U.S. patent application number 16/756100 was filed with the patent office on 2021-06-24 for thin film electrode separation method using thermal expansion coefficient.
This patent application is currently assigned to OSONG MEDICAL INNOVATION FOUNDATION. The applicant listed for this patent is OSONG MEDICAL INNOVATION FOUNDATION. Invention is credited to Jin-Woo AHN, Ha-Chul JUNG, Young-Jin KIM, Seung-A LEE, Ha Na PARK.
Application Number | 20210193452 16/756100 |
Document ID | / |
Family ID | 1000005473298 |
Filed Date | 2021-06-24 |
United States Patent
Application |
20210193452 |
Kind Code |
A1 |
JUNG; Ha-Chul ; et
al. |
June 24, 2021 |
THIN FILM ELECTRODE SEPARATION METHOD USING THERMAL EXPANSION
COEFFICIENT
Abstract
In a thin film electrode separation method using thermal
expansion coefficient, a first solution is coated on a substrate.
The first solution coated on the substrate is hardened. The
substrate is left in a predetermined time, to form a first thin
film having a first thermal expansion coefficient on the substrate.
A photoresist is coated on the substrate having the thin film
formed thereon. The photoresist coated on the substrate is
hardened, to form a photoresist film having a second thermal
expansion coefficient. A metal and a passivation layer are formed
on the photoresist film. The photoresist film is detached from the
first thin film, using difference of a thermal expansion
coefficient between the photoresist film and the first thin
film.
Inventors: |
JUNG; Ha-Chul; (Cheongju-si,
KR) ; KIM; Young-Jin; (Cheongju-si, KR) ; AHN;
Jin-Woo; (Cheongju-si, KR) ; LEE; Seung-A;
(Seoul, KR) ; PARK; Ha Na; (Cheongju-si,
KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
OSONG MEDICAL INNOVATION FOUNDATION |
Cheongju-si |
|
KR |
|
|
Assignee: |
OSONG MEDICAL INNOVATION
FOUNDATION
Cheongju-si
KR
|
Family ID: |
1000005473298 |
Appl. No.: |
16/756100 |
Filed: |
August 7, 2018 |
PCT Filed: |
August 7, 2018 |
PCT NO: |
PCT/KR2018/008921 |
371 Date: |
April 14, 2020 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01L 21/324 20130101;
H01L 21/027 20130101; H01L 21/768 20130101 |
International
Class: |
H01L 21/027 20060101
H01L021/027; H01L 21/324 20060101 H01L021/324; H01L 21/768 20060101
H01L021/768 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 5, 2017 |
KR |
10-2017-0165750 |
Claims
1. A thin film electrode separation method comprising: coating a
first solution on a substrate; hardening the first solution coated
on the substrate; leaving the substrate in a predetermined time, to
form a first thin film having a first thermal expansion coefficient
on the substrate; coating a photoresist on the substrate having the
thin film formed thereon; hardening the photoresist coated on the
substrate, to form a photoresist film having a second thermal
expansion coefficient; forming a metal and a passivation layer on
the photoresist film; and detaching the photoresist film from the
first thin film, using difference of a thermal expansion
coefficient between the photoresist film and the first thin
film.
2. The method of claim 1, wherein in coating the first solution on
the substrate, the first solution is coated on the substrate via a
spin coating.
3. The method of claim 1, wherein in hardening the first solution,
the substrate on which the first solution is coated is disposed
over a hot plate, and a plurality of hardening processes with
various kinds of temperatures and times is performed.
4. The method of claim 3, wherein in hardening the first solution,
heating the substrate on which the first solution is coated, with a
temperature of about 60.degree. C. during about 30 mins; heating
the substrate on which the first solution is coated, with a
temperature of about 80.degree. C. during about 30 mins; heating
the substrate on which the first solution is coated, with a
temperature of about 150.degree. C. during about 30 mins; heating
the substrate on which the first solution is coated, with a
temperature of about 230.degree. C. during about 30 mins; and
heating the substrate on which the first solution is coated, with a
temperature of about 300.degree. C. during about 30 mins.
5. The method of claim 1, wherein the first solution is a solution
of temporary polyimide (TPI).
6. The method of claim 5, wherein the first thermal expansion
coefficient of the first thin film is about 3, and the second
thermal expansion coefficient of the photoresist film is not less
than about 50.
7. The method of claim 1, wherein in detaching the photoresist film
from the first thin film, a laser or a cutter is used for forming a
scratch at a side of the photoresist film, and then the photoresist
film is detached using a detaching device.
Description
BACKGROUND
1. Field of Disclosure
[0001] The present disclosure of invention relates to a thin film
electrode separation method using thermal expansion coefficient,
and more specifically the present disclosure of invention relates
to a thin film electrode separation method from a substrate using
difference of thermal expansion coefficient between temporary
polyimide (TPI) with a photoresist.
2. Description of Related Technology
[0002] In manufacturing a semiconductor apparatus using a
conventional semiconductor substrate, a detaching process in which
a photoresist coated on a surface of the semiconductor substrate is
detached from the surface of the semiconductor substrate is
performed.
[0003] For example, as disclosed in Koran laid-open patent No.
10-2013-0034480, an etching process is used for detaching the
photoresist from the surface of the substrate. Here, in the etching
process, the photoresist is coated on the substrate to form a film,
the photoresist is exposed and patterned via a lithographic
process, and then the substrate is removed via a wet or dry etching
process. However, the above mentioned etching process has low
economic efficiency and the photoresist film may be damaged in the
etching process.
[0004] Alternatively, as the conventional detaching process, an
adhesive tape is provided between the photoresist film and the
substrate, for the detaching. Here, the adhesive tape like kepton
is attached on the substrate, the photoresist is coated on the
substrate to form a film, the photoresist is patterned via the
lithographic process, and then the photoresist film is detached
using the adhesive tape. However, a thickness of the photoresist
film is about several .mu.m or hundreds of .mu.m, and thus the
photoresist film may be easily damaged due to a physical force
generated in the detaching using the adhesive tape.
[0005] Related prior arts are Korean laid-open Patent No.
10-2007-0067442, Korean laid-open Patent No. 10-2012-0011608, and
Korean laid-open Patent No. 10-2013-0034480.
SUMMARY
[0006] The present invention is developed to solve the
above-mentioned problems of the related arts. The present invention
provides a thin film electrode separation method from a substrate
more easily, using difference of thermal expansion coefficient
between temporary polyimide (TPI) with a photoresist.
[0007] According to an example embodiment, in the method, a first
solution is coated on a substrate. The first solution coated on the
substrate is hardened. The substrate is left in a predetermined
time, to form a first thin film having a first thermal expansion
coefficient on the substrate. A photoresist is coated on the
substrate having the thin film formed thereon. The photoresist
coated on the substrate is hardened, to form a photoresist film
having a second thermal expansion coefficient. A metal and a
passivation layer are formed on the photoresist film. The
photoresist film is detached from the first thin film, using
difference of a thermal expansion coefficient between the
photoresist film and the first thin film.
[0008] In an example, in coating the first solution on the
substrate, the first solution may be coated on the substrate via a
spin coating.
[0009] In an example, in hardening the first solution, the
substrate on which the first solution is coated may be disposed
over a hot plate, and a plurality of hardening processes with
various kinds of temperatures and times may be performed.
[0010] In an example, in hardening the first solution, the
substrate on which the first solution is coated, may be heated with
a temperature of about 60.degree. C. during about 30 mins. The
substrate on which the first solution is coated, may be heated with
a temperature of about 80.degree. C. during about 30 mins. The
substrate on which the first solution is coated, may be heated with
a temperature of about 150.degree. C. during about 30 mins. The
substrate on which the first solution is coated, may be heated with
a temperature of about 230.degree. C. during about 30 mins. The
substrate on which the first solution is coated, may be heated with
a temperature of about 300.degree. C. during about 30 mins.
[0011] In an example, the first solution may be a solution of
temporary polyimide (TPI).
[0012] In an example, the first thermal expansion coefficient of
the first thin film may be about 3, and the second thermal
expansion coefficient of the photoresist film may be not less than
about 50.
[0013] In an example, in detaching the photoresist film from the
first thin film, a laser or a cutter may be used for forming a
scratch at a side of the photoresist film, and then the photoresist
film may be detached using a detaching device.
[0014] According to the present example embodiments, the TPI thin
film and the photoresist film are easily detached from each other,
using a thermal stress due to the difference of the thermal
expansion coefficient, and thus the substrate and the TPI thin film
may be less damaged and detached.
[0015] In addition, massive water resources and waste liquor
treating processes are unnecessary to remove the photoresist film,
and thus environmental pollution may be prevented.
[0016] In addition, additional processes for removing the
photoresist film are unnecessary, and thus the entire processes are
decreased and productivity may be increased.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] FIG. 1 is a flow chart showing a thin film electrode
separation method using thermal expansion coefficient according to
an example embodiment of the present invention; and
[0018] FIG. 2A, FIG. 2B, FIG. 2C, FIG. 2D, FIG. 2E and FIG. 2F are
process views illustrating the method of FIG. 1.
DETAILED DESCRIPTION
[0019] The invention is described more fully hereinafter with
Reference to the accompanying drawings, in which embodiments of the
invention are shown. This invention may, however, be embodied in
many different forms and should not be construed as limited to the
embodiments set forth herein. Rather, these embodiments are
provided so that this disclosure will be thorough and complete, and
will fully convey the scope of the invention to those skilled in
the art. In the drawings, the size and relative sizes of layers and
regions may be exaggerated for clarity.
[0020] It will be understood that, although the terms first,
second, third etc. may be used herein to describe various elements,
components, regions, layers and/or sections, these elements,
components, regions, layers and/or sections should not be limited
by these terms. These terms are only used to distinguish one
element, component, region, layer or section from another region,
layer or section. Thus, a first element, component, region, layer
or section discussed below could be termed a second element,
component, region, layer or section without departing from the
teachings of the present invention.
[0021] Spatially relative terms, such as "beneath," "below,"
"lower," "above," "upper" and the like, may be used herein for ease
of description to describe one element or feature's relationship to
another element(s) or feature(s) as illustrated in the figures. It
will be understood that the spatially relative terms are intended
to encompass different orientations of the device in use or
operation in addition to the orientation depicted in the figures.
For example, if the device in the figures is turned over, elements
described as "below" or "beneath" other elements or features would
then be oriented "above" the other elements or features. Thus, the
term "below" can encompass both an orientation of above and below.
The device may be otherwise oriented (rotated 90 degrees or at
other orientations) and the spatially relative descriptors used
herein interpreted accordingly.
[0022] The terminology used herein is for the purpose of describing
particular embodiments only and is not intended to be limiting of
the invention. As used herein, the singular forms "a," "an" and
"the" are intended to include the plural forms as well, unless the
context clearly indicates otherwise. It will be further understood
that the terms "comprises" and/or "comprising," when used in this
specification, specify the presence of stated features, integers,
steps, operations, elements, and/or components, but do not preclude
the presence or addition of one or more other features, integers,
steps, operations, elements, components, and/or groups thereof.
Unless otherwise defined, all terms (including technical and
scientific terms) used herein have the same meaning as commonly
understood by one of ordinary skill in the art to which this
invention belongs. It will be further understood that terms, such
as those defined in commonly used dictionaries, should be
interpreted as having a meaning that is consistent with their
meaning in the context of the relevant art and will not be
interpreted in an idealized or overly formal sense unless expressly
so defined herein.
[0023] The invention is described more fully hereinafter with
reference to the accompanying drawings, in which embodiments of the
invention are shown.
[0024] FIG. 1 is a flow chart showing a thin film electrode
separation method using thermal expansion coefficient according to
an example embodiment of the present invention. FIG. 2A, FIG. 2B,
FIG. 2C, FIG. 2D, FIG. 2E and FIG. 2F are process views
illustrating the method of FIG. 1.
[0025] Although not shown in the figure, in the present example
embodiment, a substrate 100 is cleaned with a tetramethyl ammonium
hydroxide (TMAH), before the first solution 10 is coated. For
example, the first solution 10 may be a temporary polyimide (TPI)
solution, and the TPI solution has relatively very lower viscosity
and thus a coating thickness is relatively very thinner. Thus, the
substrate 100 should be cleaned before the coating, for coating
with TPI solution more efficiently.
[0026] The TPI solution used as the first solution in the present
example embodiment, is a low viscosity liquid material having a
relatively lower thermal expansion coefficient, different from
polyimide (PI) conventionally used in the semiconductor process. In
addition, the TPI solution is chemically stably, and when hardened,
the TPI solution may be very flexible.
[0027] Then, referring to FIG. 1 and FIG. 2A, the first solution 10
is coated on the substrate 100 (step S100).
[0028] The substrate 100 may be one selected from the group
consisting of silicon, glass, quartz, metal and plastic.
[0029] The first solution 10 is coated on the substrate 100 via a
spin coating process. Here, the first solution 10 is coated on the
substrate 100 using a spin coater 20, and the spin coating process
is performed with about 1000 rpm and in about 30 seconds.
[0030] Then, referring to FIG. 1 and FIG. 2B, the first solution 10
coated on the substrate 100 is hardened step by step (step
S200).
[0031] Here, the substrate 100 on which the first solution 10 is
coated is disposed over a hot plate 30, and then is heated step by
step. The heating is performed step by step with different
temperature and time conditions, not with a single fixed condition
of temperature and time.
[0032] For example, using the hot plate 30, the heating may be
performed with a temperature of about 60.degree. C. during about 30
minutes, then the heating may be performed with a temperature of
about 80.degree. C. during about 30 minutes, then the heating may
be performed with a temperature of about 150.degree. C. during
about 30 minutes, then the heating may be performed with a
temperature of about 230.degree. C. during about 30 minutes, and
then the heating may be performed with a temperature of about
300.degree. C. during about 30 minutes.
[0033] Accordingly, after the above mentioned step by step
hardening, referring to FIG. 1 and FIG. 2C, the substrate 100 is
left with a predetermined time, to form a first thin film 11 on the
substrate 100 (step S300).
[0034] Here, the first thin film 11 has a first thermal expansion
coefficient which may be about 3. Considering a thermal expansion
coefficient of conventional polyimide (PI) is between about 19 and
about 40, the first thin film 11 which is a TPI thin film, may have
the thermal expansion coefficient much lower than that of the
conventional PI.
[0035] After the thin film 11 is formed on the substrate 100,
referring to FIG. 1 and FIG. 2D, a photoresist 200 is coated on the
substrate 100 (step S400).
[0036] Here, the first thin film 11 is formed on the substrate 100,
and thus the photoresist 200 is substantially coated on the first
thin film 11.
[0037] In addition, the photoresist 200 may be formed as a
photoresist film which is detached from the substrate, as mentioned
below, and thus may be a base of an electrode.
[0038] Then, referring to FIG. 1 and FIG. 2E, the photoresist
coated on the substrate 100 is hardened, to form a photoresist film
(step S500). Here, only heat may be provided to the substrate 100
via a heat irradiator 40, or heat and UV may be provided or
irradiated to the substrate at the same time, for the
hardening.
[0039] The photoresist film 201 has a second thermal expansion
coefficient, and the second thermal expansion coefficient may be
not less than about 50.
[0040] Thus, the photoresist film 201 has the thermal expansion
coefficient different from that of the first thin film 11, and the
difference of the thermal expansion coefficient between the
photoresist film 201 and the first thin film 11 is relatively
large.
[0041] Then, referring to FIG. 1 and FIG. 2F, a metal 300 and a
passivation layer 400 are sequentially formed on the photoresist
film 201. The metal 300 and the passivation layer 400 are
sequentially formed on the photoresist film 201, to complete an
electrode 70. Thus, the electrode 70 includes the photoresist film
201, the metal 300 and the passivation layer 400.
[0042] Here, the metal 300 may include at least one of nickel (Ni),
palladium (Pd), cobalt (Co), tungsten (W), titanium (Ti), and so
on, but not limited thereto.
[0043] In addition, the passivation layer 400 may include at least
one of a metal oxide, a carbon nanotube, a polymer electrolyte, a
glass fiber and so on, but not limited thereto. The metal oxide may
be a wire, tube, or particle type metal oxide (for example, Al2O3
or silicon oxide), and may be a silver nanowire, a copper mesh, a
silver mesh, a silver salt and so on. The above mentioned material
may be used only or at least two materials may be used
together.
[0044] As illustrated in the figure, each of the metal 300 and the
passivation layer 400 has a rectangular plate shape, but the shape
of the metal 300 and the passivation layer 400 may be variously
changed, and not limited thereto as illustrated in the figure.
[0045] Then, referring to FIG. 1 and FIG. 2G, to detach the
electrode 70 from the substrate 100, the photoresist film 201 is
detached from the first thin film 11 (step S700). Here, the
difference of the thermal expansion coefficient between the
photoresist film 201 and the first thin film 11 is important.
[0046] As mentioned above, the thermal expansion coefficient of the
first thin film 11 is about 3, and that of the photoresist film 201
is not less than about 50. Thus, the thermal expansion coefficient
of the first thin film 11 is different from that of the photoresist
film 201, and the difference between the thermal expansion
coefficient of the first thin film 11 and that of the photoresist
film 201 is relatively large.
[0047] The above difference of the thermal expansion coefficient
causes a thermal stress, and thus a thermal stress may be caused
between the first thin film 11 and the photoresist film 201.
[0048] Accordingly, due to the thermal stress caused by the
difference of the thermal expansion coefficient, an interfacial
adhesion between the first thin film 11 and the photoresist film
201 is weakened, and thus the first thin film 11 and the
photoresist film 201 may be detached more easily.
[0049] Here, as the thermal stress increases more than the
interfacial adhesion, the first thin film 11 and the photoresist
film 201 are detached from each other. As the thermal stress due to
the difference of the thermal expansion coefficient increases, the
adhesion between the first thin film 11 and the photoresist film
201 is rapidly weakened, and thus the first thin film 11 and the
photoresist film 201 are ready to be physically separated.
[0050] For the detaching of the first thin film 11 and the
photoresist film 201, a laser or a cutter may be used.
[0051] The laser is irradiated or the cutter is inserted into a
side of an interfacial surface between the first thin film 11 and
the photoresist film 201, and thus the side thereof is firstly
exfoliated. Then, a detaching device such as pincettes or forceps,
is used to detach the exfoliated side first, and then the
photoresist film 201 is entirely detached from the first thin film
11.
[0052] Accordingly, the physical exfoliation is caused between the
interfacial surface between the first thin film 11 and the
photoresist film 201, using the laser or the cutter, and thus a
conventional chemical detaching process may be omitted. Thus, the
electrode 70 may be less damaged, and the detaching process may be
performed more easily.
[0053] After the photoresist film 201 is detached from the first
thin film 11, the electrode 70 on the photoresist fil 201 is
detached from the first thin film 11, and thus the electrode 70 is
completely manufactured.
[0054] Accordingly, the electrode is formed on the photoresist film
201, and thus the electrode may be used more efficiently and easily
to manufacture a flexible device such as a stretchable device, a
wearable device and so on. In manufacturing the flexible device,
when the electrode is directly formed on a flexible substrate, a
processing error in forming the electrode increases, and thus a
relatively hard substrate is used for forming the electrode on the
substrate and the hard substrate is removed. Thus, in the method of
the present example embodiment, when removing the hard substrate,
the detaching the electrode from the hard substrate may be
performed more easily and the electrode is less damaged.
[0055] According to the present example embodiments, the TPI thin
film and the photoresist film are easily detached from each other,
using a thermal stress due to the difference of the thermal
expansion coefficient, and thus the substrate and the TPI thin film
may be less damaged and detached.
[0056] In addition, massive water resources and waste liquor
treating processes are unnecessary to remove the photoresist film,
and thus environmental pollution may be prevented.
[0057] In addition, additional processes for removing the
photoresist film are unnecessary, and thus the entire processes are
decreased and productivity may be increased.
[0058] Although the exemplary embodiments of the present invention
have been described, it is understood that the present invention
should not be limited to these exemplary embodiments but various
changes and modifications can be made by one ordinary skilled in
the art within the spirit and scope of the present invention as
hereinafter claimed.
REFERENCE NUMERALS
TABLE-US-00001 [0059] 10: first solution 11: first thin film 20:
spin coater 30: hot plate 40: heat irradiator 70: electrode 100:
substrate 200: photoresist 201: photoresist film 300: metal 400:
passivation layer
* * * * *