U.S. patent application number 10/626565 was filed with the patent office on 2004-10-21 for droplet discharge method, droplet discharge apparatus, manufacturing method for liquid crystal device, liquid crystal device, and electronic apparatus.
This patent application is currently assigned to Seiko Epson Corporation. Invention is credited to Hiruma, Kei, Kawase, Tomomi.
Application Number | 20040207800 10/626565 |
Document ID | / |
Family ID | 31497603 |
Filed Date | 2004-10-21 |
United States Patent
Application |
20040207800 |
Kind Code |
A1 |
Hiruma, Kei ; et
al. |
October 21, 2004 |
Droplet discharge method, droplet discharge apparatus,
manufacturing method for liquid crystal device, liquid crystal
device, and electronic apparatus
Abstract
A droplet discharge method for discharging a liquid material
from a discharge device and arranging the liquid material in a
specified quantity on a substrate, the discharge device includes a
nozzle for discharging the liquid material in droplets, and the
droplet discharge method include the steps of cleaning the nozzle
using the liquid material, and arranging at least a part of the
liquid material used for cleaning on the substrate.
Inventors: |
Hiruma, Kei; (Chino-shi,
JP) ; Kawase, Tomomi; (Matsumoto-shi, JP) |
Correspondence
Address: |
OLIFF & BERRIDGE, PLC
P.O. BOX 19928
ALEXANDRIA
VA
22320
US
|
Assignee: |
Seiko Epson Corporation
Tokyo
JP
|
Family ID: |
31497603 |
Appl. No.: |
10/626565 |
Filed: |
July 25, 2003 |
Current U.S.
Class: |
349/189 |
Current CPC
Class: |
G02F 1/1341 20130101;
G02F 1/13415 20210101; H01L 51/0005 20130101; C09K 2323/00
20200801 |
Class at
Publication: |
349/189 |
International
Class: |
G02F 001/1341 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 31, 2002 |
JP |
2002-223151 |
Jul 17, 2003 |
JP |
2003-198651 |
Claims
What is claimed is:
1. A droplet discharge method for discharging a liquid material
from a discharge device and arranging the liquid material in a
specified quantity on a substrate, the discharge device comprising
a nozzle for discharging the liquid material in droplets, and the
droplet discharge method comprising the steps of: cleaning the
nozzle using the liquid material; and arranging at least a part of
the liquid material used for cleaning on the substrate.
2. A droplet discharge method according to claim 1, wherein the
liquid material is warmed to room temperature or higher.
3. A manufacturing method for a liquid crystal device involving
discharging a liquid crystal from a discharge device, and arranging
the liquid crystal in a specified quantity on a first substrate,
the discharge device comprising a nozzle for discharging the liquid
crystal in droplets, and the manufacturing method comprising the
steps of: cleaning the nozzle using the liquid crystal; and
arranging at least a part of the liquid crystal used for cleaning
on the first substrate.
4. A manufacturing method for a liquid crystal device according to
claim 3, wherein a sealing material for adhering the first
substrate to a second substrate is arranged on the first substrate,
and a specified quantity of liquid crystal is arranged on the first
substrate, away from the sealing material.
5. A manufacturing method for a liquid crystal device according to
claim 4, wherein after the first substrate and the second substrate
are adhered to each other via said sealing material, the liquid
crystal is spread over a whole space between the first substrate
and the second substrate.
6. A manufacturing method for a liquid crystal device involving
discharging a liquid material from a discharge device to form a
predetermined component on a substrate, the discharge device
comprising a nozzle for discharging the liquid material in
droplets, and the droplet discharge method comprising the steps of:
cleaning the nozzle using the liquid material; and arranging at
least a part of the liquid material used for cleaning on the
substrate.
7. A manufacturing method for a liquid crystal device according to
claim 6, wherein the component is an orientated film constituting a
liquid crystal device or a protection film for a color filter, and
the liquid material contains a constituent material for the
orientated film or the protection film.
8. A droplet discharge apparatus which discharges a liquid material
from a discharge device and arranges the liquid material in a
specified quantity on a substrate, wherein the discharge device has
a nozzle for discharging the liquid material in droplets, and the
droplet discharge apparatus comprising: a liquid material supply
system which supplies the liquid material to the nozzle; and a
measuring device which measures a quantity of the liquid material
arranged on the substrate.
9. A droplet discharge apparatus according to claim 8, further
comprising a temperature control device which warms the liquid
material to room temperature or higher.
10. A liquid crystal device, comprising at least one component of a
component group consisting of a liquid crystal layer, an oriented
film, and a protection film for a color filter, wherein the droplet
discharge apparatus according to claim 8 is used to form at least
one component of the component group.
11. An electronic apparatus comprising the liquid crystal device
according to claim 10.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a technique for discharging
a liquid material from a discharge device, and arranging a
specified quantity of liquid material on a substrate. More
specifically, the present invention relates to a droplet discharge
method and a droplet discharge apparatus used in a manufacturing
process for an electrooptical device such as a liquid crystal
device.
[0003] Priority is claimed on Japanese Patent Applications No.
2002-223151, filed Jul. 31, 2002, and No. 2003-198651, filed Jul.
17, 2003, the content of which is incorporated herein by
reference.
[0004] 2. Description of Related Art
[0005] As a technique for quantitatively arranging a specified
quantity of liquid material on a substrate, there is known for
example a technique in which a specified quantity of liquid
material is continuously discharged by using a dispenser, and this
is then arranged on the substrate, for example as is shown, in
Japanese Patent Application Laid-Open (JP-A) No. 10-323601.
[0006] In the quantitative arrangement technique for the liquid
material using a dispenser, however, it is difficult to control the
discharged quantity of the liquid material and the location of the
liquid material on the substrate highly accurately, and a
nonuniform arrangement of the liquid material is likely to
occur.
[0007] For example, a manufacturing process for a liquid crystal
device includes a step for quantitatively arranging a liquid
crystal on a substrate having electrodes formed thereon, and then
adhering the substrate to another substrate. At this time, if
nonuniform arrangement of the liquid material occurs, this may
cause a drop in the display quality.
[0008] In view of the above situation, it is an object of the
present invention to provide a droplet discharge method and a
droplet discharge apparatus, which can reduce the consumption of a
liquid material, and can uniformly arrange the liquid material on a
substrate, without significantly decreasing the throughput. It is
another object of the present invention to provide a manufacturing
method for a liquid crystal device, which can realize low cost and
improved quality, and a liquid crystal device. Moreover, it is
another object of the present invention to provide electronic
apparatus including a high quality liquid crystal device at a low
cost.
SUMMARY OF THE INVENTION
[0009] The first aspect of the present invention is a droplet
discharge method for discharging a liquid material from a discharge
device and arranging the liquid material in a specified quantity on
a substrate, the discharge device comprising a nozzle for
discharging the liquid material in droplets, and the droplet
discharge method has the steps of cleaning the nozzle using the
liquid material, and arranging at least a part of the liquid
material used for cleaning on the substrate.
[0010] In the droplet discharge method in this aspect, since the
liquid material is discharged in droplets via the nozzle, the
quantity and position of the liquid material to be arranged on the
substrate can be finely controlled, thereby enabling uniform
arrangement of the liquid material. Moreover, since at least a part
of the liquid material used for cleaning the nozzle is directly
arranged on the substrate, wasteful use of the liquid material can
be avoided, and the consumption thereof can be reduced. In this
case, since cleaning of the nozzle and the quantitative arrangement
of the liquid material are conducted in parallel at least partly,
the whole processing time can be shortened, thereby improving the
throughput, as compared with a case where these are conducted
separately.
[0011] In the droplet discharge method, the liquid material may be
warmed to room temperature or higher. As a result, liquid material
having a relatively high viscosity can be used.
[0012] The second aspect of the present invention is a
manufacturing method for a liquid crystal device involving
discharging a liquid crystal from a discharge device, and arranging
the liquid crystal in a specified quantity on a first substrate,
the discharge device comprising a nozzle for discharging the liquid
crystal in droplets, and the manufacturing method has the steps of
cleaning the nozzle using the liquid crystal, and arranging at
least a part of the liquid crystal used for cleaning on the first
substrate.
[0013] With the manufacturing method for the liquid crystal device,
the quantity and position of the liquid crystal to be arranged on
the first substrate can be finely controlled. Moreover, wasteful
use of the liquid crystal can be avoided, and the consumption
thereof can be reduced.
[0014] Furthermore, preferably a sealing material for adhering the
first substrate to a second substrate is arranged on the first
substrate, and a specified quantity of liquid crystal is arranged
on the first substrate, away from the sealing material.
[0015] As a result, contact between the sealing material and the
liquid crystal can be prevented at the time of arranging the liquid
crystal, thereby preventing performance deterioration of the
sealing material. Since the liquid crystal arranged on the
substrate is discharged in droplets via the nozzle, the quantity
and position of the liquid crystal to be arranged can be finely
controlled, thereby reliably preventing contact.
[0016] In this case, it is desired that the liquid crystal be
spread over a whole space between the first substrate and the
second substrate, after these substrates are adhered to each other
via the sealing material.
[0017] As a result, performance deterioration of the sealing
material due to contact between the sealing material and the liquid
crystal can be suppressed. For example, by spreading the liquid
crystal over the whole space after the sealing material is dried to
some extent, even if the sealing material and the liquid crystal
come in contact with each other, there is little performance
deterioration of the sealing material.
[0018] The third aspect of the present invention is a manufacturing
method for a liquid crystal device involving discharging a liquid
material from a discharge device to form a predetermined component
on a substrate, the discharge device comprising a nozzle for
discharging the liquid material in droplets, and the droplet
discharge method has the steps of cleaning the nozzle using the
liquid material, and arranging at least a part of the liquid
material used for cleaning on the substrate.
[0019] With the manufacturing method for the liquid crystal device
in this aspect, the quantity and position of the components to be
formed on the substrate can be finely controlled. Moreover,
wasteful use of the liquid material can be avoided, and the
consumption thereof can be reduced.
[0020] Moreover, the component is an orientated film constituting a
liquid crystal device or a protection film for a color filter, and
the liquid material contains a constituent material for the
orientated film or the protection film.
[0021] As a result, the quantity and position of the oriented film
or the protection film to be formed on the substrate can be finely
controlled. Moreover, wasteful use of the liquid material can be
avoided, and the consumption thereof can be reduced.
[0022] The fourth aspect of the present invention is a droplet
discharge apparatus which discharges a liquid material from a
discharge device and arranges the liquid material in a specified
quantity on a substrate, wherein the discharge device has a nozzle
for discharging the liquid material in droplets, and the droplet
discharge apparatus has a liquid material supply system which
supplies the liquid material to the nozzle, and a measuring device
which measures a quantity of the liquid material arranged on the
substrate.
[0023] Since the droplet discharge apparatus in this aspect can
execute the droplet discharge method by having the above-described
configuration, the quantity and position of the liquid material to
be arranged on the substrate can be finely controlled. Moreover, by
cleaning the nozzle using the liquid material and arranging at
least a part of the liquid material used for cleaning on the
substrate as is, the consumption of the liquid material can be
reduced, and the throughput can be improved.
[0024] Furthermore, the droplet discharge apparatus may have a
temperature control device which warms the liquid material to room
temperature or higher.
[0025] As a result, liquid material having a relatively high
viscosity can be used.
[0026] In this liquid crystal device, a liquid crystal device has
at least one component of a component group consisting of a liquid
crystal layer, an oriented film, and a protection film for a color
filter, wherein the droplet discharge apparatus is used to form at
least one component of the component group.
[0027] In the liquid crystal device, being a fifth aspect of the
present invention, the component is formed by using the droplet
discharge device. As a result, the manufacturing cost can be
reduced, and the performance can be improved.
[0028] An electronic apparatus, being a sixth aspect of the present
invention, has the above described liquid crystal device. With this
electronic apparatus, the manufacturing cost can be reduced, and
the performance can be improved.
BRIEF DESCRIPTION OF THE DRAWINGS
[0029] FIG. 1 is a diagram schematically illustrating one example
of an embodiment of a droplet discharge apparatus of the present
invention.
[0030] FIG. 2 is a diagram for explaining the discharge principle
for a liquid material using a piezo method.
[0031] FIGS. 3A and 3B are diagrams illustrating an example in
which a specified quantity of liquid material is quantitatively
arranged on a substrate, by using the droplet discharge
apparatus.
[0032] FIG. 4 is a diagram schematically illustrating one example
of a sectional structure of a liquid crystal device (liquid crystal
display).
[0033] FIGS. 5A to 5D are diagrams schematically illustrating a
manufacturing method for the liquid crystal device, FIG. 5A and
FIG. 5B illustrating a process for quantitatively arranging a
liquid crystal on a glass substrate, and FIG. 5C and FIG. 5D
illustrating a process for sealing the liquid crystal.
[0034] FIG. 6 is an equivalent circuit diagram of various elements
and wiring in a plurality of pixels formed in matrix form for
constituting a screen display area on a liquid crystal panel.
[0035] FIG. 7 is a plan view illustrating the configuration of
respective pixels formed on an active matrix substrate in the
liquid crystal panel shown in FIG. 6.
[0036] FIG. 8 is a sectional view at a position corresponding to
line A-A' in FIG. 7.
[0037] FIG. 9 is an equivalent circuit diagram illustrating the
configuration of an active matrix substrate used in the liquid
crystal panel shown in FIG. 6.
[0038] FIGS. 10A to 10C are process sectional views illustrating
the process of a manufacturing method for the active matrix
substrate of the liquid crystal panel.
[0039] FIGS. 11A to 11D are process sectional views of respective
processes conducted following the process shown in FIG. 10C, in the
manufacturing method for the active matrix substrate of the liquid
crystal panel.
[0040] FIGS. 12A to 12E are process sectional views of respective
processes conducted following the process shown in FIG. 11D, in the
manufacturing method for the active matrix substrate of the liquid
crystal panel.
[0041] FIGS. 13A to 13C are process sectional views of respective
processes conducted following the process shown in FIG. 12E, in the
manufacturing method for the active matrix substrate of the liquid
crystal panel.
[0042] FIGS. 14A to 14C are process sectional views of respective
processes conducted following the process shown in FIG. 13C, in the
manufacturing method for the active matrix substrate of the liquid
crystal panel.
[0043] FIG. 15 is an explanatory diagram illustrating the condition
of the glass substrate in the manufacturing process.
[0044] FIG. 16 is an explanatory diagram illustrating the operation
of a droplet discharge head of the droplet discharge apparatus.
[0045] FIG. 17 is a plan view illustrating an exemplary arrangement
of droplets dropped on the substrate.
[0046] FIG. 18 is a plan view illustrating another exemplary
arrangement of droplets dropped on the substrate.
[0047] FIG. 19 is a plan view illustrating another exemplary
arrangement of droplets dropped on the substrate.
[0048] FIG. 20 is a plan view illustrating another exemplary
arrangement of droplets dropped on the substrate.
[0049] FIG. 21 is a plan view illustrating another exemplary
arrangement of droplets dropped on the substrate.
[0050] FIG. 22 is a plan view illustrating a discharge example of
droplets dropped on the substrate.
[0051] FIG. 23 is a plan view illustrating another discharge
example of droplets dropped on the substrate.
[0052] FIG. 24 is a plan view illustrating a first operation in the
discharge example of droplets.
[0053] FIG. 25 is a plan view illustrating another operation in the
discharge example of droplets.
[0054] FIG. 26 is a plan view illustrating other discharge example
of droplets dropped on the substrate.
[0055] FIGS. 27A to 27D are sectional views illustrating a
manufacturing process for a color filter.
[0056] FIG. 28 is a diagram illustrating an example in which the
electronic apparatus of the present invention is applied to a
mobile phone having a liquid crystal display.
[0057] FIG. 29 is a diagram illustrating an example in which the
electronic apparatus of the present invention is applied to a
portable information processor having a liquid crystal display.
[0058] FIG. 30 is a diagram illustrating an example in which the
electronic apparatus of the present invention is applied to watch
type electronic apparatus having a liquid crystal display.
DETAILED DESCRIPTION OF THE INVENTION
First Embodiment
[0059] Embodiments of the present invention will now be described,
with reference to the drawings.
[0060] FIG. 1 schematically illustrates one example of an
embodiment of a droplet discharge apparatus of the present
invention. A droplet discharge apparatus 10 comprises a droplet
discharge head 21 which discharges a liquid material toward a
substrate 20, a substrate stage 22 on which the substrate 20 is
mounted, a measuring device 23 which measures the weight of the
liquid material arranged on the substrate 20, and a control unit 25
which controls these in an integrated manner. The droplet discharge
head 21 and the substrate stage 22 are arranged in a chamber 28,
and this chamber 28 comprises a thermostat 29, which controls the
temperature therein.
[0061] For the substrate 20, various substrates may be used, such
as a glass substrate, a silicon substrate, a quartz substrate, a
ceramic substrate, a metal substrate, a plastics substrate, and a
plastic film substrate. There is also included one in which a
semiconductor film, a metal film, a dielectric film, or an organic
film are formed on the surface of a substrate of these various
materials, as a ground layer (base layer).
[0062] The droplet discharge head 21 is for discharging a liquid
material (resist) from a nozzle by a liquid discharge method. As
the liquid discharge method, various known techniques can be
applied, such as a piezo method in which an ink is discharged by
using a piezo device as a piezoelectric element, a method in which
a liquid material is heated and discharged in a form of bubbles,
and the like. Of these methods, the piezo method has an advantage
in that it does not affect the composition of the material, since
the liquid material is not heated. In this embodiment, the piezo
method is used.
[0063] FIG. 2 is a diagram for explaining the discharge principle
of a liquid material by the piezo method. In FIG. 2, a piezo device
32 is installed adjacent to a liquid chamber 31 for storing the
liquid material. The liquid material is supplied to the liquid
chamber 31 via a liquid material supply system 34 including a
material tank for storing the liquid material. The piezo device 32
is connected to a drive circuit 33, and voltage is applied to the
piezo device 32 via the drive circuit 33. By deforming the piezo
device 32, the liquid chamber 31 deforms, to discharge the liquid
material from the nozzle 30. At this time, by changing the value of
the applied voltage, the distortion of the piezo device 32 is
controlled, and by changing the frequency of the applied voltage,
the distortion speed of the piezo device 32 is controlled. In other
words, in the droplet discharge head 21, by controlling the applied
voltage to the piezo device 32, discharge of the liquid material
from the nozzle 30 is controlled.
[0064] Returning to FIG. 1, the droplet discharge head 21 is
arranged above the substrate stage 22, so as to be able to move
freely relative to the substrate stage 22.
[0065] The substrate stage 22 has a standby discharge section 40 in
which cleaning of the droplet discharge head 21 is conducted, and a
weight measuring section 41 which quantitatively arranges the
liquid material. The operations of carrying in and out of a
substrate 20 with respect to the substrate stage 22, and transfer
of the substrate 20 between the standby discharge section 40 and
the weight measuring section 41 are conducted by a transfer
mechanism (not shown) comprising a transfer arm and the like.
[0066] The measuring device 23 comprises for example a load cell
for measuring the weight of an object. In this example, the
measuring device 23 is constituted so as to measure the weight of
the substrate 20 mounted in the weight measuring section 41 on the
substrate stage 22, and the measurement result is transmitted to
the control unit 25. The control unit 25 stores the weight of the
substrate 20 before the liquid material is arranged, and determines
the weight of the liquid material arranged on the substrate 20,
based on the measurement result transmitted from the measuring
device 23 and the stored information.
[0067] The temperature in the chamber 28 is controlled by the
thermostat 29 such that the viscosity of the liquid material to be
used becomes a viscosity for favorable discharge from the droplet
discharge head 21, based on a correlation between the properties of
the liquid material, particularly, the viscosity of the liquid
material, and the temperature. By controlling the temperature in
the chamber 28 to room temperature or higher, for example, to a
predetermined temperature within a range of from 30 to 70.degree.
C., the viscosity of liquid material having a high viscosity at
room temperature can be decreased, thereby improving the discharge
property and the flatness of the application film on the substrate.
In the example, by controlling the temperature in the chamber 28,
the liquid material is warmed, but the droplet discharge head or
the substrate stage may be respectively warmed.
[0068] FIGS. 3A and 3B illustrate an example in which a specified
quantity of liquid material is quantitatively arranged on the
substrate 20, by using the droplet discharge apparatus 10 having
the above configuration.
[0069] As shown in FIG. 3A, at first, the nozzle of the droplet
discharge head 21 is cleaned (flushed). Cleaning of the nozzle of
the droplet discharge head 21 is conducted by supplying the liquid
material into the droplet discharge head 21 from the liquid
material supply system 34 and discharging the liquid material from
the nozzle. In other words, by vigorously pushing the liquid
material through the droplet discharge head 21, clogging in the
nozzle of the droplet discharge head 21, which occurs due to drying
or the like, is dissolved. The liquid material used for cleaning is
the same as the quantitatively arranged liquid material.
[0070] At the time of cleaning, the substrate 20 is mounted in the
standby discharge section 40 on the substrate stage 22, the droplet
discharge head 21 is arranged above the substrate 20, and the
liquid material discharged from the droplet discharge head 21 is
directly arranged on the substrate 20. The quantity of the liquid
material used for cleaning is less than the specified quantity to
be arranged on the substrate 20.
[0071] As shown in FIG. 3B, the substrate 20 is shifted from the
standby discharge section 40 to the weight measuring section 41,
and the cleaned droplet discharge head 21 is arranged above the
substrate 20. The liquid material is then discharged repetitively
in droplets from the droplet discharge head 21, to arrange the
specified quantity of liquid material on the substrate 20.
[0072] At this time, the arrangement of the liquid material is
conducted while weighing the weight of the substrate 20. In other
words, at the time of arranging the liquid material, the measuring
device 23 measures the weight of the substrate 20 mounted on the
weight measuring section 41, and transmits the measurement result
to the control unit 25. The control unit 25 calculates the weight
of the liquid material arranged on the substrate 20, based on the
measurement result transmitted from the measuring device 23 and the
stored information relating to the weight of the substrate 20
before arranging the liquid material. When the weight of the liquid
material has reached the specified quantity, based on the
calculation result, discharge of droplets from the droplet
discharge head 21 is stopped. As a result, the liquid material is
arranged in the specified quantity on the substrate 20. When
adjusting the gross weight of the liquid material to be discharged
on the substrate, the weight can be favorably adjusted, by
discharging the droplets in dots of a smaller size than that of the
droplets normally discharged.
[0073] In the droplet discharge method in this embodiment, since at
least a part of the liquid material used for cleaning the nozzle is
directly arranged on the substrate, the liquid material used for
cleaning can be included in the specified quantity, as a part of
the liquid material to be arranged on the substrate. As a result,
wasteful use of the liquid material is avoided, and the consumption
thereof is reduced. In other words, since it is not necessary to
dispose of the liquid material used for cleaning, there is an
advantage in that this method does not harm the environment, and
heretofore required liquid wastes processing cost is not
necessary.
[0074] Measurement of the liquid material is performed after the
cleaning, and hence even if clogging has occurred in the nozzle at
the initial stage of cleaning, it does not affect the measurement
accuracy. Moreover, in this case, since cleaning of the nozzle and
the quantitative arrangement of the liquid material are conducted
in parallel at least partly, the whole processing time can be
shortened, thereby improving the throughput, as compared with a
case where these are conducted separately.
[0075] At the time of cleaning the nozzle, the voltage applied to
the piezo device may be set higher than that for at the time of
normal discharge of the liquid material. In other words, in the
conventional droplet discharge apparatus, control for finely
adjusting the voltage applied to the piezo device at the time of
discharging the liquid material is required, for accurately
discharging the liquid material to desired application positions,
for example, like the discharge operation of ink for forming a
color filter. In the present invention, however, there is no
problem even if a change such as in the trajectory occurs in the
discharged liquid material.
Second Embodiment
[0076] An example in which the droplet discharge method is used for
a manufacturing process for a liquid crystal device will be
described below.
[0077] FIG. 4 schematically illustrates a sectional structure of a
passive matrix type liquid crystal device (a liquid crystal
display).
[0078] The liquid crystal device 100 is of a transmission type, and
has a structure such that a liquid crystal layer 103 comprising STN
(Super Twisted Nematic) liquid crystal is placed between a pair of
glass substrates 101 and 102. Moreover, the liquid crystal device
100 comprises a driver IC 113 for supplying a drive signal to the
liquid crystal layer, and a backlight 114 as a light source.
[0079] A color filter 104 is arranged on the inner face of the
glass substrate 101. The color filter 104 is formed by regularly
arranging color layers 104R, 104G and 104B respectively consisting
of colors of red (R), green (G) and blue (B). Between these color
layers 104R (104G, and 104B), partitions 105 comprising a black
matrix or a bank are formed. On the color filter 104 and the
partition 105, an over coat film 106 is arranged for removing a
difference in level formed by the color filter 104 and the
partition 105 to flatten the surface.
[0080] A plurality of electrodes 107 are formed in stripes on the
over coat film 106, and an oriented film 108 is formed thereon.
[0081] A plurality of electrodes 109 are formed in stripes on the
inner face of the other glass substrate 102, so as to be orthogonal
to the electrodes on the color filter 104 side, and an oriented
film 110 is formed on these electrodes 109. The respective color
layers 104R, 104G and 104B of the color filter 104 are arranged
respectively at positions corresponding to the crossing position of
the electrodes 109 on the glass substrate 102 and the electrodes
107 on the glass substrate 101. The electrodes 107 and 109 are
formed of a transparent conductive material such as ITO (Indium Tin
Oxide) or the like. Deflection plates (not shown) are respectively
provided on the external faces of the glass substrate 102 and the
color filter 104. Spacers 111 for maintaining a constant the gap
(cell gap) between these substrates 101 and 102, and a sealing
material 112 for cutting off the liquid crystal 103 from the
outside air are arranged between the glass substrates 101 and 102.
For the sealing material 112, for example, a thermosetting or
photocurable resin is used.
[0082] In this liquid crystal device 100, at least one of, the
oriented films 108 and 110, the over coat film 106, and the liquid
crystal layer 103 is arranged on the glass substrate by using the
droplet discharge method. As a result, the consumption of these
materials can be suppressed, thereby enabling achievement of low
cost.
[0083] FIGS. 5A to 5D schematically illustrate a manufacturing
method for the liquid crystal device 100, FIG. 5A and FIG. 5B
illustrating a process for quantitatively arranging the liquid
crystal on the glass substrate, and FIG. 5C and FIG. 5D
illustrating a process for sealing the liquid crystal.
[0084] In FIGS. 5A to 5D, illustration of the aforementioned
electrodes and the color filter on the glass substrate, and the
spacers are omitted, for brevity of explanation.
[0085] In FIGS. 5A and 5B, in the process for quantitatively
arranging the liquid crystal, the above described droplet discharge
method is used to quantitatively arrange the specified quantity of
liquid crystal on the glass substrate 101.
[0086] That is to say, as shown in FIG. 5A, the liquid crystal is
discharged in droplets Ln from the nozzle of the droplet discharge
head 21, while shifting the droplet discharge head 21 relative to
the glass substrate 101, to arrange the droplets Ln on the glass
substrate 101. As shown in FIG. 5B, the arrangement operation for
the droplets Ln is repeated a plurality of times, until the liquid
crystal arranged on the glass substrate 101 reaches the specified
quantity. The specified quantity of the liquid crystal to be
arranged on the glass substrate 101 is substantially the same as
the capacity of the space formed between the glass substrates after
sealing. In this embodiment, since the above described droplet
discharge method is used, the liquid crystal arranged on the glass
substrate 101 includes that used for cleaning (flushing) the
droplet discharge head 21. As a result, wasteful use of the liquid
crystal is avoided, and the consumption thereof can be reduced.
[0087] At the time of quantitatively arranging the liquid crystal,
the discharge conditions of the droplets Ln, such as the volume and
the location of the droplets Ln, are controlled. In this
embodiment, since the liquid crystal is arranged on the substrate
20 in droplets Ln, the quantity and the position of the liquid
crystal arranged on the substrate 20 can be finely controlled,
thereby enabling uniform arrangement of the liquid crystal 103 on
the substrate 20.
[0088] In this embodiment, as shown in FIG. 5A, the droplets Ln are
arranged at positions away from the sealing material 112 on the
substrate 20. Specifically, the droplets Ln are arranged on the
glass substrate 101, such that the gap between the central position
of the droplets Ln closest to the sealing material 112 and the
sealing material 112 is wider than the total of an impact error of
the droplets Ln and the radius of the droplets Ln. As a result,
contact between the sealing material 112 and the liquid crystal 103
can be prevented, and performance deterioration of the sealing
material 112 and deterioration of the liquid crystal 103 due to the
uncured sealing material 112 contaminating the liquid crystal 103
can be prevented.
[0089] Next, in FIGS. 5C and 5D, the other glass substrate 102 is
adhered under a reduced pressure, to the glass substrate 101 on
which the specified quantity of liquid crystal 103 is arranged, via
the sealing material 112.
[0090] Specifically, as shown in FIG. 5C, a pressure is mainly
applied to the edge of the glass substrates 101 and 102 where the
sealing materials 112 are arranged, to bond the sealing material
112 and the glass substrates 101 and 102. Then, after a
predetermined time has passed and the sealing material 112 has
dried to some degree, pressure is applied to the whole surface of
the glass substrates 101 and 102, to allow the liquid crystal 103
to spread over the space put between both substrates 101 and
102.
[0091] In this case, when the liquid crystal 103 comes in contact
with the sealing material 112, since the sealing material 112 has
dried to some degree, there is little performance deterioration of
the sealing material 112 accompanying the contact with the liquid
crystal 103 or deterioration of the liquid crystal 103. The
arrangement of the spacers 111 shown in FIG. 4 may be conducted
after the liquid crystal 103 is arranged on the glass substrate
101, or may be conducted at the same time as arranging the liquid
crystal 103. When the spacers 111 are arranged at the same time as
arranging of the liquid crystal, the spacers may be intermixed with
the liquid crystal.
[0092] After adhering the glass substrates 101 and 102 to each
other, heat or light is applied to the sealing material 112 to cure
the sealing material 112, so that the liquid crystal is sealed
between the glass substrates 101 and 102.
[0093] The liquid crystal device manufactured in this manner can
decrease the consumption of the liquid crystal, thereby enabling
low cost. Moreover, there is a minimal drop in the display quality
accompanying nonuniform arrangement of the liquid crystal, and poor
sealing hardly occurs.
[0094] Moreover, the droplet discharge apparatus of the present
invention is not limited to the above described passive matrix type
liquid crystal device, and for example, may be preferably applied
to the active matrix type liquid crystal device.
[0095] The configuration and operation of the liquid crystal panel
used in the active matrix type liquid crystal device (liquid
crystal display) will be described with reference to FIG. 6 to FIG.
9.
[0096] FIG. 6 is an equivalent circuit diagram of various elements
and wiring in a plurality of pixels formed in matrix form for
constituting a screen display area on a liquid crystal panel.
[0097] FIG. 7 is a plan view of adjacent pixels on the active
matrix substrate in which a data line, a scan line, a pixel
electrode and a shading film are formed.
[0098] FIG. 8 is a sectional view at a position corresponding to
line A-A' in FIG. 7.
[0099] FIG. 9 is a plan view showing a two-dimensional wiring
layout of an active matrix substrate.
[0100] In these figures, the scale for each layer and each member
is made different to give a size so that each layer and each member
is recognizable in the drawing.
[0101] In FIG. 6, in the screen display area of the liquid crystal
panel, in each of a plurality of pixels formed in matrix form is
formed a pixel switching TFT 215 for controlling a pixel electrode
204a, and a data line 201a to which pixel signals are supplied, is
electrically connected to a source of the TFT 215. Pixel signals
S1, S2, to Sn written to the data line 201a may be line-sequential
supplied in this order, or may be supplied for each group, with
respect to the associated adjacent plurality of data lines 201a.
Furthermore, a scan line 202a is electrically connected to the gate
of each TFT 215, and the configuration is such that scanning
signals G1, G2, to Gm are line-sequential applied pulsewise to each
of the scan lines 202a at a predetermined timing in this order. The
pixel electrode 204a is electrically connected to the drain of a
TFT 210, and by switching on the TFT 210 being a switching element,
for a fixed period, the pixel signals S1, S2, to Sn supplied from
the data line 201a are written to each pixel at a predetermined
timing. The pixel signals S1, S2, to Sn of a predetermined level
which are written to the liquid crystal via the pixel electrode
204a, are held for a fixed period between a counter electrode
formed in a counter substrate described later and the pixel
electrode 204a. The liquid crystal modulates light, enabling
gradation display by changing the orientation and order of the
molecular association change due to the applied voltage level. In a
normally white mode, the incident light cannot pass tluough this
liquid crystal portion, corresponding to the applied voltage, and
in a normally black mode, the incident light can pass through this
liquid crystal portion, corresponding to the applied voltage. As a
result, light having a contrast corresponding to the pixel signal
is emitted from the liquid crystal panel, as a whole.
[0102] In order to prevent leakage of the held pixel signals, it is
common to add a storage capacitance 220 in parallel with the liquid
crystal capacitance formed between the pixel electrode 204 and the
counter electrode. For example, the voltage of the pixel electrode
204a is held by the storage capacitance 220 for a time longer by
that for three figures, than the time while the source voltage is
applied. As a result, the holding characteristic of the electric
charge is improved, thereby realizing a liquid crystal display
having a high contrast ratio. The method for forming the storage
capacitance 220 may be used when the storage capacitance 220 is
formed between a capacitor line 202b, being wiring for forming the
capacitor, and the TFT 215, or when it is formed between the scan
line 202a in the previous stage and the TFT 215.
[0103] In FIG. 7, a plurality of transparent pixel electrodes 204a
(the outline is indicated by the dotted line portion 204a') is
formed in matrix form for each pixel, on the active matrix
substrate of the liquid crystal panel, and the data lines 201a,
scan lines 202a and capacitor lines 202b are formed along the
lengthwise and crosswise boundary areas of the pixel electrodes
204a. The data line 201a is electrically connected to a source area
described later, of a semiconductor layer 210a comprising a
polysilicon film, via a contact hole 205, and the pixel electrode
204a is electrically connected to a drain area described later, of
the semiconductor layer 210a, via a contact hole 206. Moreover, the
scan line 202a (gate electrode) passes so as to oppose a channel
forming area (a hatched area downward slanting to the right)
described later, of the semiconductor layer 210a.
[0104] As shown in FIG. 8, the liquid crystal panel 200 comprises
an active matrix substrate 230 and a counter substrate 240 arranged
opposite thereto. The base substance of the active matrix substrate
230 comprises a transparent substrate 230a such as a quartz
substrate or a heat-resisting glass plate, and the base substance
of the counter substrate 240 also comprises a transparent substrate
230a such as a quartz substrate or a heat-resisting glass plate.
Pixel electrodes 204a are provided on the active matrix substrate
230, and an oriented film 280, which has been subjected to
predetermined orientation processing such as rubbing processing, is
formed on the upper side thereof. The pixel electrodes 204a
comprise, for example, a transparent conductive thin film such as
ITO. The oriented film comprises, for example, an organic thin film
such as polyimide thin film.
[0105] On the active matrix substrate 230, there are formed pixel
switching TFTs 215 for controlling switching of the respective
pixel electrodes 204a, at positions adjacent to the respective
pixel electrodes 204a. The TFT 215 shown here has an LDD (Lightly
Doped Drain) structure, and comprises a scan line 202a (gate
electrode), a channel forming area 210a' in a semiconductor film
210a where a channel is formed by an electric field of a scanning
signal supplied from the scan line 202a, a gate insulating film 207
for insulating between the scan line 202a and the semiconductor
layer 210a, a data line 201a (source electrode), a low-density
source area (source side LDD area) 210b and a low-density drain
area (drain side LDD area) 210c in the semiconductor layer 210a,
and a high-density source area 210d and a high-density drain area
210e in the semiconductor layer 210a. To the high-density drain
area 210e is electrically connected a corresponding one of the
plurality of pixel electrodes 204a. As described below, the source
areas 210b and 210d, and the drain areas 210c and 201e are formed
by doping an n-type or p-type dopant of a predetermined density
corresponding to a case for forming an n-type channel or forming a
p-type channel in the semiconductor layer 210a. The TFT of the
n-type channel has an advantage in that the operation speed is
high, and this is frequently used for the pixel switching TFT.
[0106] The data line 201a (source electrode) comprises, for
example, a metal film such as aluminum, or an alloy film such as
metal silicide. On the scan line 202a (gate electrode), the gate
insulating film 207 and a base protection film 208, there is formed
first interlaminar insulating film 209 in which a contact hole 205
leading to the high-density source area 210d, and a contact hole
206 leading to the high-density drain area 210e are respectively
formed. The data line 201a (source electrode) is electrically
connected to high-density source area 210d via the contact hole 205
leading to the source area 210d. Moreover, a second interlaminar
insulating film 211 is formed on the data line 201a (source
electrode) and the first interlaminar insulating film 209. Since
the pixel electrode 204a is formed on the second interlaminar
insulating film 211, the contact hole 206 leading to the
high-density drain area 210e is formed in the gate insulating film
207, the first interlaminar insulating film 209 and the second
interlaminar insulating film 211. As a result, the pixel electrode
204a is electrically connected to the high-density drain area 210e
via the contact hole 206 leading to the high-density drain area
210e. The pixel electrode 204a and the high-density drain area 210e
may be electrically connected, via an aluminum electrode
simultaneously formed with the data line 201a or a polysilicon
electrode simultaneously formed with the scan line 202a.
[0107] The TFT 215 preferably has the LDD structure as described
above, but may have an offset structure in which impurity ion
implantation is not conducted in the area corresponding to the
low-density source area 210b and the low-density drain area 210c.
Moreover, the TFT 215 may be a self-alignment type TFT in which
impurity ions are implanted at a high density, using the gate
electrode 202a as a mask, to form the high-density source and drain
areas in a self-aligned manner.
[0108] In this embodiment, there is used a single gate structure in
which only one gate electrode (data line 202a) of the TFT 215 is
arranged between the source and drain areas 210b and 210e, but two
or more gate electrodes may be arranged therebetween. At this time,
the same signal is applied to the respective gate electrodes. When
the TFT is formed of at least dual gates (double gates) or triple
gates, a leak current at the junction of the channel and the source
and drain areas can be prevented, thereby enabling a reduction of
current at the off time. If at least one of these gate electrodes
has the LDD structure or the offset structure, the OFF-state
current can be further reduced, and a stable switching element can
be obtained.
[0109] In this embodiment, the gate insulating film 207 of the TFT
215 is extended from a position facing the gate electrode 202a and
is used as a dielectric film, and the semiconductor 210a is
extended as a first electrode 210f. Moreover, a part of the
capacitor line 202b facing thereto is used as a second electrode,
to form the storage capacitance 220. In other words, the
high-density drain area 210e of the semiconductor 210a is extended
up to below the data line 201a and the scan line 202a, and is
arranged opposite to the capacitor line 202b via the gate
insulating film 207 (dielectric film) along the data line 201a and
the scan line 202a, as the first electrode (semiconductor layer)
210f. The insulating film 207 as the dielectric for the storage
capacitance 220 is nothing else but the gate insulating film 207 of
the TFT 215 formed on the polysilicon film by high-temperature
oxidation, and hence, a thin and highly pressure-resistant
insulating film can be obtained. Therefore, the storage capacitance
220 can be formed as a large capacity storage capacitance with a
relatively small area. As a result, a space away from an opening
area including the area below the data line 201a and the area
parallel with the scan line 202a (that is, the area where the
capacitor line 202b is formned) can be effectively utilized, to
increase the storage capacitance with respect to the pixel
electrode 204a.
[0110] In the active matrix substrate 230 constructed in this
manner, as shown in FIG. 7 and FIG. 8, though the data line 201a,
the scan line 202a and the capacitor line 202b pass through the
boundary area between the adjacent pixel electrodes 204a, if light
leaks through this wiring, or through a gap between this wiring and
the pixel electrode 204a, the display quality deteriorates.
Therefore, in this embodiment, between the transparent substrate
230b, being the base substance of the active matrix substrate 230
and the base protection film 208, there is formed a shading film
212a (a hatched area downward slanting to the left in FIG. 7)
comprising Ti (titanium), Cr (chromium), W (tungsten), Ta
(tantalum), Mo (molybdenum) or Pd (palladium), being a high melting
metal or the alloy thereof, along the boundary area lengthwise and
crosswise of the respective pixel electrodes 204a. This shading
film 212a is formed, as seen in plan view, at positions overlapping
on the areas where the TFT 215 is formed including the channel
forming area of the semiconductor layer 210a, the data line 201a,
the scan line 202a and the capacitor line 202b, as seen from the
backside of the active matrix substrate 230.
[0111] On the other hand, a counter electrode 241 is formed over
the whole surface of the counter substrate 240, and an oriented
film (not shown), which has been subjected to predetermined
orientation processing such as rubbing processing, is formed on the
surface thereof. The counter electrode 241 is also formed from a
transparent conductive thin film such as an ITO film. Moreover, the
oriented film on the counter substrate 240 is also formed from an
organic film such as a polyimide film. A counter substrate side
shading film 242 is formed in matrix form on the counter substrate
240, in the area other than the opening area of each pixel. As a
result, the incident light from the counter substrate 240 side does
not reach the channel forming area 210a' and the LDD areas 210b and
210c in the semiconductor layer 210a. The shading film 242 on the
counter substrate side has functions of improving the contrast and
preventing color mixture of coloring materials.
[0112] The active matrix substrate 230 and the counter substrate
240 constructed as described above are arranged such that the pixel
electrode 204a faces the counter electrode 241, and the liquid
crystal 250 is sealed in the space between these substrates and
sealed by a sealing material described later, and held between
these substrates. The liquid crystal 250 takes a predetermined
orientation condition due to the oriented film in a condition where
the electric field from the pixel electrode 204a is not applied.
The liquid crystal 250 is formed by, for example, mixing one or
several kinds of nematic liquid crystals. The sealing material is
an adhesive comprising a photoresist or a thermosetting resin for
adhering the active matrix substrate 230 and the counter substrate
240 at the periphery thereof, and spacers such as glass fibers or
glass beads are mixed as gap materials for maintaining the distance
between the both substrates at a predetermined value.
[0113] In the liquid crystal panel 200 constructed as described
above, the active matrix substrate 230 is constructed as shown in
FlG. 9. A data line drive circuit 301 and a scan line drive circuit
304, which are formed by using the TFT, are formed on the active
matrix substrate 230, and these data line drive circuit 301 and
scan line drive circuit 304 are electrically connected to a
plurality of data lines 201a, scan lines 202a and capacitor lines
202b, respectively. A sampling circuit 305 is formed on the active
matrix substrate 230, and to this sampling circuit 305 are supplied
image signals converted to an immediately displayable format, from
a control circuit (not shown) via an image signal line 306.
Therefore, the data line drive circuit 301 drives the sampling
circuit 305 at the same time as when the scan line drive circuit
304 sequentially transmits scanning signals pulsewise to the scan
line 202a, to thereby transmit a signal voltage corresponding to
the image signal to the data line 201a.
[0114] As a result, in FIGS. 6, 8 and 9, the pixel signals S1, S2,
to Sn are held in the respective pixels for a fixed period between
the pixel electrode 204a and the counter electrode on the counter
substrate 240, and the liquid crystal 250 changes its orientation
and order of the molecular association due to the voltage level
applied for each pixel. Therefore, of the incident light (incident
light L1) from the counter substrate 240 side, only the light
incident to the transmittable liquid crystal portion is emitted
from the active matrix substrate 230, thereby enabling a
predetermined display.
[0115] The manufacturing method for the active matrix substrate 230
for the liquid crystal display will be described, with reference to
FIG. 10 to FIG. 14.
[0116] FIG. 10 to FIG. 14 are process sectional views illustrating
the manufacturing method for the active matrix substrate 230.
[0117] In FIGS. 10 to 14, sections at a position corresponding to
the line A-A' in FIG. 7 are shown.
[0118] As shown in FIG. 10A, a large substrate 230a from which many
active matrix substrates 230 can be formed is prepared. The
large-size substrate 230a may be subjected to heat treatment in an
inert gas atmosphere such as N.sub.2 (nitrogen) and in a high
temperature atmosphere of from about 900.degree. C. to about
1300.degree. C. in a vertical diffusion furnace, and pre-treated so
that there is little distortion in the high temperature process
executed later (heat treatment process). In other words, the
large-size substrate 230a is heat-treated beforehand at a
temperature equal to or higher than the highest temperature in the
manufacturing process (in this embodiment, at a temperature of
1150.degree. C. at the time of forming the gate insulating film).
For example, when the highest temperature in the manufacturing
process is 1150.degree. C., then in this pretreatment process, the
large-size substrate 230a is heated at about 1150.degree. C. for 30
seconds to 30 minutes. The temperature of 1150.degree. C. is a
temperature close to the distortion point for the material
constituting the large-size substrate 230a.
[0119] After a single metal of a high melting metal or the alloy
thereof, such as Ti, Cr, W, Ta, Mo or Pd is formed by sputtering or
the like on the whole surface of the large-size substrate 230a to a
film thickness of from 1000 angstroms to 3000 angstroms (film
forming process), a resist mask is formed on the metal film by
using the photolithographic technique, and the metal film is etched
via the resist mask, to form a shading film 212a as shown in FIG.
10B.
[0120] The shading film 212a is formed so as to cover at least a
part of the area of the semiconductor layer in the TFT 215, where
the channel area 210a, the source areas 210b and 210d, the drain
areas 210c and 210e, the data line 201a, the scan line 202a and the
capacitor line 202b are to be formed (see FIGS. 7 and 8), as seen
from the backside of the large-size substrate 230a.
[0121] As shown in FIG. 10C, the base protective film 208
comprising a silicate glass film such as NSG (non-silicate glass),
PSG (phosphorus silicate glass), BSG (boron silicate glass), or
BPSG (boron phosphorus silicate glass), a silicon nitride film or a
silicon oxide film is formed on the shading film 212a, using for
example a TEOS (tetraethyl orthosilicate) gas, a TEB (tetraethyl
borate) gas, or a TMOP (tetramethyloxy phosphate) gas by a normal
pressure or low pressure chemical vapor deposition (CVD) method.
The film thickness of the base protective film 208 is from about
500 angstroms to 15000 angstroms, and more preferably, from about
6000 angstroms to 8000 angstroms. Alternatively, the base
protective film 208 having a multilayer structure of a thickness of
about 2000 angstroms may be formed by depositing a high temperature
silicon oxide film (HTO film) or a silicon nitride film in a
relatively thin thickness of about 500 angstroms by the low
pressure CVD method or the like. Moreover, a flat film may be
formed by subjecting to a spin-coating SOG (spin-on-glass) process
or a CMP (Chemical Mechanical Polishing) process, overlapped on or
instead of the silicate glass film. If the upper face of the base
protective film 208 is flattened by the spin coating process or the
CMP process, the TFT 215 can be easily formed thereon. The base
protective film 208 may be subjected to annealing processing at
about 900.degree. C. in a hot wall device, to prevent contamination
and to flatten the base protective film 208 (heat treatment
process).
[0122] Then, as shown in FIG. 11A, an amorphous silicon film is
formed on the base protective film 208 by low pressure CVD (for
example, by CVD at a pressure of about 30 Pa to 40 Pa), using a
monosilane gas or disilane gas at a flow rate of from about 400
cc/min. to about 600 cc/min. in a relatively low temperature
environment of from about 450.degree. C. to about 550.degree. C.,
and preferably of about 500.degree. C. Thereafter, by applying
annealing processing at a temperature of from about 600.degree. C.
to about 700.degree. C. for about one hour to about ten hours, more
preferably, from about four hours to about six hours in a nitrogen
atmosphere in the hot wall device, a polysilicon film 260 is grown
from solid phase to a thickness of from about 500 angstroms to
about 2000 angstroms, and preferably to a thickness of about 1000
angstroms.
[0123] At this time, when the pixel switching TFT 215 is an
n-channel type, a dopant of a fifth group element such as Sb
(antimony), As (arsenic) or P (phosphorus), may be doped slightly
in the channel forming area by ion implantation or the like. When
the pixel switching TFT 215 is a p-channel type, a dopant of a
third group element such as B (boron), Ga (gallium) or In (indium),
may be doped slightly in the channel forming area by ion
implantation or the like. The polysilicon film 260 may be directly
formed by the low pressure CVD method or the like, and not through
the amorphous silicon film. Alternatively, silicon ions may be
implanted in the polysilicon film deposited by the low pressure CVD
method or the like to make the film amorphous, and the film then
recrystallized by annealing processing or the like, to form the
polysilicon film 260.
[0124] As shown in FIG. 11B, the semiconductor layer 210a having a
pattern shown in FIG. 7 is formed by the photolithographic process
or etching process. In other words, in the area where the capacitor
line 202b is formed under the data line 201a, and in the area where
the capacitor line 202b is formed along the scan line 202a, the
first electrode 210f extended from the semiconductor layer 210a
constituting the TFT 215 is formed.
[0125] As shown in FIG. 11C, the first electrode 210f is subjected
to thermal oxidation at a temperature of from about 900.degree. C.
to about 1300.degree. C., and preferably at a temperature of about
1150.degree. C. in the hot wall device, together with the
semiconductor layer 210a constituting the TFT 215, to form a
relatively thin thermally oxidized silicon film of about 300
angstroms (heat treatment process), and then a high temperature
silicon oxide film (HTO film) and the silicon nitride film are
deposited in a relatively thin thickness of about 500 angstroms by
the low pressure CVD method or the like (film-forming process), to
form the gate insulating film 207 having a multi-layer structure,
and a dielectric film for forming the storage capacitance. As a
result, the thickness of the first electrode 210f becomes about 300
angstroms to about 1500 angstroms, and more preferably, about 350
angstroms to about 500 angstroms, and the thickness of the
dielectric film for forming the storage capacitance (gate
insulating film 207) becomes about 200 angstroms to about 1500
angstroms, and more preferably, about 300 angstroms to about 1000
angstroms.
[0126] Here the polysilicon film 210 may form the gate insulating
film 207 having a single layer structure by only thermal oxidation
under a temperature condition of about 1150.degree. C. in a
vertical diffusion furnace (heat treatment process).
[0127] Moreover, P ions are doped on the semiconductor layer
portion, which becomes the first electrode 210f, of the polysilicon
layer 210, at a dose of about 3.times.10.sup.10/cm.sup.2 so as to
have a low resistance.
[0128] Then, as shown in FIG. 11D, after the polysilicon film 202
is deposited by the low pressure CVD method or the like, phosphorus
(P) is thermally diffused, to render the polysilicon film 202
conductive. Alternatively, a doped silicon film may be used, in
which P ions are implanted simultaneously with film forming of the
polysilicon film 202.
[0129] Next, as shown in FIG. 12A, the scan line 202a (gate
electrode) and the capacitor line 202b having the pattern shown in
FIG. 7 are formed by the photolithographic process using a resist
mask, etching process or the like. The film thickness of these
capacitor lines 202b and scan lines 202a is for example about 3500
angstroms.
[0130] Then, as shown in FIG. 12B, when the TFT 215 shown in FIG. 8
is an n-channel type having the LDD structure, a dopant 260 of a
fifth group element such as P, is doped at a low density (for
example, P ions are doped at a dose of about
1.times.10.sup.13/cm.sup.2 to 3.times.10.sup.13/cm.sup.2), using
the scan line 202 (gate electrode) as a diffusion mask, to form the
low-density source area 210b and the low-density drain area 210c on
the semiconductor layer 210a. As a result, the semiconductor layer
210a under the scan line 202a (gate electrode) becomes the channel
forming area 210a'. By this doping of impurities, the capacitor
line 202b and the scan line 202a are rendered to have a low
resistance.
[0131] Subsequently, as shown in FIG. 12C, after a resist mask 262
is formed on the scan line 202a (gate electrode) with a wider mask
than the width of the scan line 202a (gate electrode), to form the
high-density source area 210d and the high-density drain area 210e
in the TFT 215, a dopant 261 of a fifth group element such as P, is
doped at a high density (for example, P ions are doped at a dose of
about 1.times.10.sup.15/cm.su- p.2 to 3.times.10.sup.15/cm.sup.2).
When the TFT 215 is a p-channel type, a dopant of a third group
element such as B, is doped, to form the low-density source area
210b and the low-density drain area 210c, and the high-density
source area 210d and the high-density drain area 210e in the
semiconductor layer 210a. The TFT may have an offset structure,
without performing low-density doping, or the TFT may be a
self-aligned type TFT by the ion implantation technology using the
P ions and B ions, by designating the scan line 202a (gate
electrode) as a mask. By this doping of impurities, the capacitor
line 202b and the scan line 202a are rendered to have a lower
resistance.
[0132] In parallel with these processes, peripheral circuits (see
FIG. 9) such as the data line drive circuit 301 and the scan line
drive circuit 304 having a complimentary structure, formed of an
n-channel type TFT and a p-channel type TFT, are formed in the
periphery on the active matrix substrate 230. In this embodiment,
since the pixel switching TFT 215 is a polysilicon TFT, the
peripheral circuits such as the data line drive circuit 301 and the
scan line drive circuit 304 can be formed by substantially the same
process at the time of forming the pixel switching TFT 215, which
is advantageous in manufacturing.
[0133] As shown in FIG. 12D, a first interlaminar insulating film
264 comprising a silicate glass film such as NSG (non-silicate
glass), PSG (phosphorus silicate glass), BSG (boron silicate
glass), or BPSG (boron phosphorus silicate glass), a silicon
nitride film or a silicon oxide film is formed so as to cover the
scan line 202a (gate electrode), the capacitor line 202b and the
scan line 202a in the TFT 215, using for example the normal
pressure or low pressure CVD method or a TEOS gas or the like (film
forming process). The film thickness of the first interlaminar
insulating film 264 is preferably from about 5000 angstroms to
15000 angstroms.
[0134] After performing the annealing processing at about
1000.degree. C. for about 20 minutes in the hot wall device (heat
treatment process) to activate the high-density source area 210d
and the high-density drain area 210e, as shown in FIG. 12E, the
contact hole 205 corresponding to the data line 201a (source
electrode) is formed by dry etching such as reactive etching or
reactive ion beam etching, or wet etching.
[0135] Next, as shown in FIG. 13A, a metal film 266 such as a
low-resistant metal such as Al or a metal silicide is deposited on
the first interlaminar insulating layer 264 by sputtering
processing or the like, to a thickness of from about 1000 angstroms
to about 5000 angstroms, and preferably, to about 3000 angstroms
(film forming process).
[0136] Then, as shown in FIG. 13B, the data line 266a (source
electrode) is formed by the photolithographic process, etching
process and the like.
[0137] Next, as shown in FIG. 13C, a second interlaminar insulating
film 267 comprising a silicate glass film such as NSG, PSG, BSG, or
BPSG, a silicon nitride film or a silicon oxide film is formed so
as to cover the data line 266a (source electrode), using for
example the normal pressure or low pressure CVD method or a TEOS
gas or the like (film forming process). Alternatively, instead of
or overlapped on such a silicate film, an organic film or SOG may
be spin coated, or subjected to the CMP processing, to form a flat
film. The film thickness of the second interlaminar insulating film
267 is preferably from about 5000 angstroms to 15000 angstroms.
[0138] Then, as shown in FIG. 14A, the contact hole 206 for
electrically connecting the pixel electrode 204a and the
high-density drain area 210e in the TFT 215 is formed by dry
etching, such as reactive etching, reactive ion beam etching or the
like. At this time, there is an advantage in that the opening shape
can be made the same as the mask shape, by forming the contact hole
206 by anisotropic etching such as reactive etching, reactive ion
beam etching or the like. If opening is formed by combining dry
etching and wet etching, the contact hole 206 can be formed in a
tapered shape, and hence there is an advantage in that
disconnection at the time of connecting the wiring can be
prevented.
[0139] Next, as shown in FIG. 14B, a transparent conductive thin
film 269 such as an ITO film is deposited on the second
interlaminar insulating layer 267 by sputtering processing or the
like, to a thickness of from about 500 angstroms to about 2000
angstroms (film forming process).
[0140] Then the transparent conductive thin film 269 is patterned
by the photolithographic process, etching process or the like, to
form the pixel electrode 269a as shown in FIG. 14C. When the liquid
crystal panel 200 is used for a reflecting liquid crystal display,
the pixel electrode 269a is formed of an opaque material having
high reflectance such as aluminum.
[0141] Next, after an application liquid for a polyimide oriented
film has been applied on the pixel electrode 269a, rubbing
processing is conducted in a predetermined direction so as to have
a predetermined pre-tilt angle, to form the oriented film 280.
[0142] Then, after a large-size substrate for the counter substrate
is adhered to the large-size substrate 230a, these are cut into
individual panels, or after the large-size substrate 230a is cut to
give the active matrix substrate 230, the counter substrate is
adhered thereto, and then liquid crystal is sealed therein.
[0143] Here, in this embodiment, the active matrix substrate 230
may be manufactured by array manufacturing in which processing is
performed at the same size as when loading a mother glass
substrate. Thereafter, the rubbing step, being a step in the
assembly process, is executed, and thereafter, the panel is cut. As
a result, the influence of warp of the substrate at the time of
adhesion can be reduced, and the processing time for the alignment
processing required for one substrate can be shortened, thereby
improving the throughput.
[0144] For example, after having cleaned the active matrix
substrate 230, polyimide (PI), which becomes the oriented film, is
applied. Rubbing processing is then conducted with respect to the
oriented film (corresponding to the oriented film 280) on the
surface of the active matrix substrate.
[0145] In this case, the active matrix substrate 230 is then
subjected to the cutting process. In the cutting process, the
active matrix substrate 230 is cut into an optional size by various
methods including, for example, scribe processing using a diamond
cutter, dicing using a laser cutter and pure water, or water jet
processing.
[0146] In the scribe processing, a scribe groove having a
predetermined depth is formed, and the scribe groove portion is
broken, to cut the TFT substrate. When the laser cutter is used, it
is necessary to provide a gap for cutting between elements formed
on the active matrix substrate 230. When using the laser cutter,
since the corners on the cutting plane are rounded off by heat,
there is an advantage in that a decrease in the yield due to the
occurrence of damage to the substrate and the generated glass
pieces can be prevented.
[0147] FIG. 15 illustrates the cutting method for the active matrix
substrate in the cutting process. In FIG. 15, an example of cutting
the substrate into four is shown.
[0148] (a) in FIG. 15 illustrates the substrate in the rubbing
process, (b) in FIG. 15 illustrates the substrate in the middle of
the cutting process, and (c) in FIG. 15 illustrates the substrate
after having been cut.
[0149] The example in FIG. 15 illustrates the scribe processing,
wherein in the active matrix substrate, scribe grooves 71 are
formed in a cross shape passing through the vicinity of the center
of the substrate by the scribe processing ((b) in FIG. 15). Then,
as shown in (c) in FIG. 15, the substrate is cut into four along
the scribe grooves 71. Each of the cut substrates has substantially
the same sector shape in the example shown in FIG. 15. The
substrate may be divided not only into four, but also into two or
an appropriate division number, and the shape after cutting may not
be the same shape.
[0150] Cutting is conducted so that the substrate is not divided in
units of chips, but one TFT substrate is divided into a
predetermined number. Division is conducted corresponding to the
layout of elements formed on the active matrix substrate. To reduce
the influence of warp of the substrate, it is best to shorten the
length in one of the directions.
[0151] In the example shown in FIG. 15, the respective substrates
after cutting have two sides crossing at a right angle, and these
can be used for alignment. On the active matrix substrate in FIG.
15, alignment marks 72 used for the alignment processing after
cutting are formed beforehand. The positions of the alignment marks
72 in (b) in FIG. 15 are located at portions which are not
originally used for forming the active matrix substrate. These
portions are advantageous as forming positions for the alignment
marks when cutting the substrate into four.
[0152] The cut substrate is transferred to the respective lines for
parallel processing. In each line, the apparatus are constructed
corresponding to the shape of the cut plate and the position of the
formed elements.
[0153] Next each of the cut substrates is subjected to a cleaning
process. The cleaning process is for removing dust and dirt
generated by the rubbing processing of the active matrix substrate
and by the cutting process.
[0154] When the cleaning process has finished, the sealing material
and the conductive material (not shown) are formed. The sealing
material is formed by, for example, dispenser application. The
sealing material may also be formed by screen printing. After
having formed the sealing material, the counter substrate 240 is
adhered to the active matrix substrate 230 at the respective
element positions, and pressed while being aligned, to cure the
sealing material.
[0155] The liquid crystal empty cells formed by curing the sealing
material have relatively small differences in the magnitude of warp
at respective positions of the substrate, even if warp occurs,
since the area of the active matrix substrate becomes relatively
small in the cutting process. In other words, gap distribution in
the empty cells is substantially the same in all cells.
[0156] Moreover, since the area of the active matrix substrate at
the time of adhesion is relatively small, and the number of formed
elements is relatively small, alignment processing with respect to
one substrate can be finished within a relatively short time. As a
result, the difference in time for curing the seal, between a
processed cell and an unprocessed cell is small, and hence a
difference in quality of cells is minimal.
[0157] The liquid crystal is then filled from a notch provided in a
part of the sealing material, and the notch is covered to seal the
liquid crystal. In the liquid crystal filling process, the quantity
of the liquid crystal to be filled is controlled, while controlling
the pressure, so that the cell gaps become uniform. Since the gap
distribution in the empty cells after adhesion is uniform,
adjustment of the cell gap at the time of filling the liquid
crystal is relatively easy, and hence liquid crystal cells having
uniform cell gaps can be obtained.
[0158] Lastly, the liquid crystal cells in which the liquid crystal
has been filled and tested are divided for each cell, to obtain
liquid crystal panels.
[0159] In this embodiment, after the rubbing step in the middle of
the assembly process, the TFT substrate is cut into a predetermined
number of divisions and processes thereafter are executed. Hence,
nonuniform distribution of the gap distribution in the adhesion
process can be reduced, making the cell gaps uniform, and thereby
preventing the occurrence of nonuniform gaps. Moreover, since
adhesion is conducted on the active matrix substrate which has been
divided into a plurality of parts, the alignment processing with
respect to the elements on one substrate can be executed in short
time. As a result, the throughput can be improved, and changes with
lapse of time can be suppressed, thereby suppressing differences in
quality of the elements.
[0160] As described above, in this embodiment, since the droplet
discharge method is used, the liquid crystal to be filled includes
one used for cleaning (flushing) of the droplet discharge head 21.
Therefore wasteful use of the liquid crystal can be avoided, and
the consumption thereof can be reduced.
[0161] As a result, liquid crystal devices can be manufactured at
low cost. Moreover, there is a minimal drop in the display quality
accompanying nonuniform arrangement of the liquid crystal, and poor
sealing hardly occurs.
Third Embodiment
[0162] In the second embodiment, the droplet discharge device of
the present invention is employed for forming the passive matrix
type and active matrix type liquid crystal devices, and applied to
filling of the liquid crystal into the liquid crystal layer,
constituting the liquid crystal device, but the present invention
is not limited thereto. For example, the oriented film constituting
the liquid crystal device (for example, corresponding to the
oriented films 108 and 110) may be formed by using the droplet
discharge method in the first embodiment.
[0163] In this embodiment, a manufacturing process in which the
oriented film in the liquid crystal device is formed by using the
droplet discharge apparatus of the present invention will be
described. Explanation for the parts overlapping on the description
relating to the oriented film explained in the second embodiment is
omitted. The same members as those used in the above description
are denoted by the same reference symbols.
[0164] In this embodiment, the same apparatus as the droplet
discharge apparatus shown in the first embodiment is employed. The
oriented film material includes the organic materials such as
polyimide, as described above, and has, for example, a component
composition such as 3% of polyimide resin and 97% of a solvent.
[0165] The operation of the droplet discharge head 21, discharge
from the nozzle 30, and the operation of the substrate stage 22 are
controlled by the control unit 25. If these operation patterns are
programmed in advance, it is easy to change the application
pattern, corresponding to the application area and the application
condition of the oriented film material.
[0166] The pitch of the nozzle 30 in the droplet discharge head 21,
and the scanning pitch in the horizontal scanning direction
(rendering direction) will be described, with reference to FIG.
16.
[0167] FIG. 16 is a plan view illustrating a state in which
droplets of the oriented film material discharged from the droplet
discharge head 21 are dropped. For example, it is assumed here that
droplets of the oriented film material are dropped at a pitch of 10
.mu.m in the horizontal scanning direction (X direction) and 100
.mu.m in the vertical scanning direction (Y direction). In this
case, the pitch y of droplets in the vertical scanning direction is
the same as the pitch P of the nozzle 30, and the pitch x of
droplets in the horizontal scanning direction depends on the
scanning rate and the discharge frequency of the droplet discharge
head 21.
[0168] FIG. 17 to FIG. 21 are plan views illustrating an exemplary
arrangement of droplets according to the embodiment.
[0169] As shown in FIG. 17, when rendering of the oriented film
material is conducted by the droplet discharge method of the
present invention, the discharge pitch (when there is a plurality
of nozzles in the head, the nozzle pitch thereof) in the vertical
scanning direction (in a direction orthogonal to the horizontal
scanning direction), and the discharge pitch in the horizontal
scanning direction are made not larger than the diameter of
droplets (in this example, 30 to 40 .mu.m, reference symbol a)
immediately before impact before the droplets spread over the
substrate (which is just after the impact; hereunder simply
referred to as "immediately before impact"), so that the droplets
of the oriented film material are not arranged on the substrate
exceeding the pitch.
[0170] In other words, the respective pitches in the vertical
scanning direction and the horizontal scanning direction are not
adjusted to the impact diameter, but are adjusted not to exceed the
diameter of droplets immediately before impact, so as to arrange
the droplets of the oriented film material on the substrate. As
described above, in FIG. 17, since the droplets before the droplets
impact and spread on the substrate are connected to each other, the
occurrence of lines and nonuniformity can be suppressed.
[0171] The respective pitches need not necessarily be smaller than
the diameter of the droplets immediately before impact. In FIG. 17,
the adjacent droplets are overlapping on each other, but it is not
necessary to overlap on each other. As shown in FIG. 18, the
adjacent droplets need only to contact with each other, to connect
the droplets to each other and form a single thin film.
[0172] As shown in FIG. 18, when a plurality of nozzles 30 is
formed on the droplet discharge head 21, the pitch Py between
nozzles 30 is designated as the above described "pitch not larger
than the diameter of the droplets immediately before impact before
spreading". Moreover, in the rendering direction (horizontal
scanning direction), the pitch Px for discharging the droplets is
also made "not larger than the diameter of droplets immediately
before impact before spreading".
[0173] When rendering is conducted by the method shown in FIG. 17
and FIG. 18, droplets before spreading overlap on the adjacent
droplets before spreading, and hence drop marks do not appear. As
described above, arrangement of droplets at the time of rendering
is performed such that the pitches between the adjacent droplets
(both in the horizontal and vertical scanning directions) become
"not larger than the diameter of the droplets before
spreading".
[0174] The exemplary arrangement shown in FIG. 19 is different from
those shown in FIG. 17 and FIG. 18, in that droplets immediately
before impact and spreading in even lines in the horizontal
scanning direction are dropped at positions shifted in the vertical
scanning direction by about half the diameter of the droplet
immediately before impact and spreading, as compared with the
droplets immediately before impact and spreading in the odd
lines.
[0175] FIG. 20 illustrates an arrangement in which the central
positions of droplets in FIG. 19 are brought closer to each other.
In FIG. 17, the area surrounded by four arcs and denoted by
reference numeral 92 is not the droplet, but a portion where the
droplets spread. Therefore, theoretically it becomes nonuniform,
though slightly. On the other hand, in FIG. 20, optional droplets
overlaps on other droplets over the whole periphery. As a result,
nonuniformity does not occur.
[0176] Two methods can be mentioned as methods for realizing the
above exemplary arrangements.
[0177] The first method is such that when rendering the droplets in
even lines, then as shown by arrow Ye in FIG. 19, the droplet
discharge head 21 is shifted relatively to the substrate in the
vertical scanning direction by half the diameter of the droplet, as
compared with rendering of droplets in odd lines.
[0178] The second method is such that as shown in FIG. 21, a head
group 21a formed by fixing a pair of (a plurality of) droplet
discharge heads 21 at a position shifted to each other in the
vertical scanning direction by half the diameter of the droplet, is
scanned (in the horizontal scanning direction) with respect to the
substrate. At the time of rendering of droplets in the odd lines,
droplets are discharged from the nozzles 30 in the first head 21 of
the head group 21a, and at the time of rendering of droplets in the
even lines, droplets are discharged from the nozzles 30 in the
second head 21 of the head group 21a.
[0179] As described above, in this embodiment, the droplets are
discharged so that the droplets immediately after impact on the
substrate and before spreading are dropped at positions where
adjacent droplets in the same state are brought into contact with
each other.
[0180] Next, the application method for applying the oriented film
material using the droplet discharge method of the present
invention will be described below.
[0181] FIG. 22 illustrates a case where a plurality of chips 302 is
formed on a wafer 301. Each of the chips 302 is constructed as, for
example, a liquid crystal panel for a mobile phone. The droplets of
the oriented film material are discharged simultaneously with
respect to the plurality of chips 302, using a plurality of nozzles
30 formed in the droplet discharge head 21.
[0182] In this case, to improve the mass-productiveness, it is
desired to apply the droplets of the oriented film material with
respect to the chips 302 as wide as possible on the wafer 301 in
one horizontal scanning (in the X direction), by using all nozzles
of the droplet discharge head 21 from one end to the other end in
the lengthwise direction of the droplet discharge head 21.
[0183] In FIG. 22, the chips 302 are arranged in lines from 302a,
302b, 302c to 302z from the left end of the wafer 301. In this
case, it is assumed that as shown in the figure, when the nozzle 30
at the one end of the droplet discharge head 21 is adjusted to the
droplet arranging position for the chip 302a, the nozzle 31 at the
other end of the droplet discharge head 21 is located in the middle
position of the chip 301c.
[0184] To improve mass-productiveness, it is desired to be able to
use all nozzles 30 in the arrangement state of the droplet
discharge head 21 shown in FIG. 22. In other words, in the first
horizontal scanning, the droplets are applied with respect to all
areas of chips 302a and 302b, and the area up to the middle of the
chip 302c, and in the second scanning, the droplets are applied
with respect to the remaining half area of the chip 302c and chips
302d and after. In this manner, by using all nozzles 21 from the
one end to the other end in the longitudinal direction of the
droplet discharge head 21, the number of horizontal scannings
required for application with respect to all chips 302, of the
plurality of chips 302 on the wafer 301, can be reduced. This
method is suitable for mass production, and normally this method is
generally employed.
[0185] In the above method, however, as shown in FIG. 23, droplets
of the oriented film material are applied by two (a plurality of)
horizontal scannings with respect to the one chip 302c. Therefore,
in the area of the chip 302c where the oriented film material is to
be applied (in the application area), an interface 305 between the
air and the material is generated at the end portion of the
application area of the oriented film material applied by the first
horizontal scanning. Thereafter, the second horizontal scanning is
conducted, and the droplets of the oriented film material are also
applied on the interface 305, but the portion of the interface 305
has nonuniform dropping (application).
[0186] The application area herein stands for an area where the
material (liquid) for the oriented film is to be applied, being an
area of the maximum unit area where the occurrence of nonuniform
application should be avoided (in this embodiment, each of the
chips 302a to 302z). In other words, the application area is the
maximum unit area where the whole surface should be applied
uniformly (a chip in this embodiment, but including the substrate
when one substrate is constituted by one wafer). The application
area is generally a display area in a single panel.
[0187] As shown in FIG. 23 and FIG. 24, when there is an
application area where the droplets cannot be applied to the whole
area thereof by one horizontal scanning (the chip 302c in this
case) of the plurality of application areas (each of the chips 302a
to 302z in this embodiment), droplets of the oriented film material
are not applied in the horizontal scanning at this time, with
respect to this application area (the chip 302e in this case).
[0188] In other words, as shown in FIG. 24, when the horizontal
scanning of the droplet discharge head 21 is conducted, with the
droplet discharge head 21 covering only up to the middle of the
chip 302c, the whole area of the chip 302c cannot be applied in the
horizontal scanning at this time. In such a situation, when the
horizontal scanning is conducted, it is controlled such that
droplets of the oriented film material are not discharged from the
nozzles denoted by reference symbol 30b located above the chip
302c. Since the droplets of the oriented film material are not
discharged from these nozzles 30b, an interface between the
oriented film material and the air does not occur on the chip 302c,
thereby preventing nonuniform application.
[0189] As described above, in the first scanning, droplets of the
oriented film material are applied on the chips 302a and 302b. The
nozzles denoted by reference symbols 30a are the nozzles from which
the droplets of the oriented film material are not discharged in
the horizontal scanning at this position. This is because the
positions of the nozzles denoted by reference symbols 30a are not
in the area where the droplets of the oriented film material are to
be discharged (where no chip exists).
[0190] From the position shown in FIG. 24, the droplet discharge
head 21 conducts vertical scanning in a direction indicated by
arrow Y, and as a result, as shown in FIG. 25, when the droplet
discharge head 21 has reached the position where the whole area of
the chip 302c, to which the droplets have not been applied in the
previous (first) horizontal scanning, can be applied with the
second horizontal scanning, the droplets of the oriented film
material are applied to the chip 302c in the second horizontal
scanning.
[0191] In the second horizontal scanning, as in the first
horizontal scanning, when there is an application area where the
droplets cannot be applied to the whole area thereof by one
horizontal scanning (the chip 302e in this case) of the plurality
of application areas (each of the chips 302a to 302z in this
embodiment), droplets of the oriented film material are not applied
in the horizontal scanning at this time with respect to this
application area (the chip 302e in this case). Thereafter, the
third horizontal scanning and onward is conducted likewise.
[0192] In the above example, at the time of each horizontal
scanning, droplets of the oriented film material are discharged for
chips 302 in two lines (for chips 302a and 302b for the first time,
and chips 302c and 302d for the second time), but are not
discharged from the nozzles 30 corresponding to the positions of
the chips 302 in the third line (the chip 302c for the first time,
and the chip 302e for the second time). When the application object
of the droplets of the oriented film material is different from the
wafer 301 in FIG. 22, that is, when the size and arrangement of the
chips on the wafer are different from those shown in FIG. 22, then
at the time of each horizontal scanning, discharge of the droplets
of the oriented film material from which row of chips, and from
which nozzles 30 the oriented film material is not discharged, are
changed. For example, the number of chip lines for which the
droplets of the oriented film material are to be discharged at the
time of each horizontal scanning can be determined from the
following equation, and the maximum value of n satisfying this
equation obtained.
n.times.d1+(n-1).times.d2.ltoreq.L
[0193] As shown in FIG. 22, d1 denotes the width of the chip 302
(the length of the side of the chip 302 along the lengthwise
direction of the droplet discharge head 21, and more precisely, the
width of the area where a liquid crystal film is to be formed in
the chip 302), and d2 denotes a pitch between the chips 302 (more
precisely, a pitch between the areas where the liquid crystal film
is to be formed in the adjacent chips 302). L denotes the length of
the droplet discharge head 21 in the lengthwise direction (more
precisely, the length between the nozzle 30 at one end and the
nozzle 30 at the other end of the droplet discharge head 21 in the
lengthwise direction).
[0194] In the first horizontal scanning, the droplets of the
oriented film material are applied up to the chips in the n.sup.th
line, but are not discharged from the nozzles 30 corresponding to
the position of the chip in the (n+1).sup.th line.
[0195] In the second horizontal scanning, the droplets of the
oriented film material are applied up to the chip (n+1-1+n) in the
n.sup.th line, designating the (n+1).sup.th line as a starting
point of reckoning, but are not discharged from the nozzles 30
corresponding to the position of the chip in the (n+1-1+n+1).sup.th
line.
[0196] In the example shown in FIG. 22, since the following
equations are established,
2.times.d1+(2-1).times.d2.ltoreq.L
3.times.d1+(3-1).times.d2>L,
[0197] then the maximum value of n is 2.
[0198] In the first horizontal scanning, the droplets of the
oriented film material are applied up to the chips in the second
line (302a and 302b), but are not discharged from the nozzles 30
corresponding to the position of the chip (302c) in the
(2+1=3).sup.rd line.
[0199] In the second horizontal scanning, the droplets of the
oriented film material are applied up to the chips (302c and 302d)
in the second line (2+1-1+2=4), designating the (2+1=3).sup.rd line
as a starting point of reckoning, but are not discharged from the
nozzles 30 corresponding to the position of the chip (302e) in the
(2+1-1+2+1=5).sup.th line.
[0200] As described above, the horizontal scanning for each time
when the droplets of the oriented film material are applied to the
chips 302 in a plurality of lines is conducted for the lines of the
maximum value of n, satisfying n.times.d1+(n-1).times.d2.ltoreq.L.
As a result, any one chip 302 is not applied with the oriented film
material by a plurality of horizontal scanning. The value of n is
input to a program by an operator in advance, so that application
of the droplets of the oriented film material by the droplet
discharge head 21 can be conducted according to the input value of
n.
[0201] In other words, when single horizontal scanning is
conducted, in any single chip 302 (application area), an area where
application of the oriented film material is conducted and an area
where application of the oriented film material is not conducted do
not exist together. In any single chip 302, all application areas
in the single chip 302 are applied with the oriented film material
by a single horizontal scanning. Since the application of the
oriented film material is conducted with respect to the whole area
of one application area by a single horizontal scanning, an
interface between the oriented film material (liquid) and a gas
phase is not generated on the single application area. As a result,
a join in the scanning does not appear as a nonuniformity in the
display area.
[0202] The droplet discharge head 21 in FIG. 22 is formed to have a
pitch between nozzles 30, as shown in FIG. 17, such that a droplet
of the oriented film material overlaps on the adjacent droplet
before the droplets spread on each chip 302, and the discharge
pitch in the horizontal scanning direction also has such a
relation.
[0203] Instead of the above configuration, the droplet discharge
head 21 in FIG. 22 may be formed to have a pitch between nozzles
30, as shown in FIG. 20, such that a droplet of the oriented film
material overlaps on the adjacent droplet before the droplets
spread on each chip 302, and the discharge pitch in the horizontal
scanning direction also has such a relation. In this case, as shown
in FIG. 20, an optional droplet (reference symbol a in FIG. 20)
overlaps on other droplets (reference symbol a in FIG. 20) at the
periphery thereof over the whole area in the peripheral
direction.
[0204] FIG. 26 illustrates a modified example of this
embodiment.
[0205] In FIG. 22, the length L of the droplet discharge head 21 is
longer than the width d1 of a single application area, so that the
whole area of at least one application area can be applied by one
horizontal scanning. On the other hand, in FIG. 26, a single
substrate 311 is formed on a single wafer 310. In the case of FIG.
26, the application area (substrate 311) is larger than the
application area (chip 302) in the case of FIG. 22. To apply the
droplets to the whole area in the application area by single
horizontal scanning, it is necessary that the nozzles 30 are formed
in the same range as the width d1' of the substrate 311.
[0206] When the length of one droplet discharge head 21 is smaller
than the width d1' of the substrate 311, a plurality of droplet
discharge heads 21A and 21B are connected so that the nozzles 30
are located in the same range as the width d1'. Moreover as shown
in FIG. 22, even when the length of a single droplet discharge head
21 is larger than the chip width d1 in the application area (chip
302), a plurality of droplet discharge heads 21 may be connected to
apply the droplets to a wider application area by single horizontal
scanning.
[0207] In this case, the pitches Q1 and Q3 of the nozzle droplet
discharge head 21 in the plurality of droplet discharge heads 21A
and 21b to be connected are the same, and are set to match with a
specified pitch (see FIG. 17 and FIG. 20).
[0208] A nozzle pitch Q2 at the junction of the plurality of
droplet discharge heads 21A and 21B is set to have the same length
as the specified nozzle pitch Q1. For example, it is desired to
have a relation of Q1=Q2=Q3 =30 to 40 .mu.m.
[0209] According to the manufacturing method for the liquid crystal
device in this embodiment, when the droplet discharge head conducts
a plurality of scannings to drop the oriented film material onto
the display area, an interface is generated between the oriented
film material and the air by the number of scans in the display
area, to cause nonuniform rendering in this portion. However, in
this embodiment, dropping of the oriented film material is
conducted with respect to the whole display area in the panel by
one rendering (scanning), thereby removing the interface between
the oriented film material and the air in the display area and
preventing nonuniform dropping of the oriented film material.
[0210] Moreover in this embodiment, since the above described
droplet discharge method is used, the oriented film material
includes one used for cleaning (flushing) of the droplet discharge
head 21. Therefore, wasteful use of the oriented film material is
avoided, and the consumption thereof can be reduced.
[0211] As a result, liquid crystal devices can be manufactured at
low cost.
Fourth Embodiment; Third Manufacturing Method for Liquid Crystal
Devices
[0212] In the third embodiment, explanation was given for a case
where an oriented film constituting the liquid crystal device was
formed by using the droplet discharge method shown in the first
embodiment. The protection film (for example, corresponding to the
over coat film 106) constituting the liquid crystal device may
similarly be formed by using the droplet discharge method.
[0213] In this embodiment, the manufacturing method for a color
filter in the liquid crystal will be described in detail, and the
manufacturing process for forming the protection film formed on the
color filter by using the droplet discharge apparatus of the
present invention will be described. Explanation for the parts
overlapping on the description relating to the color filter
explained in the second embodiment is omitted. The same members as
those used in the above description are denoted by the same
reference symbols.
[0214] FIG. 27A to FIG. 27D schematically illustrate the
manufacturing method for the color filter 104 in process sequence.
At first, partitions 105 are formed of a resin material, which does
not have transmittance, on the surface of a glass substrate 101 in
a lattice pattern, as seen from a direction of arrow B. Portions
120 at the lattice hole in the lattice pattern are areas where a
filter element 104R, 104G, or 104B is formed, that is, filter
element areas. The surface dimensions of the individual filter
element area 120 formed by the partitions 105, as seen in the
direction of arrow B, is formed to be for example 30
.mu.m.times.100 .mu.m.
[0215] The partitions 105 have both a function of preventing the
flow of filter element material supplied to the filter element area
120 and a function of a black matrix. The partitions 105 are formed
by an optional patterning method, for example, a photolithographic
method, and according to need, heated by a heater and fired.
[0216] After having formed the partitions 105, as shown in FIG.
27B, droplets 121 of filter element material are supplied to the
respective filter element areas 120, to fill the respective filter
element areas 120 with the filter element material 1104. In FIG.
27B, reference symbol 1104R denotes a filter element material
having red (R) color, reference symbol 1104G denotes a filter
element material having green (G) color, and reference symbol 1104B
denotes a filter element material having blue (B) color.
[0217] When a specified quantity of filter element material has
been filled in the respective filter element areas 120, the
substrate 101 is heated to about 70.degree. C. by a heater, to
evaporate the solvent of the filter element material. By this
evaporation, as shown in FIG. 27C, the volume of the filter element
material 1104 decreases and is flattened. If a decrease in the
volume is excessive, supply and heating of droplets of the filter
element material are repeated until a sufficient film thickness as
the color filter can be obtained. By the above processing, only the
solid of the filter element material remains finally and is formed
as a film. As a result, desired respective color filter elements
104R, 104G and 104B are formed.
[0218] After the filter elements 104R, 104G and 104B are formed,
heat treatment is executed at a predetermined temperature for
predetermined time, to dry these filaments 104R, 104G and 104B
completely. Thereafter, an over coat layer 106 is formed by using
the droplet discharge method described in the first embodiment. The
over coat layer 106 is formed for protecting the filter elements
104R, 104G and 104B, and flattening the surface of the color filter
104.
[0219] In this embodiment, since the droplet discharge method is
used, the material for the over coat layer 106 includes one used
for cleaning (flushing) of the droplet discharge head 21.
Therefore, wasteful use of the material for the over coat layer is
avoided, and the consumption thereof can be reduced.
[0220] As a result, liquid crystal devices can be manufactured at a
low cost.
Fifth Embodiment
[0221] A specific example of electronic apparatus of the present
invention will be described below.
[0222] FIG. 28 is a perspective view illustrating one example of a
mobile phone. In FIG. 28, reference numeral 600 denotes a mobile
phone body, and 601 denotes a liquid crystal display section having
the liquid crystal device shown in FIG. 4.
[0223] FIG. 29 is a perspective view illustrating one example of a
portable information processor such as a word processor or a
personal computer. In FIG. 29, reference numeral 700 denotes an
information processor, 701 denotes an input section such as a
keyboard, 703 denotes an information processing body, and 702
denotes a liquid crystal display section having the liquid crystal
device shown in FIG. 4.
[0224] FIG. 30 is a perspective view illustrating one example of a
watch type electronic device. In FIG. 30, reference numeral 800
denotes a watch body, and 801 denotes a liquid crystal display
section having the liquid crystal device shown in FIG. 4.
[0225] The electronic apparatus shown in FIG. 28 to FIG. 30
comprises the liquid crystal device in the above embodiments, and
hence a drop in display quality and poor sealing hardly occur,
while achieving a low cost.
[0226] In the above embodiments, a passive matrix type liquid
crystal device and an active matrix type liquid crystal device
using a TFT as a switching element have been employed, but for
example, an active matrix type liquid crystal device using a TFD
(Thin Film Diode) as a switching element may be used.
[0227] Moreover, in the above embodiments, the liquid crystal and
oriented film material used in the liquid crystal device, and the
liquid material for the protective film (such as the material for
the over coat film) are mentioned as the liquid material to be
arranged quantitatively, but the present invention is not limited
to these liquid materials.
[0228] Other adoptable liquid materials include a resist
(photoresist), a color ink, an SOG (Spin On Glass), a Low-k
material for forming a low-permittivity interlaminar insulating
film, other liquid materials such as volatile liquid materials,
liquids containing fine metal particles, materials for a light
emitting layer of an organic EL, and materials for hole injection
transport beds. For example, in the second embodiment, explanation
has been given to a process for forming a resist mask on a metal
film by using the photolithographic technique, to form the shading
film 212a. However, instead of the resist application method, the
droplet discharge method of the present invention may be
adopted.
[0229] The electronic apparatus in the above embodiments comprises
the liquid crystal device, but the electronic apparatus may
comprise other electro-optic devices such as an organic
electroluminescence display or a plasma display.
[0230] Preferred embodiments of the present invention has been
described above with reference to the accompanying drawings, but
needless to say, the present invention is not limited to these
embodiments. The various shapes and combination of the respective
components in the embodiments are examples only, and may be
variously changed based on design requirement or the like within
the range which does not depart from the gist of the present
invention.
* * * * *