and
a semiconductor device manufacturing method and, more particularly,
a semiconductor device and a semiconductor device manufacturing
method for forming an interlayer insulating film containing a
coating insulating film having a low dielectric constant.
[0003] 2. Description of the Prior Art
[0004] In recent years, the multi-layered wiring structure using
the interlayer insulating film having the low dielectric constant
is employed with the higher integration degree and the higher
density of the semiconductor integrated circuit devices. In such
case, the coating insulating film that is excellent in flatness and
has the low relative dielectric constant is often employed as the
interlayer insulating film.
[0005] The coating insulating film having the low relative
dielectric constant can be obtained by coating the coating liquid
containing the silicon-containing inorganic compound or the coating
liquid containing the silicon-containing organic compound on the
film forming surface by the spin coating method and then removing
the solvent in the coating liquid by the heating.
[0006] However, the coating insulating film contains a large amount
of moisture in the film and has the high hygroscopicity. Also, the
strength of the coating insulating film itself is relatively low.
Since the coating insulating film has a poor adhesiveness with a
CVD (Chemical Vapor Deposition) film or a metal wiring layer, there
is a fear of resulting in peeling-off of the film.
[0007] In order to compensate the weak point of the coating
insulating film, such a structure is often employed that a cap
layer (upper protection layer) and a liner layer (lower protection
layer) containing Si and N or Si and C are formed on and under the
coating insulating film to wrap the coating insulating film
therein.
[0008] The semiconductor device having a multi-layered wiring
comprises an interlayer insulating film that is formed between the
upper and lower wirings by laminating in order the lower protection
layer containing Si and N or Si and C, the coating insulating film
and the upper protection layer containing Si and N or Si and C.
[0009] However, since the insulating film containing Si and N has a
high relative dielectric constant, the entire interlayer insulating
film results in having a higher dielectric constant even if
employing the lower and upper protection layers of thinner
thickness.
[0010] It is difficult for the lower and upper protection layers
containing Si and C to sufficiently suppress an increase of a
leakage current while the lower and upper protection layers
containing Si and C have lower relative dielectric constants than
the lower and upper protection layers containing Si and N.
[0011] In addition, it is impossible to say that the adhesiveness
between the coating insulating film and the lower and upper
protection layers containing Si and N or Si and C is good, and thus
the barrier characteristic to the moisture, etc. is not
perfect.
[0012] On the other hand, there is an occasion where the other
lower and upper protection layers are formed on the lower and upper
surfaces of the coating insulating film using a plasma enhanced
chemical vapor deposition method (hereinafter, referred to as
PE-CVD method). PE-CVD method is capable of film-forming at a
relatively lower range of temperature while using a gas containing
SiH.sub.4 and N.sub.2O, a gas containing SiH.sub.4 and O.sub.2, or
a gas containing TEOS and O.sub.2 as a film-forming gas in order to
improve the adhesiveness.
[0013] However, in the other lower and upper protection layers,
there are problems as follows for the reasons why the adhesiveness
to the coating insulating film and a mechanical strength of the
film itself is not sufficient, and a gas having a strong oxidizing
reaction is employed.
[0014] (i) There arises the peeling-off of the coating insulating
film at an interface between the coating insulating film and the
lower or upper protection layer.
[0015] (ii) The laminated structure in the semiconductor device is
destroyed through the destroy of the lower protection layer as a
stopper which serves as a framework (for reinforcement) during
processing, especially CMP (Chemical mechanical Polishing).
[0016] (iii) At a formation of the upper protection layer, the
usage of the film-forming gas including the gas having the strong
oxidizing reaction results in an increase of the dielectric
constant due to an oxidization of the coating insulating film.
SUMMARY OF THE INVENTION
[0017] It is an object of the present invention to provide a
semiconductor device and a semiconductor device manufacturing
method, in a cover insulating film constituted by a coating
insulating film and a protection layer for covering an upper
surface or a lower surface of the coating insulating film, or in an
interlayer insulating film constituted by a coating insulating film
and a protection layer for covering an upper surface and a lower
surface of the coating insulating film, capable of forming the
cover insulating film or the interlayer insulating film that can
achieve a lower dielectric constant as a whole, has a more complete
barrier characteristic to the moisture, or the leakage current,
etc., and is excellent in flatness.
[0018] It is another object of the present invention to provide a
semiconductor device and a semiconductor device manufacturing
method capable of improving an adhesiveness between the protection
layer and the coating insulating film and a mechanical strength of
the protection layer itself.
[0019] Advantages that are achieved by a configuration of the
present invention will be explained as follows.
[0020] In the present invention, a protection layer is formed to
cover a coating insulating film by plasmanizing a first film
forming gas to react, wherein the first film forming gas consists
of any one selected from a group consisting of alkoxy compound
having Si--H bonds and siloxane having Si--H bonds and any one
oxygen-containing gas selected from a group consisting of O.sub.2,
N.sub.2O, NO.sub.2, CO, CO.sub.2, and H.sub.2O.
[0021] According to the experiment made by the inventors of the
present invention, it is found that the silicon-containing
insulating film formed by plasmanizing the first film forming gas
to react has a good adhesiveness to the coating insulating film, is
dense to the same extent as the silicon nitride film, is excellent
in the water resistance, and contains the small content of moisture
in the film.
[0022] In this manner, the plasma CVD insulating film according to
the present invention has the good adhesiveness to the coating
insulating film and also has the density equivalent to the silicon
nitride film. Therefore, when the plasma CVD insulating film
according to the present invention is formed to come into contact
with the coating insulating film and to cover the coating
insulating film like the configuration of the present invention,
there can be obtained the cover insulating film that can have the
more complete barrier characteristic to the entering of the
moisture into the coating insulating film from the outside and to
the flowing-out of the moisture to the outside, while being
excellent in flatness.
[0023] Also, the plasma CVD insulating film according to the
present invention has the lower relative dielectric constant than
the silicon nitride film in addition to the above characteristics.
The protection layer made of the plasma CVD insulating film
according to the present invention are formed on at least any one
of an upper surface and a lower surface of the coating insulating
film which serves as the main cover insulating film or the main
interlayer insulating film and has the low relative dielectric
constant. There can be obtained the cover insulating film or
interlayer insulating film that has more completely the barrier
characteristic to the entering/flowing-out of the moisture
into/from the coating insulating film, the barrier characteristic
to the leakage current, etc. and also achieves the low dielectric
constant as a whole.
[0024] In this manner, according to the present invention, there
can be obtained the cover insulating film or interlayer insulating
film that can achieve the lower dielectric constant as a whole, has
a barrier characteristic to the entering/flowing-out of the
moisture into/from the coating insulating film and a barrier
characteristic to the leakage current, etc. more completely, and is
excellent in flatness.
[0025] The silicon-containing insulating film of the present
invention has a peak of the absorption intensity of the infrared
rays in a range of the wave number 2270 to 2350 cm.sup.-1, a film
density in a range of 2.25 to 2.40 g/cm.sup.3, and a relative
dielectric constant in a range of 3.3 to 4.3.
[0026] According to the experiment of the inventors of this
application, it is found that the silicon-containing insulating
film having such characteristics has the high mechanical strength,
is dense, is excellent in the water resistance, and has the small
amount of contained moisture in the film like the silicon nitride
film, and has the relative dielectric constant smaller than the
silicon nitride film. Further, it is found that the
silicon-containing insulating film has a good adhesiveness to the
coating insulating film.
[0027] Therefore, if the silicon-containing insulating film having
aforementioned characteristics is employed as the protection layer
for covering the wirings, etc., the corrosion of the wiring can be
prevented by blocking a penetration of the incoming moisture into
the semiconductor device, while the parasitic capacitance between
the wirings can be reduced.
[0028] Also, the upper and lower wirings and the interlayer
insulating film interposed between the upper and lower wirings are
provided on the substrate. The interlayer insulating film is
constructed by laminating in order from the bottom the lower
protection layer formed of the silicon-containing insulating film
according to the present invention, the main insulating film, and
the upper protection layer formed of the silicon-containing
insulating film according to the present invention.
[0029] The silicon-containing insulating film having aforementioned
characteristics has a good adhesiveness with the coating insulating
film, and has the high mechanical strength. Therefore, the
laminated structure is prevented from a destroy such as a
peeling-off of the films, etc., even if a mechanical shock is
applied to the laminated structure from outside.
[0030] The silicon-containing insulating film having aforementioned
characteristics is dense. Therefore, the moisture contained in the
coating insulating film can be prevented from flowing out to the
peripheral portions of the silicon-containing insulating film.
BRIEF DESCRIPTION OF THE DRAWINGS
[0031] FIG. 1 is a side view showing a configuration of the plasma
CVD film forming apparatus employed in a film forming method
according to a first embodiment of the present invention;
[0032] FIG. 2A to FIG. 2E are sectional views showing structures of
samples employed to examine characteristics of a silicon-containing
insulating film that is formed by the film forming method according
to the first embodiment of the present invention, and structures of
comparative samples;
[0033] FIG. 3A and FIG. 3B are tables showing examined results of a
film density of the insulating film that is formed by the film
forming method according to the second embodiment of the present
invention using the sample of FIG. 2A;
[0034] FIG. 4 is a graph showing examined results of a moisture
content and a water resistance of the silicon-containing insulating
film that is formed by the film forming method according to a
second embodiment of the present invention using the sample of FIG.
2A;
[0035] FIG. 5A is a graph showing examined results of an infrared
absorption intensity of the silicon-containing insulating film that
is formed by the film forming method according to a second
embodiment of the present invention using the sample of FIG.
2A;
[0036] FIG. 5B is a graph showing examined results of an infrared
absorption intensity of the silicon-containing insulating film
using the comparative sample of FIG. 2A;
[0037] FIG. 6 is a graph showing examined results of a water
resistance of the silicon-containing insulating film that is formed
by the film forming method according to a second embodiment of the
present invention using the sample of FIG. 2B;
[0038] FIG. 7 is a graph showing examined results of a water
resistance due to a pressure-cooker test of the silicon-containing
insulating film that is formed by the film forming method according
to a second embodiment of the present invention using the sample of
FIG. 2B;
[0039] FIG. 8 is a table showing examined results of an
adhesiveness of the silicon-containing insulating film, that is
formed by the film forming method according to the second
embodiment of the present invention, to a coated insulating film
using the sample of FIG. 2C;
[0040] FIG. 9 is a graph showing examined results of a defect
generating rate due to a heat cycle using the sample of FIG. 2D
according to the second embodiment of the present invention;
[0041] FIG. 10 is a graph showing examined results of a barrier
characteristic to a copper of the silicon-containing insulating
film that is formed by the film forming method according to the
second embodiment of the present invention;
[0042] FIGS. 11A and 11E are sectional views showing a
semiconductor device manufacturing method according to a third
embodiment of the present invention;
[0043] FIGS. 12A to 12D are sectional views showing a semiconductor
device manufacturing method according to a fourth embodiment of the
present invention; and
[0044] FIG. 13 is a sectional view showing a semiconductor device
manufacturing method according to a fifth embodiment of the present
invention.
DESCRIPTION OF THE PREFRRED EMBODIMENTS
[0045] Embodiments of the present invention will be explained with
reference to the accompanying drawings hereinafter.
[0046] (First Embodiment)
[0047] FIG. 1 is a side view showing a configuration of the
parallel-plate type plasma CVD film forming apparatus 101 employed
in a film forming method according to an embodiment of the present
invention.
[0048] This plasma CVD film forming apparatus 101 comprises a film
forming portion 101A that is the place at which a
silicon-containing insulating film is formed by the plasma gas on a
substrate 20, and a film forming gas supplying portion 101B having
a plurality of gas supply sources constituting film forming
gases.
[0049] As shown in FIG. 1, the film forming portion 101A has a
chamber 1 whose pressure can be reduced, and the chamber 1 is
connected to an exhausting device 6 via an exhaust pipe 4. A
switching valve 5 for controlling the open and the close between
the chamber 1 and the exhausting device 6 is provided in the middle
of the exhaust pipe 4. A pressure measuring means such as a vacuum
gauge (not shown) for monitoring the pressure in the chamber 1 is
provided to the chamber 1.
[0050] A pair of an upper electrode (a first electrode) 2 and a
lower electrode (a second electrode) 3 opposing each other are
provided to the chamber 1. A high frequency power supply (RF power
supply) 7 for supplying a high frequency power having a frequency
of 13.56 MHz is connected to the upper electrode 2, while a low
frequency power supply 8 for supplying a low frequency power having
a frequency of 380 kHz is connected to the lower electrode 3. The
film forming gas is plasmanized by supplying the power to the upper
electrode 2 and the lower electrode 3 from these power supplies 7,
8. The upper electrode 2, the lower electrode 3, and the power
supplies 7, 8 constitute the plasma generating means for
plasmanizing the film forming gas.
[0051] As the plasma generating means, there are the means for
generating the plasma by the first and second electrodes 2, 3 of
the parallel-plate type, the means for generating the plasma by ECR
(Electron Cyclotron Resonance) method, the means for generating the
helicon plasma by irradiating the high frequency power from the
antenna, etc., for example.
[0052] The upper electrode 2 is also used as a film forming gas
distributor. A plurality of through holes are formed in the upper
electrode 2, and opening portions of the through holes in the
surface opposing to the lower electrode 3 serve as discharge ports
(inlet ports) of the film forming gas. The discharge ports of the
film forming gas, etc. are connected to the film forming gas
supplying portion 101B via a pipe 9a. Also, a heater (not shown)
may be provided to the upper electrode 2, as the case may be. This
is because, if the upper electrode 2 is heated at the temperature
of almost 100.degree. C. during the film formation, particles made
of reaction products of the film forming gas, etc. can be prevented
from sticking onto the upper electrode 2.
[0053] The lower electrode 3 is also used as a loading table for
the substrate 20. A heater 12 for heating the substrate 20 on the
loading table is provided to the lower electrode 3.
[0054] In the film forming gas supplying portion 101B, a supply
source for the alkoxy compound having Si--H bonds; a supply source
for the siloxane having Si--H bonds; a supply source for any one
oxygen-containing gas selected from a group consisting of oxygen
(O.sub.2), nitrogen monoxide (N.sub.2O), nitrogen dioxide
(NO.sub.2), carbon monoxide (CO), carbon dioxide (CO.sub.2), and
water (H.sub.2O); a supply source for the hydrogen (H.sub.2); and a
supply source for the nitrogen (N.sub.2) are provided.
[0055] As for the alkoxy compound having Si--H bonds or the
siloxane having Si--H bonds as the film forming gas to which the
present invention is applied, followings may be employed as the
typical examples.
[0056] (i) alkoxy compound having Si--H bonds trimethoxysilane
(TMS: SiH(OCH.sub.3).sub.3)
[0057] (ii) siloxane having Si--H bonds tetramethyldisiloxane
(TMDSO: (CH.sub.3).sub.2HSi--O--SiH(CH.sub.3).sub.2)
[0058] These gases are supplied appropriately to the chamber 1 of
the film forming portion 101A via branch pipes 9b to 9f and a pipe
9a to which all branch pipes 9b to 9f are connected. Flow rate
controlling means 11a to 11e and switching means 10b to 10k for
controlling the open and the close of the branch pipes 9b to 9f are
provided in the middle of the branch pipes 9b to 9f. A switching
means 10a for controlling the open and the close of the pipe 9a is
provided in the middle of the pipe 9a. Also, in order to purge the
residual gas in the branch pipes 9b to 9e by flowing the N.sub.2
gas, switching means 101 to 10n, 10p for controlling the open and
the close between the branch pipe 9f, that is connected to the
N.sub.2 gas supply source, and remaining branch pipes 9b to 9e are
provided. The N.sub.2 gas purges the residual gas in the pipe 9a
and the chamber 1 in addition to the branch pipes 9b to 9e.
[0059] According to the film forming apparatus 101 described above,
the supply source for supplying at least any one of the alkoxy
compound having Si--H bonds and the siloxane having Si--H bonds and
the oxygen-containing gas supply source are provided, and also the
plasma generating means 2, 3, 7, 8 for plasmanizing the film
forming gas are provided.
[0060] The insulating film containing Si, 0, C, H can be formed by
the plasma CVD method by using the above plasma CVD equipment.
Therefore, as shown in a second embodiment described in the
following, it is possible to form the insulating film that has the
low dielectric constant, has the small amount of moisture content,
is dense and is excellent in water resistance. Also, this
insulating film has the good adhesiveness to the organic coating
insulating film or the inorganic coating insulating film, and has
the higher capability for preventing the diffusion of copper
(Cu).
[0061] In particular, the power supplies 7, 8 for supplying the
powers having two high and low frequencies to the first and second
electrodes 2, 3 of parallel-plate type respectively are connected
to them. Therefore, the plasma can be generated by applying the
powers having these two high and low frequencies to the electrodes
2, 3 respectively. Thus, the insulating film formed in this manner
is dense.
[0062] (Second Embodiment)
[0063] The examination made by the inventors of the present
invention for the silicon-containing insulating film that is formed
by the above plasma CVD equipment will be explained hereunder.
[0064] First, the well-known parallel-plate type plasma CVD
equipment is employed as the above plasma CVD equipment. The lower
electrode 3 of the upper and lower electrodes 2, 3 is also used as
a substrate holder, and the heater 12 for heating the substrate is
built in the lower electrode 3.
[0065] (Formation of Samples)
[0066] FIGS. 2A to 2E are sectional views showing samples having a
silicon oxide film (a silicon-containing insulating film) of the
present invention.
[0067] As shown in FIG. 2A, a sample S1 has the silicon oxide film
(this means the silicon-containing insulating film, and referred to
as a "PE-CVD TMS SiO.sub.2 film" hereinafter) 42a, that is formed
by the PE-CVD method using the film forming gas containing
trimethoxysilane (TMS) on a silicon substrate 41. For the sake of
comparison, a comparative sample CS1 having a silicon oxide film
(referred to as a "PE-CVD TEOS SiO.sub.2 film" hereinafter) 51a,
that is formed by the PE-CVD method using the film forming gas
containing tetraethoxysilane (TEOS) on the silicon substrate 41,
and a comparative sample CS2 having a silicon oxide film (referred
to as a "PE-CVD SiH.sub.4 SiO.sub.2 film" hereinafter) 52a, that is
formed by the PE-CVD method using the film forming gas containing
monosilane (SiH.sub.4) on the silicon substrate 41, are
prepared.
[0068] As shown in FIG. 2E, a sample S1A is formed by further
forming an electrode 45 on the PE-CVD TMS SiO.sub.2 film 42a, in
the sample Si in which the PE-CVD TMS SiO.sub.2 film 42a is formed
on the silicon substrate 41. The mercury probe is employed as the
electrode 45, and a contact area between the mercury probe and the
PE-CVD TMS SiO.sub.2 film 42a is 0.0230 cm.sup.2.
[0069] As shown in FIG. 2B, samples S2, S3 are formed by forming a
BPSG film 43 having an amount of contained phosphorus of 7 mol %
and a film thickness of about 500 nm and a PE-CVD TMS SiO.sub.2
film 42b to be tested in sequence on the silicon substrate (Si
substrate) 41. A film thickness of the PE-CVD TMS SiO.sub.2 film
42b is set to 100 nm in the sample S2, and a film thickness of the
PE-CVD TMS SiO.sub.2 film 42b is set to 200 nm in the sample S3.
For comparison, a comparative sample CS3 employing a PE-CVD TEOS
SiO.sub.2 film 51b having a film thickness of 200 nm in place of
the PE-CVD TMS SiO.sub.2 film 42b, a comparative sample CS4
employing a PE-CVD SiH.sub.4 SiO.sub.2 film 52b having a film
thickness of 200 nm similarly, and a comparative sample CS5
employing a silicon nitride film (referred to as a "PE-CVD SiN
film" hereinafter) 53, that is formed by the plasma CVD method
using the film forming gas containing SiH.sub.4, NH.sub.3 and
N.sub.2 similarly to have a film thickness of 200 nm, are
prepared.
[0070] As shown in FIG. 2C, samples S4, S5 are formed by forming
low dielectric constant insulating films 44a, 44b and a PE-CVD TMS
SiO.sub.2 film 42c in sequence on the silicon substrate (Si
substrate) 41. An inorganic coating insulating film 44a is employed
as the low dielectric constant insulating film in the sample S4,
and an organic coating insulating film 44b is employed similarly in
the sample S5. For comparison, comparative samples CS6, CS7
employing a PE-CVD TEOS SiO.sub.2 film 51c in place of the PE-CVD
TMS SiO.sub.2 film 42c are formed. The inorganic coating insulating
film 44a is employed as the low dielectric constant insulating film
in the comparative sample CS6, and the organic coating insulating
film 44b is employed similarly in the comparative sample CS7.
[0071] The inorganic coating insulating film is such an insulating
film that is formed by coating the coating liquid such as HSQ
(product name: manufactured by Dow Corning Co., Ltd.), MSQ (product
name), R7 (product name: Hitachi Chemical Co., Ltd.), etc. The
compound having one carbon or less is distinctively contained as
the component compound in the coating liquid. The organic coating
insulating film is formed by coating the coating liquid such as
FLARE (product name: manufactured by Allied Signal Co., Ltd.), SiLK
(product name: manufactured by The Dow Chemical Co.), etc. The
compound having two carbons or more is distinctively contained as
the component compound in the coating liquid.
[0072] As shown in FIG. 2D, a sample S6 is formed by forming a
PE-CVD TMS SiO.sub.2 film (lower protection layer) 42d having a
film thickness of about 150 nm, a coating insulating film (main
insulating film) 44c having a film thickness of about 200 nm, and a
PE-CVD TMS SiO.sub.2 film (upper protection layer) 42e having a
film thickness of about 200 nm in sequence on the silicon substrate
41. The coating insulating film 44c is formed by spin-coating the
coating liquid (FOx (product name)), that is produced by dissolving
HSQ (Hydrogen silsesquioxane) into the solvent, then baking the
coated liquid at the temperature of 150, 200, and 350.degree. C.
for one minute in the nitrogen respectively, and then curing the
resultant at the temperature of 400.degree. C. for 50 minutes in
the nitrogen. For comparison, a comparative sample CS8 in which a
PE-CVD TEOS SiO.sub.2 film 51d is formed in place of the PE-CVD TMS
SiO.sub.2 film 42d as the lower protection layer and a comparative
sample CS9 in which PE-CVD TEOS SiO.sub.2 films 51d, 51e are formed
in place of the PE-CVD TMS SiO.sub.2 films 42d, 42e as the upper
and lower protection layers are prepared.
[0073] The PE-CVD TMS SiO.sub.2 films 42a to 42e of the samples S1
to S6 are formed by using the above plasma CVD equipment under
following film forming conditions.
[0074] Film forming gas: TMS+N.sub.2O
[0075] TMS gas flow rate: 100 sccm
[0076] N.sub.2O gas flow rate: 3000 sccm
[0077] Gas pressure: 0.7 Torr
[0078] Plasmanizing conditions
[0079] Power density applied to the upper electrode 2: 0.3
W/cm.sup.2
[0080] (frequency 13.56 MHz)
[0081] Power density applied to the lower electrode 3: 0.3
W/cm.sup.2
[0082] (frequency 380 kHz)
[0083] In this film-forming apparatus, these power densities
correspond to the applied powers 750W to the electrodes,
respectively.
[0084] Substrate temperature: 300 to 400.degree. C.
[0085] Film forming thickness: t nm
[0086] The above plasma CVD apparatus 101 is also employed for
forming the PE-CVD TEOS SiO.sub.2 film 51a of the comparative
sample CS1, the PE-CVD SiH.sub.4 SiO.sub.2 film 52a of the
comparative sample CS2, the PE-CVD TEOS SiO.sub.2 films 51b to 51e
of the comparative samples CS3, CS4, CS6 to CS9, the PE-CVD SiN
film 53 of the comparative sample CS5.
[0087] Following characteristics of the PE-CVD TMS SiO.sub.2 film
42a to 42e formed as above are examined.
[0088] (i) Basic Characteristic
[0089] The film forming rate of the above film forming conditions
is at the range of about 160 to 170 nm/min.
[0090] Also, the refractive index of the formed PE-CVD TMS
SiO.sub.2 film is at the range of 1.477 to 1.48, and the film
stress is -250 Mpa or 3.0.times.10.sup.9 dyne/cm.sup.2. The
ellipsometer using the He--Ne laser having a wavelength of 6338
angstrom is employed to measure the refractive index. Also, the
optilever laser scanning system is employed to measure the film
stress.
[0091] Also, the film thickness (t) is 500 nm, and the relative
dielectric constant of the PE-CVD TMS SiO.sub.2 film is 3.9. The
sample C1A is employed as a sample to examine the relative
dielectric constant.
[0092] The relative dielectric constant is calculated based on the
result that is obtained by superposing a small signal having a
frequency of 1 MHz onto the DC voltage (V) applied between the Si
substrate 41 and the electrode 45 in the examined sample S1A, and
then measuring the change in a capacitance (C) in response to the
change in the DC voltage (V).
[0093] (ii) Concentration of Carbon and Nitrogen in the Film
[0094] A concentration of carbon and nitrogen in the PE-CVD TMS
SiO.sub.2 film 42a is measured by the auger electron spectroscopy
method (AES method) using the sample S1.
[0095] According to the measuring results, the concentration of
carbon is 1.0 atoms %, and the concentration of carbon is 2.1 atoms
%.
[0096] (iii) Film Density
[0097] The film density of the PE-CVD TMS SiO.sub.2 film 42a is
examined employing the sample S1 by the well-known X-ray
interference method or weight measuring method.
[0098] By way of comparison, similar examinations are carried out
to the thermal SiO.sub.2 film, the comparative sample CS1 of the
PE-CVD TEOS SiO.sub.2 film 51a, and the comparative sample CS2 of
the PE-CVD SiH.sub.4 SiO.sub.2 film 52a in place of the PE-CVD TMS
SiO.sub.2 film 42a.
[0099] As shown in FIGS. 3A and 3B, it is found that the PE-CVD TMS
SiO.sub.2 film 42a has the high film density of 2.33 rather than
other insulating films and is dense.
[0100] (iv) Moisture Content in the Film
[0101] An amount of contained moisture in both the film that is
obtained immediately after the formation (as deposited) and the
film that is left for two weeks in the air is measured employing
the sample S1 by the TDS (Thermal Desorption Mass Spectroscopy)
method. This TDS method is the way of heating the sample and then
measuring the molecules emitted from the sample. For the sake of
comparison, the similar examination is carried out to the
comparative sample CS1 employing the PE-CVD TEOS SiO.sub.2 film
51a.
[0102] The examination is carried out by heating the sample from
the room temperature to 800.degree. C. by the TDS analysis
equipment and then quantitating the amount of moisture extracted
from the sample.
[0103] FIG. 4 is a graph showing the examined results. In FIG. 4,
an ordinate denotes the amount of moisture (wt %) represented in a
linear scale and an abscissa denotes the temperature (.degree. C.)
represented in a linear scale.
[0104] According to the measurement executed immediately after the
film formation (as deposited), when the temperature is risen from
the room temperature to 800.degree. C., the amount of moisture in
the PE-CVD TMS SiO.sub.2 film 42a is 0.11 wt % whereas the amount
of moisture in the PE-CVD TEOS SiO.sub.2 film 51a is 0.49 wt %. In
addition, according to the measurement executed two weeks later,
the amount of moisture in the PE-CVD TMS SiO.sub.2 film 42a is
increased merely by +0.2 to 0.3 wt % and thus the amount of
moisture is seldom varied.
[0105] As described above, it is found that both the structural
water (the moisture contained in the film due to the film forming
gas and the film structure immediately after the film formation)
and the physical adsorption water (the incoming moisture that is
adsorbed and absorbed physically) in the PE-CVD TMS SiO.sub.2 film
42a are small in contrast to the PE-CVD TEOS SiO.sub.2 film
51a.
[0106] (v) FT-IR Absorption Intensity
[0107] Then, examined results of the infrared rays absorption
intensity in the sample S1 by the FT-IR analysis method (Fourier
Transform Infrared analysis method) are shown in FIG. 5A.
Similarly, examined results in the comparative samples CS1, CS2 are
shown in FIG. 5B.
[0108] An ordinate of FIG. 5A denotes the absorption intensity
expressed in a linear scale (arbitrary unit), and an abscissa
denotes the wave number expressed in a linear scale (cm.sup.-1).
Similarly, this is true of FIG. 5B.
[0109] As shown in FIG. 5A, the peak of the infrared rays
absorption intensity having a center wave number in a range of 2270
to 2350 cm.sup.-1 is confirmed. In contrast, as shown in FIG. 5B,
such peak is not watched in the comparative samples CS1, CS2.
[0110] (vi) Water Resistance
[0111] The water resistance of the PE-CVD TMS SiO.sub.2 film 42b is
exampled by the high pressure humidifying test (pressure-cooker
test) while using the samples S2, S3 shown in FIG. 2B. By way of
comparison, the similar examination is applied to the comparative
sample CS3 employing the PE-CVD TEOS SiO.sub.2 film 51b in place of
the PE-CVD TMS SiO.sub.2 film 42b and the comparative sample CS5
employing the PE-CVD SiN film 53 similarly.
[0112] The conditions of the high pressure humidifying test are
given as follows. The leaving time is used as a parameter.
[0113] Temperature: 121.degree. C.
[0114] Pressure: 2.0 atm
[0115] Humidity: 100% R.T. (Room Temperature)
[0116] Evaluation of the water resistance is carried out by
evaluating an amount of P.dbd.O bonds contained in the examined
insulating film after the high pressure humidifying test. In order
to evaluate the amount of P.dbd.O bonds contained in the BPSG film
43, the P.dbd.O absorption coefficient is measured by the FT-IR
analysis method. If the moisture enters the BPSG film 43, the
P.dbd.O bonds in the film react with the moisture to destroy. In
this case, if the PE-CVD TMS SiO.sub.2 film 42b for covering the
BPSG film 43 has the high water resistance, the moisture does not
pass through such film and thus the P.dbd.O bonds in the BPSG film
43 are never destroyed. As a result, it is possible to say that, if
the time dependent change of the P.dbd.O absorption coefficient
becomes smaller, the water resistance becomes higher.
[0117] FIG. 6 is a graph showing the time dependent change of an
amount of contained phosphorus in the insulating film after the
high pressure humidifying test is carried out. An ordinate denotes
the P.dbd.O absorption coefficient (arbitrary unit) expressed in a
linear scale, and an abscissa denotes the leaving time (H (hour))
expressed in a linear scale.
[0118] Based on the results shown in FIG. 6, it is found that, even
after both the samples S2, S3 are left for 150 hours as they are,
their P.dbd.O absorption coefficients are seldom changed from the
initial P.dbd.O absorption coefficient regardless of the magnitude
of the thickness of the PE-CVD TMS SiO.sub.2 film 42b, like the
PE-CVD SiN film 53 in the comparative sample CS5, i.e., the PE-CVD
TMS SiO.sub.2 film 42b has the water resistance equivalent to the
PE-CVD SiN film 53.
[0119] Also, the water resistance is examined by another high
pressure humidifying test while using the examined sample S3 and
the comparative samples CS3, CS4.
[0120] The conditions of the high pressure humidifying test are the
same as above.
[0121] The results are shown in FIG. 7. An ordinate of FIG. 7
denotes the water resistance (%) expressed in a linear scale, and
an abscissa denotes the leaving time (H (hour)) expressed in a
linear scale. The sample S3 and the comparative samples CS3, CS4
are used as a parameter.
[0122] Like the above, the evaluation of the water resistance is
carried out by evaluating an amount of P.dbd.O bonds contained in
the examined insulating film after the high pressure humidifying
test. The water resistance in FIG. 7 is derived by calculating the
P.dbd.O absorption coefficient obtained after the high pressure
humidifying test on the basis of the P.dbd.O absorption coefficient
before the leaving-off, that is assumed as 100.
[0123] As shown in FIG. 7, it is found that the sample S3 has the
water resistance of 97.4% (100 H), that exceeds the comparative
samples CS3, CS4.
[0124] (vii) Leakage Current of the Film
[0125] The examined sample S1A shown in FIG. 2E is formed. That is,
the electrode 45 is formed on the PE-CVD TMS SiO.sub.2 film 42
having a film thickness (t) of 200 nm in the sample S1 according to
the present invention.
[0126] The leakage current flowing through the silicon substrate 41
and the electrode 45 is measured by applying the voltage between
the silicon substrate 41 and the electrode 45. The silicon
substrate 41 is grounded, and the negative voltage is applied to
the electrode 45.
[0127] According to the results, the leakage current of the PE-CVD
TMS SiO.sub.2 film 42a as the single substance is on the order of
10.sup.-8 A/cm at the electric field strength of 5 MV/cm, and the
breakdown voltage is about 10 MV/cm in terms of the electric
field.
[0128] (viii) Adhesiveness of the Film
[0129] The adhesiveness between the PE-CVD TMS SiO.sub.2 film 42c
according to the present invention and the underlying low
dielectric constant insulating film 44a, 44b is examined employing
the samples S4, S5. Also, the sample which is subjected to the
surface treatment prior to the film formation and the sample which
is not subjected to the surface treatment are prepared, and then
the similar examination is carried out. The surface treatment
executed prior to the film formation is the treatment for reforming
the surface of the processed film by employing the plasma of
N.sub.2, NH.sub.3, H.sub.2, etc.
[0130] By way of comparison, the PE-CVD TEOS SiO.sub.2 film 51c is
employed in place of the PE-CVD TMS SiO.sub.2 film 42c, and similar
examinations are carried out employing the inorganic coating
insulating film 44a (the comparative sample CS6) and the organic
coating insulating film 44b (the comparative sample CS7)as the low
dielectric constant insulating film.
[0131] As the test for examining the adhesiveness of the film, the
peel test by using the tape and the peel test by the CMP (Chemical
Mechanical Polishing) on the entire surface of the wafer are
carried out.
[0132] According to the examined results, regardless of the
presence of the surface treatment prior to the film formation, the
PE-CVD TMS SiO.sub.2 film 42c has the good adhesiveness to the
inorganic coating insulating film 44a and the organic coating
insulating film 44b. In contrast, a degree of the adhesiveness of
the PE-CVD TEOS SiO.sub.2 film 51c is inferior to the PE-CVD TMS
SiO.sub.2 film 42c as a whole. Then, difference in the adhesiveness
appeared in response to whether or not the surface treatment is
applied prior to the film formation. That is, the sample which is
subjected to the surface treatment prior to the film formation had
the higher adhesiveness than the sample which is not subjected to
the surface treatment.
[0133] (ix) Defect Generating Rate Due to Heat Cycle
[0134] The defect generating rate due to the heat cycle about the
sample S6 and the comparative samples CS8, CS9 is examined.
Respective samples are sealed in the package. Test conditions of
the heat cycle are given as follows. The cycle number is used as a
parameter.
[0135] High temperature (holding time): 150.degree. C. (20
minutes)
[0136] Low temperature (holding time): -55.degree. C. (20
minutes)
[0137] Cycle number: 100, 200, 300, 500 C
[0138] The defect is defined as the sample in which a peeling-off
of a film or a crack of a film has generated. The results are shown
in FIG. 9. An ordinate of FIG. 9 denotes the defect generating rate
(%) expressed in a linear scale, and an abscissa denotes the types
of the sample. The types of the sample are the sample S6, and the
comparative samples CS8, CS9, as explained above, in order from the
left side. The partition area indicated by a bar graph denotes a
fraction defective at a particular cycle number, the partition area
hatched by lateral lines denotes the fraction defective at
100.degree. C., the partition area hatched by vertical lines
denotes the fraction defective at 200.degree. C., the partition
area hatched by oblique lines denotes the fraction defective at
300.degree. C., and the white partition area on a black ground
denotes the fraction defective at 500.degree. C.
[0139] As shown in FIG. 9, in the sample S6 employing the silicon
oxide film of the present invention as both the upper protection
layer and the lower protection layer, the defect is generated at
300.degree. C. or more, but the defect generating rate is about 2
to 3% even if the defect generating rates at 300.degree. C. and
500.degree. C. are added. In the comparative sample CS8 employing
the silicon oxide film 52d of the present invention only as the
lower protection layer out of the upper protection layer and the
lower protection layer, the defect is generated almost uniformly
from 100.degree. C. to 500.degree. C., and the defect generating
rate is about 25% in total. In the comparative sample CS9 not
employing the silicon oxide film 42d, 42e of the present invention
as both the upper protection layer and the lower protection layer,
the defect is generated from 100.degree. C. to 500.degree. C. In
particular, the defect generating rate at 300.degree. C. and
500.degree. C. are increased, and the defect generating rate is
about 53% in total.
[0140] (x) Examination of the Barrier Characteristic to the Copper
(Cu)
[0141] (a) TDDB (Time Dependent Dielectric Breakdown) Test
[0142] The TDDB test measures a time required to come up to the
dielectric breakdown when the voltage is applied to the sample.
[0143] The examined sample is prepared by stacking the PE-CVD TMS
SiO.sub.2 film according to the present invention and the Cu film
on the Si substrate in sequence. By way of comparison, the similar
examination is applied to the sample employing the PE-CVD TEOS
SiO.sub.2 film in place of the PE-CVD TMS SiO.sub.2 film, and the
sample interposing the TiN film between the Cu film and the PE-CVD
TEOS SiO.sub.2 film.
[0144] According to the examined results, the breakdown lifetime of
10.times.10.sup.5 seconds is obtained at the electric field
strength of 8 MV/cm.
[0145] In contrast, in the sample employing the PE-CVD TEOS
SiO.sub.2 film, the electric field strength is 8 MV/cm to get the
breakdown lifetime on the order of 10.times.10.sup.5 seconds. This
means that the breakdown lifetime of the sample employing the
PE-CVD TMS SiO.sub.2 film is longer by almost six figures than the
sample employing the PE-CVD TEOS SiO.sub.2 film.
[0146] In the sample interposing the TiN film between the Cu film
and the PE-CVD TEOS SiO.sub.2 film, the electric field strength is
7.5 MV/cm to get the breakdown lifetime on the order of
10.times.10.sup.5 seconds.
[0147] With the above, it is possible to say that the sample
employing the PE-CVD TMS SiO.sub.2 film has the longer breakdown
lifetime by almost six figures than the sample employing the PE-CVD
TEOS SiO.sub.2 film and has the barrier characteristic to Cu, that
is equivalent to or more than the TiN film.
[0148] (b) Examination of Heat Resistance
[0149] As shown in FIG. 10, the examined sample is prepared by
stacking the PE-CVD TMS SiO.sub.2 film of 125 nm thickness
according to the present invention and the Cu film on the Si
substrate (not shown) to contact to each other.
[0150] The examination is made by measuring the Cu concentration
distribution state in the PE-CVD TMS SiO.sub.2 film on the basis of
the state obtained immediately after the film formation (indicated
by a dotted line in FIG. 10) after the sample is processed for a
predetermined time (three types, i.e., 1 hour (chain double-dashed
line), 7 hours (solid line), and 15 hours (dot-dash line)) at the
temperature of 470.degree. C.
[0151] FIG. 10 is a graph showing the examined results. In FIG. 10,
an ordinate on the left side denotes a Cu concentration and a Si
concentration (cm.sup.-3) represented in a logarithmic scale. An
abscissa denotes a depth (nm) measured from one surface of the
PE-CVD TMS SiO.sub.2 film toward the Cu film side and represented
in a linear scale.
[0152] As shown in FIG. 10, the distribution is seldom changed from
the distribution obtained immediately after the film formation. In
other words, it is found that the PE-CVD TMS SiO.sub.2 film has the
sufficient barrier characteristic to the Cu.
[0153] In the above, the alkoxy compound (ex. TMS) having Si--H
bonds is employed as the silicon-containing gas in the film forming
gas. But the siloxane having Si--H bonds may be employed.
[0154] Also, N.sub.2O is employed as the oxygen-containing gas in
the above. But any one selected from the group consisting of oxygen
(O.sub.2), nitrogen dioxide (NO.sub.2), carbon monoxide (CO),
carbon dioxide (CO.sub.2) and water (H.sub.2O) may be employed.
[0155] In addition, if any one selected from the group consisting
of hydrogen (H.sub.2) and nitrogen (N.sub.2) is added to the above
film forming gas, the density can be further enhanced.
[0156] (Third Embodiment)
[0157] Next, a semiconductor device and a method of manufacturing
the same according to a third embodiment of the present invention
will be explained with reference to FIGS. 11A and 11E
hereunder.
[0158] FIG. 11E are sectional views showing the semiconductor
device according to the third embodiment of the present
invention.
[0159] A base protection layer 23 consisting of a
silicon-containing insulating film according to the present
invention is formed on a base substrate 22. Three-layered wirings
24, 29, 34 which interpose an interlayer insulating film between
any two adjacent wirings are formed on the base protection layer
23. These interlayer insulating films are constructed by a lower
protection layer 25, 30, a main insulating film 26, 31, and an
upper protection layer 27, 32. The lower protection layer 25, 30
and upper protection layer 27, 32 are made of the
silicon-containing insulating film according to the present
invention. A protection layer 35 made of the silicon-containing
insulating film according to the present invention and a coating
insulating film 36 are formed on the uppermost wiring 34.
[0160] The silicon-containing insulating film according to the
present invention, which constitutes the protection layer 23, 25,
27, 30, 32, 35, has a peak of the absorption intensity of the
infrared rays in a range of the wave number 2270 to 2350 cm.sup.-1,
a film density in a range of 2.25 to 2.40 g/cm.sup.3, and a
relative dielectric constant in a range of 3.3 to 4.3.
[0161] A silicon substrate or a base substrate in which a wiring or
an insulating film is formed on a silicon substrate is employed as
the base substrate 22.
[0162] According to the experiment carried out by the inventor of
the present application, the silicon-containing insulating film 23,
25, 27, 30, 32, 35 having aforementioned characteristics has a high
mechanical strength, is dense, is excellent in the water
resistance, is little in a moisture content in the film similar to
the silicon nitride film, and is lower in the relative dielectric
constant in contrast to the silicon nitride film. Further, the
silicon-containing insulating film 23, 25, 27, 30, 32, 35 has a
good adhesiveness with the coating insulating film.
[0163] Accordingly, an employment of the silicon-containing
insulating film having aforementioned characteristics as the
protection layer 23, 25, 27, 30, 32, 35 for covering the wiring 24,
29, 34, etc, contributes to a prevention of a corrosion of the
wirings 24, 29, 34 through blocking a penetration of incoming water
as well as a reduction of a parasitic capacitance between the
wirings 24, 29, 34.
[0164] Moreover, an employment of the silicon-containing insulating
film having aforementioned characteristics as the protection layer
23, 25, 27, 30, 32, 35 for protecting an upper and a lower surfaces
of the coating insulating film 26, 31, 36 contributes to a
prevention of a corrosion of the wirings 24, 29, 34 through
blocking a flowing-out of moisture to outer periphery of the
protection layer 23, 25, 27, 30, 32, 35 and a penetration of
incoming water as well as a reduction of a parasitic capacitance
between the wirings 24, 29, 34.
[0165] Further, since the silicon-containing insulating film having
aforementioned characteristics has a good adhesiveness to the
coating insulating film 26, 31, 36 and a high mechanical strength,
the laminated structure is prevented from a destroy such as a
peeling-off of the films, etc., even if a mechanical shock is
applied to the laminated structure from outside.
[0166] FIGS. 11A and 11E are sectional views showing the method of
manufacturing the semiconductor device according to the third
embodiment of the present invention. TMS+N.sub.2O is employed as
the film forming gas for the base protection layer, the lower
protection layer, the upper protection layer, and the protection
layer, which are formed on at least any surface of the upper and
lower surfaces of the coating insulating film and to which the
present invention is applied.
[0167] First, as shown in FIG. 11A, a base insulating film 23 made
of the PE-CVD TMS SiO.sub.2 film is formed on the silicon substrate
(base substrate) 22 by the plasma CVD method using TMS+N.sub.2O as
the film forming gas.
[0168] In order to form the PE-CVD TMS SiO.sub.2 film (base
protection layer) 23, first the silicon substrate 22 is loaded into
the chamber 1 of the plasma film forming apparatus 101 shown in
FIG. 1 and then held by the substrate holder 3. Then, the silicon
substrate 22 is heated to be held at the temperature of 350.degree.
C. TMS and N.sub.2O gas are introduced into the chamber 1 of the
plasma film forming apparatus 101 at flow rates of 100 sccm and
3000 sccm respectively to hold the pressure at 0.7 Torr. Then, the
power 0.3 W/cm.sup.2 having the frequency of 380 kHz is applied to
the lower electrode 3 and also the power 0.3 W/cm.sup.2 having the
frequency of 13.56 MHz is applied to the upper electrode 2.
[0169] Accordingly, TMS and N.sub.2O are plasmanized. The PE-CVD
TMS SiO.sub.2 film 23 of about 200 nm thickness is formed while
holding this condition for a predetermined time. According to the
examination, the formed PE-CVD TMS SiO.sub.2 film 23 has the
relative dielectric constant of about 3.9 that is measured at the
frequency of 1 MHz, and the leakage current of 10.sup.-8 A/cm.sup.2
at the electric field strength of 5 MV/cm.
[0170] Then, a first wiring 24 is formed on the base protection
layer 23. Then, a first barrier insulating film (a lower protection
layer) 25 made of the PE-CVD TMS SiO.sub.2 film having the
thickness of about 500 nm is formed thereon by the plasma CVD
method that is set to the same film forming conditions used when
the above PE-CVD TMS SiO.sub.2 film 23 is formed.
[0171] The formed first barrier insulating film 25 has the relative
dielectric constant of about 3.9 that is measured at the frequency
of 1 MHz, and the leakage current of 10.sup.-8 A/cm.sup.2 at the
electric field strength of 5 MV/cm.
[0172] In this case, if the first wiring 24 is formed of the copper
wiring, a TaN film serving as the copper barrier to the base
protection layer 23 and a Cu film formed by the sputter, although
not shown, are formed between the base protection layer 23 and the
first wiring 24 from the bottom.
[0173] Then, as shown in FIG. 11B, a first coating insulating film
26 having the low relative dielectric constant and the film
thickness of about 500 to 1000 nm is formed by the spin coating
method employing the coating liquid containing the
silicon-containing inorganic compound or the silicon-containing
organic compound. The first coating insulating film 26 constitutes
a main insulating film. These elements constitute the substrate
20.
[0174] Where the coating liquid containing the silicon-containing
inorganic compound is the coating liquid used to form the inorganic
coating insulating film, explained in the above (Formation of
Samples) item in the second embodiment, and contains the silicon.
Similarly, the coating liquid containing the silicon-containing
organic compound is the coating liquid used to form the organic
coating insulating film and contains the silicon.
[0175] Then, as shown in FIG. 11C, a second barrier insulating film
(an upper protection layer) 27 made of the PE-CVD TMS SiO.sub.2
film having the thickness of about 50 nm is formed on the first
coating insulating film 26 by the plasma CVD method that is set to
the same film forming conditions used for the formation of the
above PE-CVD TMS SiO.sub.2 film 23.
[0176] Then, a photoresist film (not shown) is formed on the second
barrier insulating film 27. Then, as shown in FIG. 11D, an opening
portion in the photoresist film is formed in the via-hole forming
area by patterning the photoresist film. Then, first the second
barrier insulating film 27 is etched and removed via the opening
portion in the photoresist film by the reactive ion etching (RIE)
using the plasmanized CF.sub.4+CHF.sub.3-based mixed gas. Then, the
first coating insulating film 26 is etched and removed by using the
CF.sub.4+CHF.sub.3-based mixed gas, whose composition ratio is
changed from the gas used in the etching of the second barrier
insulating film 27. Accordingly, an opening portion is formed to
expose the first barrier insulating film 25 at the bottom of the
opening portion. A concentration of the CF.sub.4+CHF.sub.3-based
mixed gas may be adjusted by adding Ar+O.sub.2, etc. in addition to
CF.sub.4+CHF.sub.3.
[0177] After this, the ashing of the photoresist film is carried
out.
[0178] Then, the first barrier insulating film 25 is etched and
removed via the opening portion in the second barrier insulating
film 27 and the opening portion in the first coating insulating
film 26 by the reactive ion etching (RIE) using the plasmanized
CF.sub.4+CHF.sub.3-based mixed gas, that has the same composition
ratio as the gas used in the etching of the above second barrier
insulating film 27. Accordingly, a first via hole is formed to
expose the first wiring 24 from its bottom portion. At this time,
the first wiring 24 has the etching resistance against the etching
gas for the above barrier insulating film 25. As a result, the
first wiring 24 is not badly affected by the etching gas. In this
case, if a surface of the first wiring 24 is oxidized, an oxide
film may be removed by exposing to the hydrogen plasma diluted with
a reducing gas, for example, NH.sub.3, an inert gas such as argon,
nitrogen, or the like after the ashing step of the photoresist film
and the etching step of the first barrier insulating film 25 are
completed.
[0179] Then, the photoresist film is removed, and then a conductive
film is filled in the first via hole 28. Then, a second wiring 29
made of copper or aluminum is formed to be connected to the first
wiring 24 via the conductive film. In this case, if the second
wiring 29 is made mainly of copper, an underlying conductive film
consisting of a barrier metal film such as tantalum nitride (TaN),
etc. and a copper film formed by the sputter method is provided in
the via hole 28 and on the second barrier insulating film 27, and
then a conductive film made of copper is deposited thereon.
[0180] Then, a third barrier insulating film (a lower protection
layer) 30 made of the PE-CVD TMS SiO.sub.2 film having the film
thickness of about 50 nm; a second coating insulating film 31
having the low dielectric constant and the film thickness of about
500 to 1000 nm, that is formed on the third barrier insulating film
30 by the same material and conditions as the coating method in
FIG. 11B; and a fourth barrier insulating film (an upper protection
layer) 32 made of the PE-CVD TMS SiO.sub.2 film having the film
thickness of about 50 nm are formed in sequence by repeating the
steps shown in FIGS. 11A to 11D. Then, a second via hole 33 is
formed to pierce the fourth barrier insulating film 32, the second
coating insulating film 31, and the third barrier insulating film
30. Then, a third wiring 34 that is connected to the second wiring
29 via the second via hole 33 is formed on the fourth barrier
insulating film 32.
[0181] Then, a fifth barrier insulating film (a lower protection
layer) 35 made of the PE-CVD TMS SiO.sub.2 film having the film
thickness of about 50 nm is formed by the plasma CVD method of the
present invention to cover the third wiring 34. Then, a third
coating insulating film 36 having the low dielectric constant and
the film thickness of about 500 to 1000 nm is formed on the fifth
barrier insulating film 35 by the same material and conditions as
the coating method in FIG. 11B.
[0182] With the above, the formation of the second wiring 29 that
is connected to the first wiring 24 and the third wiring 34 that is
connected to the second wiring 29 is completed.
[0183] According to the third embodiment, the upper and lower
surfaces of the first coating insulating film 26 having the low
dielectric constant are covered with the first barrier insulating
film 25 made of the PE-CVD TMS SiO.sub.2 film and the second
barrier insulating film 27 made of the PE-CVD TMS SiO.sub.2 film.
Similarly, the upper and lower surfaces of the second coating
insulating film 31 having the low dielectric constant are covered
with the third barrier insulating film 30 made of the PE-CVD TMS
SiO.sub.2 film and the fourth barrier insulating film 32 made of
the PE-CVD TMS SiO.sub.2 film.
[0184] By the way, as indicated by the examined results in the
second embodiment, the PE-CVD TMS SiO.sub.2 film to which the
present invention is applied has the qualities such that such film
is dense, is excellent in the water resistance, and has the small
amount of contained moisture in the film, that are equivalent to
the silicon nitride film.
[0185] Accordingly, the entering of the incoming moisture into the
first coating insulating film 26 and the second coating insulating
film 31 can be blocked. Also, if the moisture is contained
originally in the first coating insulating film 26 and the second
coating insulating film 31, such moisture can be prevented from
flowing out to the peripheral portions of the first coating
insulating film 26 and the second coating insulating film 31.
Therefore, variation in the relative dielectric constant due to the
amount of moisture contained in the first coating insulating film
26 and the second coating insulating film 31 can be suppressed.
[0186] Further, the PE-CVD TMS SiO.sub.2 film has the equivalent
quality to the silicon nitride film in the respect of density, but
has the quality of the small relative dielectric constant, that is
largely different from the silicon nitride film. As a result, if
the PE-CVD TMS SiO.sub.2 film is employed as the interlayer
insulating film, the smaller relative dielectric constant of the
interlayer insulating film can be achieved.
[0187] In particular, if the PE-CVD TMS SiO.sub.2 film is employed
as the first barrier insulating film 25 and the second barrier
insulating film 27 that protect the lower and upper surfaces of the
first coating insulating film 26 respectively, the smaller relative
dielectric constant can be achieved as the overall first interlayer
insulating film that is constructed by these films. Similarly, the
PE-CVD TMS SiO.sub.2 film is employed as the third barrier
insulating film 30 and the fourth barrier insulating film 32 that
protect the lower and upper surfaces of the second coating
insulating film 31, the smaller relative dielectric constant can be
achieved as the overall second interlayer insulating film that is
constructed by these films.
[0188] Moreover, the peripheral portions of the first wiring 24,
the second wiring 29, and the third wiring 34 are wrapped by the
base insulating film 23 and the first barrier insulating film 25,
the second barrier insulating film 27 and the third barrier
insulating film 30, and the fourth barrier insulating film 32 and
the fifth barrier insulating film 35 respectively. Therefore, the
corrosion of the first wiring 24, the second wiring 29, and the
third wiring 34 can be prevented by blocking the enter of the
incoming moisture.
[0189] Particularly, since the base insulating film 23 is also
formed of the PE-CVD TMS SiO.sub.2 film to which the present
invention is applied, all peripheral portions of the first wiring
24 are protected by the PE-CVD TMS SiO.sub.2 film. Therefore, the
corrosion of the first wiring 24 can be prevented more completely
by blocking the permeation of the moisture from all peripheral
portions.
[0190] In the above third embodiment, the PE-CVD TMS SiO.sub.2 film
formed by the plasma enhanced CVD method according to the present
invention is employed as the base protection layer 23. However, a
thermal oxide film formed by oxidizing the silicon substrate 22 by
heating it in the oxygen-containing atmosphere may be employed as
the base insulating film 23. Further, an NSG film or a BPSG
(BoroPhosphoSilicate Glass) film, etc. which is formed by the CVD
method using the organic silicon-containing gas may be employed as
the base insulating film 23.
[0191] (Fourth Embodiment)
[0192] Next, a semiconductor device and a method of manufacturing
the same according to a fourth embodiment of the present invention
will be explained with reference to FIGS. 12A and 12E
hereunder.
[0193] FIG. 12D is a sectional view showing a semiconductor device
according to a fourth embodiment of the present invention.
[0194] A difference from the third embodiment resides in that
sidewalls in the first via hole 28 and the second via hole 33 are
covered with the PE-CVD TMS SiO.sub.2 films 37, 38 to which the
present invention is applied and thus the first coating insulating
film 26 and the second coating insulating film 31 are not exposed
in the first via hole 28 and the second via hole 33.
[0195] Next, the method for implementing the above structure is
explained. FIGS. 12A to 12D are sectional views showing a method of
manufacturing the semiconductor device according to a fourth
embodiment of the present invention. TMS+N.sub.2O is used as the
film forming gas applied to the formation of a sidewall protection
layer other than the lower and upper protection layers, to which
the present invention is applied.
[0196] In order to implement the above structure, as shown in FIG.
12A, the first via hole 28 is formed after the step shown in FIG.
11C. Then, as shown in FIG. 12B, the PE-CVD TMS SiO.sub.2 film 37a
having the film thickness of about 50 nm, to which the present
invention is applied, is formed on the second barrier insulating
film 27 so as to cover the first via hole 28. Then, as shown in
FIG. 12C, the PE-CVD TMS SiO.sub.2 film 37a is etched by the
anisotropic etching to leave the PE-CVD TMS SiO.sub.2 film (a
sidewall protection layer) 37 on the sidewall of the first via hole
28.
[0197] Then, as shown in FIG. 12D, the second wiring 29 made of
copper or aluminum is formed to be connected to the first wiring 24
via the conductive film. Then, the interlayer insulating film
consisting of the second coating insulating film 31 and the third
and fourth barrier insulating films 30, 32, that are formed to
cover a lower and an upper surfaces of the second coating
insulating film 31 and to have the film thickness of about 50 nm;
the second via hole 33 to pierce the interlayer insulating film; a
sixth barrier insulating film 38 made of the PE-CVD TMS SiO.sub.2
film having the film thickness of about 50 nm to cover the sidewall
of the second via hole 33; the third wiring 34 connected to the
second wiring 29 via the second via hole 33; the fifth barrier
insulating film 35 made of the PE-CVD TMS SiO.sub.2 film having the
film thickness of about 50 nm to cover the third wiring 34; and the
third coating insulating film 36 are formed by repeating the above
steps.
[0198] According to the fourth embodiment, the first coating
insulating film 26 and the second coating insulating film 31
including the insides of the first via hole 28 and the second via
hole 33 are completely protected by the PE-CVD TMS SiO.sub.2 films
25, 27, 37 and 30, 23, 38. Therefore, both the entering of the
moisture into the first coating insulating film 26 and the second
coating insulating film 31 and the flowing-out of the moisture from
the first coating insulating film 26 and the second coating
insulating film 31 to the peripheral portions can be blocked more
completely.
[0199] As a result, the time dependent change in the relative
dielectric constant of the interlayer insulating film and the
corrosion of the upper and lower wirings 24, 29, 34 under and on
the interlayer insulating film can be prevented.
[0200] (Fifth Embodiment)
[0201] FIG. 13 is a sectional view showing a semiconductor device
and a method of manufacturing the same according to a fifth
embodiment of the present invention.
[0202] This semiconductor device has a configuration in which four
sets of laminated structures are laminated. The laminated structure
of one set comprises a set of a protection layer, a wiring group on
the protection layer and an interlayer insulating film or a cover
insulating film covering a wiring group.
[0203] In other words, this semiconductor device has a first wiring
group of wirings 63a to 63d, a second wiring group of wirings 66a
to 66c, a third wiring group of wirings 69a to 69d, and a fourth
wiring group of wirings 72a to 72d on first to fourth protection
layers 62, 65, 68, 71 made of the PE-CVD SiO.sub.2 film according
to the present invention, respectively. The symbols indicating the
wiring groups are occasionally omitted in the following description
in order to simplify the explanation.
[0204] The respective wiring groups are covered with interlayer
insulating films 64, 67, 70 made of a coating insulating film and a
cover insulating film 73 made of a coating insulating film in order
from the bottom first wiring group of wirings 63a to 63d.
[0205] The PE-CVD SiO.sub.2 film constituting each of the first to
fourth protection layers 62, 65, 68, 71 has a peak of the
absorption intensity of the infrared rays in a range of the wave
number 2270 to 2350 cm.sup.-1, a film density in a range of 2.25 to
2.40 g/cm.sup.3, and a relative dielectric constant in a range of
3.3 to 4.3.
[0206] As described above, according to the fifth embodiment, the
protection layers 65, 68, 71 according to the present invention are
put between any adjacent two wiring groups.
[0207] The protection layers 65, 68, 71 themselves are dense, and
are excellent in the water resistance. From the characteristics,
they have a function of blocking a penetration of incoming moisture
and a pass of leakage current. Accordingly, the semiconductor
device according to a fifth embodiment can prevent the wirings from
corrosion, and can suppress leakage current between the wiring
groups.
[0208] Further, the protection layers 65, 68, 71 are formed to
contact the interlayer insulating film 64, 67, 70 and the cover
insulating film 73. Since the PE-CVD SiO.sub.2 film constituting
each of the protection layers 62, 65, 68, 71 has a good
adhesiveness to the coating insulating film constituting each of
the interlayer insulating film 64, 67, 70 and the cover insulating
film 73, the semiconductor device according to a fifth embodiment
can prevent the films from peeling-off.
[0209] Further, since the coating insulating films are employed as
the interlayer insulating film 64, 67, 70 and the cover insulating
film 73, the interlayer insulating film 64, 67, 70 and the cover
insulating film 73 which are excellent in flatness can be
obtained.
[0210] The manufacturing method will be explained hereunder.
[0211] As shown in FIG. 13, first the first protection layer (the
first barrier insulating film) 62 made of the PE-CVD TMS SiO.sub.2
film having the film thickness of 200 nm, to which the present
invention is applied, is formed on the substrate 61. In this case,
the semiconductor substrate itself or the structure obtained by
forming the base insulating film and the wiring on the
semiconductor substrate may be employed as the substrate 61.
[0212] Then, the first wiring group of wirings 63a to 63d are
formed on the first protection layer 62. Then, the first coating
insulating film 64 is formed by covering the first wiring group of
wirings 63a to 63d with the same material as the third and fourth
embodiments and by employing the same film forming method as
them.
[0213] Then, the second protection layer (the second barrier
insulating film) 65 made of the second PE-CVD TMS SiO.sub.2 film
having a film thickness of about 50 nm, to which the present
invention is applied, is formed on the first coating insulating
film 64. Then, the second wiring group of second wirings 66a to 66c
are formed on the second protection layer 65. Then, the second
coating insulating film 67 is formed by covering the second wiring
group of wirings 66a to 66c with the same material as the third and
fourth embodiments and by employing the same film forming method as
them.
[0214] Then, the third protection layer (the third barrier
insulating film) 68 having a film thickness of about 50 nm and made
of the PE-CVD TMS SiO.sub.2 film; the third wiring group of wirings
69a to 69d; the third coating insulating film 70; the fourth
protection layer (the fourth barrier insulating film) 71 having a
film thickness of about 50 nm and made of the PE-CVD TMS SiO.sub.2
film; the fourth wiring group of wirings 72a to 72c; and the fourth
coating insulating film 73 are formed in sequence on the second
coating insulating film 67, by repeating twice sequentially the
step of forming the above PE-CVD TMS SiO.sub.2 film, the step of
forming the wiring, and the step of forming the coating insulating
film.
[0215] Accordingly, there can be formed a semiconductor integrated
circuit device including the multi-layered, e.g., four-layered in
total, wiring groups 63a to 63d, 66a to 66c, 69a to 69d, 72a to
72c, that are insulated and separated by the coating insulating
films 64, 67, 70 and the protection layers 65, 68, 71.
[0216] As descried above, according to the fifth embodiment, the
protection layers 65, 68, 71 are interposed between the wiring
groups 63a to 63d, 66a to 66c, 69a to 69d, 72a to 72c.
[0217] That is, since the coating insulating films 64, 67, 70 are
employed as the main interlayer insulating film, the interlayer
insulating film that is excellent in the flatness can be
obtained.
[0218] Also, the protection layers 65, 68, 71 per se are dense and
have the water resistance, they have functions of preventing the
permeation of the incoming moisture and preventing the flow of the
leakage current. Therefore, the corrosion of the wiring groups 63a
to 63d, 66a to 66c, 69a to 69d, 72a to 72c due to the incoming
moisture can be prevented, and also the leakage current between the
wiring groups 63a to 63d, 66a to 66c, 69a to 69d, 72a to 72c can be
suppressed.
[0219] With the above, the present invention is explained in detail
based on the embodiments, but the scope of the present invention is
not limited to examples given concretely in the above embodiments.
Variations of the above embodiments may be contained in the scope
of the present invention without departing from the gist of the
present invention.
[0220] As described above, according to the present invention,
after the coating insulating film is formed on the substrate, the
protection layer made of the silicon-containing insulating film for
covering the coating insulating film is formed by plasmanizing the
film forming gas, that consists of the alkoxy compound having Si--H
bonds or the siloxane having Si--H bonds and any one
oxygen-containing gas out of O.sub.2, N.sub.2O, NO.sub.2, CO,
CO.sub.2, and H.sub.2O, to react.
[0221] The silicon-containing insulating film of the present
invention constituting the protection layer has a peak of the
absorption intensity of the infrared rays in a range of the wave
number 2270 to 2350 cm.sup.-1, a film density in a range of 2.25 to
2.40 g/cm.sup.3, and a relative dielectric constant in a range of
3.3 to 4.3.
[0222] The protection layer formed in this manner to have the above
characteristics has the good adhesiveness to the coating insulating
film, is dense to the same extent as the silicon nitride film, is
excellent in the water resistance, and contains the small amount of
contained moisture in the film. Therefore, if the coating
insulating film and the protection layer for coating the coating
insulating film are formed, there can be obtained the interlayer
insulating film that can have the more complete barrier
characteristic to the entering of the moisture into the coating
insulating film from the outside and the flowing-out of the
moisture to the outside, and is excellent in flatness.
[0223] Also, the above protection layer has the smaller relative
dielectric constant than the silicon nitride film in addition to
the above characteristics. Therefore, if the barrier insulating
film according to the present invention are formed to cover the
lower and upper surfaces of the coating insulating film serving as
the main interlayer insulating film between the wiring layers,
there can be obtained the interlayer insulating film that has more
completely the barrier characteristic to the entering/flowing-out
of the moisture into/from the coating insulating film, the barrier
characteristic to the leakage current, etc. and also achieves the
low dielectric constant as a whole.
[0224] The silicon-containing insulating film having aforementioned
characteristics has a good adhesiveness with the coating insulating
film, and has the high mechanical strength. Therefore, the
laminated structure can be prevented from a destroy such as a
peeling-off of the films, etc., even if a mechanical shock is
applied to the laminated structure from outside.
* * * * *