U.S. patent application number 12/010037 was filed with the patent office on 2008-07-03 for organic semiconductor element having multi protection layers and process of making the same.
This patent application is currently assigned to INDUSTRIAL TECHNOLOGY RESEARCH INSTITUTE. Invention is credited to Cheng-Chung Hsieh, Tarng-Shiang Hu, Liang-Ying Huang, Cheng-Chung Lee.
Application Number | 20080157070 12/010037 |
Document ID | / |
Family ID | 36814769 |
Filed Date | 2008-07-03 |
United States Patent
Application |
20080157070 |
Kind Code |
A1 |
Hsieh; Cheng-Chung ; et
al. |
July 3, 2008 |
Organic semiconductor element having multi protection layers and
process of making the same
Abstract
An organic semiconductor element having multi protection layers
and process of making the same are provided. Firstly, forming a
first protection layer on the thin film transistor. Next, forming a
second protection layer which is thick enough to serve as the photo
spacers on said first protection layer. The multi protection layers
are then grown on said organic thin film transistor, so as to
enable the second protection layer to have the additional function
of the photo spacers by the patterning process. Thus the organic
thin film transistor can be prevented from being damaged, and
achieving the simplification of the manufacturing process and the
reduction of the production cost.
Inventors: |
Hsieh; Cheng-Chung;
(Hsinchu, TW) ; Huang; Liang-Ying; (Hsinchu,
TW) ; Hu; Tarng-Shiang; (Hsinchu, TW) ; Lee;
Cheng-Chung; (Hsinchu, TW) |
Correspondence
Address: |
RABIN & Berdo, PC
1101 14TH STREET, NW, SUITE 500
WASHINGTON
DC
20005
US
|
Assignee: |
INDUSTRIAL TECHNOLOGY RESEARCH
INSTITUTE
Hsinchu
TW
|
Family ID: |
36814769 |
Appl. No.: |
12/010037 |
Filed: |
January 18, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
11149158 |
Jun 10, 2005 |
7344914 |
|
|
12010037 |
|
|
|
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Current U.S.
Class: |
257/40 ;
257/E51.001 |
Current CPC
Class: |
H01L 51/107 20130101;
H01L 51/0545 20130101; H01L 51/0021 20130101 |
Class at
Publication: |
257/40 ;
257/E51.001 |
International
Class: |
H01L 51/00 20060101
H01L051/00 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 16, 2005 |
TW |
094104491 |
Claims
1. An organic semiconductor element having multi production layers,
including: an organic thin film transistor; a first protection
layer formed on said organic thin film transistor; and a second
protection layer formed on said first protection layer through a
patterning process, said second protection layer is of sufficient
thickness to serve as a photo spacer.
2. The organic semiconductor element having multi production layers
of claim 1, wherein the thickness of said second protection layer
is over 4 .mu.m.
3. The organic semiconductor element having multi production layers
of claim 1, further comprising a substrate, said substrate is kept
a distance apart from said organic thin film transistor and said
first protection layer by said second protection layer.
4. The organic semiconductor element having multi production layers
of claim 1, wherein said second protection layer is provided with a
contact hole, which is used to penetrate said second protection
layer and said first protection layer thus to expose said organic
thin film transistor.
5. The organic semiconductor element having multi production layers
of claim 4, further comprising an electrode, formed on top of said
second protection layer, and is electrically connected to said thin
film transistor via said contact hole.
6. The organic semiconductor element having multi production layers
of claim 1, wherein said organic thin film transistor is selected
from the group consisted of the bottom contact organic thin film
transistor, the top contact organic thin film transistor, the
bottom gate organic thin film transistor, and the top gate organic
thin film transistor.
7. The organic semiconductor element having multi production layers
of claim 1, wherein the formation method of said first protection
layer and said second protection layer is selected from the group
consisted of solution treatment method and the vapor deposition
method.
8. The organic semiconductor element having multi production layers
of claim 7, wherein said first protection layer and said second
protection layer are formed by the same process using different
solutions.
9. The organic semiconductor element having multi production layers
of claim 7, wherein the solution treatment process is selected from
the group consisting of spin coating, screen printing, inject
printing, and spinless coating.
10. The organic semiconductor element having multi production
layers of claim 7, wherein the vapor deposition method is selected
from the group consisting of the chemical vapor deposition (CVD)
method, the organic chemical vapor deposition (OCVD) method, and
the co-evaporation method.
11. The organic semiconductor element having multi production
layers of claim 1, wherein said second protection layer is made of
a developable material.
12. The organic semiconductor element having multi production
layers of claim 11, wherein the patterning process is realized
through the photolithography process.
13. The organic semiconductor element having multi production
layers of claim 11, wherein the developable material is the SU-8
2002 photoresist.
14. The organic semiconductor element having multi production
layers of claim 1, wherein the patterning process is realized
through the laser processing.
15. The organic semiconductor element having multi production
layers of claim 1, wherein said protection layer is made of the
Dichromated Poly Vinyl Alcohol (DCPVA).
16-30. (canceled)
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The invention relates to an organic semiconductor element
and a method of its manufacturing, in particular to an organic
semiconductor element having multi protection layers and process of
making the same.
[0003] 2. Related Art
[0004] The organic semiconductor device has been the hot topic and
keen interest of the scientific research in recent years. With
regard to the organic thin film transistor (OFET), its unique and
advanced technology of flexible substrate has already gained a most
prominent and promising place in this field. The thin film
transistor is mainly made of organic material, and it is essential
and indispensable to the roll-to-roll (R2R) manufacturing process,
due to its basic property of intrinsic flexibility. The application
and utilization of the organic thin film transistor in
cooperation/coordination with the liquid crystal display panel may
further expand the scope of application of the organic thin film
transistors.
[0005] In the application of the organic thin film transistor in
cooperation with the liquid crystal display panel, the processes of
manufacturing the protection layers and the photo spacers are
essential. In the past, the photo spacers were formed on the
protection layer of the organic thin film transistor after its
completion, by means of the spraying method. Due to the fact that
it is extremely difficult to have effective control of the spray
distribution density, the application of this process is liable to
lead to the local concentration and condensation of the photo
spacers, thus affecting the evenness of the surface of the
substrate and the overall quality of the image. In addition, the
requisition and installation of the spraying device increase the
production cost significantly.
[0006] Therefore, the acquisition of a proper solution to this
problem to improve and optimize the manufacturing process of the
protection layers and the photo spacers of the organic
semiconductor element, for example, of the above-mentioned organic
thin film transistor, is the most important task for research and
development in this field.
SUMMARY OF THE INVENTION
[0007] In view of the above-mentioned problems and shortcomings of
the prior art, the object of the invention is to provide an organic
semiconductor element, having multi protection layers, and its
manufacturing method, which are utilized to solve the overall
problem of the prior art by forming the multi protection layers on
the organic thin film transistor, wherein the second protection
layer is of sufficient thickness, to enable the multi protection
layers to effectively protect the organic thin-film-transistor
through the patterning process. In addition, the second protection
layer can be utilized as photo spacers, so as to eliminate the
process of disposing the photo spacers and solve the problem of the
prior art.
[0008] To achieve the above-mentioned objective, the invention
provides an organic semiconductor element having multi protection
layers, comprising a thin film transistor, a first protection
layer, and a second protection layer, wherein the first protection
layer is formed on the organic thin film transistor, and the second
protection layer is formed on the first protection layer by the
patterning process, such, that the second protection layer is of
sufficient thickness to serve as the photo spacers. Thus, the
second protection layer is capable of providing both functions of
the protection layer and the photo spacers, so as to achieve the
purpose of reducing the manufacturing cost.
[0009] Besides, the invention provides a process of making for the
organic semiconductor element having multi protection layers,
comprising the following steps. Firstly, providing an organic thin
film transistor; then, forming a first protection layer on the thin
film transistor. Subsequently, forming the second protection layer
on the first protection layer, such, that the second protection
layer is thick enough to be utilized as photo spacers. Finally,
patterning the second protection layer to form the organic
semiconductor element having multi protection layers.
[0010] In the above-mentioned organic semiconductor element, the
second protection layer is used to separate the substrate from the
first protection layer of the organic thin film transistor, thus
replacing the step of the prior art of spraying the photo spacers
on the protection layer after the completion of the protection
layer, so as to simply the manufacturing process, so that the photo
spacers can be distributed more evenly on the substrate of an
organic thin film transistor. Alternatively, the top ITO (Indium
Tin Oxide) electrode type of the organic thin film transistor
substrate could be utilized in the invention, such, that the
contact hold is made in the second protection layer, which is used
to penetrate the second protection layer and the first protection
layer to expose the organic thin film transistor. Therefore, the
second protection layer is capable of having both the functions of
an over-coat layer and a protection layer, and finally the
electrode is formed on top of the second protection layer and
connected electrically to the organic thin film transistor through
the contact hole.
[0011] Further scope of the applicability of the present invention
will become apparent from the detailed description given
hereinafter. However, it should be understood that the detailed
description and specific examples, while indicating preferred
embodiments of the present invention, are given by way of
illustration only, since various changes and modifications within
the spirit and scope of the invention will become apparent to those
skilled in the art from this detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] The present invention will become more fully understood from
the detailed description given below, which is for illustration
only and thus is not limitative of the present invention,
wherein:
[0013] FIG. 1 is a flowchart of the process of making the organic
semiconductor element having multi protection layers according to
the invention;
[0014] FIG. 2A to 2D are the schematic diagrams illustrating the
cross sections of mentioned element in the various manufacturing
processes of the organic semiconductor element, having multi
protection layers according to the first embodiment of the
invention;
[0015] FIG. 2E is a schematic diagram of the cross section of the
organic semiconductor element, having multi protection layers as
shown in FIG. 2D after the inclusion of the substrate;
[0016] FIGS. 3A & 3B are the ID-VD characteristic curves of
mentioned organic, semiconductor element respectively before and
after the formation of the first protection layer, using the
Dichromated Poly Vinyl Alcohol (DCPVA) according to the first
embodiment of the invention;
[0017] FIGS. 4A & 4B are the I.sub.D-V.sub.D characteristic
curves of the organic semiconductor element, respectively before
and after the formation of the first protection layer, using
parylene according to the first embodiment of the invention;
and
[0018] FIG. 5 is the schematic cross section diagram illustrating
the organic semiconductor element having multi protection layers
according to the second embodiment of the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0019] The purpose, construction, features, and functions of the
present invention can be appreciated and understood further through
the following detailed description with reference to the attached
drawings.
[0020] Refer to FIG. 1, which shows the system flowchart for the
process of making the organic semiconductor element having multi
protection layers according to the first embodiment of the
invention, mainly comprising the following steps. Firstly,
providing an organic thin film transistor (step 100). Next, forming
a first protection layer on the organic thin film transistor (step
110). Then, forming a second protection layer on the first
protection layer by means of the vapor deposition or the solution
treatment process (step 120), mentioned second protection layer
must be of sufficient thickness to serve as the photo spacers.
Finally, patterning the second protection layer (step 130), so as
to realize the organic semiconductor element having multi
protection layers.
[0021] In the following illustrations, the organic semiconductor
element having multi protection layers and the method of its
manufacturing are described in detail by the embodiments. Please
refer to FIG. 2A to 2D for the schematic diagrams illustrating the
cross sections of mentioned element in the various manufacturing
processes of the organic semiconductor element having multi
protection layers according to the first embodiment of the
invention.
[0022] As shown in FIG. 2A, firstly, a thin film transistor 10 is
formed on a substrate, mentioned thin film transistor 10 is
realized by growing sequentially a gate 12 (step 100). An
insulation layer 13, a source 14, a drain 15, and an organic
semiconductor layer 16 are on a substrate 11.
[0023] Next, as shown in FIG. 2B, the Dichromated Poly Vinyl
Alcohol (DCPVA) solution is applied on the organic thin film
transistor 10, which is used to form the first protection layer 20
after the exposure and baking processes.
[0024] Then, as shown in FIG. 2C, a negative photoresist SU-8 2002
is applied on the first protection layer 20 by means of spin
coating, to directly realize the second protection 30 of the
organic thin film transistor 10 having the thickness of 5
.mu.m.
[0025] Subsequently, as shown in FIG. 2D, the second protection
layer 30 is patterned through the photolithography process. Next,
after removing mentioned solution, the protection layer is exposed
to light by making use of a shadow mask having the exposed
channels.
[0026] Then, it is developed with Propylene Glycol Monomethyl Ether
Acetate (PMA) serving as the developing solution. Afterwards, it is
baked to dry the solution, so as to form the second protection
layer 30 composed of a plurality of photo spacer shapes on the
first protection layer 20, thus finally realizing the organic
semiconductor element 40 having multi protection layers of the
invention.
[0027] Now, refer to FIG. 2D for the detailed description of the
structure of the organic semiconductor element 40 having multi
protection layers. As shown in FIG. 2D, mentioned element 40 is
composed of an organic thin film transistor 10, a first protection
layer 20, and a second protection layer 30. The organic thin film
transistor 10 is composed of a gate 12, an insulation layer 13, a
source 14, a drain 15, and an organic semiconductor layer 16
sequentially formed on the organic thin film transistor 10. The
first protection layer 20 is formed on the organic thin film
transistor 10, and the second protection layer 30 is formed on the
first protection layer 20 by means of the patterning process, and
it must be thick enough to serve as photo spacers, with its
standard thickness reaching over 4 .mu.m (5 .mu.m in this
embodiment), so that the multi protection layers 10, having the
first protection layer 20 and the second protection layer 30, are
capable of achieving the effect of protecting the organic thin film
transistor 10.
[0028] Furthermore, as shown in FIG. 2E, since the second
protection layer 30 could be utilized as photo spacers to separate
the substrate 90 from the organic thin film transistor 10 and the
first protection layer 20 disposed thereon, as such replacing and
eliminating the subsequent process of applying the photo spacers as
previously done in the prior art, the photo spacers can be formed
more evenly on the organic thin film transistor 10.
[0029] As mentioned earlier, in the present embodiment, the second
protection layer 30 of the organic thin film transistor 10 is
composed of the patterns defined by the spin coating and
photolithography processes, and is thick enough to be served as
photo spacers. Besides, the equipment utilized in these processes
is the same as that utilized in the manufacturing process of the
protection layer of the prior art, namely, the two processes can be
merged into one single process, so that not only the manufacturing
process can be simplified, but the cost of the equipment and
production can also be significantly reduced. Moreover, since the
second layer 30 utilized as the photo spacer as defined by the
photolithography process indicates excellent uniformity, the
quality of the organic semiconductor elements produced is improved
significantly.
[0030] In the description of the above-mentioned organic
semiconductor element, the organic thin firm transistor TFT 10 may
be chosen from one of the following: the bottom contact type
organic TFT, the top contact type organic TFT, the bottom gate type
organic TFT, and the top gate type organic TFT. The first
protection layer 20 and the second protection layer 30 may be
formed by the vapor deposition process or the solution treatment
process using different solutions, wherein the vapor deposition
process may include: Chemical Vapor Deposition (CVD), Organic
Chemical Vapor Deposition (OCVD) or co-evaporation process, while
the solution treatment process may include: a spin coating process,
a screen printing process, a inject printing process, or a spinless
coating process. In addition, the developable material may be
utilized to define the patterns by means of the photolithography
process, or it may be utilized in cooperation with the shadow mask
or laser processing, so as to realize the patterned second
protection layer 30, having the functions of the photo spacers.
[0031] Subsequently, different materials are utilized to form the
first protection layer according to the embodiment of the
invention. Then, the protection layer is used to produce the
organic semiconductor element in cooperation/combination with
mentioned SU-8 2002 of the second protection layer, and is then
subjected to the various electric functional tests.
[0032] Firstly, upon the completion of the process of formation of
the first protection layer by making use of the Dichromated Poly
Vinyl Alcohol (DCPVA) and parylene, the negative photoresist
material SU-8 2002 is spin coated on mentioned first protection
layer at the first revolution speed 150 rpm for 20 seconds, and the
second revolution speed 300 rpm for 40 seconds respectively, to
form the second protection layer 30. Then, it is heated at
35.degree. C. in vacuum for 2 hours. Next, applying the shadow mask
is applied, evaporated with pentacene on mentioned second
protection layer. Then, it is exposed to light having the energy of
300 mill-joules. Afterwards, it is developed with Propylene Glycol
Monomethyl Ether Acetate (PMA) as the developing solution for one
minute.
[0033] Finally, it is heated at 70.degree. C. and 130.degree. C.
respectively for one hour, thus realizing the organic semiconductor
element having multi protection layers.
[0034] Now, please refer to FIG. 3A, FIG. 3B, FIG. 4A, and FIG. 4B,
which show the I.sub.D-V.sub.D characteristic curves of the organic
semiconductor element before and after the formation of the first
protection layer, by making use of the Dichromated Poly Vinyl
Alcohol (DCPVA) or parylene respectively. As shown in these
drawings, the electric property is better for the organic
semiconductor element having its first protection layer made of
DCPVA, since its I.sub.D-V.sub.D characteristic curves do not
indicate too many differences before and after the manufacturing
process. That means that the electric property of the organic
semiconductor element does not deteriorate after the manufacturing
process. However, the organic semiconductor element having its
first protection layer made of parylene indicates the tendency of
increasing threshold voltage along with the manufacturing process.
Therefore, it is determined that the organic semiconductor element,
having its first protection layer made of DCPVA, may have better
property and performance. Furthermore, the thickness of the second
protection layer made of SU-8 2002, disposed on the two kinds of
first protection layers, are both 5 .mu.m, thus able to be utilized
as the photo spacer of the organic thin film transistor.
[0035] On the other hand, when the top ITO (Indium Tin Oxide)
electrode is utilized in the organic semiconductor element, since
the ITO electrode is formed on top of the over-coat layer made of
photo-sensitive polymer, the ITO is connected electrically to the
drain of the organic thin film transistor through the contact hole
in the over-coat layer, as such the over-coat layer must be
extremely even, to avoid the deterioration of the electric property
of the ITO thin film, due to the unevenness of the over-coat layer.
According to the above-mentioned process of manufacturing, the
manufacturing process of the over-coat layer can be replaced and
eliminated, since the second protection layer thus produced may
serve both as over-coat layer and protection layer, as such it is
capable of providing a fairly even thin film surface for the top
ITO electrode to put thereon.
[0036] Subsequently, refer to FIG. 5 for the schematic diagram of
the cross section of the organic semiconductor element, having
multi protection layers according to the second embodiment of the
invention. As shown in FIG. 5, the organic semiconductor element
having multi protection layers comprises: an organic thin film
transistor 50, a first protection layer 60, a second protection
layer 70, and an electrode 80. Wherein the organic thin film
transistor 50 includes a gate 52, an insulation layer 53, a source
54, a drain 55, and an organic semiconductor layer 56, sequentially
formed on a substrate 51. The first protection layer 60 is formed
on the organic thin film transistor 50, and the second protection
layer 70 is formed on the first protection layer 60, such, that the
thickness of the second protection layer 70 must be greater than 4
.mu.m, and is used to form a contact hole 71 through the patterning
process. The contact hole is used to penetrate the second
protection layer 70 and the first protection 60, to expose the
organic thin film transistor 50. Finally, the electrode 80 is
formed on top of the second protection layer 70, and is
electrically connected to the drain 55 of the thin film transistor
50 via the contact hole 71. As such, the first protection layer 60
and the second protection layer 70 can be utilized to protect the
organic thin film transistor 50 from being damaged. Moreover, the
second protection layer 70 may also be utilized to achieve the
function of over-coat layer and have fairly good evenness.
[0037] Summing up the above, the organic semiconductor element
having multi protection layers and the method of its manufacturing
are realized through growing the patterned second protection layer
on the first protection layer, to form the multi protection layers
of the thin film transistor. The multi protection layers are
utilized to effectively protect the organic thin film transistor,
and its second protection layer can also be used as photo spacer,
to replace the subsequent process of disposing the photo spacers.
In addition, the second protection layer may also be utilized to
achieve the functions of both the protection layer and the
over-coat layer, to replace and eliminate the manufacturing process
of the over-coat layer according to the method of the invention.
Therefore, the organic semiconductor element having multi
protection layers and the method of its manufacturing can be
utilized to maximize the protection effects of the multi protection
layers, thus achieving the purpose of simplifying the manufacturing
process and reducing the production cost.
[0038] Knowing the invention thus described, it will be obvious
that the same may be varied in many ways. Such variations are not
to be regarded as a departure from the spirit and scope of the
present invention, and all such modifications as would be obvious
to one skilled in the art are intended to be included within the
scope of the following claims.
* * * * *