U.S. patent application number 10/820130 was filed with the patent office on 2005-02-17 for mask and container and manufacturing apparatus.
This patent application is currently assigned to Semiconductor Energy Laboratory Co., Ltd.. Invention is credited to Kuwabara, Hideaki, Sakata, Junichiro, Yamazaki, Shunpei.
Application Number | 20050034810 10/820130 |
Document ID | / |
Family ID | 33468415 |
Filed Date | 2005-02-17 |
United States Patent
Application |
20050034810 |
Kind Code |
A1 |
Yamazaki, Shunpei ; et
al. |
February 17, 2005 |
Mask and container and manufacturing apparatus
Abstract
The present invention provides a large mask with a high mask
accuracy for conducting selective deposition on a substrate with a
large surface area. In accordance with the present invention, the
mask body is fixed in a fixing position disposed on a line passing
through a thermal expansion center in the width of the mask frame.
Further, in accordance with the present invention, the substrate
and mask body are fixed and deposition is carried out by moving the
deposition source in the X direction or Y direction. A method
comprising moving the deposition source in the X direction or Y
direction is suitable for deposition on large substrates.
Inventors: |
Yamazaki, Shunpei; (Tokyo,
JP) ; Sakata, Junichiro; (Atsugi, JP) ;
Kuwabara, Hideaki; (Isehara, JP) |
Correspondence
Address: |
NIXON PEABODY, LLP
401 9TH STREET, NW
SUITE 900
WASHINGTON
DC
20004-2128
US
|
Assignee: |
Semiconductor Energy Laboratory
Co., Ltd.
Atsugi-shi
JP
|
Family ID: |
33468415 |
Appl. No.: |
10/820130 |
Filed: |
April 8, 2004 |
Current U.S.
Class: |
156/345.3 |
Current CPC
Class: |
G03F 7/70741 20130101;
C23C 14/042 20130101; H01L 51/0011 20130101; G03F 1/66
20130101 |
Class at
Publication: |
156/345.3 |
International
Class: |
C23F 001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 10, 2003 |
JP |
2003-106139 |
Claims
1. A thin-sheet mask having a pattern opening, characterized in
that the mask is fixed to a frame in a stretched state and said
mask is adhesively bonded in a location coinciding with a line
passing through a thermal expansion center in the members of the
frame.
2. The mask according to claim 1, characterized in that four
corners of said frame have a curvature.
3. The mask according to claim 1, characterized in that said mask
is adhesively bonded to the frame with an adhesive material having
heat resistance.
4. A thin-sheet mask having a pattern opening, characterized in
that the mask is fixed to a frame in a stretched state and said
mask is adhesively bonded in a location on the outside of a line
passing through a thermal expansion center in the members of the
frame, the frame is caused to expand by heating during deposition
and the mask maintains the stretched state.
5. The mask according to claim 4, characterized in that four
corners of said frame have a curvature.
6. The mask according to claim 4, characterized in that said mask
is adhesively bonded to the frame with an adhesive material having
heat resistance.
7. A container for accommodating a deposition material, which is
disposed in a deposition source of a deposition apparatus,
characterized in that the cross section in a plane of said
container has a rectangular or square shape and the opening portion
through which the deposition material passes has a thin elongated
shape.
8. A production apparatus comprising a loading chamber, a
transportation chamber linked to said loading chamber, a plurality
of film forming chambers linked to said transportation chamber, and
a disposition chamber linked to said film forming chambers,
characterized in that the plurality of film forming chambers
comprise means for fixing a substrate which is linked to an
evacuation chamber for evacuating the inside of the film forming
chambers, a mask, a frame for fixing said mask, alignment means for
aligning the mask and the substrate, one or two deposition sources,
means for moving said deposition sources inside said film forming
chambers, and means for heating the substrate, and the end portion
of the mask is adhesively bonded in a location matching a line
passing through a thermal expansion center in the members of said
frame.
9. The production apparatus according to claim 8, characterized in
that said film forming chambers and said disposition chamber
comprise means capable of introducing a material gas or cleaning
gas and linked to the evacuation chamber for evacuating the inside
of the chambers.
10. The production apparatus according to claim 8, characterized in
that said deposition source can be moved in the X direction, Y
direction, or Z direction inside the film forming chamber.
11. The production apparatus according to claim 8, characterized in
that a shutter for partitioning the inside of the film forming
chamber and shielding the deposition on said substrate is provided
in said film forming chamber.
12. A production apparatus comprising a loading chamber, a
transportation chamber linked to said loading chamber, a plurality
of film forming chambers linked to said transportation chamber, and
a disposition chamber linked to said film forming chambers,
characterized in that the plurality of film forming chambers
comprise means for fixing a substrate which is linked to an
evacuation chamber for evacuating the inside of the film forming
chambers, a mask, a frame for fixing said mask, alignment means for
aligning said mask and the substrate, one or two deposition
sources, means for moving said deposition sources inside the film
forming chambers, and means for heating the substrate, and the
cross section in a plane of the container for accommodating a
deposition material, which is disposed in said deposition source,
has a rectangular or square shape and the opening portion has a
thin elongated shape.
13. The production apparatus according to claim 12, characterized
in that said container is composed of an upper part and a lower
part, and evaporation of the material from said deposition source
is adjusted by the shape of the opening portion in the upper part
of the container.
14. The production apparatus according to claim 12, characterized
in that said film forming chambers and said disposition chamber
comprise means capable of introducing a material gas or cleaning
gas and linked to the evacuation chamber for evacuating the inside
of the chambers.
15. The production apparatus according to claim 12, characterized
in that said deposition source can be moved in the X direction, Y
direction, or Z direction inside the film forming chamber.
16. The production apparatus according to claim 12, characterized
in that a shutter for partitioning the inside of the film forming
chamber and shielding the deposition on said substrate is provided
in said film forming chamber.
Description
DETAILED DESCRIPTION OF THE INVENTION
TECHNICAL FIELD TO WHICH THE INVENTION BELONGS
[0001] The present invention relates to a film forming apparatus
employed for forming a film of a material capable of forming a film
by deposition (referred to hereinbelow as a deposition material)
and a production apparatus comprising such a film forming
apparatus. In particular, the present invention relates to a mask
employed for deposition in which a film is formed by evaporating a
deposition material from a deposition source provided opposite to a
substrate, a container for accommodating the deposition material,
and a production apparatus.
PRIOR ART
[0002] Light-emitting elements using organic compounds featuring
small thickness and weight, fast response, DC low-voltage drive,
and the like, as light-emitting substances have been expected to
find application in flat panel displays of the next generation. In
particular, display devices in which light emitting elements are
disposed as a matrix have been considered to be superior to the
conventional liquid-crystal displays in that they have a wide
viewing angle and excellent visibility.
[0003] As for the light emission mechanism of light-emitting
elements, it is thought that electrons introduced from a cathode
and holes introduced from an anode recombinate in an organic
compound layer at the light-emitting center and form molecular
excitons under the effect of the voltage applied to a pair of
electrodes sandwiching a layer containing the organic compound and
energy is then released and light is emitted when the molecular
excitons return to a ground state. Singlet excitation and triplet
excitation are known as excited states and light emission is
considered to be possible via any excited state.
[0004] In light-emitting devices formed by arranging such
light-emitting elements as a matrix, drive methods such as a
passive matrix drive (simple matrix type) and active matrix drive
(active matrix type) can be used. However, when the pixel density
is increased, the active matrix type, in which a switch is provided
for each pixel (or 1 dot) is considered to be advantageous because
a low-voltage drive is possible.
[0005] Further, a layer comprising an organic compound has a
multilayer structure, typically in the form of "hole transfer
layer/light-emitting layer/electron transfer layer". EL materials
forming an EL layer are generally classified into low-molecular
(monomer) materials and high-molecular (polymer) materials, and
low-molecular materials are employed to form films in deposition
apparatuses.
[0006] The conventional deposition apparatuses have a substrate
disposed in a substrate holder and comprise a crucible (or a
deposition boat) having an EL material, that is, a deposition
material, introduced therein, a shutter preventing the sublimated
EL material from rising, and a heater for heating the EL material
located inside the crucible. The EL material heated with the heater
is sublimated and forms a film on the rotating substrate. In order
to conduct uniform film formation in this process, the distance
between the substrate and the crucible is set to 1 m or more.
[0007] With the conventional deposition apparatus or deposition
method, when an EL layer was formed by deposition, almost the
entire sublimated EL material adhered to the inner walls, shutter,
or adhesion-preventing shield (a protective sheet for preventing
the deposition material from adhering to the inner walls of the
film forming chamber) of the film forming chamber of the deposition
apparatus. For this reason, the utilization efficiency of expensive
EL materials In the formation of the EL layer was extremely low,
about 1% or less, and the production cost of light-emitting devices
was extremely high.
[0008] Further, in the conventional deposition apparatuses, the
spacing between the substrate and the deposition source was set to
1 m or more in order to obtain a uniform film. Further, a problem
associated with substrates with a large surface area is that the
film thickness can easily become nonuniform in the central zone and
peripheral edges of the substrate. Moreover, because the deposition
apparatus has a structure with a rotating substrate, a limitation
is placed on the deposition apparatuses designed for substrates
with a large surface area.
[0009] In addition, if a substrate with a large surface area and a
mask for deposition are rotated together after being brought into
intimate contact with each other, there is a risk of the
displacement occurring between the mask and the substrate. Further,
if the substrate or mask is heated during deposition, then
dimensions change due to thermal expansion. As a result, the
dimensional accuracy and positional accuracy decrease owing to the
difference in thermal expansion coefficient between the mask and
substrate.
[0010] With the foregoing in view, the applicant of the present
application has suggested a deposition apparatus (Patent Document
1, Patent Document 2) as means for resolving the aforementioned
problems. [Patent Document 1] JP-A-2001-247959. [Patent Document 2]
JP-A-2002-60926.
[0011] [Problems Addressed by the Invention]
[0012] The present invention provides a production apparatus
equipped with a deposition apparatus, which is a production
apparatus reducing production cost by increasing the utilization
efficiency of EL materials and having excellent uniformity and
throughput of EL layer deposition.
[0013] Further, the present invention also provides a production
apparatus for efficient deposition of EL materials on substrates
with a large surface area such as 320 mm.times.400 mm, 370
mm.times.470 mm, 550 mm.times.650 mm, 600 mm.times.720 mm, 680
mm.times.880 mm, 1000 mm.times.1200 mm, 1100 mm.times.1250 mm, and
1150 mm.times.1300 mm. Further, the present invention also provides
a deposition apparatus for obtaining a uniform film thickness over
the entire substrate surface even on a substrate with a large
surface area.
[0014] In addition, a large mask with a high mask accuracy is
provided for conducting selective deposition on a substrate with a
large surface area.
[0015] [Means to Resolve the Problems]
[0016] In accordance with the present invention, in order to
resolve the above-mentioned problems, a mask is fixed to the
thermal expansion center in a frame. The fixing is conducted
locally only to the thermal expansion center with an adhesive that
has high resistance to temperature variations. The thermal
expansion center is determined by the material, shape, outer
periphery, and inner periphery of the frame.
[0017] Further, the mask body is formed from a material having the
same thermal linear expansion coefficient as the substrate.
Because, the mask body is also caused to expand thermally following
the expanded-state of the substrate, a deposition position accuracy
can be maintained. Because the position in which the mask is fixed
is the thermal expansion center, the alignment position is not
changed even when the frame thermally expands under heating in a
certain temperature range and the outer periphery and inner
periphery thereof change.
[0018] Further, in accordance with the present invention, the
substrate and mask are fixed, without rotation, during deposition.
A film is formed on the substrate by moving the deposition source
holder in the X direction, Y direction, or Z direction during
deposition.
[0019] The constitution of the invention disclosed in the present
specification is
[0020] a thin-sheet mask having a pattern opening, characterized in
that
[0021] the mask is fixed to a frame in a stretched state and the
mask is adhesively bonded in a location coinciding with a line
passing through a thermal expansion center in the members of the
frame.
[0022] Another constitution of the invention is
[0023] a thin-sheet mask having a pattern opening, characterized in
that
[0024] the mask is fixed to a frame in a stretched state and the
mask is adhesively bonded in a location on the outside of a line
passing through a thermal expansion center in the members of the
frame, and
[0025] the frame is caused to expand by heating during deposition
and the mask maintains the stretched state.
[0026] If fixing is conducted on the outside of the thermal
expansion center in the frame, the mask body is stretched as the
frame expands under heating and the deflection can be prevented.
Thus, tension of the mask can be maintained by using thermal
expansion of the frame. Deposition is preferably carried out by
conducting heating appropriate for the material that will be
deposited, and the fixing position may be suitably determined so
that the appropriate tension is applied to the mask at this heating
temperature.
[0027] Further, in each of the above-described constitutions, four
corners of the frame may have a curvature. Further in each of the
above-described constitutions, the mask is characterized in that it
is adhesively bonded to the frame with an adhesive having heat
resistance. The mask may be also fixed to the frame by welding.
[0028] Yet another constitution of the present invention is
[0029] a container for accommodating a deposition material, which
is disposed in a deposition source of a deposition apparatus,
characterized in that
[0030] the cross section in a plane of the container has a
rectangular or square shape and the opening portion through which
the deposition material passes has a thin elongated shape.
[0031] A configuration may be also used in which the mounting angle
of the deposition source can be freely set to match the evaporation
center with a point on the substrate into which deposition is to be
made when co-deposition is conducted. However, a certain spacing
between the two deposition sources is required to tilt each
deposition source at the angle. Therefore, it is preferred that the
container has a prismatic columnar shape, as shown in FIG. 10, and
the evaporation center be adjusted in the direction of the opening
of the container. The container is composed of an upper part and a
lower part. A plurality of upper parts with different angles at
which the deposition material flies out from the opening may be
prepared and an appropriate upper part may be selected. Because the
spread of deposition differs depending on the deposition material,
two deposition sources having different upper parts mounted thereon
may be prepared when co-deposition is conducted.
[0032] Yet another constitution of the present invention is
[0033] a production apparatus comprising a loading chamber, a
transportation chamber linked to the loading chamber, a plurality
of film forming chambers linked to the transportation chamber, and
a disposition chamber linked to the film forming chambers,
characterized in that
[0034] the plurality of film forming chambers comprise means for
fixing a substrate which is linked to an evacuation chamber for
evacuating the inside of the film forming chambers, a mask, a frame
for fixing the mask, alignment means for aligning the mask and the
substrate, one or two deposition sources, means for moving the
deposition sources inside the film forming chambers, and means for
heating the substrate, and
[0035] the end portion of the mask is adhesively bonded in a
location matching a line passing through a thermal expansion center
in the members of the frame.
[0036] Yet another constitution of the present invention is a
production apparatus comprising a loading chamber, a transportation
chamber linked to the loading chamber, a plurality of film forming
chambers linked to the transportation chamber, and a disposition
chamber linked to the film forming chambers, characterized in
that
[0037] the plurality of film forming chambers comprise means for
fixing a substrate which is linked to an evacuation chamber for
evacuating the inside of the film forming chambers, a mask, a frame
for fixing the mask, alignment means for aligning the mask and the
substrates, one or two deposition sources, means for moving the
deposition sources inside the film forming chambers, and means for
heating the substrate, and
[0038] the cross section in a plane of the container for
accommodating a deposition material, which is disposed in the
deposition source, has a rectangular or square shape and the
opening portion has a thin elongated shape.
[0039] The above-described constitution is characterized in that,
the container is composed of an upper part and a lower part, and
evaporation of the material from the deposition source is adjusted
by the shape of the opening portion in the upper part of the
container. Furthermore, a middle lid having a plurality of orifices
opened inside thereof may be provided in addition to the upper part
and lower part in the container.
[0040] Further, each of the above-described configurations is
characterized in that the aforementioned film forming chamber and
disposition chamber comprise means capable of introducing a
material gas or cleaning gas and linked to the chamber for
evacuating the inside of the chambers.
[0041] Further, each of the above-described configurations is
characterized in that the deposition source can be moved in the X
direction, Y direction, or Z direction inside the film forming
chamber.
[0042] Furthermore, each of the above-described configurations is
characterized in that a shutter for partitioning the inside of the
film forming chamber and shielding the deposition on the substrate
is provided in the film forming chamber.
BRIEF DESCRIPTION OF THE DRAWINGS
[0043] FIG. 1 is a perspective view and a cross-sectional view
(Embodiment 1) illustrating the mask in accordance with the present
invention.
[0044] FIG. 2 illustrates Embodiment 2.
[0045] FIG. 3 illustrates Embodiment 3.
[0046] FIG. 4 is a perspective view illustrating the mask in
accordance with the present invention (Embodiment 1).
[0047] FIG. 5 illustrates a multichamber production apparatus
(Example 1).
[0048] FIG. 6 is a top view of the deposition apparatus (Example
2).
[0049] FIG. 7 illustrates the disposition chamber and
transportation mode (Example 2).
[0050] FIG. 8 is a top view of the inside of the film forming
chamber (Working Example 3).
[0051] FIG. 9 is a top view of the inside of the film forming
chamber (Example 3).
[0052] FIG. 10 illustrates the container in accordance with the
present invention (Embodiment 4).
[0053] FIG. 11 illustrates the deposition apparatus in accordance
with the present invention (Embodiment 4).
[0054] FIG. 12 illustrates the configuration of an active matrix EL
display device.
[0055] FIG. 13 illustrates an example of an electronic device.
[0056] FIG. 14 is a block diagram of an electronic device shown in
Example 6.
[0057] FIG. 15 is a block diagram of a controller.
[0058] FIG. 16 illustrates the charging mode of an electronic
device shown in Example 6.
PREFERRED EMBODIMENTS OF THE INVENTION
[0059] The preferred embodiments of the invention will be described
below.
[0060] (Embodiment 1)
[0061] FIG. 1(A) is a perspective view of the mask in accordance
with the present invention. A mask body 122 is fixed in a fixing
position A124a disposed on a line passing through a thermal
expansion center 121 in the width of a mask frame 120. Further, it
is preferred that an arm (not shown in the figure) for supporting
the mask frame be also supported in the fixing position A124a
inside the deposition chamber.
[0062] Further, FIG. 1(B) is a cross-sectional view illustrating
how a substrate 124 is carried during deposition. During
deposition, the substrate 124, mask body 122, and mask frame 120
are aligned to a fixed position, and the mask body is brought into
intimate contact over the entire surface with the deposition
surface of the substrate by a magnetic force created by a magnet
(not shown in the figure) provided at the rear surface of the
substrate. In the example shown herein, fixing was conducted with
the magnet, but mechanical fixing also may be employed. Further, an
opening portion 123 is provided in the mask body, the deposition
material that passed through the opening portion 123 forms a film,
and a pattern is formed on the substrate 124.
[0063] Further, in accordance with the present invention, the
substrate 124 and mask body 122 are fixed and deposition is
conducted by moving the deposition source in the X direction or Y
direction. A method involving moving the deposition source in the X
direction or Y direction is suitable for deposition on large
substrates.
[0064] In accordance with the present invention, a mask body using
a material having a thermal expansion coefficient identical to that
of the substrate is preferably used. For example, when a glass
substrate is used, a 42 Alloy (Fe--Ni alloy: Ni 42%) or 36 Invar
(Fe--Ni alloy: Ni 36%), which have a thermal expansion coefficient
close to that of the glass, may be used for the mask body. Though
the mask body and substrate are heated during deposition, because
they expand to the same degree, hardly any displacement occurs.
Further, the mask frame 120 is also heated, but because the
position of the thermal expansion center does no change, hardly any
displacement occurs, even if the mask frame 120 and mask body 122
are from different material and have different thermal expansion
coefficients. The present invention is especially effective for
deposition on large substrates in which displacement to easily
caused by heating.
[0065] Further, the mask may be formed by an etching method or
electroforming method. Further, the mask may be also formed by
combining an etching method based on dry etching or wet etching
with an electroforming method carried out in an electroforming tank
of the same metal as that of the deposition mask.
[0066] Further, because the tension of the mask body 122 is
maintained in a heated state, if fixing is conducted in a fixing
position B124b located to the outer periphery from the thermal
expansion center, instead of the fixing position A124a, then the
tension of the mask body 122 can be maintained by using the
expansion amount of the mask frame. The distance from the thermal
expansion center to the fixing position B124b may be suitably
determined according to the heating temperature during deposition,
thermal expansion coefficient of the frame, and outer periphery and
inner periphery of the frame.
[0067] Further, FIG. 1(C) illustrates an example in which four
corners of the mask frame were rounded. Rounding the four corners
of the mask prevents the corners of the mask frame is prevented
from being damaged by any impacts. In FIG. 1(C), the reference
numeral 130 stands for a mask frame, 131--a thermal expansion
center, 132--a mask body, and 133--an opening portion.
[0068] Further, FIG. 4 shows an example in which a clearance is
formed and a play portion 223b is provided in the four corners of
the opening portion 223a. Providing the play portion 223b prevents
cracks from entering the mask body 232 from the corner of the
adjacent opening portion even when a tension is applied to the mask
body 232 and it is thermally expanded. Further, in FIG. 4, the
reference numeral 230 stands for a mask frame, 231--a thermal
expansion center, 232--a mask body, and 224--a fixing position.
[0069] (Embodiment 2)
[0070] Here, the configuration of substrate holding means will be
described in greater detail with reference to FIG. 2. When a
substrate with a large surface area is used and gang printing is
carried out (a plurality of panels are formed from one substrate),
substrate holding means is provided to support the substrate so as
to be in contact with the portions that will be scribe lines. Thus,
a substrate is placed on substrate holding means and a deposition
material is sublimated from the deposition source holder provided
below the substrate holding means and deposited on the areas that
are not in contact with the substrate holding means. As a result,
the deflection of substrates with a large surface area can be
suppressed to 1 mm or less.
[0071] FIG. 2(A) is a perspective view showing a substrate holding
means 301 having a substrate 303 and a mask 302 placed thereon.
FIG. 2(B) shows only the substrate holding means 301.
[0072] Further, FIG. 2(C) shows a cross-sectional view of the
substrate holding means in which the substrate 303 was placed on
the mask 302; the substrate holding means is composed of a metal
sheet (typically, Ti or a shape memory alloy) with a height, h, of
10 mm-50 mm and a width 1 mm-5 mm. Further, the substrate holding
means may be also a wire composed of a shape memory alloy. The
substrate holding means is fixed to the mask 302 by welding or
adhesively. Further, the mask 302 is fixed with an adhesive
material in a position serving as a thermal expansion center of the
mask frame 304.
[0073] The substrate holding means 301 inhibits the deflection of
the substrate or the deflection of the mask under the weight of the
substrate. Further, the substrate holding means 301 can inhibit the
deflection of the mask and maintain the tension of the mask.
[0074] The shape of the substrate holding means 301 is not limited
to that shown in FIG. 2(A)-FIG. 2(C) and is a shape which does not
overlap the opening portion of the mask which is provided in the
mask.
[0075] The present embodiment can be freely combined with
Embodiment 1.
[0076] (Embodiment 3)
[0077] Here, an example of conducting the deposition of a RGB
pattern is shown.
[0078] FIG. 3(A) is an exploded perspective view of a mask composed
of a mask frame 420 and a mask body 422.
[0079] A thermal expansion center 421 of the mask frame 420
coincides with the adhesive bonding location 426 with the mask body
422. Further, the mask body is provided with an opening portion
423. The opening portion 423 is provided as a pattern of one kind
among the RGB. Here, for the sake of simplicity, a mask having an
opening portion with 9 rows.times.15 columns is shown, but it goes
without saying that this shape is not limiting, and the mask may
correspond to the desired number of pixels, for example, to
640.times.480 pixels of a VGA class or 1024.times.768 pixels of a
XGA class.
[0080] Three masks are prepared for RGB patterning. When three
masks are prepared, a common mask design is employed for the mask
bodies, but when the masks are fixed to the mask frame, each mask
is individually adhesively bonded to obtain the prescribed pixel
position. Alternatively, the deposition may be conducted by
employing one mask and shifting the mask with respect to the
substrate for each RGB during alignment. Further, the deposition
may be also conducted by employing one mask and shifting the mask
with respect to the substrate for each RGB during alignment inside
one chamber.
[0081] FIG. 3(B) is a perspective view of the substrate after the
deposition of three kinds of RGB was conducted. A deposited film
431 for red color, a deposited film 432 for green color, and a
deposited film 433 for blue color have been regularly deposited on
the substrate 430. A pattern comprising a total of 405 (27
rows.times.15 columns) units has been formed.
[0082] This embodiment can be freely combined with Embodiment 1 or
Embodiment 2.
[0083] (Embodiment 4)
[0084] Here, a container for accommodating a deposition material is
shown in FIG. 10. FIG. 10(A) is a perspective view of the
container. FIG. 10(B) is a cross-sectional view obtained by cutting
along the chain line A-B. FIG. 10(C) is a cross-sectional view
obtained by cutting along the dot line C-D.
[0085] When the mounting angle of the deposition source is changed,
a cylindrical crucible and a heater surrounding the crucible are
also inclined. Therefore, when co-deposition is carried out by
using two crucibles, the spacing therebetween is increased. If the
spacing is increased, two different deposition materials are
difficult to mix homogeneously. Furthermore, when it is desirable
to conduct deposition with a small gap between the deposition
source and the substrate, then a uniform film is difficult to
obtain.
[0086] In accordance with the present invention, the evaporation
center is adjusted with an opening B10 in the container upper part
800a, rather than by changing the mounting angle of the deposition
source. The container is composed of the container upper part 800a,
a container lower part 800b, and a middle lid 800c. A plurality of
small orifices are provided in the middle lid 800c, and the
deposition material passes through those orifices during
deposition. Further, the container is formed of a material such as
a BN sintered body, a BN and AlN composite sintered body, quartz
glass, and graphite and can withstand high temperature, high
pressure, and low pressure. The deposition direction and spread
differ depending on the deposition material. Therefore, the
container is appropriately prepared in which the surface area of
the opening 810, the guide portion of the opening, and the position
of the opening are adjusted according to each deposition
material.
[0087] With the container in accordance with the present invention,
the deposition center can be adjusted without tilting the heater of
the deposition source. Further, as shown in FIG. 10(D), in
co-deposition, the orientations of the opening 810a and 810b can be
aligned, spacing between a plurality of containers accommodating a
plurality of different deposition materials (materials A805,
material B806) can be decreased, and deposition can be conducted,
while homogeneously mixing the materials. Referring to FIG. 10(D),
heating means 801-804 are connected to individual power sources and
mutually independent temperature control thereof is conducted.
Furthermore, a uniform film can be obtained even when it is
desirable to conduct deposition with a spacing between the
deposition source and substrate decreased, for example, to 20 cm or
less.
[0088] Further, an example different from that shown in FIG. 10(D)
is shown in FIG. 10(E). In the example shown in FIG. 10(E),
deposition is conducted by using an upper part with an opening 810c
provided for evaporation in the vertical direction and by using an
upper part having an opening 810d inclined according to this
direction. In the configuration shown in FIG. 10(E), too, heating
means 801, 803, 807, and 808 are connected to separate power
sources and mutually independent temperature control thereof is
conducted.
[0089] The container in accordance with the present invention shown
in FIG. 10 has a fine long opening. Therefore, the uniform
deposition region is expanded and the container is suitable for
uniform deposition on a fixed substrate with a large surface
area.
[0090] FIG. 11 is a top view of a film forming apparatus for
conducting deposition by using the container shown in FIG. 10 with
a fixed substrate with a large surface area.
[0091] A substrate 815 is transported from a transportation chamber
813 into a film forming chamber 812 through a shutter 814. If
necessary, alignment of the substrate and a mask (not shown in the
figure) is conducted in the transportation chamber 813 or film
forming chamber 812.
[0092] The container 800 composed of the container upper portion
800a having the opening 810 and the container lower portion 800b is
disposed in the deposition source holder 811. The deposition source
holder 811 is moved below the substrate 815 with movement means
(not shown in the figure) that can move in the X direction, Y
direction, or Z direction. A chain line in FIG. 11 shows an example
of the movement path of the deposition source holder.
[0093] In the deposition apparatus shown in FIG. 11, the clearance
distance, d, between the substrate 813 and the deposition source
holder 811 is typically decreased to 30 cm or less, preferably 20
cm or less, even more preferably 5 cm-15 cm, and the utilization
efficiency of the deposition material is greatly increased.
[0094] Further, there is a risk of the deposition mask (not shown
in the figure) being heated due to the decrease in the clearance
distance, d, between the substrate 813 and the deposition source
holder 811 typically to 30 cm or less, preferably to 5 cm-15 cm.
Therefore, it is preferred that a metal material (for example, a
material such as a metal with a high melting point such as
tungsten, tantalum, chromium, nickel, or molybdenum or alloys
containing such elements, stainless steel, Inconel, and Hastelloy)
that has a low thermal expansion coefficient and high resistance to
heat-induced deformation be used for the deposition mask 14. An
example of such a material is an alloy with low thermal expansion
which contains nickel 42% and iron 58%. Further, a structure in
which a cooling medium (cooling water, cooling gas) is circulated
to the deposition mask for cooling the heated deposition mask may
be also provided.
[0095] This embodiment can be freely combined with any of
Embodiments 1 to 3.
[0096] The present invention of the above-described constitution
will be explained in greater detail with the examples described
hereinbelow.
EXAMPLES
Example 1
[0097] FIG. 5 is a top view of the production apparatus of a
multichamber type. In the production apparatus shown in FIG. 5, the
chambers are disposed in the order of tasks performed.
[0098] In the production apparatus shown in FIG. 5, at least the
transportation chambers 504a, 504b, 508, 514 are constantly
maintained under vacuum and the film forming chambers 506W1, 506W2,
506W3 are constantly maintained under vacuum. Therefore, the
operations of evacuating the film forming chambers and the
operations of filling the film forming chambers with nitrogen can
be omitted and a film forming treatment can be carried out
continuously within a short time.
[0099] Deposited in one film forming chamber is only one layer of
the EL layer (comprises a hole transfer layer, a hole injection
layer, a light-emitting layer, an electron transfer layer, an
electron injection layer, and the like) composed of a stack of
layers composed of different materials. A deposition source holder
capable of moving inside a film forming chamber is provided in each
film forming chamber. A plurality of such deposition source holders
are prepared and a plurality of containers (crucibles) having EL
materials introduced therein are appropriately provided and
disposed in the film forming chambers. The substrate can be set in
a face-down system, the position alignment of the deposition mask
can be carried out with a CCD or the like, and film formation can
be selectively carried out by conducting the deposition by a
resistance heating method.
[0100] The disposition of the containers (crucibles) having EL
materials introduced therein, replacement of components of the
deposition holder, and the like, are conducted in the disposition
chambers 526p, 526g, 526r, 526s. The EL materials are accommodated
in advance in the containers (typically, crucibles) by material
makers. The disposition is preferably conducted without contact
with the atmosphere, and when transported from material makers, the
crucibles are introduced into the disposition chambers in a state
in which they are air-tightly sealed in a second container. The
disposition chambers are evacuated, the crucibles are removed from
the second containers In the disposition chambers, and the
crucibles are disposed in the deposition holders. In this case, the
crucibles and EL materials accommodated in the crucibles can be
prevented from contamination.
[0101] In accordance with the present invention, because a white
light-emitting element with a three-layer structure of a layer
comprising an organic compound was realized, the formation of the
layer comprising the organic compound may be conducted with a
three-chamber configuration at a minimum. Employing three chambers
can shorten the process time and also can reduce the cost of
production apparatus. Furthermore, the thickness of each film may
be as small as 20 nm-40 nm which is also advantageous from the
standpoint of material cost.
[0102] For example, when a white light-emitting element is formed,
a hole transfer layer (HTL) serving as a first light-emitting layer
may be deposited in a film forming chamber 506W1, a second
light-emitting layer may be deposited in a film depositing chamber
506W2, an electrode transfer layer (ETL) may be deposited in the
film forming chamber 506W3, and then a cathode may be formed in a
film forming chamber 510. A blue fluorescent material having hole
transfer capability, such as TPD and .alpha.-NPD, may be used as
the light-emitting material in the first light-emitting layer. An
organometallic complex comprising platinum as a central metal is
effective as a light-emitting material in the second light-emitting
layer. More specifically, if a substance represented by the
following structural formulas (1)-(4) is admixed to a host material
at a high concentration (10 wt. %-40 wt. %, preferably 12.5 wt.-20
wt. %), then both the phosphorescent emission and excimer emission
thereof can be led out. The present invention is, however, not
limited to those materials and any material may be used, provided
that it is a phosphorescent material generating phosphorescent
emission and excimer emission at the same time.
[0103] [Formula 1]
[0104] [Formula 2]
[0105] [Formula 3]
[0106] [Formula 4]
[0107] Furthermore, examples of electron transfer materials that
can be used for the electron transfer layer (ETL) include metal
complexes such as tris(8-quinolinolato)aluminum (abbreviation:
Alq.sub.3), tris(4-methyl-8-quinolinolato)aluminum (abbreviation:
Almq.sub.3), bis (10-hydroxybenzo[h]-quinolinolato)beryllium
(abbreviation: BeBq.sub.2),
bis(2-methyl-8-quinolinolato)-(4-hydroxy-biphenylyl)-aluminum
(abbreviation: BAlq), bis[2-(2-hydroxyphenyl)-benzoxalato]zinc
(abbreviation: Zn(BOX).sub.2),
bis[2-(2-hydroxyphenyl)-benzothiazolato]zi- nc (abbreviation:
Zn(BTZ).sub.2). Examples of suitable compounds other than metal
complexes include oxadiazole derivatives such as
2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole
(abbreviation: PBD), and
1,3-bis[5-(p-tert-butylphenyl)-1,3,4-oxadiazole-2-yl]benzene
(abbreviation: OXD-7), triazole derivatives such as
3-(4-tert-butylphenyl)-4-phenyl-5-(4-biphenylyl)-1,2,4-triazole
(abbreviation: TAZ) and
3-(4-tert-butylphenyl)-4-(4-ethylphenyl)-5-(4-bip-
henylyl)-1,2,4-triazole (abbreviation: p-EtTAZ), imidazole
derivatives such as
2,2',2"-(1,3,5-benzenetriyl)tris[1-phenyl-1H-benzimidazole]
(abbreviation: TPBI), and phenanthroline derivatives such as
bathophenanthroline (abbreviation: BPhen) and bathocuproine
(abbreviation: BCP).
[0108] In particular, in the second light-emitting layer, a metal
complex of one kind may be admixed at a high concentration (10 wt.
%-40 wt. %, preferably 12.5 wt. %-20 wt. %) by co-deposition.
Therefore, concentration control is facilitated and the process is
suitable for mass production.
[0109] Further, a simple mask for deposition in the region outside
the location where a lead-out electrode is exposed (location where
a FPC will be thereafter pasted) may be used as the deposition
mask.
[0110] In order to obtain a double-side light-emitting panel, the
cathode can be a laminate of a thin metal film and a transparent
conductive film. The thin metal film (Ag or MgAg) may be with a
thickness of 1 nm-10 nm by a resistance heating method, and a
transparent conductive film is formed by sputtering. Therefore, the
cathode can be formed within a short time.
[0111] Here an example of fabricating a white light-emitting panel
was described, but panels with monochromatic light emission (green
light, red light, blue light, and the like) can be also
fabricated.
[0112] Described hereinbelow is a procedure in which a substrate
that was provided in advance with an anode (first electrode) and an
insulator (partition wall) for covering the end portions of the
anode is transported into the production apparatus shown in FIG. 5
and a light emitting device is fabricated. When a light-emitting
device of an active matrix type is fabricated, a plurality of
thin-film transistors connected to the anode (TFT for current
control) and other thin film transistors (TFT for switching and the
like) are provided in advance on the substrate and a drive circuit
composed of a thin-film transistor is also provided. Further,
fabrication with the production apparatus shown in FIG. 5 can be
also conducted when a light-emitting device of a simple matrix type
is fabricated.
[0113] The aforementioned substrate (600 mm.times.720 mm) is set
into a substrate placing chamber 520. The substrate size is 320
mm.times.400 mm, 370 mm.times.470 mm, 550 mm.times.650 mm, 600
mm.times.720 mm, 680 mm.times.880 mm, 1000 mm.times.1200 mm, 1100
mm.times.1250 mm. Even a substrate with a surface area as large as
1150.times.1300 can be processed.
[0114] The substrate (the substrate provided with an anode and an
insulator covering the end portions of the anode) set into the
substrate placing chamber 520 is transported into a transportation
chamber 518 maintained under atmospheric pressure. A transportation
mechanism (transportation robot or the like) for transporting and
turning over the substrate is provided in the transportation
chamber 518.
[0115] Further, respective transportation mechanisms and evacuation
means are provided in the transportation chambers 508, 514, 502.
The robot provided in the transportation chamber 518 can turn the
substrate over and can turn it over and transport into a receiving
chamber 505. The receiving chamber 505 is linked to an evacuation
chamber and can be evacuated to vacuum. Upon evacuation, an
inactive gas can be introduced to obtain the atmospheric
pressure.
[0116] A turbomolecular pump of a magnetic levitation type, a
cryopump, or a dry pump is provided as the aforementioned
evacuation chamber. As a result, the attained degree of vacuum in
the transportation chambers linked to various chambers can be
reduced to 10.sup.-5-10.sup.-6 Pa. Further, a reverse diffusion of
impurities from the pump or evacuation system can be controlled. An
inactive gas such as nitrogen or rare gas is used as the gas
introduced into the apparatus in order to prevent impurities from
penetrating into the apparatus. Those gases that are introduced
into the apparatus are purified to a high degree of purity with a
gas purifier prior to introduction into the apparatus. Therefore, a
gas purifier has to be provided so that the gases are introduced
into the deposition apparatus after purification. In this case,
oxygen or water and other impurities contained in the gases can be
removed in advance. Therefore, those impurities can be prevented
from being introduced into the apparatus.
[0117] Further, prior to setting into the substrate placing chamber
520, surface dust is preferably removed by washing the surface of
the first electrode (anode) with a porous sponge (typically made
from PVA (polyvinyl alcohol), Nylon, and the like) Impregnated with
a surfactant (with weak alkaline properties) in order to reduce
point defects. A washing apparatus comprising a roll brush
(manufactured from PVA) which rotates around an axial line parallel
to the substrate surface and is in contact with the substrate
surface may be used or a washing apparatus comprising a disk brush
(manufactured from PVA) which rotates around an axial line
perpendicular to the substrate surface and is in contact with the
substrate surface may be used as the cleaning mechanism.
[0118] The substrate is then transported from the transportation
chamber 518 into the receiving chamber 505, and the substrate is
then transported from the receiving chamber 505 into the
transportation chamber 502, without contact with the
atmosphere.
[0119] Further, in order to prevent shrinking, vacuum heating is
preferably conducted immediately prior to depositing a film
containing an organic compound. Thus, the substrate is transported
from the transportation chamber 502 into a multistage vacuum
heating chamber 521 and annealing for degassing is carried out
under vacuum (5.times.10.sup.-3 Torr (0.665 Pa) or below,
preferably, 10.sup.-4-10.sup.-6 Pa) in order to remove thoroughly
moisture and other gases contained in the substrate. In the
multistage vacuum heating chamber 521, a plurality of substrates
are uniformly heated by using flat-plate heaters (typically, sheath
heaters). A plurality of such flat-plate heaters are disposed and
heating can be conducted from both sides, so that the substrates
are sandwiched between the flat-plate heaters. It goes without
saying that heating can be also conducted from one side. In
particular, when an organic resin film is used as a material for an
insulating film or partition wall, because some of organic resin
materials easily adsorb moisture and there is a risk of degassing,
an effective approach is to conduct heating at a temperature of
100.degree. C.-250.degree. C., preferably 150.degree.
C.-250.degree. C., for example, for 30 min or longer and then
conduct natural cooling for 30 min and vacuum heating to remove the
adsorbed moisture prior to forming a layer containing the organic
compound.
[0120] Further, UV irradiation may be employed, while conducting
heating at a temperature of 200-250.degree. C. in an inactive gas
atmosphere, in addition to the aforementioned vacuum heating.
Further, the treatment of irradiating with UV rays, while
conducting heating at a temperature of 200-250.degree. C. in an
inactive gas atmosphere, may be also conducted without conducting
vacuum heating.
[0121] Further, if necessary, a hole injection layer composed of a
polymer material may be formed by an ink-jet method, spin coating
method, or spray method under an atmospheric pressure or reduced
pressure in the film forming chamber 512. After coating with the
ink-jet method, a uniform film thickness may be obtained with a
spin coater. Similarly, after coating with the spray method, a
uniform film thickness may be obtained with a spin coater. A film
may be also formed by the ink-jet method in vacuum with vertical
parallel arrangement of substrates.
[0122] For example, a poly(ethylene
dioxythiophene)/poly(styrenesulfonic acid) aqueous solution
(PEDOT/PSS), polyaniline/camphorsulfonic acid aqueous solution
(PANI/CSA), PTPDES. Et-PTPDEK, or PPBA used as a hole injection
layer (anode buffer layer) may be coated and fired over the entire
surface on the first electrode (anode) in the film forming chamber
512. The firing is preferably conducted in the multistage heating
chambers 523a, 523b.
[0123] When the hole injection layer (HIL) composed of a polymer
material is formed with a coating method using a spin coater or the
like, the flatness is increased and coverage of the film formed
thereon and the uniformity of film thickness can be improved. In
particular, because the film thickness of the light-emitting layer
is uniform, homogeneous light emission is obtained. In this case,
after the hole injection layer has been formed by the coating
method, heating under atmospheric pressure or vacuum heating
(100-200.degree.) is preferably conducted immediately prior to film
formation by a deposition method.
[0124] For example, the formation of an EL layer may be carried out
by the deposition method, without contact with air, by washing the
surface of the first electrode (anode) with a sponge, transporting
into the substrate placing chamber 520, transporting into the film
forming chamber 512a, coating a poly(ethylene
dioxythiophene)/poly(styrenesulfonic acid) aqueous solution
(PEDOT/PSS), over the entire surface to a film thickness of 60 nm
by a spin coating method, then transporting into multistage heating
chambers 523a, 523b, pre-firing for 10 min at a temperature of
80.degree. C., main firing for 1 h at a temperature of 200.degree.
C., then transporting into a multistage vacuum heating chamber 521,
vacuum heating (170.degree. C., heating 30 min, cooling 30 min)
immediately prior to deposition, and then transporting into film
forming chambers 506W1, 506W2, and 506W3. In particular, when an
ITO film is used as an anode material and peaks and valleys of fine
particles are present on the surface, the effect thereof can be
reduced by forming the PEDOT/PSS film to a thickness of 30 nm or
more. Further, it is preferred that ultraviolet irradiation be
carried out in the UV treatment chamber 531 in order to improve
wettability of PEDOT/PSS.
[0125] Further, when a PEDOT/PSS film is formed by a spin coating
method, the film is formed over the entire surface. Therefore, it
is preferred that the end surfaces or peripheral edges of the
substrate, terminal portions, and zones of contact with the cathode
and lower wiring be selectively removed. The selective removal is
preferably conducted by O.sub.2 ashing by using a mask in a
pretreatment chamber 503. The pretreatment chamber 503 comprises
plasma generation means and dry etching is conducted therein by
exciting one or a plurality of gases selected from Ar, H, F, and O
and generating plasma. Using a mask makes it possible to remove
selectively only the unnecessary portions.
[0126] Further, the deposition masks are stocked in mask stock
chambers 524a, 524b and appropriately transported into the film
forming chamber when deposition is conducted. If a large substrate
is used, then the surface area of the mask increases. As a result,
a frame for fixing the mask becomes larger and a large number of
masks are difficult to stock. For this reason, here, two mask stock
chambers 524a, 524b were prepared. Cleaning of deposition masks may
be conducted in the mask stock chambers 524a, 524b. Further, during
deposition, the mask stock chambers are empty. Therefore,
substrates can be stocked therein after film formation or
treatment.
[0127] The substrates are then transported from the transportation
chamber 502 into the receiving chamber 507 and then the substrates
are transported from the receiving chamber 507 into the
transportation chamber 508, without contact with air.
[0128] The substrates are then appropriately transported into film
forming chambers 506W1, 506W2, 506W3 linked to the transportation
chamber 508 and organic compound layers composed of low-molecular
materials and serving as the hole transfer layer, light-emitting
layer, and electron transfer layer are appropriately formed.
Appropriately selecting the EL material makes it possible to form a
light-emitting element demonstrating monochromatic (more
specifically, white) light emission as the entire light emitting
element. Further substrate transportation between the
transportation chambers is conducted via the receiving chambers
540, 541, 511, without contact with air.
[0129] Then, the substrates are transported into the film forming
chamber 510 by the transportation mechanism disposed in the
transportation chamber 514 and a cathode is formed. The cathode is
preferably transparent or semitransparent. It is preferred that the
cathode be formed from a thin (1 nm-10 nm) metal film (alloys such
as MgAg, MgIn, CaF.sub.2, LiF, and CaN, or films formed by
co-deposition of an element of Group 1 or Group 2 of the periodic
table of the elements and aluminum, or laminated films of those
films) formed by a deposition method using resistance heating or a
laminate of such thin metal film (1 nm-10 nm) and a transparent
conductive film. After the substrates have been transported from
the transportation chamber 508 into the transportation chamber 514
via the receiving chamber 511, they are transported into the film
forming chamber 509 and a transparent conductive film is formed by
using a sputtering method.
[0130] A light-emitting element of a laminated structure having a
layer comprising an organic compound is formed by the
above-described process.
[0131] It is also possible to conduct sealing by transporting into
a film forming chamber 513 linked to the transportation chamber 514
and forming a protective film composed of a silicon nitride film or
a silicon nitride oxide film. Here, a target composed of silicon, a
target composed of silicon oxide, or a target composed of silicon
nitride oxide is provided inside the film forming chamber 513.
[0132] Further, a protective film may be formed by moving a
rod-like target with respect to the fixed substrate. Further, a
protective film may be formed by moving the substrate with respect
to a fixed rod-like target.
[0133] For example, a silicon nitride film can be formed an the
cathode by using a disk-like target composed of silicon and
employing a nitrogen atmosphere or an atmosphere comprising
nitrogen and argon as the atmosphere of the film forming chamber.
Further, a thin film comprising carbon as the main component (DLC
film, CN film, amorphous carbon film) may be formed as the
protective film, and a film forming chamber using a CVD method may
be provided separately. A diamond-like carbon film (also called a
DLC film) can be formed by a plasma CVD method (typically, a RF
plasma CVD method, microwave CVD method, electron cyclotron
resonance (ECR) CVD method, thermal filament CVD method, and the
like), combustion flame method, sputtering method, ion beam
deposition method, laser deposition method and the like. Hydrogen
gas and a hydrocarbon gas (for example, CH.sub.4, C.sub.2H.sub.2,
C.sub.6H.sub.6, and the like) is used as the reaction gas employed
for film formation and the film is formed by ionization with a glow
discharge and acceleration bombardment with the ions of the cathode
with a negative self-bias applied thereto. Further, a CN film may
be formed by using C.sub.2H.sub.4 gas and N.sub.2 gas as the
reaction gas. The DLC film and CN film are insulting films
transparent or semitransparent to visible light. Transparency to
visible light indicates a transmittance of visible light of
80-100%, and semitransparency to visible light indicates a
transmittance of visible light of 50-80%.
[0134] Further, a protective film composed of a laminate of a first
inorganic insulating film, a stress relaxation film, and a second
inorganic insulating film may be formed instead of the
above-described protective film on the cathode. For example, it may
be formed by forming a cathode, then transporting into the film
forming chamber 513, forming a first inorganic insulating film to 5
nm-50 nm, transporting to the film forming chamber 506W1, 506W2, or
506W3, forming a stress relaxation film having moisture
absorptivity and transparency by a deposition method (inorganic
layer or a layer comprising an organic compound) to 10 nm-100 nm,
then again transporting to the film forming chamber 513 and forming
a second inorganic insulating film to 5 nm-50 nm.
[0135] The substrate having the light-emitting elements formed
thereon is then transported to a sealing chamber 519.
[0136] A sealing substrate is set from the outside into the loading
chamber 517 and prepared. The sealing substrate is transported from
the loading chamber 517 into the transportation chamber 527 and
into an optical film attaching chamber 529 for attaching an optical
filter (color filter, polarizing film, and the like) and, if
necessary, a drying agent. Further, a sealing substrate which has
an optical film (color filter, polarizing plate) attached thereto
in advance may be also set into the loading chamber 517.
[0137] Further, annealing is preferably carried out in advance in a
multistage heating chamber 516 to remove impurities such as
moisture present in the sealing substrate. Further, when a sealing
material for pasting to the substrate provided with the
light-emitting element is formed on the sealing substrate, the
sealing material is formed in a dispenser chamber 515, the sealing
substrate with the sealing material formed thereon is transported
into the transportation chamber 514 via the receiving chamber 542
and then to the sealing substrate stock chamber 530. Here, an
example was presented in which the sealing material was formed on
the sealing substrate, but this example is not limiting and the
sealing material may be formed on the substrate where the
light-emitting element was formed. Further, deposition masks used
during deposition may be also stocked in the sealing substrate
stock chamber 530.
[0138] Further, because the present example relates to a
double-side emission structure, the sealing substrate may be
transported to the optical film attachment chamber 529 and an
optical film may be attached to the inner side of the sealing
substrate. Alternatively, the substrate provided with the
light-emitting element may be bonded to the sealing substrate and
then transported into the optical film attachment chamber 529,
where an optical film (color filter or polarizing plate) may be
attached to the outer side of the sealing substrate.
[0139] Then, the substrate and sealing substrate are bonded in the
sealing chamber 519 and the sealing material is cured by
irradiating the pair of bonded substrates with UV rays by using the
UV irradiation mechanism provided in the sealing chamber 519. It is
preferred that irradiation with U rays be conducted from the side
of the sealing substrate where TFTs, which shield the light, are
not provided. Further, a UV-curable and heat-curable resin was used
as a sealing material, but no limitation is placed thereon,
provided that it is an adhesive material. For example, a resin
curable only with UV rays may be used.
[0140] Further, the air-tight space may be filled with a resin
rather than with an inactive gas. When UV irradiation is conducted
from the side of the sealing substrate in case of bottom-side
emission type, the light does not pass through the cathode.
Therefore, no limitation is placed on the resin material for
filling and a UV-curable resin or non-transparent resin may be
used. However, when irradiation with UV rays is conducted from the
side of the sealing substrate in case of double-side emission, the
UV rays pass through the cathode and the EL layer is damaged.
Accordingly, it is preferred that UV-curable resin be not used.
Therefore, in case of double-side emission type, it is preferred
that a thermosetting transparent resin be used as the resin for
filling.
[0141] Then, the pair of bonded substrates are transported from the
sealing chamber 519 to the transportation chamber 514 and then via
the receiving chamber 542 from the transportation chamber 527 to a
removal chamber 525 for removal.
[0142] Upon removal from the removal chamber 525, heating is
conducted and the sealing material is cured. In case of upper
surface emission and filling with a thermosetting resin, curing can
be conducted simultaneously with heat treatment conducted to cure
the sealing material.
[0143] As described hereinabove, with the production apparatus
shown in FIG. 5, the light-emitting elements are not exposed to air
till they are sealed in an air-tight space. Therefore, highly
reliable light-emitting devices can be fabricated.
[0144] A control unit (not shown in the figures) is provided for
realizing full automation by controlling a path of moving the
substrates through individual treatment chambers.
Example 2
[0145] FIG. 6 is an example of the top view of a deposition
apparatus.
[0146] Referring to FIG. 6, a film forming chamber 101 comprises a
substrate holding means (not shown in the figures), a first
deposition source holder 104a and a second deposition source holder
104b having deposition shutters (not shown in the figures) disposed
therein, means (not shown in the figure) for moving those
deposition source holders, and means (evacuation means) for
creating the atmosphere under reduced pressure. The film forming
chamber 101 is evacuated to a vacuum degree of 5.times.10.sup.-3
Torr (0.665 Pa) or less, preferably to 10.sup.-4-10.sup.-6 Pa with
the means for creating the atmosphere under reduced pressure.
[0147] Further, a gas introduction system (not shown in the
figures) for introducing a material gas at several sccm during
deposition and inactive gas (Ar, N.sub.2, and the like)
introduction system (not shown in the figures) for creating normal
pressure inside the film forming chamber are linked to the film
forming chamber. Further, a cleaning gas (one or several gases
selected from H.sub.2, F.sub.2, NF.sub.3, or O.sub.2) introduction
system may be also provided. It is preferred that the material gas
does not flow to the gas release opening at the shortest distance
from the gas introduction opening.
[0148] A high-density film may be obtained by introducing the
material gas intentionally during film formation and including the
components of the material gas into the organic compound layer, and
permeation and diffusion of impurities such as oxygen or moisture
that cause deterioration into the film may be blocked. Specific
examples of the material gas include one or a plurality of gases
selected from silane gases (monosilane, disilane, trisilane, and
the like), SiF.sub.4, GeH.sub.4, GeF.sub.4, SnH.sub.4, or
hydrocarbon gases (CH.sub.4, C.sub.2H.sub.2, C.sub.2H.sub.4,
C.sub.6H.sub.6, and the like). Further, a gas mixture obtained by
diluting those gases with hydrogen, argon, or the like, is also
included. Those gases that are introduced into the apparatus are
purified to a high degree of purity with a gas purifier prior to
introduction into the apparatus. Therefore, a gas purifier has to
be provided so that the gases are introduced into the deposition
apparatus after purification. In this case, residual gases (oxygen,
water and other impurities) contained in the gases can be removed
in advance. Therefore, those impurities can be prevented from being
introduced into the apparatus.
[0149] For example, when defective portions such as pinholes and
short circuits occur after Si was included in the film by
introducing monosilane gas during deposition and the light-emitting
elements were produced, a self-healing effect can be obtained in
which the Si participates in a reaction due to heat generation in
those defective portions and forms an insulator with insulating
properties such as SiOx and SiCx, leakage in the pinholes and short
circuit portions is reduced, and the development of point defects
(dark spots and the like) is prevented.
[0150] Further, when the aforementioned material gas is introduced,
a turbomolecular pump or dry pump is preferably provided in
addition to a cryopump.
[0151] Further, in the film forming chamber 101, the deposition
source holder 104 can move many times along the movement path shown
by a chain line in FIG. 6. The movement path shown in FIG. 6 is
merely an example and is not limiting. In order to obtain a uniform
film thickness, it is preferred that the deposition source holder
be moved by shifting the movement path as shown in FIG. 6 and
deposition be conducted. Further, reciprocal movement along the
same movement path is also possible. The film thickness uniformity
may be improved and time required to deposit a film may be
shortened by appropriately changing the movement rate of the
deposition holder for each segment of the movement path. For
example, the deposition source holder may be moved in the X
direction or Y direction at a rate of 30 cm/min to 300 cm/min.
[0152] Further, when a white light-emitting element is fabricated,
deposition may be conducted locally, as shown in FIG. 9. The
deposition is conducted locally so that at least a region that will
be a display region is contained in the region that will be a
panel. Conducting the deposition locally prevents the deposition on
the regions where the deposition is not required. A shutter (not
shown in the figure) is used for local deposition and the
deposition is conducted without a mask, by appropriately opening
and closing the shutter. FIG. 9 shows an example in which gang
printing is carried out. Here, the reference symbol 900 stands for
a large substrate, 901--a film forming chamber, 904--a movable
deposition holder, and 906--a crucible.
[0153] Further, a container (crucible 106) with the deposition
material introduced therein is disposed in the deposition source
holders 104a, 104b. In the example shown herein, two crucibles are
disposed in one deposition source holder 104a, 104b. Another
specific feature is that a film thickness meter (not shown in the
figure) is provided in the disposition chamber 103. Here,
monitoring with the film thickness meter is not conducted while the
deposition source is moved and the frequency of replacing the film
thickness meter is reduced.
[0154] When there are several containers (crucibles and deposition
boats accommodating organic compounds) provided in one deposition
source holder, the mounting angles of the crucibles are preferably
selected so that the directions (evaporation centers) of
evaporation that allow the organic compounds to be mixed together
intersect in the position of the deposition object.
[0155] Further, the deposition source holder is constantly in a
stand-by mode in a disposition chamber for crucibles and heating
and temperature holding are carried out till the deposition rate is
stabilized. A film thickness monitor (not shown in the figure) is
disposed in the disposition chamber for crucibles. Once the
deposition rate has stabilized, the substrate is transported into
the film forming chamber 102 and alignment with a mask (not shown
in the figure) is conducted. Then, the shutter is opened and the
deposition holder is moved. Here, the alignment of the deposition
mask or substrate is preferably confirmed by using a CCD camera
(not shown in the figure). Position control may be carried out by
providing respective alignment markers on the substrate and
deposition mask. Once the deposition has been completed, the
deposition holder is moved to the disposition chamber for crucibles
and the shutter is closed. Once the shutter has been closed, the
substrate is transported into the transportation chamber 102.
[0156] Further, referring to FIG. 6, a plurality of deposition
holders 104a, 104b are in a stand-by mode in the disposition
chamber 103, and once the material located in one deposition holder
has been consumed, this deposition holder is replaced with another
deposition holder and film formation can be carried out in a
continuous mode by successively moving the deposition holders.
While one deposition holder is moved in the film forming chamber,
the emptied deposition holder can be refilled with the EL material.
Using a plurality of deposition holders 104 makes it possible to
form a film efficiently.
[0157] Further, only two crucibles can be set into the deposition
holders 104a, 104b, but the deposition may be conducted by setting
four crucibles or by setting two or only one crucible.
[0158] In accordance with the present invention, the time required
for film deposition can be reduced. In prior art when the EL
material was replenished, it was necessary to open the film forming
chamber to atmosphere, refill the crucibles and then evacuate the
chamber. Therefore, a long time was required for refilling, causing
decrease in throughput.
[0159] Further, if it were possible to reduce also the adhesion to
the inner walls of the film forming chamber, the maintenance
frequency such as cleaning of the inner walls of the film forming
chamber could be decreased.
[0160] Further, disposing the crucibles 106 in the deposition
holders 104a, 104b is also conducted in the disposition chamber
103b. The transportation pattern is shown in FIG. 7(A) and FIG.
7(B). Components corresponding to those shown in FIG. 6 are
assigned with identical reference symbols. The crucible 106
air-tightly sealed under vacuum in a container composed of an upper
part 721a and a lower part 721b is inserted from a door 112 of the
disposition chamber 103. First, the inserted container is placed on
a rotary stand 109 for container disposition and a latch 702 is
released. Because the inside (FIG. 7(A)) is under vacuum, the
removal under atmospheric pressure is impossible even if the latch
702 is released. The disposition chamber 103a is then evacuated,
and a state is assumed in which the lid (upper part 721a) of the
container can be removed.
[0161] The form of the transported container will be described
specifically with reference to FIG. 7(A). A second container
divided into an upper part (721a) used for transportation and a
lower part (721b) comprises fixing means 706 for fixing a first
container (crucible) provided in the upper part of the second
container, a spring 705 for applying pressure to the fixing means,
a gas introducing opening 708 serving as a gas path for maintaining
a reduced pressure in the second container provided in the lower
part of the second container, an O ring for fixing the upper
container 721a and the lower container 721b, and a latch 702. A
first container 106 having a purified deposition material inserted
therein is disposed inside the second container. Further, the
second container may be formed from a material comprising a
stainless steel, and the first container 106 may be formed from a
material comprising titanium.
[0162] The purified deposition material is inserted into the first
container 106 by the material maker. Then, the second upper part
721a and lower part 721b are mated via the O ring, the upper
container 721a and lower container 721b are fixed with the latch
702, and the first container 106 is air-tightly sealed inside the
second container. Then, the pressure inside the second container is
reduced via the gas introducing opening 708, the atmosphere is
replaced with a nitrogen atmosphere, and the spring 705 is adjusted
to fix the first container 106 with the fixing means 706. A drying
agent may be disposed inside the second container. If the inside of
the second container is thus maintained under vacuum or reduced
pressure and nitrogen atmosphere, the adhesion of even slight
amounts of oxygen or water to the deposition material can be
prevented.
[0163] Then, the lid of the container is lifted and moved to a
stand 107 for lid disposition by a robot 108 for lid
transportation. The transportation mechanism in accordance with the
present invention is not limited to the configuration in which the
first container is transported while being held from above the
first container 106, as described with reference to FIG. 7(B), and
a configuration may be used in which it is transported while being
held on the side surfaces of the first container.
[0164] Further, after the rotary stand 109 for container
disposition has been rotated, only the crucible is lifted by a
robot 110 for crucible transportation, while the lower part of the
container is being left on the stand (FIG. 7(B)). Finally, the
crucible is set into the deposition holders 104a, 104b that were
waiting in the disposition chamber 103.
[0165] The disposition chamber 103 may be provided with a cleaning
gas (one or several gases selected from H.sub.2, F.sub.2, NF.sub.3,
or O.sub.2) and the components such as the deposition holders and
shutter may be cleaned by using the cleaning gas. Further, it is
also possible to clean the components such as the inner walls of
the disposition chamber, deposition holder, and shutter by
providing plasma generating means and generating plasma or by
introducing gas ionized by plasma into the disposition chamber and
to release gas with vacuum gas release means. Plasma for cleaning
may be generated by exciting one or a plurality of gases selected
from Ar, N.sub.2, H.sub.2, F.sub.2, NF.sub.3, or O.sub.2.
[0166] The degree of cleaning of the film forming chamber can be
thus maintained by moving the deposition holders 104a, 104 as far
as the disposition chamber 103 and conducting cleaning in the
disposition chamber.
[0167] Further, this example can be freely combined with Example 1.
The deposition apparatus shown in FIG. 6 may be disposed in any of
the film forming chambers 506W1, 506W2, 506W3 shown in FIG. 5 and
the disposition chamber shown in FIG. 7 may be disposed in the
disposition chambers 526a-526n shown in FIG. 5.
Example 3
[0168] An example of the film forming chamber allowing the cleaning
of the inside of the film forming chamber and the deposition mask
to be conducted without opening the chamber to the atmosphere is
shown hereinbelow. FIG. 8 is an example of the cross-sectional view
of the film forming apparatus of the present example.
[0169] In the example shown in FIG. 8, plasma 1301 is generated
between a deposition mask 1302a and an electrode 1302b connected
via a high-frequency power source 1300a and a capacitor 1300b.
[0170] Referring to FIG. 8, the deposition mask 1302 fixed in a
holder is installed close to a place (a place shown by a dot line
in the figure) where the substrate is provided, and a deposition
source holder 1322 that can conduct heating to respective different
temperatures is provided therebelow. The deposition source holder
1322 can be moved with movement mechanism 1328 In the X direction,
Y direction, Z direction, or .theta. direction which is a rotation
direction.
[0171] If the organic compound located inside is heated to a
sublimation temperature with heating means (typically, a resistance
heating method) disposed in the deposition holder, the organic
compound is gasified and deposited on the substrate surface. During
deposition, the substrate shutter 1320 is moved to a position in
which it does not impede the deposition. Further, a shutter 1321
that moves together with the deposition holder is also provided
therein and when deposition is to be conducted, it is moved into a
position in which it does not impede the deposition.
[0172] Further, a gas introduction system is provided such that
during deposition, a gas composed of particles smaller than the
particles of the organic compound material, that is, a gas composed
of a material with a small atomic radius can be passed in a very
small quantity and a material with a small atomic radius can be
introduced into the organic compound film. Specific examples of
gases that may be used as the gas of material with a small atomic
radius include one or a plurality of gases selected from silane
gases (monosilane, disilane, trisilane, and the like), SiF.sub.4,
GeH.sub.4, GeF.sub.4, SnH.sub.4, or hydrocarbon gases (CH.sub.4,
C.sub.2H.sub.2, C.sub.2H.sub.4, C.sub.6H.sub.6, and the like).
Further, a gas mixture obtained by diluting those gases with
hydrogen, argon, or the like, is also included. Those gases that
are introduced into the apparatus are purified to a high degree of
purity with a gas purifier prior to the introduction into the
apparatus. Therefore, a gas purifier has to be provided so that the
gases are introduced into the deposition apparatus after
purification. In this case, residual gases (oxygen, water and other
impurities) contained in the gases can be removed in advance.
Therefore, those impurities can be prevented from being introduced
into the apparatus.
[0173] For example, when defective portions such as pinholes and
short circuits occur after Si was included in the film by
introducing monosilane gas during deposition and the light-emitting
elements were produced, a self-healing effect can be obtained in
which the Si participates in a reaction due to heat generation in
those defective portions and forms an insulator with insulating
properties such as SiOx and SiCx, leakage in the pinholes and short
circuit portions is reduced and development of point defects (dark
spots and the like) is prevented.
[0174] The components of the introduced material gas may be
deposited with good efficiency on the substrate by heating the
substrate with heating means such as a heater 1304 for substrate
heating.
[0175] Further, radicals may be produced with plasma generation
means. For example, in case of monosilane, a silicon oxide
precursors such as SiHx, SiHxOy, and SiOy are formed with plasma
generation means and they are deposited together with the organic
compound material from the evaporation source on the substrate.
Monosilane easily reacts with oxygen or moisture and the
concentration of oxygen or quantity of moisture in the film forming
chamber can be reduced.
[0176] A turbomolecular pump 1326 of a magnetic levitation type and
a cryopump 1327 are provided as a vacuum gas release chamber to
enable the introduction of a variety of gases. As a result, the
attained degree of vacuum in the film forming chamber can be
reduced to 10.sup.-5-10.sup.-6 Pa. After vacuum gas release with
the cryopump 1327, the cryopump 1327 is stopped and deposition is
conducted, while conducting vacuum gas release with the
turbomolecular pump 1326 and passing the material gas at several
sccm. Further, an ion plating method may be used and the deposition
may be carried out, while ionizing the material gas inside the film
forming chamber and causing it to adhere to the evaporated organic
material.
[0177] Upon completion of deposition, the substrate is removed and
cleaning is carried out for removing the deposition material that
adhered to the inner walls of the film forming apparatus and jigs
provided inside the film forming apparatus, without opening to the
atmosphere.
[0178] Further, it is preferred that the deposition holder 1322 be
moved to the disposition chamber (not shown in the figures) during
cleaning.
[0179] In the course of the cleaning a wire electrode 1302b is
moved to the position facing the deposition mask 1302a. Further, a
gas is introduced into the film forming chamber 1303. One gas or a
plurality of gases selected from Ar, H.sub.2, F.sub.2, NF.sub.3, or
O.sub.2 may be used as the gas introduced into the film forming
chamber 1303. Further, plasma 1301 is generated by applying
high-frequency electric field to the deposition mask 1302a from a
high-frequency power source 1300a and exciting the gas (Ar. H. F,
NF.sub.3, or O) Plasma 1301 is thus generated inside the film
forming chamber 1303, and the deposited matter that adhered to the
inner walls of the film forming chamber, a deposition-preventing
shield 1305, or the deposition mask 1302 is gasified and released
to the outside of the film forming chamber. With the film forming
apparatus shown in FIG. 4, cleaning can be conducted without
exposing the inside of the film forming chamber or deposition mask
to the atmosphere during maintenance.
[0180] Here, an example was shown in which plasma was induced
between the deposition mask 1302a and the electrode 1302b disposed
between the mask and the deposition source holder 1306, but this
example is not limiting as long as plasma generation means is
employed. Further, a high-frequency powder source may be connected
to the electrode 1302b and the wire electrode 1302b may be in the
form of a plate-like or mesh-like electrode and it may be an
electrode capable of introducing a gas as a shower head. An ECR,
ICP, helicon, magnetron, two-period wave, triode, LEP, or the like,
can be appropriately used as a plasma generation method.
[0181] Further, the above-described plasma cleaning may be
conducted for each cycle of film forming process or can be
conducted after several cycles of the film forming process have
been completed.
[0182] Further, this example can be freely combined with any of
Embodiments 1 to 4, Example 1, and Example 2.
Example 4
[0183] In the present working example, an example of fabricating a
light-emitting device (double-side emission structure) comprising a
light-emitting element employing an organic compound layer as a
light-emitting layer on a substrate having an insulated surface is
shown in FIG. 12.
[0184] Further, FIG. 12(A) is a top view of the light-emitting
device, FIG. 12(B) is a cross-sectional view obtained by cutting
FIG. 12(A) along A-A'. The reference numeral 1101 stands for a
source signal line drive circuit (shown by a dot line), 1102--a
pixel unit, 1103--a gate signal line drive circuit. Further, the
reference numeral 1104 stands for a transparent sealing substrate
and 1105--a first sealing material. The space surrounded by the
first sealing material 1105 is filled with a transparent second
sealing material 1107. The first sealing material 1105 comprises a
gaps material for maintaining the substrate clearance.
[0185] Further, the reference numeral 1108 stands for a wiring for
transmitting signals inputted into the source signal line drive
circuit 1101 and gate signal line drive circuit 1103. It receives a
video signal or clock signal from a FPC (flexible printed circuit)
1109 serving as an external input terminal. Here, only the FPC is
shown, but a printed wiring board (PWB) may be mounted on the
FPC.
[0186] The cross-sectional configuration will be explained below by
using FIG. 12(B). A drive circuit and an Image portion are formed
on a transparent substrate 1110. Here, the source signal line drive
circuit 1101 as the drive circuit and the image portion 1102 are
shown.
[0187] A CMOS circuit combining a n-channel TFT 1123 and a
p-channel TFT 1124 is formed as the source signal line drive
circuit 1101. The TFT forming the drive circuit may be formed from
a well-known CMOS circuit, PMOS circuit, or NMOS circuit.
Furthermore, in the present working example, a driver-unified
configuration is shown in which the drive circuit is formed on the
substrate, but such a configuration is not always necessary and the
drive circuit can be formed on the outside, rather than on the
substrate. Further, the structure of a TFT in which a polysilicon
film or amorphous silicon film serves as an active layer is not
particularly limiting, and a top-gate TFT or a bottom-gate TFT may
be used.
[0188] Further, the pixel portion 1102 is composed of a plurality
of pixels comprising a TFT 1111 for switching, a TFT 1112 for
current control, and a first electrode (anode) 113 electrically
connected to the drain thereof. An n-channel TFT or a p-channel TFT
may be used as the TFT 1112 for current control, but when
connection is made to the anode, the p-channel TFT is preferably
used. Further, it is preferred that an appropriate holding
capacitance (not shown in the figure) be provided. Here, only the
cross-sectional structure of one pixel of an extremely large number
of pixels is shown and an example is shown in which two TFTs were
used for this one pixel, but three or more TFT may be used
appropriately.
[0189] In this configuration the first electrode 1113 is directly
connected to the drain of TFT. Therefore, it is preferred that the
lower layer of the first electrode 1113 be a material layer
providing for ohmic contact with the drain composed of silicon and
that the uppermost layer which is in contact with the layer
containing an organic compound be a material layer with a large
work function. For example, a transparent conductive film (ITO
(indium oxide tin alloy), indium oxide zinc oxide alloy
(In.sub.2O.sub.3--ZnO), zinc oxide (ZnO), and the like) is
used.
[0190] Further, an insulator (called a bank, a partition wall, a
separating wall, an embankment, and the like) 1114 is formed at
both ends of the first electrode (anode) 1113. The insulator 1114
may be formed from an organic resin film or an insulating film
containing silicon. Here, an insulator of the shape shown in FIG.
12 is formed as the insulator 1114 by using a positive-type
photosensitive acrylic resin film.
[0191] A curved surface having a curvature is formed at the upper
end portion or lower end portion of the insulator 1114 with the
object of improving coverage. For example, when a positive-type
photosensitive acryl is used as the material of the insulator 1114,
it is preferred that the curved surface having a curvature radius
(0.2 .mu.m-3 .mu.m) be provided only at the upper end portion of
the insulator 1114. Furthermore, either negative-type
photosensitive compositions that are made insoluble in an enchant
under light or positive-type compositions that are made soluble in
an etchant under light can be used as the insulator 1114.
[0192] Further, the insulator 1114 may be covered with a protective
film composed of an aluminum nitride film, an aluminum nitride
oxide film, a thin film containing carbon as the main component, or
a silicon nitride film.
[0193] Further, a layer 1115 comprising an organic compound is
selectively formed by a deposition method on the first electrode
(anode) 1113. In the present working example, the layer 1115
comprising an organic compound is formed in the production
apparatus described in Embodiment 2 and a uniform film thickness is
obtained. Furthermore, a second electrode (cathode) 1116 is formed
on the layer 1115 comprising an organic compound. A material with a
low work function (Al, Ag, Li, Ca, alloys thereof, MgAg, MgIn,
AlLi, CaF.sub.2, or CaN) may be used for the cathode. Here, in
order to pass the emitted light, a laminated layer of a thin metal
film (MgAg: film thickness 10 nm) with a decreased film thickness
and a transparent electrically conductive film (ITO (indium oxide
tin oxide alloy) with a film thickness of 110 nm, an indium oxide
zinc oxide alloy (In.sub.2O.sub.3--ZnO), zinc oxide (ZnO), and the
like) is used as the second electrode (cathode) 1116. A
light-emitting element 1118 composed of the first electrode (anode)
1113, the layer 1115 comprising an organic compound, and a second
electrode (cathode) 1116 is thus formed. In the present working
example, white emitted light is obtained by use of a layer composed
of organic compounds 1115 formed by successively laminating CuPc
(film thickness 20 nm), .alpha.-NPD (film thickness 30 nm), CBP
(film thickness 30 nm) comprising an organometallic complex
comprising platinum as a central metal (Pt (ppy)acac), BCP (film
thickness 20 nm),and BCP:Li (film thickness 40 nm). This working
example is an example in which the light-emitting element 1118
emits white light. Therefore, a color filter (here, for the sake of
simplicity, the overcoat is not shown in the figure) composed of a
coloration layer 1131 and a light-shielding layer (BM) 1132 is
provided.
[0194] Further, in such double-side light-emission display device,
optical films 1140, 1141 are provided in order to prevent the
background from penetration and to prevent the external light
reflection. A polarizing film (a polarizing plate of a high
transmittance type, a thin light polarizing plate, a white light
polarizing plate, a polarizing plate comprising high-performance
dyes, an AR polarizing plate, and the like), a phase-difference
film (a broadband 1/4 plate, a temperature-compensated
phase-difference film, a twisted phase-difference film, a
phase-difference film with a wide viewing angle, a biaxially
oriented phase-difference film, and the like), and a
luminosity-increasing film may be used in an appropriate
combination as the optical films 1140, 1141. For example, if
polarizing films are used as the optical films 1140, 1141 and
arranged so that the light polarization directions are orthogonal
to each other, it is possible to obtain an effect of preventing the
penetration of background and an effect of preventing the
reflection. In this case, zones outside the portions where light is
emitted and display is conducted, become black and the background
can be prevented from penetrating and being seen even when the
display is viewed from any side. Further, because the emitted light
from the light-emitting panel passes only through one polarizing
plate, it is displayed as is.
[0195] The same effects as described hereinabove can be obtained in
case that even if the two polarizing films are not orthogonal, the
light polarization directions are within an angle of
.+-.45.degree., preferably, within .+-.20.degree. with respect to
each other.
[0196] With the optical films 1140, 1141, it is possible to prevent
the background from penetrating, becoming visible and making it
difficult to recognize the display when a person views the display
from one surface.
[0197] Further, one more optical film may be added. For example,
one polarizing film absorbs S waves (or P waves), but a luminosity
increasing film for reflecting S waves (or P waves) onto the
light-emitting elements and reproducing them may be provided
between the polarizing plate and light-emitting panel. As a result,
the number of P waves (or S waves) that pass through the polarizing
plate increases and the increase in integral quantity of light can
be obtained. In the double-side light-emitting panels, the
structures of layers that pass the light from the light-emitting
elements are different. Therefore, the light emission patterns
(luminosity, chromaticity balance, and the like) are different and
the optical films are suitable for adjusting the light emission
balance on both sides. Further, in the double side light-emitting
panels, the external light reflection intensities are also
different. Therefore, it is preferred that the luminosity
increasing film be provided between the polarizing plate and
light-emitting panel on the surface with a larger reflection.
[0198] Further, a transparent protective laminated layer 1117 is
formed for sealing the light-emitting element 1118. The transparent
protective laminated layer 1117 is composed of a laminated layer of
a first inorganic insulating film, a stress relaxation film, and a
second inorganic insulating film. A silicon nitride film, silicon
oxide film, silicon oxide nitride film (SiNO film (composition
ratio N<O). a SiON film (composition ratio N<O)), or a thin
film containing carbon as the main component (for example, a DLC
film, a CN film) obtained by a sputtering method or a CVD method
can be used as the first inorganic insulating film and second
inorganic insulating film. Those inorganic insulating films have a
strong blocking effect with respect to moisture, but if the film
thickness increases, the film stresses increase and the film can be
easily peeled or detached. However, stresses can be relaxed and
moisture can be absorbed by sandwiching a stress relaxation film
between the first inorganic insulating film and second inorganic
insulating film. Further, even when fine holes (pinholes and the
like) are formed for whatever reason in the first inorganic
insulating film during deposition, they are filled with the stress
relaxation film. Further, providing the second inorganic insulating
film thereupon produces a very strong blocking effect with respect
to moisture or oxygen. Further a hygroscopic material with stresses
less than those in the inorganic insulating films is preferred as
the stress relaxation film. Moreover, a transparent material is
preferred. Further, material films comprising organic compounds
such as .alpha.-NPD
(4,4'-bis-[N-(naphthyl)-N-phenyl-amino]biphenyl), BCP
(bathocuproine), MTDATA
(4,4',4"-tris(N-3-methylphenyl-N-phenyl-amino)triphenylamine),
Alq.sub.3 (tris-8-quinolinolatoaluminum complex) may be used as the
stress relaxation film. Those material films have hygroscopicity
and are almost transparent if the film thickness is small.
Furthermore, because MgO, SrO.sub.2, and SrO have hygroscopicity
and light transparency and thin films thereof can be obtained by a
deposition method, they can be used for the stress relaxation film.
In the present example, a film formed in an atmosphere comprising
nitrogen and argon by using a silicon target, that is, a silicon
nitride film with a strong blocking effect with respect to moisture
and impurities such as alkali metals is used as a first inorganic
insulating film or second inorganic insulating film, and a thin
film of Alq.sub.3 produced by a deposition method is used as the
stress relaxation film. Further, in order to pass the emitted light
to the transparent protective laminated layer, the total film
thickness of the transparent protective laminated layer is
preferably as small as possible.
[0199] Further, the sealing substrate 1104 is pasted with a first
sealing material 1105 and a second sealing material 1107 under an
inactive gas atmosphere in order to seal the light-emitting element
1118. An epoxy resin is preferably used as the first sealing
material 1105. Further, no specific limitation is placed on the
second sealing material 1107, provided it is a material transparent
to light. Typically, it is preferred that a UV-curable or
thermosetting epoxy resin be used. Here, a UV epoxy resin
(manufactured by Electrolight Co., 1500Clear) with high heat
resistance is used. This resin has a refractive index of 1.50, a
viscosity of 500 cps, a Shore D hardness of 90, a tensile strength
of 3000 psi, a Tg point of 150.degree. C., a volume resistance of
1.times.10.sup.15 .OMEGA..multidot.cm, and a voltage resistance of
450 V/mil. Further, filling the space between a pair of substrates
with the second sealing material 1107 makes it possible to increase
the transmittance of the entire body with respect to that obtained
when the space between the two substrates is empty (inactive gas).
Further, it is preferred that the moisture or oxygen permeability
of the first sealing material 1105 and second sealing material 1107
be as low as possible.
[0200] Further, in the present working example, a plastic substrate
composed of FRP (Fiberglass-Reinforced Plastics), PVF (polyvinyl
fluoride), Mylar, polyesters, acryls, and the like, can be used
besides a substrate or quartz glass substrate as the material
constituting the sealing substrate 1104. Further, after the sealed
substrate 1104 has been adhesively bonded by using the first
sealing material 1105 and second sealing material 1107, sealing can
be conducted with a third sealing material so as to cover the side
surfaces (exposed surfaces).
[0201] Sealing the light-emitting element with the first sealing
material 1105 and second sealing material 1107 in the
above-described manner makes it possible to completely shield the
light-emitting element from the outside and to prevent the
penetration of substances, such as moisture or oxygen, that enhance
the deterioration of the organic compound layer. Therefore, a
light-emitting device with high reliability is obtained.
[0202] Further, when a light-emitting device of an upper-surface
emission type is fabricated, the cathode is preferably a reflective
metal film (chromium, titanium nitride, and the like). Furthermore,
when a light-emitting device of a lower-surface emission type is
fabricated, a metal film (film thickness 50 nm-200 nm) composed of
Al, Ag, Li, Ca, alloys thereof, MgAg, MgIn, and AlLi is preferably
used for the cathode.
[0203] This example can be freely combined with Embodiments 1 to 4
and Examples 1 to 3.
Example 5
[0204] In this working example, an electronic device comprising two
or more display devices will be explained with reference to FIG.
12. An electronic device equipped with an EL module can be created
by implementing the present invention. Examples of electronic
devices include video cameras, digital cameras, goggle-type
displays (head-mounted displays), navigation systems, acoustic
reproduction devices (car audio, audio component stereo systems,
and the like), notebook personal computers, game devices, portable
information terminals (mobile computers, cellular phones, portable
game machines, electronic books, and the like), and image
reproducing devices comprising recording medium (more specifically,
devices equipped with displays capable of reproducing the recorded
medium, such as Digital Versatile Disk. (DVD) and displaying the
image).
[0205] FIG. 12(A) is a perspective view of a notebook personal
computer, FIG. 12(B) is a perspective view illustrating the folded
state. The note-book personal computer comprises a body 2201, a
case 2202, display portions 2203a, 2203b, a keyboard 2204, an
external connection port 2205, and a pointing mouse 2206.
[0206] The notebook personal computer shown in FIG. 12(A), and FIG.
12(B) comprises the high-quality display portion 2203a mainly for
full-color displaying the images and the monochromatic display
portion 2203b for displaying mainly text and symbols.
[0207] Further, FIG. 12(C) is a perspective view of a mobile
computer. FIG. 12(D) is a perspective view showing the back surface
side. The mobile computer comprises a body 2301. display portions
2302a, 2302b, a switch 2303, a control key 2304, and an IR port
2305. It mainly comprises the high-quality display portion 2302a
for full-color displaying images and the monochromatic display
portion 2302b for displaying mainly text and symbols.
[0208] Further, FIG. 12(E) shows a video camera comprising a body
2601, a display portion 2602, a case 2603, an external connection
port 2604, a remote control socket 2605, an image pickup unit 2606,
a battery 2606, a voice input unit 2608, and a control key 2609.
The display portion 2602 is a double-side light-emitting panel
capable of high-quality display mainly for full-color displaying
the images on one surface and monochromatically displaying mainly
text and symbols on the other surface. Further, the display portion
2602 can be rotated in the mounting portion. The present invention
can be employed in the display portion 2602.
[0209] Further, FIG. 12(F) is a perspective view of a cellular
phone. FIG. 12(G) is a perspective view illustrating the folded
state. The cellular phone comprises a body 2701, a case 2702,
display portions 2703a, 2703b, a voice input unit 2704, a voice
output unit 2705, a control key 2706, an external connection port
2707, and an antenna 2708.
[0210] The cellular phone shown in FIG. 12(F) and FIG. 12(G)
comprises the high-quality display portion 2703a mainly for
full-color displaying the images and the display portion 2703b for
displaying mainly text and symbols by area colors. In this case, a
color filter is used in the display portion 2703a, and an optical
film serving as an area color is used for the display portion
2703b.
[0211] Further, this example can be freely combined with
Embodiments 1 to 4 and Examples 1 to 4.
Example 6
[0212] FIG. 16 is a drawing which illustrates charging of a
cellular phone using the display device in accordance with the
present invention. FIG. 16 illustrates a state in which the
cellular phone is opened and light is emitted from both sides, but
charging may be also conducted in a closed state. In display
devices using light-emitting elements, the light-emitting elements
generally deteriorate with time and luminosity decreases. In
particular, in case of display devices in which light-emitting
elements are disposed at a one-to-one ratio with pixels, because
the frequency at which the pixels come on differs depending on the
location, the degree of deterioration also differs depending on the
location. Therefore, in the pixels with a high switching frequency,
the degree of deterioration is high and image quality decreases as
an image persistence effect. Accordingly, image persistence can be
made inconspicuous by conducting certain display during charging,
which is not a usual usage state, and switching on the pixels with
a low usage frequency. A full-screen operation mode, an image with
brightness inverted with respect to the standard image (stand-by
screen and the like), and an image displayed by detecting pixels
with a low usage frequency are examples of display contents during
charging.
[0213] FIG. 14 is a block diagram corresponding to the drawing. A
CPU 2001 obtaining charging state detection signal from a charger
2017 issues a command instructing a display controller 2004 to
display a signal corresponding to the above-described and a
double-side light-emitting display conducts light emission.
[0214] FIG. 15 illustrates an example of means for producing an
image with a brightness inverted with respect to the standard
image. The output of a video signal selection switch 2106 is
inputted into a switch 2107 and a selection can be made whether to
input the signal of a switch 2106 into a display 2101 as is or
after inversion. When brightness inversion is necessary, the input
may be made after inversion. This selection is conducted with the
display controller. Further, in a full-screen operation mode, a
fixed voltage may be inputted to the display 2101 (not shown in the
figures).
[0215] The deterioration of displayed images can be thus inhibited
by conducting light emission which decreases image persistence
during charging.
[0216] Further, the present example can be freely combined with any
of Embodiments 1 to 4 and Examples 1 to 5.
[0217] [Effect of the Invention]
[0218] With the present invention, a large mask with a high mask
accuracy can be realized for conducting selective deposition on a
substrate with a large surface area. Further, the present invention
makes it possible to realize a deposition apparatus allowing a
uniform film thickness to be obtained over the entire substrate
surface even on substrates with a large surface area.
* * * * *