U.S. patent application number 09/339849 was filed with the patent office on 2001-07-19 for film forming apparatus.
Invention is credited to ISHIKAWA, HIROICHI, KAKINUMA, MASAYASU.
Application Number | 20010008209 09/339849 |
Document ID | / |
Family ID | 16187239 |
Filed Date | 2001-07-19 |
United States Patent
Application |
20010008209 |
Kind Code |
A1 |
ISHIKAWA, HIROICHI ; et
al. |
July 19, 2001 |
FILM FORMING APPARATUS
Abstract
A film forming apparatus comprises a sputtering chamber, a
cooling drum disposed at an central portion thereof for cooling a
roll film in contact with the surface thereof, a roll chamber, an
SiO.sub.x film forming chamber and a monitor room disposed to the
periphery of the drum, a sputter cathode disposed to the SiO.sub.x
film forming chamber, and a moisture pump such as a cryogenic panel
disposed in the film forming chamber for effectively discharging
the moisture by which the partial pressure of the moisture in the
film forming chamber is kept roll, in which the light absorption of
the SiO.sub.x film after formation is monitored by an InSitu
transmission light monitor, the value x for the SiO.sub.x is judged
by the transmittance of light of the SiO.sub.x film to control the
oxygen flow rate by an MFC such that the value x reaches an aimed
value, thereby enabling to form an adhesion layer having sufficient
adhesion and good permeability on the substrate.
Inventors: |
ISHIKAWA, HIROICHI;
(KANAGAWA, JP) ; KAKINUMA, MASAYASU; (KANAGAWA,
JP) |
Correspondence
Address: |
SONNENSCHEIN NATH & ROSENTHAL
P.O. BOX 061080
WACKER DRIVE STATION
CHICAGO
IL
60606-1080
US
|
Family ID: |
16187239 |
Appl. No.: |
09/339849 |
Filed: |
June 25, 1999 |
Current U.S.
Class: |
204/298.24 ;
204/192.14; 204/298.03; 204/298.07; 204/298.09; 204/298.25 |
Current CPC
Class: |
C23C 14/562 20130101;
C23C 14/10 20130101 |
Class at
Publication: |
204/298.24 ;
204/298.03; 204/298.07; 204/298.09; 204/298.25; 204/192.14 |
International
Class: |
C23C 014/34 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 1, 1998 |
JP |
P10-186372 |
Claims
What is claimed is:
1. A film forming apparatus having a film forming chamber for
forming an adhesion film on a substrate, wherein a moisture
discharging means is disposed in the film forming chamber for
discharging a moisture.
2. A film forming apparatus as defined in claim 1, wherein an
O.sub.2 supplying means is further disposed to the film forming
chamber for supplying O.sub.2 while controlling a flow rate.
3. A film forming apparatus as defined in claim 1, wherein the
substrate comprises a rolled film and a roll for winding the film
is further disposed.
4. A film forming apparatus as defined in claim 1, wherein the
substrate comprises a rolled PET or PEN film.
5. A film forming apparatus as defined in claim 1, wherein the
substrate comprises a rolled film, and a roll for winding the film
and a cooling drum for cooling the film upon formation of the
adhesion film on the film are further disposed.
6. A film forming apparatus as defined in claim 1, wherein a film
forming chamber for forming a thin film on the adhesion film is
further disposed, and the thin film comprise one or plurality
layers of optical thin film.
7. A film forming apparatus as defined in claim 1, wherein a film
forming chamber for forming a thin film on the adhesion film is
further disposed and the thin film comprise one or plurality layers
of anti-reflection film.
8. A film forming apparatus as defined in claim 1, wherein the
adhesion film comprises an SiO.sub.x film.
9. A film forming apparatus as defined in claim 1, wherein the
adhesion film comprises a TiO.sub.x film.
10. A film forming apparatus as defined in claim 1, wherein a film
forming chamber is further disposed for forming a thin film
continuously on the adhesion film.
11. A film forming apparatus as defined in claim 1, wherein
formation of the adhesion film is conducted by sputtering.
12. A film forming apparatus as defined in claim 1, wherein the
moisture discharging means is a pump having a high moisture
discharging performance which is a POLYCOLD adsorbing the moisture
to a cooling unit.
13. A film forming apparatus as defined in claim 1, wherein a
vacuum pump is further disposed for evacuating the inside of the
film forming chamber.
14. A film forming apparatus as defined in claim 1, wherein a
transmittance measuring means for measuring the transmittance of
light of the adhesion layer to be formed in the film forming
chamber is further disposed.
15. A film forming apparatus as defined in claim 1, wherein an
InSitu transmission light monitor for controlling the transmittance
of light of the adhesion layer formed in the film-forming chamber
is further disposed.
16. A film forming apparatus as defined in claim 1, wherein a
transmittance measuring means is further disposed for measuring the
transmittance of light of the adhesion layer formed in the
film-forming chamber, and the wavelength of light measured by the
means is 450 nm or less.
17. A film forming apparatus as defined in claim 1, wherein a
transmittance measuring means is further disposed for measuring the
transmittance of light of the adhesion layer formed in the
film-forming chamber, and the wavelength of light measured by the
means is 400 nm.
18. A film forming apparatus as defined in claim 1, wherein the
substrate comprises a plastic substrate having on the surface a
layer formed in a process of coating a hard coating.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a film forming apparatus
for forming a film of an adhesion layer on a substrate and more
particularly to a film forming apparatus capable of forming a film
of an adhesion layer having a sufficient adhesion and good
permeability to a substrate by keeping the partial pressure of
moisture low in the film forming apparatus.
[0003] 2. Description of the Related Art
[0004] In existent film forming apparatus, when a thin film (for
example, an optical thin film or an anti-reflection film) is formed
on a plastic substrate, poor adhesion between the thin film and the
plastic substrate often gives rise to a problem. As a method of
dissolving the problem, it may be considered a method of increasing
the adhesion strength by forming an adhesion layer for adhering a
thin film to a plastic substrate, in which an SiO.sub.x film
(x<2) or the like is used as the adhesion layer.
[0005] However, in the existent film forming apparatus, it is
difficult to stably form on SiO.sub.x film on the plastic substrate
in the existent film forming apparatus. This is because SiO.sub.x
has no stoichiometrically stable composition as in SiO.sub.2, so
that x can not be defined constant easily and it is difficult to
property control the amount of oxygen supplied to the plastic
substrate upon film formation in order to make x constant. Further,
the effect of the adhesion layer (adhesion strength) varies
depending on the value for x, in which the adhesion is reduced as x
approaches 2, whereas the adhesion is improved as x decreases.
However, as x decreases, the transmittance of light of the
SiO.sub.x film is lowered and the film is not suitable to the
application use for the optical film.
[0006] In view of the foregoing situations, it may be considered
the following method of stably forming an SiO.sub.x film with good
transmission of light and adhesion. This is a method of observing
the transmittance of light of a formed SiO.sub.x film upon forming
the SiO.sub.x film on the plastic substrate in the film forming
apparatus, judging based on the value whether the current flow rate
of oxygen supplied by an MFC or the like to a plastic substrate is
excessive or insufficient and controlling the flow rate of oxygen
to be supplied depending on the result of the judgement.
[0007] Then, in order to control x for the SiO.sub.x film to an
appropriate value, another factor should be taken into
consideration. This is a requirement that the partial pressure of
the moisture in a film-forming chamber be kept low upon formation
of the SiO.sub.x film in the film forming apparatus. For example,
when an SiO.sub.x film is formed by a sputter device having an Si
target, if the partial pressure of moisture in the SiO.sub.x film
forming chamber is high, oxygen contained in the moisture reacts
with Si tending to increase the value x for the SioX film exceeding
an aimed value. This makes it difficult to control the
transmittance of the SiO.sub.x film to an aimed value.
[0008] Namely, as described above, the transmittance of a light of
the formed SiO.sub.x film is monitored, and the flow rate of oxygen
supplied by an MFC or the like is properly controlled based on the
value to form an SiO.sub.x film having a desired value for x, in
which oxygen other than oxygen supplied is already present if the
partial pressure of the moisture in the SiO.sub.x film forming
chamber is high. Then, a margin upon controlling the amount of
oxygen supplied by the MFC is extremely narrowed and, as a result,
the amount of oxygen to be supplied can no more be controlled
appropriately and the value x for the formed SiO.sub.x film can not
be controlled stably. If the partial pressure of the moisture in
the SiO.sub.x film forming chamber is excessively high, the value x
is increased more than the aimed value even with no supply of
oxygen at all from the MFC to the film forming chamber, thereby
making it impossible to control the transmittance of the SiO.sub.x
film to an aimed value.
SUMMARY OF THE INVENTION
[0009] The present invention has been accomplished in view of the
foregoing situations and an object thereof is to provide a film
forming apparatus is already present capable of forming an adhesion
layer is already present good light transmittance of light onto a
substrate by keeping a partial pressure of moisture low in a film
forming chamber.
[0010] The foregoing subject can be attained in accordance with a
film forming apparatus of the present invention in which a
film-forming chamber is disposed for forming an adhesion film on a
substrate, wherein a moisture discharging means is disposed in the
film-forming chamber for discharging the moisture.
[0011] The film forming apparatus preferably comprises an O.sub.2
supply means for supplying O.sub.2 under flow rate control to the
film forming chamber.
[0012] The substrate preferably comprises a rolled film and,
further, a roll for winding the film is disposed preferably.
[0013] The substrate preferably comprises a rolled PET or PEN
film.
[0014] The substrate is preferably a rolled film and the film
forming apparatus further comprises preferably a roll for winding
the film and a cooling drum for cooling the film upon formation of
the adhesion film on the film.
[0015] The film forming apparatus preferably comprises a film
forming chamber for forming a thin film on the adhesion film, and
the thin film preferably comprises one or plurality of layers of
optical thin films.
[0016] The film forming apparatus further comprises a film forming
chamber for formation of a thin film on the adhesive layer, and the
thin film preferably comprises one or plurality of layers of
anti-reflection films.
[0017] The adhesion film is preferably a SiO.sub.x film.
[0018] The adhesion film preferably comprises a TiO.sub.x film.
[0019] The film forming apparatus further preferably comprises a
film forming chamber for continuously forming a thin film on an
adhesive film.
[0020] Formation of the adhesion film is preferably conducted by
sputtering.
[0021] The moisture discharging means preferably comprises a pump
of high moisture discharging performance, which is a POLYCOLD for
adsorbing the moisture in a cooling unit.
[0022] The film forming apparatus further comprises vacuum pump for
evacuating the inside of the film forming chamber.
[0023] The film forming apparatus further comprises preferably a
transmittance observing means for observing the transmittance of
light of the adhesion layer formed in the film forming chamber.
[0024] The film forming apparatus further comprises preferably an
InSitu transmission light monitor for observing the transmittance
of light of the adhesion layer to be formed in the film forming
chamber.
[0025] The film forming apparatus further comprises preferably a
transmittance observing means for observing the light transmittance
of the adhesion layer formed in the film forming chamber, the
wavelength of light observed by the means being 450 nm or less. The
film forming apparatus preferably comprises a transmittance
measuring means for measuring the transmittance of light of the
adhesion layer formed in the film forming chamber, the wavelength
of light observed by the means being 400 nm.
[0026] The substrate preferably comprises a plastic substrate
having, on the surface, a layer formed in a coating process of a
hard coating.
DESCRIPTION OF THE ACCOMPANYING DRAWINGS
[0027] FIG. 1A is a plan view schematically showing a film forming
apparatus as a preferred embodiment of the present invention;
[0028] FIG. 1B is an enlarged schematic view showing a transmission
light monitor 35 and the vicinity thereof shown in FIG. 1A; and
[0029] FIG. 2 is a view explaining a method of evaluating adhesion
between a film strip and a thin film.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0030] A preferred embodiment of the present invention is to be
explained with reference to the drawings.
[0031] FIG. 1A is a plan view schematically showing a film forming
apparatus as a preferred embodiment of the present invention;
and
[0032] FIG. 1B is an enlarged schematic view showing a transmission
light monitor 35 and the vicinity thereof shown in FIG. 1A, for
explaining a method of monitoring the transmittance of light of a
SiO.sub.x film (x<2). The film- forming apparatus is a
sputtering device for forming a film by sputtering on a roll film
(for example, plastic roll film).
[0033] As shown in FIG. 1A, a sputtering apparatus 1 has a
sputtering chamber 3, and a cooling drum 7 is disposed to a central
portion of the sputtering chamber 3 for cooling a roll film
(plastic substrate) 5 in contact with the surface thereof. In the
sputtering chamber 3 and at the periphery of the cooling drum 7,
are disposed an SiO.sub.x film forming chamber 11, a monitor
chamber 13, a first film forming chamber 15 and a second forming
film chamber 17. The plastic substrate 5 may be a rolled PET or PEN
film.
[0034] A roll 19 and a roll 21 each having a film 5 wound
therearound are disposed in the roll chamber 9. The film 5 wound
around the roll 21 is wound by way of a guide 23 around the
periphery of the roll 19. The film 5 is further wound around the
roll 19 by way of a guide 25. The film 5 is constituted to be
transported as shown by an arrow. Further, a turbo pump (vacuum
pump) 26 for evacuating the inside of the roll chamber 9 is
connected with the chamber 9.
[0035] In the SiO.sub.x film forming chamber 11, an SiO.sub.x
sputtering cathode (for example, a dual magnetron cathode) 27 is
disposed at a position opposing the film 5 wound around the cooling
drum 7. The film 5 is sputtered on the cooling drum 7 by the
sputter cathode 27. Two Si targets (not illustrated) are disposed
side by side in the vicinity of the surface of the cooling drum 7.
Further, an MFC 33 is connected for supplying oxygen while
controlling the flow rate by way of a pipeline 33a into the chamber
11. Further, the SiO.sub.x film forming chamber 11 is constituted
such that Ar is supplied at a predetermined flow rate (not
illustrated). Further, a moisture pump 29 such as a cryogenic panel
is disposed in the chamber 11 for effectively discharging the
moisture. A pump having a high moisture discharging performance is
used for the moisture pump 29, for example, POLYCOLD (registered
trade mark), a pump for adsorbing moisture to a cooling portion.
Further, a vacuum pump 31 for evacuating the SiO.sub.x film forming
chamber 11 is connected for evacuating the inside of the chamber
11.
[0036] The monitor chamber 13 is a chamber for monitoring the
transmittance of light (or absorption of light) of the SiO.sub.x
film formed on the film 5 in the SiO.sub.x film forming chamber 11.
Accordingly, an InSitu 35 as a transmission light monitor is
disposed in the monitor chamber 13 and the InSitu 35 monitors the
absorption of light in the SiO.sub.x film after film formation.
Further, the transmission light monitor 35 is connected with a
control unit 37, which is then connected with the MFC 33, and is so
constituted to monitor the state of light absorption of the
SiO.sub.x film after film formation, send the thus obtained
transmittance of light to the control section 37, judge the value x
for the SiO.sub.x film by the control unit 37, deliver an
instruction to increase the oxygen flow rate from the control unit
37 to the MFC 33 if the value x is smaller than a desired value,
while deliver an instruction to decrease the oxygen flow rate from
the control unit 37 to the MFC 33 if the value x is larger than the
desired value. In this way, the flow rate of oxygen supplied to the
film 5 upon formation of the SiO.sub.x film on the film 5 is
controlled to an appropriate amount. If x is small, the
transmittance of light of the SiO.sub.x film tends to be lowered.
Further, a vacuum pump 39 for evacuating the inside of the monitor
chamber 13 is connected to the chamber 13.
[0037] The transmission monitor 35 is to be explained more
specifically.
[0038] As shown in FIG. 1B, the transmission light monitor 35 has
an optical fiber 35a. A light at a wavelength of about 400 nm is
irradiated by way of the optical fiber 35a as shown by an arrow in
the monitor chamber 13 to an SiO.sub.x film 6 formed on a plastic
roll film 5. The light transmits the SiO.sub.x film 6 and the film
5 and, reaches the cooling drum 7, and a light reflected on the
surface of the cooling drum 7 transmits again the film 5 and the
SiO.sub.x film 6 and returns to the InSitu transmission light
monitor 35. The intensity of the returned light is detected by the
monitor 35, and the intensity of the reflected light and the
intensity of the irradiated light are compared to measure the
transmittance of light of the SiO.sub.x film 6. The wavelength of
the irradiated light is set to 400 nm, because SiO.sub.x has a
stronger absorption for a light in a shorter wavelength area, so
that the sensitivity to the light transmission relative to the
amount of O.sub.2 is increased when measuring or observing the
transmission of light at 400 nm and, as a result, the
controllability for the oxygen flow rate by the transmission light
monitor is improved.
[0039] Further, when the transmittance of the light (wavelength:
400 nm) of the SiO.sub.x film 6 is measured by the method described
above, and the transmittance is about 95%, then the SiO.sub.x film
6 has a satisfactory adhesion.
[0040] In the first film forming chamber 15, a first sputter
cathode 41 is disposed at a position opposing to the film 5 wound
around the cooling drum 7. The film 5 is sputtered by the sputter
cathode 41 on the cooling drum 7. Thus, a thin film (for example,
optical thin film or anti-reflection thin film) can be formed on
the SiO.sub.x film 6 formed on the film 5. In this case, since the
SiO.sub.x film 6 between the plastic roll film 5 and the optical
thin film acts as an adhesion layer, close adhesion between the
film 5 and the optical thin film is made firm. Further, a vacuum
pump 43 for evacuating the inside of the first film forming chamber
15 is connected for evacuating the inside of the chamber 15.
[0041] In the second film forming chamber 17, a second sputter
cathode 45 is disposed at a position opposing to the film 5 wound
around the cooling drum 7. The film 5 is sputtered by the sputter
cathode 45 on the cooling drum 7. Thus, a thin film can be formed
further on the optical thin film. Further, a vacuum pump 47 for
evacuating the inside of the second film forming chamber 17 is
connected for evacuating the inside of the chamber 17.
[0042] Concrete conditions when the SiO.sub.x film 6 was formed on
the plastic film roll 5 by the sputtering device 1 shown in FIG.
1A, are as described below. The following conditions are shown as a
mere example, and can be changed optionally. The SiO.sub.x film 6
formed under the conditions has a sufficient adhesion and good
transmittance.
1 Substrate (film): PET (with hard coating) 188 .mu.m thickness,
1.2 m width Cathode: Dual magnetron Power: 1.5 kW (AC power source)
Ar flow rate: 100 sccm O.sub.2 flow rate: -15 sccm (controlled by
NFC) Target: Si; 100 mm width, 1500 mm length, 12 mm .times. 2
height (dual)
[0043] In the embodiment described above, the partial pressure of
the moisture in the SiO.sub.x film forming chamber 11 can be kept
low by disposing the moisture pump 29 such as a cryogenic panel in
the film forming chamber 11. Therefore, the flow rate of oxygen
supplied to the film forming chamber 11 can be controlled by the
MFC 33 with a large margin. This can facilitate the control for the
oxygen flow rate by the MFC 33 in accordance with the instruction
from the control section 37. Accordingly, the value x for the
SiO.sub.x film 6 can be controlled to a desired value and the
SiO.sub.x film 6 having a sufficient adhesion and good
transmittance can be formed to the film 5.
[0044] In the embodiment described above, the first and the second
film forming chambers 15 and 17 are disposed in the sputter chamber
3, but only the first film forming chamber 15 may be disposed in
the sputter chamber 3 or three or more film forming chambers may
also be disposed in the sputter chamber 3. Thus, a single or
plurality of thin films can be formed on the film 5 by the film
forming apparatus.
[0045] In the embodiment described above, the SiO.sub.x film 6 is
used as the adhesion layer but other oxygen-containing adhesion
layer may also be used and, for example, a TiO.sub.x film may also
be used.
[0046] In other words, if the cryogenic panel 29 is not disposed in
the SiO.sub.x film forming chamber 11, the transmittance of light
(wavelength: 400 nm) of the SiO.sub.x film 6 is increased to 95% or
higher even if oxygen is not introduced by the MFC 33 into the film
forming chamber 11, so that an SiO.sub.x film having sufficient
adhesion can no more be formed on the film 5.
[0047] Then, a method of evaluating close adhesion between the thin
film (anti-reflection film or the like) formed by way of the
SiO.sub.x film as the adhesion film on the film 5 by the sputtering
device 1, and the film 5 will be explained with reference to FIG.
2. FIG. 2 is a view for explaining the method of evaluating the
close adhesion between the film and the thin film.
[0048] At first, a thin film (anti-reflection film or the like) is
formed by way of an SiO.sub.x film on the film 5 by the film
forming apparatus shown in FIG. 1A and then the film 5 is left in
an atmosphere at a temperature of 50.degree. C. and a humidity of
90% for 48 hours. Then, as shown in FIG. 2, the film was placed on
a bed not illustrated. Four sheets of bleached cotton fabric 51
wound around a 2 kg weight 53 and impregnated with an alcohol are
brought into contact with the thin film on the film 5 and they are
rubbed by reciprocating for 20 times forwardly and backwardly as
shown by arrows.
[0049] After giving a damage by the method described above to the
anti-reflection film formed on the film 5, peeling of the
anti-reflection film is observed. As a result, peeling of the
anti-reflection film was not observed for the anti- reflection film
with the SiO.sub.x adhesion layer in which the SiO.sub.x film was
formed between the film 5 and the anti-reflection film. On the
contrary, peeling was observed for the anti-reflection film with no
SiO.sub.x film in which the SiO.sub.x film was not formed between
the film 5 and the anti-reflection film, and this did not pass the
test described above.
[0050] As has been described above, the present invention can
provide a film forming apparatus capable of forming an adhesion
layer having sufficient adhesion and good transmittance on the
substrate by keeping the partial pressure of moisture low in the
film-forming chamber.
* * * * *