U.S. patent application number 14/851472 was filed with the patent office on 2016-05-05 for evaporation system and evaporation method.
The applicant listed for this patent is Industrial Technology Research Institute. Invention is credited to SHIH-HSIANG LAI, FU-CHING TUNG, CHING-CHIUN WANG.
Application Number | 20160122866 14/851472 |
Document ID | / |
Family ID | 55852019 |
Filed Date | 2016-05-05 |
United States Patent
Application |
20160122866 |
Kind Code |
A1 |
TUNG; FU-CHING ; et
al. |
May 5, 2016 |
EVAPORATION SYSTEM AND EVAPORATION METHOD
Abstract
An evaporation system and an evaporation method are disclosed,
which are adapted for performing an evaporation process upon a
surface of an evaporation target substrate. In an embodiment, the
evaporation system comprises an evaporation material and an
evaporation source plate, whereas the evaporation source plate is
arranged to be heated by a heater so as to evaporate the
evaporation material form its solid state into its gaseous state,
and then enable the gaseous state evaporation material to travel
passing through holes by the use of a shutter device so as to
spread toward the surface of the evaporation target substrate for
forming a film thereon. In addition, the evaporation system further
comprises a transmission device, which is to be used for
controlling the opening/closing of the holes of the shutter
device.
Inventors: |
TUNG; FU-CHING; (Hsinchu
City, TW) ; WANG; CHING-CHIUN; (Miaoli County,
TW) ; LAI; SHIH-HSIANG; (New Taipei City,
TW) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Industrial Technology Research Institute |
HSIN-CHU |
|
TW |
|
|
Family ID: |
55852019 |
Appl. No.: |
14/851472 |
Filed: |
September 11, 2015 |
Current U.S.
Class: |
427/561 ;
118/726; 427/248.1 |
Current CPC
Class: |
C23C 14/24 20130101;
C23C 14/542 20130101; C23C 14/28 20130101 |
International
Class: |
C23C 14/54 20060101
C23C014/54; C23C 14/28 20060101 C23C014/28 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 31, 2014 |
TW |
103137848 |
Claims
1. An evaporation system for performing an evaporation process upon
a surface of a target substrate, comprising: an evaporation source
plate, configured with at least one planar surface; an evaporation
material, coated on the at least one planar surface of the
evaporation source plate; a heater, disposed at a position for
allowing the same to heat the evaporation source plate and thus
transform the solid state evaporation material into its gaseous
state; a shutter device with a plurality of holes, arranged at a
position between the evaporation source plate and the target
substrate; and a transmission device, coupled to the shutter device
for controlling the opening/closing of the shutter device so as to
allow the gaseous evaporation material to travel passing the holes
and thereby reaching the surface of the target substrate for film
deposition.
2. The evaporation system of claim 1, wherein the heater is a
device selected from a group consisting of: an infrared (IR)
heater, a radio frequency (RF) heater, a microwave (MW) heater and
a high-power heater.
3. The evaporation system of claim 1, wherein the shutter device
further comprises: a shutter plate and a diffuser plate in a manner
that shutter plate is coupled to the transmission device.
4. The evaporation system of claim 1, wherein the shutter device is
a combination of an upper panel and a lower panel, and the plural
holes are formed respectively on the upper panel and the lower
panel while allowing the transmission device to couple to one panel
selected between the upper panel and the lower panel in a manner
that the upper panel and the lower panel can be driven to move and
displaced by a relative displacement related to each other for
enabling the holes of the upper panel to align or misalign with the
holes of the lower panel.
5. An evaporation method for performing an evaporation process upon
a surface of a target substrate, comprising the steps of: providing
an evaporation material and an evaporation source plate while
allowing the evaporation material to be coated on a surface of the
evaporation source plate; heating the evaporation source plate by
the use of a heater for transforming the evaporation material from
its solid state to its gaseous state; and providing a shutter
device with a plurality of holes for enabling the gaseous
evaporation material to travel passing the holes and thus reach the
surface of the target substrate for film deposition; wherein, the
shutter device is coupled to a transmission device which is used
for controlling the opening/closing of the holes.
6. The evaporation method of claim 5, wherein the evaporation
material and the evaporation source plate are disposed inside a
vacuum chamber while allowing an enclosed heating area being formed
between the shutter device and the evaporation source plate; and
thereby, when the evaporation material is being heated and
transformed from its solid state into its gaseous state to a point
that the pressure difference between the enclosed heating area and
the vacuum chamber is ranged between 1.about.2 order, the
transmission device is activated for enabling the shutter device to
open.
7. The evaporation method of claim 5, wherein the heater is a
device selected from a group consisting of: an infrared (IR)
heater, a radio frequency (RF) heater, a microwave (MW) heater and
a high-power heater.
8. The evaporation method of claim 5, wherein the shutter device
further comprises: a shutter plate, arranged coupling to the
transmission device; and a diffuser plate, formed with a plurality
of holes; and thereby, the shutter can be driven to move by the
transmission device for allowing the plural holes on the diffuser
plate to expose and thus enabling the gaseous evaporation material
to flow passing through the plural holes to reach a surface of the
target substrate for film deposition.
9. The evaporation method of claim 5, wherein the shutter device is
a combination of an upper panel and a lower panel, and the plural
holes are formed respectively on the upper panel and the lower
panel while allowing the transmission device to couple to one panel
selected between the upper panel and the lower panel in a manner
that the upper panel and the lower panel can be driven to move and
displaced by a relative displacement related to each other for
enabling the holes of the upper panel to align or misalign with the
holes of the lower panel.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application also claims priority to Taiwan Patent
Application No. 103137848 filed in the Taiwan Patent Office on Oct.
31, 2014, the entire content of which is incorporated herein by
reference.
TECHNICAL FIELD
[0002] The present disclosure relates to an evaporation system and
an evaporation method, and more particularly to an evaporation
technique for large-area thin film deposition capable of achieving
precise film quality control with improved high deposition rate and
material utilization ratio.
BACKGROUND
[0003] In a conventional film deposition technique for OLED
devices, it is common to use point evaporation sources.
Nevertheless, the adopting of such point evaporation source can
only be suitably applied in an evaporation process for forming thin
films onto a small-size substrate, such as a piece of 370
mm.times.470 mm substrate, with a low material utilization rate
ranged between 5% to 6%, and a low deposition rate of about 0.3 to
0.8 nm/s in a comparatively longer tact time, i.e. as long as 40
min to 50 min Although there are already linear evaporation sources
being adopted and used in some advanced evaporation processes, the
shortcoming of low material utilization rate that is commonly seen
in the process using point evaporation source still exists, despite
that it had been improved from 5% in point evaporation sources to
20%.about.50% in linear evaporation sources. In addition, in the
early stage of a conventional evaporation process, not matter it is
using a point evaporation source or a linear evaporation source,
the evaporation source must be shielded and covered by a shutter.
Since in the early stage the powder-like or granular-like
evaporation material is just started being heated and thus the
evaporation process is in a transient period when the consequent
vapor flow rate is increasing gradually, the vapor flow that is
increasing can cause unstable film deposition rate which will
eventually cause film to be formed non-uniformly on the substrate.
Therefore, at early stage of an evaporation process, the
evaporation source should be shielded and covered until an
equilibrium vapor saturation has been reached and thereby the
resulting deposition rate is stabled, that is when the shutter can
be opened for enabling an evaporation process.
[0004] For an evaporation technique of large-area thin film
deposition, no matter it is using a point evaporation source or a
linear evaporation source, the cosine law of distribution angle
must be considered as the larger the substrate to be deposited is,
the larger the distance between the evaporation source and the
substrate should be. In addition, the size of the shutter is
increased to cope with the larger substrate. For instance, for
performing an evaporation process on a substrate that is longer
than 1 meter, the distance between the used evaporation source and
the substrate must be over 1 meter. Consequently, the film can
still be deposited on the substrate non-uniformly as it can take
too long for the one-meter-long substrate to travel passing the
deposition chamber during the shutter is being activated to open
and close in a reciprocation manner.
SUMMARY
[0005] The present disclosure provides an evaporation system for
performing an evaporation process upon a surface of an evaporation
target substrate, which comprises: an evaporation source plate, an
evaporation material, a heater, a shutter device, and a
transmission device. In addition, the evaporation source plate is
configured with at least one planar surface; the evaporation
material is coated on the planar surface of the evaporation source
plate; the heater is disposed at a position for allowing the same
to heat the evaporation source plate and thus transform the solid
state evaporation material into its gaseous state; the shutter
device is formed with a plurality of holes while being arranged at
a position between the evaporation source plate and the evaporation
target substrate; and the transmission device is coupled to the
shutter device for controlling the opening/closing of the shutter
device so as to allow the gaseous evaporation material to travel
passing the holes and thereby reaching the surface of the
evaporation target substrate for film deposition.
[0006] The present disclosure further provides an evaporation
method for performing an evaporation process upon a surface of an
evaporation target substrate. Operationally, first an evaporation
material and an evaporation source plate are provided, while
allowing the evaporation material to be coated on a surface of the
evaporation source plate, and then the evaporation source plate is
heated by a heater for transforming the evaporation material from
its solid state to its gaseous state. Thereafter, a shutter device
with a plurality of holes is provided for enabling the gaseous
evaporation material to travel passing the holes and thus reaching
the surface of the evaporation target substrate for film
deposition, whereas the shutter device is coupled to a transmission
device which is used for controlling the opening/closing of the
holes of the shutter device.
[0007] Further scope of applicability of the present application
will become more apparent from the detailed description given
hereinafter. However, it should be understood that the detailed
description and specific examples, while indicating exemplary
embodiments of the disclosure, are given by way of illustration
only, since various changes and modifications within the spirit and
scope of the disclosure will become apparent to those skilled in
the art from this detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] The present disclosure will become more fully understood
from the detailed description given herein below and the
accompanying drawings which are given by way of illustration only,
and thus are not limitative of the present disclosure and
wherein:
[0009] FIG. 1 is a schematic diagram showing an evaporation system
according to an embodiment of the present disclosure.
[0010] FIG. 2 is a schematic diagram showing an evaporation system
according to another embodiment of the present disclosure whereas
its shutter device is closed.
[0011] FIG. 3 is a schematic diagram showing the evaporation system
of FIG. 2 where its shutter device is opened.
[0012] FIG. 4 is a flow chart depicting steps performed in an
evaporation method of the present disclosure.
DETAILED DESCRIPTION
[0013] In the following detailed description, for purposes of
explanation, numerous specific details are set forth in order to
provide a thorough understanding of the disclosed embodiments. It
will be apparent, however, that one or more embodiments may be
practiced without these specific details. In other instances,
well-known structures and devices are schematically shown in order
to simplify the drawing.
[0014] Please refer to FIG. 1, which is a schematic diagram showing
an evaporation system according to a first embodiment of the
present disclosure. In the evaporation system 100 shown in FIG. 1,
there is an evaporation source plate 110 being used for performing
an evaporation process upon an target substrate 120, whereas the
evaporation source plate 110 is substantially a source plate having
at least one surface that is covered with an evaporation material
111 in a manner selected from the group consisting of: coating,
inkjet printing and evaporation and the like, but is not limited
thereby. There can be a variety of evaporation source plates 110
that are provided for various evaporation materials 111 to dispose
thereon. For instance, it is noted that the surface of the
evaporation source plate 110 provided for the evaporation material
111 to dispose thereon can be a surface selected from a planar
surface, a smooth surface, a rough surface, and a pitted surface
and correspondingly, the evaporation material 111 can be formed as
a film with a planar surface, a smooth surface, a rough surface, or
a pitted surface, or can be disposed on the surface of the source
plate 110 into an array pattern composed of points, lines or planes
of the evaporation material 111 by a means selected from the group
consisting of: coating, inkjet printing and evaporation. The
evaporation source plate 110 is made of a material with a specific
heat resistance. That is, since the evaporation source plate 110 is
provided for an evaporation process, the melting point of the
evaporation source plate should at least be higher than the working
temperature of the evaporation material 111 in the evaporation
process. Moreover, the evaporation material 111 can be a pure
substance or a composition of various substances, such as an
evaporation material for forming copper indium gallium selenide
(CIGS) films or an organic light-emitting layer for emitting red,
green or blue light. Moreover, the evaporation material 111 is
coated on a surface of the evaporation source plate 110 for forming
a layer of evaporation material thereon, and for allowing the
evaporation material 111 after being evaporated into a gaseous
state to be distributed onto the target substrate 120 for film
deposition.
[0015] As the evaporation system 100 shown in FIG. 1, an
evaporation process is performed inside a vacuum evaporation
chamber 130, while an evaporation source plate 110 which can be a
two-dimensional planar structured crucible for housing an
evaporation material 111 is placed at the lower portion of the
vacuum chamber 130. It is noted that the surface of the evaporation
source plate 110 provided for the evaporation material 111 to
dispose thereon can be a smooth surface, a rough surface, a surface
with grooved, or a surface with array of blind holes and blind
slots. In addition, there is a heater 140 being disposed at a
position under the evaporation source plate 110 for allowing the
same to heat the evaporation material 111 disposed on the
evaporation source plate 110, and thus transforming the solid-state
evaporation material 111 into its gaseous state. Moreover, there
can be a cooling device 150 being attached to the back of the
target substrate 120 for cooling the same.
[0016] There is a shutter device 160 being disposed at a position
between the evaporation source plate 110 and the evaporation target
substrate 120, and thereby, there is an enclosed heating area 112
being formed by the shutter device 160 and the evaporation source
plate 110. In this embodiment, the shutter device 160 further
comprises a shutter plate 161 and a diffuser plate 162 in a manner
that shutter plate 161 is coupled to a transmission device 170. In
addition, the shutter plate 161 is disposed close to a side of the
target substrate 120 while the diffuser plate 162 is disposed on
top of the evaporation source plate 110. Before heating, the
shutter device 160 is closed that the shutter plate 161 is arranged
at a position for allowing the diffuser plate 162 to be shielded
thereby, and thus enabling a confined enclosed space, i.e. the
enclosed heating area 112, to be formed between the evaporation
source plate 110 and the shutter device 160. The heater 140 is then
being activated for heating the evaporation source plate 110,
whereas the heater 140 can be an infrared (IR) heater, a radio
frequency (RF) heater, a microwave (MW) heater or a high-power
heater. In an embodiment, for example, the heater 140 is being
activated to perform a heating procedure at a rapid rate, likely
100.degree. C./sec, for allowing the evaporation material 111 to
reach its evaporating temperature quickly, likely within 5 seconds.
As soon as the evaporation material 111 is heated by the heater 140
to its evaporating temperature, the evaporation material 111 is
transformed from its solid state into its gaseous state for
starting to fill the enclosed heating area 112 with the vaporized
evaporation material 111. At a time when the pressure difference
between the enclosed heating area 112 and the vacuum chamber 130 is
over to 1.about.2 order, the transmission device 170 is activated
for enabling the shutter plate 161 to open in a flash so as to
expose the holes 1621 formed on the diffuser plate 162 for the
gaseous evaporation material 111 to flow passing through and reach
the surface of the target substrate 120. By the flash evaporation
effect happened when the high-pressure vapor flow of the gaseous
evaporation material 111 flows into the vacuum chamber 130 of lower
pressure and also by the sizes, shapes and distribution of the
holes 1621 on the diffuser plate 162 well designed, an uniform
distributed vapor laminar flow can be achieved so as to form a
uniform film deposition on the target substrate 120.
[0017] The transmission device 170 can be a manual transmission
device, a ball screw transmission device, or a cam driving device.
Nevertheless, different transmission devices will correspondingly
have different configurations of power sources and driving
mechanisms. In the embodiment shown in FIG. 1, a motor 170 is
disposed outside the evaporation chamber 130 while allowing the
driving force of the motor 171 to be fed to a ball nut 173 by a
gear set or a pulley set 172. As the ball nut 173 is further
coupled to a ball screw rod 174 while the ball nut 173 itself is
fixed inside the evaporation chamber 130, the rotating ball nut 173
will bring along the ball screw rod 174 to move left or right, and
thus enabling an upper panel 161 that is fixedly attached to the
ball screw rod 174 to be moved by a displacement C.
[0018] In an evaporation system 200 shown in FIG. 2, there is an
evaporation source plate 210 that is provided for an evaporation
material 211 to be disposed thereon is placed inside a vacuumed
evaporation chamber 230, whereas the evaporation source plate 210
is disposed on top of a heater 240 while allowing the evaporation
source plate 210 to be confined by a shutter device 260 that is
arranged above the evaporation source plate 210. Moreover, there is
a cooling device 250 being disposed at the back of the target
substrate 220 for cooling the same. In this embodiment, the shutter
device 260 is a composition of an upper panel 261 and a lower panel
262, while both of the two panels 261, 262 are formed respectively
with a plurality of holes. Moreover, the upper panel 261 is
disposed close to a side of the target substrate 220 while the
lower panel 262 is disposed on top of the evaporation source plate
210. As shown in FIG. 2, the shutter device 260 is closed before
heating, while the holes 2611 on the upper panel 261 are not
aligned with holes 2621 on the lower panel 262, so that an enclosed
space 212 is formed on top of the evaporation source plate 210. In
addition, there is at least one panel that is selected from the
upper panel 261 and the lower panel 262 is arranged coupling to a
transmission device 270.
[0019] At the starting of the heated evaporation material 211 on
the evaporation source plate 210 being evaporated, the upper panel
261 and the lower panel 262 remain at their respective initial
positions without movement, i.e. the holes of the upper panel 261
and the lower panel 262 are not aligned with one another and thus
are not in communication with one another, so that the space above
the evaporation source plate 210 is an enclosed space, i.e. the
enclosed heating area 212. As the evaporation source plate 210 is
being heated by the heater 240, the evaporation material 211 is
gradually being heated to its evaporating temperature and thus
starts filling the confined enclosed heating area 212 with gaseous
evaporation material 211. At the point when the pressure difference
between the enclosed heating area 212 and the vacuum chamber 230 is
over to 1.about.2 order, the transmission device 270 is activated
for enabling the either the upper panel 261 or the lower panel 262
to move in a flash in a manner that the holes of the upper panel
261 and the lower panel 262 are aligned with one another and thus
are in communication with one another, and thus the gaseous
evaporation material 211 can be allowed to flow into the
evaporation chamber 230 where the pressure is lower for enabling a
flash evaporation effect, as shown in FIG. 3. In addition, by the
sizes, shapes and distribution of the holes 2611, 2621 on the upper
panel 261 and lower panel 262 well designed, a uniform distributed
vapor laminar flow can be achieved so as to form a uniform film
deposition on the target substrate 220.
[0020] In the embodiment shown in FIG. 3, the transmission device
270 is composed of: a motor 271, a gear/pulley set 272, a ball nut
273, and a ball screw rod 274. As the upper panel 261 in FIG. 3 is
fixedly coupled to the ball screw rod 274, the upper panel 261 can
be brought along to move by a displacement C by the moving ball
screw rod 274. The configuration of the transmission device 270 is
about the same as the transmission device 170 shown in FIG. 1, but
is different in that: the ball screw rod 274 is arranged extending
from one side of the upper panel 261 to an opposite side
thereof.
[0021] Please refer to FIG. 4, which is a flow chart depicting
steps performed in an evaporation method of the present disclosure.
The evaporation method 400 of FIG. 4 comprises the steps of: [0022]
Step 402: providing an evaporation material and an evaporation
source plate while allowing the evaporation material to be coated
on a surface of the evaporation source plate; [0023] Step 404:
heating the evaporation source plate by the use of a heater for
transforming the evaporation material from its solid state to its
gaseous state; and [0024] Step 406: providing a shutter device with
a plurality of holes for enabling the gaseous evaporation material
to travel passing the holes and thus reach the surface of the
target substrate for film deposition, wherein the shutter device is
coupled to a transmission device which is used for controlling the
opening/closing of the holes.
[0025] The following description relating to the evaporation method
of FIG. 4 is exemplified by the use of the evaporation system 100
of FIG. 1. In the step 402, first, the evaporation chamber 130
having the evaporation source plate 110 that is coated with the
evaporation material 111 is provided, while the shutter device 160
is closed by the transmission device 170, i.e. the holes 1621 on
the diffuser plate 162 is shielded by the shutter plate 161; and
then the heater 140 is activated for heating the evaporation
material 111 rapidly to its evaporating temperature. In this
embodiment, the heater 140, which can be an infrared (IR) heater, a
radio frequency (RF) heater, a microwave (MW) heater or a
high-power heater, is being activated to perform a heating
procedure at a rapid rate, likely 100.degree. C./sec, for allowing
the evaporation material 111 to reach its evaporating temperature
quickly, likely within 5 seconds, as described in step 404. In step
404, as soon as the evaporation material 111 is heated by the
heater 140 to its evaporating temperature, the evaporation material
111 is transformed from its solid state into its gaseous state for
starting to fill the enclosed heating area 112, that is a space
formed between the shutter device 160 and the evaporation source
plate 110, with the vaporized evaporation material 111. At a time
when the pressure difference between the enclosed heating area 112
and the vacuum chamber 130 is over to 1.about.2 order, the
transmission device 170 is activated for enabling the shutter plate
161 to open in a flash so as to expose the holes 1621 formed on the
diffuser plate 162 for the gaseous evaporation material 111 to flow
passing through and reach the surface of the target substrate 120
so as to form a uniform film deposition on the target substrate
120, as described in step 406.
[0026] The following description relating to the evaporation method
of FIG. 4 is exemplified by the use of the evaporation system 200
of FIG. 2. In the step 402, first, the evaporation chamber 230
having the evaporation source plate 210 that is coated with an
evaporation material 211 is provided, while the shutter device 260
is closed by the transmission device 270, i.e. the holes 2611, 2621
respectively on the upper panel 261 and the lower panel 262 are not
aligned with one another; and then the heater 240 is activated for
heating the evaporation material 211 rapidly to its evaporating
temperature. In step 404, as soon as the evaporation material 211
is heated by the heater 240 to its evaporating temperature, the
evaporation material 211 is transformed from its solid state into
its gaseous state for starting to fill the enclosed heating area
212, that is a space formed between the shutter device 260 and the
evaporation source plate 210, with the vaporized evaporation
material 211. At a time when the pressure difference between the
enclosed heating area 212 and the vacuum chamber 230 is over to
1.about.2 order, the transmission device 270 is activated for
enabling the shutter plate 260 to open by aligning the holes 2611
on the upper panel 261 with the holes 2621 on the lower panel 262
for allowing the gaseous evaporation material 211 to flow passing
through the holes 2611, 2621 and reach the surface of the target
substrate 220 so as to form a uniform film deposition on the target
substrate 220, as described in step 406.
[0027] To sum up, by the rapid heating means that is operated
cooperating with an instant-opened shutter device in the
evaporation system and method of the present disclosure, the
saturated vapor flow of the evaporation material with high
pressure, i.e. the pressure difference between the enclosed heating
area and the vacuum chamber is over to 1.about.2 order, can be
enabled to flow passing a shutter device in a flash, and thereby, a
uniform distributed flash evaporation effect can be achieved. In
another embodiment of the present disclosure, by the use of the
shutter device that can be opened in a very brief period of time,
holes formed respectively on two porous panels can be enabled to
communicate with one another for allowing the saturated vapor flow
of the evaporation material passing through and thus to be diffused
with uniformly distributed flash evaporation effect. Moreover, by
the sizes, shapes and distribution of the holes on the shutter
device well designed, a uniform distributed vapor laminar flow can
be achieved so as to form a uniform film deposition on the target
substrate, and thereby, not only the unevenly film deposition
caused by unstable vapor flow in the early stage of a conventional
evaporation process is solved, but also the thermal crystal
degradation of deposited film that is caused by the requiring of
the evaporation chamber to be heated for a long period of time in
conventional evaporation processes can be suppressed.
[0028] With respect to the above description then, it is to be
realized that the optimum dimensional relationships for the parts
of the disclosure, to include variations in size, materials, shape,
form, function and manner of operation, assembly and use, are
deemed readily apparent and obvious to one skilled in the art, and
all equivalent relationships to those illustrated in the drawings
and described in the specification are intended to be encompassed
by the present disclosure.
* * * * *