U.S. patent application number 11/511205 was filed with the patent office on 2007-03-01 for laser induced thermal imaging apparatus with contact frame.
Invention is credited to Tae Min Kang, Jin Soo Kim, Mu Hyun Kim, Sun Hoe Kim, Noh Min Kwak, Sang Bong Lee, Seong Taek Lee, Seung Hyun Lee, Sok Won Noh, Jin Wook Seong, Myung Won Song, Yeun Joo Sung, Byeong Wook Yoo.
Application Number | 20070045540 11/511205 |
Document ID | / |
Family ID | 37802755 |
Filed Date | 2007-03-01 |
United States Patent
Application |
20070045540 |
Kind Code |
A1 |
Kang; Tae Min ; et
al. |
March 1, 2007 |
Laser induced thermal imaging apparatus with contact frame
Abstract
A laser induced thermal imaging (LITI) apparatus and a method of
making an electronic device using the same are disclosed. The LITI
apparatus includes a chamber, a substrate support, a contact frame,
and a laser source or oscillator. The LITI apparatus transfers a
transferable layer from a film donor device onto a surface of an
intermediate electronic device. The LITI apparatus uses a magnetic
force to provide a close contact between the transferable layer and
the surface of the intermediate device. The magnetic force is
generated by magnetic materials formed in two components of the
LITI apparatus that are spaced apart interposing transferable layer
and the surface of the intermediate device. Magnets or magnetic
materials are formed in the two following components of the LITI
apparatus: 1) the intermediate device and the film donor device; 2)
the intermediate device and the contact frame; 3) the substrate
support and the film donor device; or 4) the substrate support and
the contact frame.
Inventors: |
Kang; Tae Min; (Yongin-si,
KR) ; Kim; Jin Soo; (Yongin-si, KR) ; Kim; Mu
Hyun; (Yongin-si, KR) ; Kim; Sun Hoe;
(Jeongeup-si, KR) ; Kwak; Noh Min; (Yongin-si,
KR) ; Lee; Sang Bong; (Yongin-si, KR) ; Lee;
Seong Taek; (Yongin-si, KR) ; Lee; Seung Hyun;
(Yongin-si, KR) ; Noh; Sok Won; (Seoul, KR)
; Seong; Jin Wook; (Seoul, KR) ; Song; Myung
Won; (Yongin-si, KR) ; Sung; Yeun Joo;
(Yongin-si, KR) ; Yoo; Byeong Wook; (Yongin-si,
KR) |
Correspondence
Address: |
KNOBBE MARTENS OLSON & BEAR LLP
2040 MAIN STREET
FOURTEENTH FLOOR
IRVINE
CA
92614
US
|
Family ID: |
37802755 |
Appl. No.: |
11/511205 |
Filed: |
August 28, 2006 |
Current U.S.
Class: |
250/330 |
Current CPC
Class: |
H01L 51/0013 20130101;
B41M 5/265 20130101; B41M 5/38221 20130101 |
Class at
Publication: |
250/330 |
International
Class: |
G02F 1/01 20060101
G02F001/01 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 30, 2005 |
KR |
10-2005-0080347 |
Aug 30, 2005 |
KR |
10-2005-0080348 |
Aug 30, 2005 |
KR |
10-2005-0080349 |
Nov 16, 2005 |
KR |
10-2005-0109814 |
Nov 16, 2005 |
KR |
10-2005-0109815 |
Nov 16, 2005 |
KR |
10-2005-0109816 |
Nov 16, 2005 |
KR |
10-2005-0109819 |
Nov 16, 2005 |
KR |
10-2005-0109820 |
Nov 16, 2005 |
KR |
10-2005-0109821 |
Nov 16, 2005 |
KR |
10-2005-0109822 |
Claims
1. An apparatus for laser induced thermal imaging (LITI),
comprising: a substrate support configured to support an
intermediate electronic device and a film donor device; a laser
source; and a contact frame positioned between the substrate
support and the laser source, the contact frame being movable
relative to the substrate support between a first position and a
second position, the first position being a first distance from the
substrate support, the second position being a second distance from
the substrate support, the second distance being greater than the
first distance, the contact frame being configured to press the
film donor device against the intermediate device about the first
position, the contact frame comprising at least one magnetic
material selected from the group consisting of a permanent magnet
and an electromagnet.
2. The apparatus of claim 1, wherein the electromagnet is
electrically connected to an external power source and is
configured to be selectively stimulated.
3. The apparatus of claim 1, wherein the at least one magnetic
material comprises one or more forms selected from the group
consisting of plates, pieces, chips, rods, and particles.
4. The apparatus of claim 1, wherein the contact frame comprises a
magnetic portion and a non-magnetic portion, and wherein the
magnetic portion comprises the at least one magnetic material.
5. The apparatus of claim 4, wherein the magnetic portion is
arranged generally closer to the substrate support than the
non-magnetic portion.
6. The apparatus of claim 1, wherein the substrate support
comprises at least one magnetic material selected from the group
consisting of a permanent magnet, an electromagnet and a
magnetically attractable material.
7. The apparatus of claim 1, further comprising: an intermediate
device comprising a receiving surface and placed over the substrate
support; and a film donor device comprising a transferable film
layer and placed over the intermediate device.
8. The apparatus of claim 7, wherein the intermediate device and
film donor device are arranged such that the receiving surface and
the transferable film layer are in contact.
9. The apparatus of claim 8, wherein there is substantially no air
bubble between the receiving surface and the transferable film
layer.
10. The apparatus of claim 7, wherein the film donor device further
comprises a light-to-heat conversion layer.
11. The apparatus of claim 7, wherein the film donor device does
not comprise a magnetic layer comprising a permanent magnet or an
electromagnet.
12. The apparatus of claim 7, wherein the intermediate electronic
device comprises at least one magnetic material selected from the
group consisting of a permanent magnet, an electromagnet and a
magnetically attractable material.
13. A method of making an electronic device using the apparatus of
claim 1, the method comprising: placing an intermediate device on
the substrate support, the intermediate device comprising a first
surface and a second surface, the first surface facing the contact
frame, the second surface contacting the substrate support; placing
a film donor device on the first surface of the intermediate
device, the film donor device comprising a third surface and a
fourth surface, the third surface facing the contact frame, the
fourth surface facing the substrate support; moving the contact
frame to contact the third surface of the film donor device so that
the fourth surface of the film donor device contacts the first
surface of the intermediate device; and pressing the film donor
device against the intermediate device.
14. The method of claim 13, wherein the contact frame comprises an
opening, and wherein the method further comprises irradiating a
laser beam on the film donor device through the opening of the
contact frame.
15. The method of claim 13, wherein the method is conducted in a
vacuum atmosphere.
16. The method of claim 13, wherein the contact frame comprises an
electromagnet, and wherein inducing the magnetic force comprises
activating the electromagnet.
17. The method of claim 13, wherein pressing the film donor device
comprises causing the weight of the contact frame to apply to the
film donor device.
18. The method of claim 13, wherein pressing the film donor device
further comprises causing the at least one magnetic material to
magnetically interact with a magnet or magnetically attractable
material underlying the first surface of the intermediate
device.
19. The method of claim 18, wherein the intermediate device
comprises the magnet or magnetically attractable material.
20. The method of claim 18, wherein the substrate support comprises
the magnet or magnetically attractable material.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of Korean Patent
Application Nos. 10-2005-0080347, 10-2005-0080348, and
10-2005-0080349, filed on Aug. 30, 2005, and Korean Patent
Application Nos. 10-2005-0109814, 10-2005-0109815, 10-2005-0109816,
10-2005-0109819, 10-2005-0109820, 10-2005-109821, and
10-2005-0109822, filed on Nov. 16, 2005, in the Korean Intellectual
Property Office, the disclosures of which are incorporated herein
by reference.
[0002] This application is related to and incorporates herein by
reference the entire contents of the following concurrently filed
applications: ORGANIC LIGHT EMITTING DISPLAY DEVICE (Atty. Docket
No. SDISHN.035AUS, filed ______, Application No. ______); FILM
DONOR DEVICE FOR LASER INDUCED THERMAL IMAGING (Atty. Docket No.
SDISHN.037AUS, filed ______ Application No. ______ ); LASER INDUCED
THERMAL IMAGING APPARATUS (Atty. Docket No. SDISHN.038AUS, filed
______, Application No. ______); and METHOD OF MAKING AN ORGANIC
LIGHT EMITTING DISPLAY DEVICE (Atty. Docket No. SDISHN.039AUS,
filed ______, Application No. ______).
BACKGROUND OF THE INVENTION
[0003] 1. Field of the Invention
[0004] The present invention relates to production of electronic
devices, and more particularly, forming organic material layers in
electronic devices using a laser induced thermal imaging (LITI)
technology.
[0005] 2. Description of the Related Technology
[0006] Certain electronic devices include organic layers. For
example, an organic light emitting device (OLED) includes various
organic layers. Various methods have been used to form such organic
layers. For example, such methods include a deposition method, an
inkjet method, and a laser-induced thermal imaging (LITI)
method.
[0007] In the LITI method, a film donor device is used to provide a
transferable layer. The donor device is placed on a partially
fabricated electronic device (intermediate device) such that the
transferable layer contacts a surface (receiving surface) of the
intermediate device on which the transferable layer is to be
transferred. Then, a laser beam is applied onto selected areas of
the donor device, which creates heat in the donor device in the
selected area. The heat causes delamination of desired portions of
the transferable layer. The delaminated portions of the
transferable layer remain on the surface of the intermediate device
when the donor device is removed.
[0008] A typical LITI apparatus uses suction to make and keep the
transferable layer contact the surface of the intermediate device
during this processing. FIG. 1 is a cross-sectional view of an LITI
apparatus 100. The LITI apparatus 100 includes a chamber 110, a
substrate support 120 and a laser source or oscillator 130. The
substrate support 120 includes an intermediate device receiving
groove 121 to receive an intermediate electronic device 140 therein
and a donor device receiving groove 123 to receive a film donor
device 150 therein.
[0009] To transfer organic material portions to the intermediate
device with high precision and with fewer defects, a close contact
between the transferable layer and the receiving surface is needed.
The LITI apparatus 100 includes a suction mechanism to form such a
close contact. The suction mechanism includes pipes 161 and 163 and
a vacuum pump P. Suction through the pipes 161 brings and keeps the
intermediate device (not shown) placed in the groove 121 down.
Suction through the pipes 163 brings and keeps the donor device
(not shown) placed in the groove 123 down and in contact with the
intermediate device. To conduct these suctions, air or other
gaseous medium is required within the chamber.
[0010] However, processes performed prior to or subsequent to the
LITI process are typically carried out in a vacuum atmosphere.
Thus, the LITI process using the suction described above needs to
break the vacuum between the preceding and subsequent
processes.
[0011] The discussion in this section is to provide background
information of the related technology and does not constitute an
admission of prior art.
SUMMARY OF CERTAIN INVENTIVE ASPECTS
[0012] One aspect of the invention provides an apparatus for laser
induced thermal imaging (LITI), comprising: a substrate support
configured to support an intermediate electronic device and a film
donor device; a laser source; and a contact frame positioned
between the substrate support and the laser source, the contact
frame being movable relative to the substrate support between a
first position and a second position, the first position being a
first distance from the substrate support, the second position
being a second distance from the substrate support, the second
distance being greater than the first distance, the contact frame
being configured to press the film donor device against the
intermediate device about the first position, the contact frame
comprising at least one magnetic material selected from the group
consisting of a permanent magnet and an electromagnet.
[0013] The electromagnet may be electrically connected to an
external power source and may be configured to be selectively
stimulated. The at least one magnetic material may comprise one or
more forms selected from the group consisting of plates, pieces,
chips, rods, and particles. The contact frame may comprise a
magnetic portion and a non-magnetic portion, and the magnetic
portion may comprise the at least one magnetic material. The
magnetic portion may be arranged generally closer to the substrate
support than the non-magnetic portion. The substrate support may
comprise at least one magnetic material selected from the group
consisting of a permanent magnet, an electromagnet and a
magnetically attractable material.
[0014] The apparatus may further comprise: an intermediate device
comprising a receiving surface and placed over the substrate
support; and a film donor device comprising a transferable film
layer and placed over the intermediate device. The intermediate
device and film donor device may be arranged such that the
receiving surface and the transferable film layer are in contact.
There may be substantially no air bubble between the receiving
surface and the transferable film layer. The film donor device may
further comprise a light-to-heat conversion layer. The film donor
device may not comprise a magnetic layer comprising a permanent
magnet or an electromagnet. The intermediate electronic device may
comprise at least one magnetic material selected from the group
consisting of a permanent magnet, an electromagnet and a
magnetically attractable material.
[0015] Another aspect of the invention provides a method of making
an electronic device using the apparatus described above. The
method comprises: placing an intermediate device on the substrate
support, the intermediate device comprising a first surface and a
second surface, the first surface facing the contact frame, the
second surface contacting the substrate support; placing a film
donor device on the first surface of the intermediate device, the
film donor device comprising a third surface and a fourth surface,
the third surface facing the contact frame, the fourth surface
facing the substrate support; moving the contact frame to contact
the third surface of the film donor device so that the fourth
surface of the film donor device contacts the first surface of the
intermediate device; and pressing the film donor device against the
intermediate device.
[0016] The contact frame may comprise an opening, and the method
may further comprise irradiating a laser beam on the film donor
device through the opening of the contact frame. The method may be
conducted in a vacuum atmosphere. The contact frame may comprise an
electromagnet, and inducing the magnetic force may comprise
activating the electromagnet. Pressing the film donor device may
comprise causing the weight of the contact frame to apply to the
film donor device. Pressing the film donor device may further
comprise causing the at least one magnetic material to magnetically
interact with a magnet or magnetically attractable material
underlying the first surface of the intermediate device. The
intermediate device may comprise the magnet or magnetically
attractable material. The substrate support may comprise the magnet
or magnetically attractable material.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] Aspects and advantages of the invention will become apparent
and more readily appreciated from the following description, taken
in conjunction with the accompanying drawings.
[0018] FIG. 1 illustrates a schematic cross-sectional view of a
laser-induced thermal imaging apparatus.
[0019] FIG. 2 illustrates a schematic cross-sectional view of a
laser-induced thermal imaging apparatus according to one embodiment
of the invention.
[0020] FIG. 3 illustrates a schematic exploded perspective view of
a laser-induced thermal imaging apparatus according to one
embodiment of the invention.
[0021] FIGS. 4A and 4B illustrate schematic cross-sectional views
of partially fabricated electronic devices according to embodiments
of the invention.
[0022] FIG. 4C illustrates a schematic top plan view of a partially
fabricated electronic device according to one embodiment of the
invention.
[0023] FIG. 5A illustrates a schematic perspective view of a
substrate support according to one embodiment of the invention.
[0024] FIG. 5B illustrates a schematic cross-sectional view of the
substrate support of FIG. 5A, taken along the line I-I.'
[0025] FIGS. 6A-6C illustrate schematic partial cross-sectional
views of donor devices according to embodiments of the
invention.
[0026] FIG. 7 illustrates a schematic perspective view of a contact
frame according to one embodiment of the invention.
[0027] FIG. 8 is a flowchart of a laser-induced thermal imaging
method according to one embodiment of the invention.
[0028] FIGS. 9A-9F illustrate a laser-induced thermal imaging
method according to one embodiment of the invention.
[0029] FIGS. 10A-10D illustrate a laser-induced thermal imaging
method according to one embodiment of the invention.
[0030] FIG. 11 illustrates a schematic perspective view of a laser
oscillator according to one embodiment of the invention.
DETAILED DESCRIPTION OF CERTAIN INVENTIVE EMBODIMENTS
[0031] Various embodiments of the invention will be described in
detail with reference to the accompanying drawings. In the
drawings, like reference numerals indicate identical or
functionally similar parts or elements.
Laser-Induced Thermal Imaging Apparatus
[0032] In embodiment, a LITI apparatus uses a magnetic force to
provide a close contact between a film donor device and an
intermediate device. Unlike suctioning in the LITI apparatus of
FIG. 1, the magnetic force does not require air or fluid within the
chamber. In embodiments, contacting the film donor device and
intermediate device using the magnetic force can be performed
either in vacuum or non-vacuum.
[0033] FIG. 2 illustrates a LITI apparatus 200 in accordance with
one embodiment. The illustrated LITI apparatus includes a chamber
210, a substrate support 260, a contact frame 230, and a laser
source or oscillator 220. The chamber 210 provides a space for
processing an intermediate (or partially fabricated) electronic
device 250 with a film donor device 241. The substrate support 260
is configured to support the intermediate device 250 and the film
donor device 241. The contact frame 230 is movably connected to the
chamber 210 for providing a weight downward over the film donor
device 241. In certain embodiments, the contact frame 230 may be
omitted. The film donor device 241 includes a transferable layer
(not shown). The transferable layer will be transferred onto the
intermediate device by a laser. The laser oscillator 220 is
positioned over the contact frame 230. The laser oscillator 220 is
configured to irradiate a laser onto the film donor device 241
through the contact frame 230.
[0034] In one embodiment, the LITI apparatus 200 operates as
follows. First, the intermediate device 250 is introduced into the
chamber 210 and is placed onto the substrate support 260. Then, the
film donor device 241 is placed over the intermediate device 250.
The film donor device 241 comes at least partially in contact with
the intermediate device 250. The film donor device 241 is pressed
against the intermediate device 250, using a magnetic force. During
this step, the transferable layer is closely contacted with the
intermediate device. The laser oscillator 220 is activated to
irradiate a laser onto the film donor device 241. Then, the
transferable layer is transferred from the film donor device 241 to
the intermediate device 250.
[0035] FIG. 3 illustrates a schematic exploded view of the LITI
apparatus 200. The chamber 210 is shown in dotted lines. In the
illustrated embodiment, the laser oscillator 220, the contact frame
230 and the substrate support 260 are vertically aligned with one
another. During the LITI process, an intermediate device 250 is
placed on the substrate support 260, and a film donor device 241 is
placed over the intermediate device 250. In another embodiment, the
foregoing components may have a different arrangement, for example,
a reversed configuration. In some embodiments, the substrate
support may be configured to hold the intermediate device from the
top. Such a substrate support may be referred to as a substrate
holder.
[0036] The chamber 210 provides a reaction space for the LITI
process. The chamber may be any suitable enclosed space in which
the LITI process can be carried out. The chamber 210 houses the
contact frame 230 and the substrate support 260. The chamber also
includes a door for introducing or removing the intermediate device
250 and the film donor device 241. In one embodiment, the chamber
210 may be configured to provide a vacuum atmosphere.
[0037] In the illustrated embodiment, the laser oscillator 220 is
positioned at the top central portion of the chamber 210 over the
contact frame 230 although not limited thereto. The laser
oscillator 220 is configured to irradiate a laser beam onto the
film donor device 241. FIG. 11 illustrates one embodiment of the
laser oscillator 220. The illustrated laser oscillator 220 may be a
CW ND:YAG laser (1604 nm). The laser oscillator 220 has two
galvanometer scanners 221, 222. The laser oscillator 220 also has a
scan lens 223 and a cylinder lens 224. A skilled artisan will
appreciate that various types of laser oscillators can be adapted
to provide a laser for the film donor device.
[0038] In the illustrated embodiment, the contact frame 230 is
positioned over the substrate support 260 although not limited
thereto. The contact frame 230 is movably connected via a
transmission unit 231 to the top central portion of the chamber
210. The contract frame 230 has a contact plate 232 configured to
provide a weight over the film donor device 241. The contact plate
232 is patterned to expose portions of the underlying film donor
device 241 while blocking other portions. To expose the portions of
the film donor device 241, the contact plate 232 includes a
plurality of openings 233. The openings 233 allow the laser beam to
be directed to the portions of the film donor device 241. This
configuration allows to transfer portions of the transferable layer
onto the intermediate device 250 as will be described later in
detail. In certain embodiments, the LITI apparatus may have no
contact frame.
[0039] In the illustrated embodiment, the substrate support 260 is
positioned at the bottom of the reaction chamber 210 although not
limited thereto. The illustrated substrate support 260 has a recess
263 to accommodate the intermediate device 250. The substrate
support 260 also supports the film donor device 241. In addition,
the substrate support 260 accommodates a substrate lifter 265 and a
film donor device lifter 266 underneath. The substrate support 260
has through-holes 261 and 262 through which the substrate lifter
265 and the film donor device lifter 266 move in a vertical
direction.
[0040] The intermediate device 250 is placed on the substrate
support 260 during the LITI process. The term, "intermediate
device" refers to any devices having a surface to form an organic
material using the LITI process. Typically, such devices are
partially fabricated electronic device. In one embodiment, the
intermediate device 250 is a partially fabricated organic light
emitting device. The intermediate device 250 includes a surface
onto which the transferable layer is to be transferred.
[0041] The film donor device 241 is placed over the intermediate
device 250 during the LITI process. In one embodiment, the film
donor device 241 includes a base substrate, a light-to-heat
conversion layer, and a transferable layer, which will be further
described later. The illustrated film donor device 241 also
includes a film donor device tray 240 surrounding the film donor
device 241. The film donor device tray 240 serves as a frame for
maintaining the shape of the film donor device 241. The
transferable layer is arranged to face the surface of the
intermediate layer during LITI processing.
[0042] The LITI apparatus 200 of FIG. 3 uses a magnetic force to
provide a close contact between the film donor device 241 and the
intermediate device 250. The magnetic force holds the devices 241
and 250 in close contact, substantially free of air gaps or bubbles
from between the devices 241 and 250.
[0043] In one embodiment, the magnetic force may be generated by
two or more magnetic materials spaced apart. In embodiments,
magnetic materials are formed in two components of the LITI system
that are spaced apart interposing transferable layer and the
surface on which the transferable layer is to be transferred, i.e.,
one positioned over the transferable layer and the other positioned
under the surface. Here, the term "components" refer to parts and
devices used in the LITI process, which include the intermediate
device 250, the film donor device 241, the contact frame 230 and
the substrate support 260. In embodiments, magnets or magnetic
materials are formed in the two following components of the LITI
system, but not limited to: 1) the intermediate device 250 and the
film donor device 241; 2) the intermediate device 250 and the
contact frame 230; 3) the substrate support 260 and the film donor
device 241; or 4) the substrate support 260 and the contact frame
230.
[0044] Optionally, the magnetic materials may be provided in one of
the following combinations of components of the LITI system: 5) the
substrate support 260, the intermediate device 250, and the contact
frame 230; 6) the substrate support 260, the intermediate device
250, and the film donor device 241; 7) the substrate support 260,
the film donor device 241, and the contact frame 230; or 8) the
intermediate device 250, the film donor device 241, and the contact
frame 230. In yet another embodiment, the magnetic material may be
provided in 9) the substrate support 260, the intermediate device
250, the film donor device 241, and the contact frame 230. A
skilled artisan will appreciate that the magnetic material may be
provided in certain other components, depending on the design of a
LITI apparatus.
[0045] The magnetic materials in the pair of components are
configured to attract each other such that the film donor device
241 and the intermediate device 250 form a close contact between
the transferable layer and the surface on which the layer is to be
transferred. The term, "magnetic material," as used herein, refers
to either a magnet or a magnetically attractive material. A
"magnet" may generally refer to a permanent or electromagnet unless
otherwise indicated. The term, "magnetically attractable material,"
as used herein, refers to a material which is not a magnet, but can
be attracted by a magnet. In some embodiments, one of the two LITI
components may include a magnet whereas the other may include a
magnetically attractable material that is not a magnet. In other
embodiments, both of the two LITI components may include magnets.
In certain embodiments, components including a magnet may also
contain a magnetically attractable material. In all the
embodiments, the components include the magnetic materials in an
amount to generate a sufficient magnetic force to provide a close
contact between the film donor device 241 and the intermediate
device 250.
[0046] The magnetic force can be created in a vacuum atmosphere
unlike suction. Thus, in some embodiments, the LITI process may be
performed in vacuum using the magnetically induced contact between
the film donor device 241 and the intermediate device 250 without
breaking the vacuum. Further, in other embodiments, the magnetic
force system may also be used together with the suction system to
improve the LITI process. The positions and configurations of the
magnet or magnetically attractable material in each component will
be described below in detail.
[0047] In one embodiment, the magnetic material below the
transferable layer is positioned in the intermediate device 250.
FIGS. 4A and 4B illustrate cross-sectional views of embodiments of
the intermediate devices 400A and 400B. The illustrated
intermediate devices 400A and 400B are partially fabricated organic
light emitting devices (OLEDs). Each of the intermediate devices
400A and 400B includes a substrate 401, a buffer layer 402, a thin
film transistor 440, a passivation layer 409, an electrode 420 and
a pixel partitioning walls 430. The thin film transistor 440
includes insulating layers 403, 404, a semiconductor layer 405, a
source electrode 406, a drain electrode 407 and a gate electrode
408. The pixel partitioning walls 430 are formed over the
passivation layer 409 and portions of the electrode 420, exposing a
substantial portion of a top surface of the electrode 420. The
electrode 420 will serve as a cathode or anode of an organic light
emitting diode. The transferable layer will be formed over the
exposed top surface of the electrode 420.
[0048] In FIG. 4A, a magnetic layer 410a is attached to the bottom
surface of the substrate 401. In another embodiment shown in FIG.
4B, a magnetic layer 410b is positioned between the substrate 401
and the buffer layer 402. The magnetic layers 410a, 410b include a
magnetic material which will be described below in detail. In one
embodiment, the magnetic layer 410a or 410b has a thickness between
about 5,000 .ANG. and about 10,000 .ANG..
[0049] In certain embodiments, the intermediate device may include
magnetic materials embedded in any components under the electrode
420, for example, the substrate 401, the buffer layer 402, the
insulating layers 403, 404, and/or the passivation layer 409,
depending on the design of the device. In any case, the
intermediate device includes the magnetic material in an amount
sufficient to make a close contact between the film donor device
layer and the intermediate device.
[0050] In yet another embodiment, the intermediate device may
include magnetic material strips in certain regions of the
intermediate device. FIG. 4C illustrates a top plan view of one
embodiment of an intermediate device 400C. The illustrated device
is a partially fabricated organic light emitting device 400C. The
device 400C includes a display region 460, a data driver 430, a
scan driver 440, and power source connectors 415 and 420. The
display region 460 includes a plurality of pixels 470 in a matrix
form. The illustrated device 400C includes magnetic material strips
450a and 450b. In the illustrated embodiment, the strips 450a are
positioned in peripheral regions outside the display region 460. In
addition, the strips 450b are formed in the display region 460. The
illustrated strips 450b are substantially in parallel to one
another. In other embodiments, the strips of the magnetic materials
are formed in the pixel region, but not in the peripheral regions.
A skilled artisan will appreciate that various other configurations
of strips can be used to provide a magnetic force.
[0051] In one embodiment, the magnetic material may be a magnet
including a permanent magnet or an electromagnet. The permanent
magnet may be alnico magnet, ferrite magnet, rare-earth magnet,
rubber magnet or plastic magnet. The permanent magnet may take at
least one form selected from plates, pieces, chips, rods and
particles. In one embodiment, the permanent magnet may be nanometer
scale magnetic particles, plates, pieces, chips or rods. Such
nano-scale particles may be deposited on a surface of a component
of the intermediate device, using spin coating, e-beam deposition,
or inkjet deposition. In other embodiments, the plates, pieces,
chips, rods and particles can be greater than nano-scale sizes.
[0052] The permanent magnet may be substantially uniformly
distributed in the magnetic layer 410a or 410b. In another
embodiment, the magnetic layer 410a or 410b may have permanent
magnet portions only in regions over which the transferable layer
is to be transferred. In yet another embodiment, the magnetic layer
may be a single plate formed of a permanent magnet.
[0053] In another embodiment, the magnetic material may be an
electromagnet. The electromagnet may have at least one form
selected from a solenoid and a toroid. A solenoid refers to a coil
forming a shape of a straight tube. A toroid refers to a coil
forming a shape of a doughnut. Typically, a toroid is a solenoid
that is bent so that the ends meet. In some embodiments, a solenoid
or toroid may include a core of paramagnetic or ferromagnetic
material (for example, iron) inside the coil. Because an
electromagnet requires an electric current to be magnetized, the
electromagnet is connected to an external power source through a
conductive line. In one embodiment, a non-display region of the
intermediate device may include one or more electrodes electrically
connected to designated for the electromagnet. The electrode(s) is
configured to receive power from an external power source. In
addition, the electrode(s) is connected to the electromagnet
through the conductive line(s). In embodiments, the electrode(s)
may be formed on an external surface of the device or body where
the electromagnet is incorporated so as to make electrical
connection to the external power source. In other embodiments, the
electrode(s) may protrude outside the device or body where the
electromagnet is incorporated. In a finished electronic device
formed from the intermediate device, the electrode(s) may be
inactive and buried in a dielectric material. Similar to the
permanent magnet, the electromagnet may be either substantially
uniformly or non-uniformly distributed, depending on the design of
the intermediate device.
[0054] In yet another embodiment, the magnetic material may be a
magnetically attractable material while not being a magnet.
Examples of the magnetically attractable material include, but are
not limited to, Fe, Ni, Cr, Fe.sub.2O.sub.3, Fe.sub.3O.sub.4,
CoFe.sub.2O.sub.4, MnFeO.sub.4, their alloys, and a mixture of two
or more of the foregoing materials. Other examples of the
magnetically attractable material may also include plastic and
ceramic magnetic materials. Similar to the permanent magnet, the
magnetically attractable material may be in at least one form
selected from plates' pieces, chips, rods, and particles. These may
be nanometer-sized particles or greater. The magnetically
attractable material may be uniformly distributed in the magnetic
layer 410. In another embodiment, the magnetic layer 410 may have
magnetically attractable material portions only in regions over
which the transferable layer is to be transferred. In yet another
embodiment, the magnetic layer may be a single plate formed of the
magnetically attractable material.
[0055] In another embodiment, the magnetic material below the
transferable layer may be positioned in the substrate support.
FIGS. 5A and 5B illustrate one embodiment of the substrate support
260 including the magnetic material. The illustrated substrate
support 260 includes electromagnets 264 in a region 263 (denoted in
dotted lines) under a recess to accommodate the intermediate
device. The illustrated electromagnets 264 are aligned in a
vertical direction. The electromagnets, however, may be arranged in
various other configurations, depending on the design of the
substrate support. The electromagnets may also have various shapes
and configurations as described above with respect to the
intermediate device. In certain embodiments, the magnetic material
may be a permanent magnet or magnetically attractable material as
described above with respect to the intermediate device.
[0056] In one embodiment, the magnetic material over the
transferable layer may be positioned in the film donor device.
FIGS. 6A-6C are partial cross-sectional views of film donor devices
600A-600C in accordance with embodiments. Each of the film donor
devices 600A-600C includes a base substrate 601, a light-to-heat
conversion layer 602 overlying the base substrate 601, an
intermediate layer 603 overlying the light-to-heat conversion layer
602, and a transferable layer 604 overlying the intermediate layer
603. Optionally, the film donor devices may include a buffer layer
(not shown) between intermediate layer 603 and the transferable
layer 604.
[0057] The base substrate 601 serves to provide the film donor
device with a film structure. The base substrate 601 may be made of
a transparent polymer. Examples of the transparent polymer include,
but are not limited to, polyethylene, polyester, teleptalrate,
polyacryl, polyepoxy, polyethylene, and polystyrene. The base
substrate 601 has a thickness between about 10 .mu.m and about 500
.mu.m, optionally about 100 .mu.m and about 400 .mu.m.
[0058] The light-to-heat conversion layer 602 is configured to
absorb laser and convert it to heat. The conversion layer 602
includes a light-absorbing material. The light-absorbing material
may have an optical density of about 0.1 to about 0.4. The
light-absorbing material may include a metal, a metal oxide, and/or
an organic material. Examples of the metal/metal oxide include, but
are not limited to, aluminum, silver, chromium, tungsten, tin,
nickel, titanium, cobalt, zinc, gold, copper, tungsten, molybdenum,
lead and oxides of the foregoing. The organic material may include
a photosynthetic material. Examples of the organic material include
polymers made from a (meth)acrylate monomer or oligomer, such as an
acryl (metha)acrylate oligomer, an ester (metha)acrylate oligomer,
an epoxy (metha)acrylate oligomer, an urethane (metha)acrylate
oligomer, etc., or mixtures of two or more of the foregoing. In
addition, the conversion layer 602 may also include other additives
such as carbon black, graphite or infrared dye.
[0059] The thickness of the light-heat converting layer 602 may
vary, depending on the light-absorbing materials and the
fabrication methods. For example, the conversion layer may have a
thickness of about 100 to about 5000 .ANG. when using a vacuum
deposition method, a laser beam deposition method, or sputtering.
In another embodiment, the conversion layer may have a thickness of
about 0.1 to about 2 .mu.m when using an extrusion coating method,
a gravure coating method, a spin coating method and a knife coating
method.
[0060] The intermediate layer 603 functions to protect the
light-to-heat conversion layer 603. In one embodiment, the
intermediate layer 603 has a high heat resistance. The intermediate
layer 603 may be made of organic or inorganic materials such as
poly imide. The intermediate layer 603 has a thickness between
about 1 .mu.m and about 1.5 .mu.m. In certain embodiments, the
intermediate device may be omitted.
[0061] The transferable layer 604 is a layer which will be
transferred onto the intermediate device. The transferable layer
604 may be formed of an organic material. In one embodiment where
the electronic device is an organic light emitting device, the
material can be an organic light emitting material. However, the
material can also be other organic materials used for forming other
organic elements of the organic light emitting device. Such other
elements include, but are not limited to, a hole injection layer
(HIL), a hole transport layer (HTL), an electron injection layer
(EIL), and an electron transport layer (ETL). In other electronic
devices, any material suitable for forming a target component may
be used as the material for the transferable layer. The
transferable layer 604 has a thickness between about 200 .ANG. and
about 1,000 .ANG.. The transferable layer 604 may be formed, using
any suitable method, for example, extrusion coating, gravure
coating, spin coating, knife coating, vacuum deposition, or
chemical vapor deposition (CVD).
[0062] The buffer layer (not shown) serves to improve transfer
properties of the transferable layer 604. The buffer layer may
include one or more of metal oxides, metal sulfides, non-metal
inorganic compounds, and organic materials. Examples of the
inorganic compounds include Al and Au. Examples of the organic
materials include polyimide.
[0063] Referring to FIG. 6A, the light-to-heat conversion layer 602
includes a magnetic material. For example, the light-to-heat
conversion layer 602 may include a permanent magnet and/or
electromagnet. In other embodiments, the conversion layer 602 may
include a magnetically attractive material. The magnetic material
may have various configurations as described above with respect to
the intermediate device. In other embodiments, the magnetic
material may be embedded in the base substrate 601 or the
intermediate layer 603. In certain embodiments, the magnetic
material may be embedded in at least two of the base substrate 601,
the light-to-heat conversion layer 602, and the intermediate layer
603. In other embodiments, the magnetic material may be embedded
only in certain portions of one or more of the layers 601-603, not
throughout the entire layers. For example, one or more of the
layers 601-603 may include the magnetic materials only under
portions of the transferable layer which will be transferred to the
intermediate device.
[0064] Referring to FIGS. 6B and 6C, the film donor devices 600B
and 600C include a magnetic layer 605. The magnetic layer 605
includes a magnetic material such as a permanent magnet,
electromagnet, and/or magnetically attractable material. The
magnetic material may have-various configurations as described
above with respect to the intermediate device.
[0065] In FIG. 6B, the film donor device 600B includes the magnetic
layer 605 between the base substrate 601 and the light-to-heat
conversion layer 602. In FIG. 6C, the film donor device 600C
includes the magnetic layer 605 between the light-to-heat
conversion layer 602 and the intermediate layer 603; In another
embodiment, the film donor device may include the magnetic layer
interposed between the intermediate layer 603 and the transferable
layer 604. In yet another embodiment, the film donor device may
include the magnetic layer on a bottom surface of the base
substrate 601, which faces away from the light-to-heat conversion
layer 602. In certain embodiments, the film donor device may have
two or more magnetic layers interposed between two consecutive ones
of the layers 601-604. In such embodiments, a magnetic material may
further be embedded in at least one of the base substrate 601, the
light-to-heat conversion layer 602 and the intermediate layer 603.
A skilled artisan will appreciate that the configuration and
combination of the magnetic layers can be varied depending on the
design of the film donor device.
[0066] In another embodiment, the magnetic material over the
transferable layer may be positioned in the contact frame. FIG. 7
illustrates one embodiment of the contact frame 230. The
illustrated contact frame 230 includes a magnetic material embedded
in the frame. The magnetic material may be a permanent magnet or
electromagnet, as described above with respect to the intermediate
device. In another embodiment, the magnetic material may be a
magnetically attractable material, as described above.
[0067] In certain embodiments, the contact frame 230 may include a
separate magnetic layer. The magnetic layer includes a magnetic
material as described above with respect to the intermediate
device. The magnetic layer can be attached on at least one of top
and bottom surfaces of the contact frame 230. In another
embodiment, the magnetic layer may be embedded in the contact frame
230. In such embodiments, the layer is patterned to have openings
corresponding to the openings of the contact frame. The openings of
the contact frame and the layer allow the laser beam to be directed
onto portions of the film donor device 241. This configuration
allows selective transfer of the transferable film onto the
intermediate device 250. In another embodiment, the contact frame
itself may be formed of the magnetic material. In all of the
foregoing embodiments, the contact frame includes the magnetic
material in an amount sufficient to provide a magnetic force to
press the film donor device against the intermediate device.
Laser-Induced Thermal Imaging Process
[0068] The laser-induced thermal imaging (LITI) process according
to embodiments employs a magnetic force to provide a close contact
between a film donor device and an intermediate device. FIG. 8 is a
flowchart illustrating one embodiment of the LITI process.
[0069] First, in step 810, an intermediate device 250 is placed on
a substrate support 260. During this step, the intermediate device
250 is moved by any suitable moving mechanism, for example, a
robotic mechanism. Next, in step 820, a film donor device 241 is
placed over the intermediate device 250. First, the film donor
device 241 is vertically aligned with the intermediate device 250
with its transferable layer facing down. Then, the film donor
device 241 is moved downward onto the intermediate device 250. At
least a portion of the transferable layer is contacted with the
intermediate device 250. Similar to the step 810, the film donor
device 241 may be moved by the moving mechanism.
[0070] In step 830, a magnetic force is provided to pressure the
film donor device 241 against the intermediate device 250. The
magnetic force may be generated by magnetic materials positioned in
two of the LITI components as described above: one over the
transferable layer and the other under the surface on which the
layer is to be transferred. In some embodiments, one of the two
LITI components may include a magnet whereas the other may include
a magnetically attractable material that is not a magnet. In other
embodiments, both of the two LITI components may include magnets.
The magnet may include a permanent magnet and/or electromagnet. In
one embodiment where the magnet includes an electromagnet, the
magnetic force may be time-selectively produced depending on the
needs of the LITI process. In certain embodiments, components
including a magnet may also contain a magnetically attractable
material.
[0071] At this step, the magnetic force makes the film donor device
241 pushed against the intermediate device 250, which makes the
transferable layer to more closely contact the surface on which the
layer is to be transferred. In this process, all or at least some
of air gaps or bubbles from between the film donor device 241 and
the intermediate device 250 may be removed. This step facilitates a
transfer of the transferable layer onto the intermediate device
250.
[0072] In step 840, a laser is irradiated onto the film donor
device 241. The laser provides thermal energy required to transfer
the transferable layer onto the intermediate device 250. In this
step, a laser oscillator 220 is activated to irradiate a laser onto
a top surface of the film donor device 241. In one embodiment
employing a contact frame 230 with openings, the laser passes
through the openings, and reaches the top surface of the film donor
device 241. During this process, the laser is directed to selected
areas of the film donor device 241. The laser reaches the
light-to-heat conversion layer of the film donor device 241 through
the base substrate. The light-to-heat conversion layer converts the
light energy into thermal energy, generating heat. The heat is
transferred to selected portions of the transferable layer. With
this process, the portions of the transferable layer are released
from the film donor device 241 and transferred to the intermediate
device 250. In another embodiment where no contact frame is used,
laser is selectively irradiated onto certain portions of the top
surface of the film donor device 241.
[0073] Subsequently, in step 850, the film donor device 241 is
removed from over the intermediate device 250, leaving portions of
the transferable layer on the top surface of the intermediate
device 250. The film donor device 241 may be removed using the same
moving mechanism as that used in the step 820.
[0074] Referring to FIGS. 9A-9F, an intermediate device 250 is
introduced into a transfer chamber 900. The intermediate device 250
is placed on an end-effector 910 of an robot arm 920 in the
transfer chamber 900. Subsequently, the intermediate device 250 is
transported into a LITI chamber 210, as shown in FIG. 9B. Then, the
intermediate device 250 is placed on a substrate support 260, as
shown in FIG. 9C.
[0075] Next, a film donor device 241 is placed on the end effector
910, as shown in FIG. 9C. Subsequently, the film donor device 241
is introduced into the LITI chamber 210, as shown in FIG. 9D. The
film donor device 241 is vertically aligned with the intermediate
device 250. Then, the film donor device 241 is moved down onto the
intermediate device 250, as shown in FIG. 9E. The end-effector 910
is then retrieved from the LITI chamber 210. Subsequently, a gate
valve 930 is shut to provide a closed reaction chamber. In one
embodiment, a vacuum atmosphere may be maintained throughout the
transfer chamber and the LITI chamber during these steps.
[0076] Optionally, a contact frame may be provided over the film
donor device. In FIG. 9F, the contact frame 230 is moved down over
the film donor device 241. The contact frame 230 provides a weight
over the film donor device 241. The contact frame 230 may
facilitate making a close contact between the film donor device 241
and the intermediate device 250. In other embodiments, the contact
frame may be omitted.
[0077] Next, a magnetic force is provided to make a close contact
between the intermediate device and the film donor device. The
magnetic force may be generated by magnetic materials positioned in
two of the LITI apparatus components: one below the transferable
layer and the other over the transferable layer as described above.
A skilled artisan will appreciate that the magnetic material may be
provided in certain other components, depending on the design of a
LITI apparatus. In all of the foregoing embodiments, the magnetic
force is exerted between the intermediate device and the film donor
device in a sufficient strength to make a contact without air gaps
or bubbles therebetween. Details of the magnetic material positions
and configurations are as described above with respect to the LITI
apparatus.
[0078] FIGS. 10A-10D are cross-sectional views illustrating how a
transferable layer is transferred onto an intermediate device. The
illustrated intermediate device is a partially fabricated organic
light emitting device 400. In the illustrated embodiment, magnetic
materials are positioned in the intermediate device and the film
donor device. In other embodiments, the magnetic materials may be
provided in other components of the LITI apparatus as described
above.
[0079] Referring to 10A, an intermediate device 400 includes a thin
film transistor (TFT) structure 411, a magnetic layer 410, an
electrode 420, and a pixel partitioning layer 430. A portion 412 of
the electrode 420 is exposed through the pixel partitioning layer
430. An organic layer will be formed on the exposed portion 412 as
will be better understood from later descriptions.
[0080] Next, as shown in FIG. 10B, a film donor device 600 is
placed over the intermediate device 400. The film donor device 600
includes a base substrate 601, a magnetic layer 605, a
light-to-heat conversion layer 602, an intermediate layer 603, and
a transferable layer 604 as described above with respect to FIG.
6B. The transferable layer 604 is at least partially in contact
with a top surface of the pixel partitioning layer 430, as shown in
FIG. 10B. During this step, a magnetic force is exerted between the
film donor device 600 and the intermediate device 400.
[0081] Then, laser is irradiated onto a selected portion of the
film donor device 600. The selected portion is positioned over the
exposed portion 412 of the electrode 420. The laser passes through
the base substrate and the magnetic layer 605, and reaches the
light-to-heat conversion layer 602. The light-to-heat conversion
layer 602 converts the light energy into thermal energy, generating
heat. The heat is transferred to the transferable layer 604 via the
intermediate layer 603.
[0082] Then, upon receiving the heat, a portion of the transferable
layer 604 is delaminated from the film donor device 600 and comes
in contact with the exposed portion 412 of the electrode 420, as
shown in FIG. 10C. In the illustrated embodiment, portions of the
conversion layer 602, the intermediate layer 603 and the
transferable layer 604 are separated from the magnetic layer 605.
In other embodiments, only the transferable layer 604 may be
separated from the film donor device 600.
[0083] Subsequently, as shown in FIG. 10D, the film donor device
600 is removed from over the intermediate device 400. After this
step, only a portion 604a of the transferable layer remains on the
intermediate device 400.
[0084] In the embodiments described above, a magnetic force is used
to provide a close contact between the film donor device and the
intermediate device. This configuration, unlike suctioning, does
not need air pressure in the LITI chamber. Therefore, the LITI
process can be performed in a vacuum atmosphere. Since processes
performed prior to or subsequent to the LITI process are typically
also carried out in a vacuum atmosphere, the LITI process can be
performed without breaking vacuum throughout the processes. The
vacuum atmosphere may be maintained from the process of depositing
the hole injection layer(HIL) to the process of depositing the
second electrode layer. In addition, the LITI process reduces
occurrence of impurities or gaps between the donor film and the
intermediate device. This improves a lifetime, yield, and
reliability of the resulting electronic device.
[0085] Although various embodiments of the present invention have
been shown and described, it will be appreciated by those
technologists in the art that changes might be made in these
embodiments without departing from the principles and spirit of the
invention, the scope of which is defined in the claims and their
equivalents.
* * * * *