U.S. patent application number 15/247216 was filed with the patent office on 2016-12-15 for structure including thin primer film and method of producing said structure.
The applicant listed for this patent is TAIYO YUDEN CHEMICAL TECHNOLOGY CO., LTD.. Invention is credited to Kunihiko SHIBUSAWA.
Application Number | 20160361942 15/247216 |
Document ID | / |
Family ID | 47668599 |
Filed Date | 2016-12-15 |
United States Patent
Application |
20160361942 |
Kind Code |
A1 |
SHIBUSAWA; Kunihiko |
December 15, 2016 |
STRUCTURE INCLUDING THIN PRIMER FILM AND METHOD OF PRODUCING SAID
STRUCTURE
Abstract
One object is to provide a structure including a thin primer
film formed by a dry process and tightly bound to a
fluorine-containing silane coupling agent. In accordance with one
aspect, a structure according to an embodiment of the present
disclosure includes: a substrate; and a thin primer film containing
at least one substance selected from the group consisting of
silicon, titanium, aluminum, aluminum oxide, and zirconium and
formed on a surface of the substrate by a dry process.
Inventors: |
SHIBUSAWA; Kunihiko; (Gunma,
JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
TAIYO YUDEN CHEMICAL TECHNOLOGY CO., LTD. |
Gunma |
|
JP |
|
|
Family ID: |
47668599 |
Appl. No.: |
15/247216 |
Filed: |
August 25, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14237830 |
Mar 7, 2014 |
9469097 |
|
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PCT/JP2012/070529 |
Aug 10, 2012 |
|
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15247216 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C23C 14/04 20130101;
C23C 14/0605 20130101; C23C 16/517 20130101; B41N 1/247 20130101;
Y10T 428/24917 20150115; C23C 14/0641 20130101; C23C 14/081
20130101; C23C 16/401 20130101; C23C 16/56 20130101; Y10T 442/10
20150401; Y10T 428/24999 20150401; C23C 16/42 20130101; B41N 1/242
20130101; Y10T 428/24802 20150115; C23C 14/5846 20130101; B41C
1/147 20130101; B41F 15/34 20130101; C23C 16/405 20130101; C23C
28/042 20130101; C23C 16/34 20130101 |
International
Class: |
B41N 1/24 20060101
B41N001/24; B41C 1/14 20060101 B41C001/14 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 10, 2011 |
JP |
2011-174908 |
Feb 14, 2012 |
JP |
2012-029090 |
Claims
1. A stencil printing plate comprising: a substrate having formed
therein openings corresponding to a printing pattern; a thin primer
film formed directly or indirectly on the substrate by a dry
process and containing at least one substance selected from the
group consisting of silicon, titanium, aluminum, aluminum oxide,
and zirconium; and a coating layer formed on the thin primer film
and having water repellence and/or water and oil repellence.
2. The stencil printing plate of claim 1 wherein the thin primer
film further contains oxygen or nitrogen.
3. The stencil printing plate of claim 1 wherein the thin primer
film contains an Si oxide, a Ti oxide, or a Zr oxide.
4. The stencil printing plate of claim 1 wherein the coating layer
comprises a fluorine-containing coupling agent.
5. The stencil printing plate of claim 1 wherein the coating layer
comprises a fluorine-containing silane coupling agent.
6. The stencil printing plate of claim 1 wherein the coating layer
comprises: a first layer formed on the thin primer film and
composed mainly of a coupling agent capable of forming, with the
thin primer film, a hydrogen bonding and/or an --O-M bonding (M is
any one element selected from a group consisting of Si, Ti, Al, and
Zr) by condensation reaction; and a second layer formed on the
first layer and composed mainly of a water repellent material or a
water and oil repellent material.
7. The stencil printing plate of claim 6 wherein the coupling agent
is a coupling agent selected from a group consisting of silane
coupling agent, titanate-based coupling agent, aluminate-based
coupling agent, and zirconate-based coupling agent.
8. The stencil printing plate of claim 1 wherein an amorphous
carbon film substantially comprising carbon only or an amorphous
carbon film substantially comprising carbon and hydrogen only is
formed on an area of the surface of the substrate where the thin
primer film is not formed.
9. A method of producing a stencil printing plate, the method
comprising: preparing a substrate having formed therein openings
corresponding to a printing pattern; forming a thin primer film
directly or indirectly on the substrate by a dry process, the thin
primer film containing at least one substance selected from the
group consisting of silicon, titanium, aluminum, aluminum oxide,
and zirconium; and forming on the thin primer film a coating layer
having water repellence and/or water and oil repellence.
10. The method of producing a stencil printing plate of claim 9,
further comprising the step of subjecting the thin film to a plasma
process with any one of nitrogen, oxygen, and a mixture gas of
nitrogen and oxygen.
11. A stencil printing plate comprising: a printing mesh body; a
thin primer film formed directly or indirectly on the printing mesh
body by a dry process and containing at least one substance
selected from the group consisting of silicon, titanium, aluminum,
aluminum oxide, and zirconium; and a coating layer formed on the
thin primer film and having water repellence and/or water and oil
repellence.
12. The stencil printing plate of claim 11 wherein the thin primer
film further contains oxygen or nitrogen.
13. The stencil printing plate of claim 11 wherein the thin primer
film contains an Si oxide, a Ti oxide, or a Zr oxide.
14. The stencil printing plate of claim 11 wherein the coating
layer comprises a fluorine-containing coupling agent.
15. The stencil printing plate of claim 11 wherein the coating
layer comprises a fluorine-containing silane coupling agent.
16. The stencil printing plate of claim 11 wherein the coating
layer comprises: a first layer formed on the thin primer film and
composed mainly of a coupling agent capable of forming, with the
thin primer film, a hydrogen bonding and/or an --O-M bonding (M is
any one element selected from a group consisting of Si, Ti, Al, and
Zr) by condensation reaction; and a second layer formed on the
first layer and composed mainly of a water repellent material or a
water and oil repellent material.
17. The stencil printing plate of claim 16 wherein the coupling
agent is a coupling agent selected from a group consisting of
silane coupling agent, titanate-based coupling agent,
aluminate-based coupling agent, and zirconate-based coupling
agent.
18. The stencil printing plate of claim 11 further comprising an
emulsion layer formed on the printing mesh body, wherein the thin
primer film is formed on the emulsion layer.
19. The stencil printing plate of claim 11 wherein an amorphous
carbon film substantially comprising carbon only or an amorphous
carbon film substantially comprising carbon and hydrogen only is
formed on an area of the surface of the printing mesh body where
the thin primer film is not formed.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. application Ser.
No. 14/237,830, filed Mar. 7, 2014, which is a U.S. National Stage
Application of PCT/JP2012/070529, filed Aug. 10, 2012, which claims
the benefit of priority to Japanese Application No. 2011-174908,
filed on Aug. 10, 2011, and Japanese Patent Application No.
2012-029090, filed Feb. 14, 2012. The entire contents of all
applications are hereby incorporated by reference in their
entireties.
TECHNICAL FIELD
[0002] The present disclosure relates to a structure including a
thin primer film, and particularly to a structure including a thin
primer film for fluorine-containing silane coupling agent. The
present disclosure also relates to a method for producing the
structure.
BACKGROUND
[0003] There are known surface modification processes in which
coating is applied to a surface of a substrate with silane coupling
agent containing fluorine so as to provide the surface of the
substrate with oil repellence. For example, in some studies, a
fluorine coating layer composed of fluorine-containing silane
coupling agent is formed on a surface of a screen printing mesh to
provide the mesh with oil repellence and enhance demoldability of
printing paste. In many cases, fluorine-containing silane coupling
agent is not applied directly on a mesh body but applied on a thin
primer film as an intermediate, so as to ensure the fixity of the
agent on the mesh. For example, there are known methods in which
the mesh body is coated with a liquid primer and then
fluorine-containing silane coupling agent is applied onto the
liquid primer (see Japanese Patent Application Publication Nos.
2006-347062 and 2009-45867). Additionally, there are known
techniques for electronic component conveyors, wherein a porous
sheet provided on an adsorbing port of an adsorbing collet is
coated with fluorine-containing silane coupling agent so as to
prevent electronic components being conveyed from being adhered to
the porous sheet. Such a porous sheet is coated with
fluorine-containing silane coupling agent via a liquid primer.
RELEVANT REFERENCES
List of Relevant Patent Literature
[0004] Patent Literature 1: Japanese Patent Application Publication
No. 2006-347062
[0005] Patent Literature 2: Japanese Patent Application Publication
No. 2009-45867
SUMMARY
[0006] Unfortunately, a liquid primer tends to spread into an
opening in a work such as a mesh and a porous sheet and clog the
opening. Particularly, a liquid primer used on a screen printing
mesh may clog printing pattern openings and prevent accurate
application of printing paste in accordance with a printing
pattern.
[0007] To overcome this problem, a thin primer film may be formed
on a substrate in place of the liquid primer by a dry process such
as the chemical vapor deposition (CVD) method. The thin primer film
may be, for example, an amorphous carbon film composed of an
amorphous carbon material such as diamond-like carbon (DLC) formed
by the CVD method. However, fluorine-containing silane coupling
agent does not have sufficient fixity on the amorphous carbon
film.
[0008] To overcome this problem, various embodiments of the present
disclosure provide a structure including a thin primer film formed
by a dry process and tightly bound to a fluorine-containing
coupling agent. Additionally, various embodiments of the present
disclosure provide a method of producing the structure.
[0009] The Inventors found a primer composition layer containing
silicon (Si), titanium (Ti), aluminum (Al), aluminum oxide
(Al.sub.2O.sub.x (x may be any number)), or zirconium (Zr) tightly
binds to a fluorine-containing silane coupling agent. In this
primer layer, a hydroxyl group originating from silicon (Si),
titanium (Ti), aluminum (Al), aluminum oxide (Al.sub.2O.sub.x),
zirconium (Zr), or an oxide of these substances forms a covalent
bond due to a dehydration condensation reaction, a hydrogen bond,
and/or another bond, with a functional group of the
fluorine-containing silane coupling agent; therefore, it is
presumed that the primer layer and the fluorine-containing silane
coupling agent are bound tightly. Herein, the term "primer layer"
is used exchangeably with the term "thin primer film."
[0010] A primer composition according to an embodiment of the
present disclosure contains at least one of silicon, titanium,
aluminum, aluminum oxide, and zirconium and is formed on a surface
of a substrate by a dry process.
[0011] A structure according to an embodiment of the present
disclosure comprises: a substrate; and a thin primer film
containing at least one of silicon, titanium, aluminum, aluminum
oxide, and zirconium and formed on a surface of the substrate by a
dry process.
In an embodiment of the present disclosure, the primer composition
containing at least one of silicon, titanium, aluminum, aluminum
oxide, and zirconium is formed either directly on the substrate or
indirectly on the substrate via an intermediate layer.
[0012] A method of producing the structure according to an
embodiment of the present disclosure comprises the steps of:
preparing a substrate; and forming a thin film containing at least
one of silicon, titanium, aluminum, aluminum oxide, and zirconium
directly or indirectly on the substrate by a dry process.
[0013] Various embodiments of the present disclosure provide a
structure including a thin primer film formed by a dry process and
tightly bound to a fluorine-containing silane coupling agent.
Additionally, various embodiments of the present disclosure provide
a method of producing the structure.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1 is a schematic plan view illustrating the general
configuration of a screen printing plate including a mesh according
to an embodiment of the present disclosure.
[0015] FIG. 2 is a schematic cross-sectional view illustrating the
screen printing plate including a mesh according to an embodiment
of the present disclosure.
[0016] FIG. 3 is a schematic view illustrating a part of an
electronic component conveyor having a porous sheet according to an
embodiment of the present disclosure.
[0017] FIG. 4 is a graph showing a measurement result of contact
angles with water in Examples 1 to 9 subjected to five minutes of
ultrasonic cleaning.
[0018] FIG. 5 is a graph showing a measurement result of contact
angles with water in Examples 1 to 3 and 8 to 9 subjected to 120
minutes of ultrasonic cleaning.
[0019] FIG. 6 is a graph showing a measurement result of contact
angles with water in Examples 1 to 7 subjected to 240 minutes of
ultrasonic cleaning.
[0020] FIG. 7 is a photograph of a printing pattern opening in the
sample surface of Example 10.
[0021] FIG. 8 is a photograph of a printing pattern opening in the
sample surface of Example 11.
[0022] FIG. 9 is a photograph of a printing pattern opening in the
sample surface of Comparative Example 2.
[0023] FIG. 10 is a photograph of an emulsion part on the sample
surface of Example 10.
[0024] FIG. 11 is a photograph of an emulsion part on the sample
surface of Example 11.
[0025] FIG. 12 is a photograph of an emulsion part on the sample
surface of Comparative Example 2.
DESCRIPTION OF EXAMPLE EMBODIMENTS
[0026] Various embodiments of the present disclosure will now be
described with reference to the attached drawings. In the drawings,
the same or similar components are denoted by the same or similar
reference signs, and the detailed description of the same or
similar components is appropriately omitted.
[0027] A thin primer film according to an embodiment of the present
disclosure contains at least one of silicon, titanium, aluminum,
aluminum oxide, and zirconium and is formed on a surface of a
substrate by a dry process. The thin primer film may be used as a
primer layer for fixing a fluorine-containing silane coupling agent
on various structures. For example, the thin primer film according
to an embodiment of the present disclosure may be used in the form
of a primer layer when a fluorine-containing silane coupling agent
is applied on a screen printing mesh. FIG. 1 is a schematic plan
view illustrating the general configuration of a screen printing
plate, and FIG. 2 is a schematic cross-sectional view illustrating
the screen printing plate according to an embodiment of the present
disclosure. On the screen printing plate is formed a thin primer
film according to an embodiment of the present disclosure. FIGS. 1
and 2 each schematically illustrate the configuration of the screen
printing plate according to an embodiment of the present
disclosure, and it should be noted that dimensional relationship is
not accurately reflected in the drawings. The primer layer in the
present disclosure may also be formed in an opening in a stencil
printing plate or a porous sheet not having a screen mesh.
[0028] As shown, the screen printing plate 10 may comprise a frame
12 and a mesh 16 attached to the frame 12. The frame 12 may be
composed of cast iron, stainless steel, or aluminum alloy. The mesh
16 may be composed of a resin such as polyester or stainless steel
(SUS304). The mesh 16 may be entirely or partially coated with an
emulsion 14.
[0029] The mesh 16 according to an embodiment of the present
disclosure may be fabricated by weaving threads of various
materials and diameters. The surface roughness, sectional shape,
and weaving method of the threads constituting the mesh 16 may be
appropriately varied in accordance with the applications. The
sectional shapes may include, for example, circular, oval,
rectangular, polygonal, irregular, and star shapes. Examples of
weaving method may include plain weave, twill weave, and
three-dimensional weave. The material of the threads constituting
the mesh 16 may be, for example, a metal such as stainless steel,
steel, copper, titanium, or tungsten or an alloy thereof. The metal
may also be an amorphous metal, etc. Further, the material of the
threads constituting the mesh 16 may also be a chemical fiber such
as polypropylene, polyester, polyethylene, nylon, or vinyl, a mixed
fiber such as rayon, a carbon fiber, an inorganic material such as
glass fiber, or a natural fiber such as wool, silk, cotton, or
cellulose. For example, the mesh 16 may be a mesh #500-19. In a
mesh #500-19, the wire rods (fiber threads) constituting the mesh
may have a diameter of 19 .mu.m, the mesh openings (i.e., the
interval between the neighboring wire rods) may have a width of
about 30 .mu.m, and the mesh count may be 500. The mesh count of
500 may indicate that 500 mesh wire rods are present in a width of
one inch. The mesh 16 may be fixed at the portions where fibers
cross each other (intersections) with a plating extract, adhesive,
vapor-deposited film, or sputtered film. The plating extract may be
formed by, for example, electrolytic Ni plating, electrolytic
Ni--Co alloy plating, or electrolytic Cr plating. In an embodiment,
the intersections between the threads of the mesh may be compressed
to reduce the thickness of the mesh 16 to the thickness of one
thread of the mesh. The specifications of the mesh 16 are not
limited to those described herein such as the substance, wire
diameter, mesh count, uniformity of the size of mesh openings,
positions of mesh openings, taper angle of mesh openings, and shape
of the openings; these specifications may be varied in accordance
with printing method, printing pattern, printing medium, and
required endurance. In an embodiment, the mesh 16 may be ordinarily
fabricated by weaving thread-like material but may also be
fabricated by other methods. For example, the mesh 16 may be
fabricated by electrotyping, printing, and photolithography. Also,
the mesh 16 may be fabricated by forming through-halls in a
substrate by various methods such as laser processing, etching,
drilling, punching, and electric discharging. The through-halls
formed in these processes may correspond to the openings of the
mesh 16. The above materials and fabrication methods may be
appropriately combined. Further, the edges of the openings of the
mesh 16 may be appropriately chamfered. The mesh 16 may be a
combination of a plurality of meshes. For example, meshes of the
same type or different types may be combined together.
[0030] In an embodiment, a diazo-based photosensitive emulsion can
be used as the emulsion 14. A printing pattern opening 18 may be
formed in the emulsion 14 by, for example, photolithography so as
to correspond to a printing pattern. The printing pattern opening
18 may be formed so as to penetrate the emulsion 14 in the
thickness direction. In a photolithographic process, the emulsion
14 applied to the mesh 16 may be exposed to light in a photomask
pattern to cure part of the emulsion 14, and then the other region
of the emulsion 14 than the part cured by the exposure to light may
be removed to leave only the cured part on the mesh 16, so that the
printing pattern opening 18 is formed. The printing pattern opening
18 may be defined by inner walls 22 of the emulsion 14.
Furthermore, in place of directly attaching the mesh 16 with a
printing pattern to the frame 12, a support screen (not
illustrated) separate from the mesh 16 may be attached to the frame
12, and then the mesh 16 may be attached to the support screen. In
an embodiment, part of the support screen which overlaps the mesh
16 may be removed with a cutter knife. The printing pattern
openings 18 may be formed by methods other than photolithography.
For example, in the case where reproducibility of a printing
pattern is not strictly required, any material that can form
printing pattern openings on the screen mesh, such as clay and
plaster, can be used. The mesh 16 may also be used for solid
printing. When the mesh 16 is used for solid printing, the emulsion
14 may not be required.
[0031] In other embodiments, the emulsion 14 may be replaced with a
printing pattern retainer shaped in a plate or foil and provided
with printing pattern openings 18. The printing pattern retainer
may be formed of various materials such as metals, alloys, resins,
or ceramics. Examples of the metals that can be used as a material
of the printing pattern retainer include steel, copper, nickel,
gold, silver, zinc, aluminum, and titanium. Examples of the alloys
that can be used as a material of the printing pattern retainer
include aluminum alloy, titanium alloy, stainless steel alloy,
binary alloy such as chrome molybdenum steel alloy, Ni--Co alloy,
or Ni--W alloy, and multi-component alloy. Examples of resins that
can be used as a material of the printing pattern retainer include
polypropylene, polyester, polyethylene, nylon, acrylic, PET, PEN,
polyimide, polyimide-amide, glass epoxy, and FRP. In addition,
materials usable for printing pattern retainer include cellulose,
glass, ceramic, synthetic rubber such as nitrile, and natural
rubber. These materials may be combined with other materials, if
necessary. The printing pattern retainer formed of these materials
and shaped in a plate or foil may be affixed on the mesh 16. The
printing pattern in the printing pattern retainer may be formed
either before or after affixture on the mesh 16.
[0032] In an embodiment, the printing pattern retainer having
printing pattern openings may be formed of, for example, a plating
film extracted by electroforming. The printing pattern retainer in
another embodiment may be made of a plate-like or foil-like
substrate having through-holes formed by laser processing, etching,
drilling, punching, electrodischarge machining, and/or other
various methods.
[0033] The stencil printing plate according to an embodiment of the
present disclosure may be free of the mesh 16 and may be provided
with a printing pattern retainer directly on the frame 12. The
stencil printing plate according to another embodiment of the
present disclosure may be free of the frame 12 and may be provided
with a printing pattern retainer installed on a printing machine
directly or via a desired fixture. A primer layer according to an
embodiment of the present disclosure contains at least one of
silicon, titanium, aluminum, aluminum oxide, and zirconium and is
formed on the surface of each of the threads of the mesh 16. The
thin primer film is so thin that it is omitted from the drawings.
In the case where the screen printing plate 10 is replaced with a
stencil printing plate not having a mesh in the printing pattern
openings, a thin primer film containing at least one of silicon,
titanium, aluminum, aluminum oxide, and zirconium or a compound of
these substances may be formed in the vicinity of, or on the inner
wall of, the openings in the stencil printing plate. In an
embodiment, a primer layer composed of an amorphous carbon film or
a polymerized carbon film formed by a plasma-based dry process may
contain at least one of silicon, titanium, aluminum, aluminum
oxide, and zirconium. Such a primer layer may be tightly bound to
the fluorine-containing silane coupling agent and may have improved
slidability, gas barrier quality, and ductility.
[0034] The primer composition according to an embodiment of the
present disclosure may be formed on the surface of the mesh 16 by
various known dry processes including various plasma sputtering
methods such as bipolar sputtering, tripolar sputtering, magnetron
sputtering, and facing target sputtering, various ion beam
sputtering methods such as ion beam sputtering and ECR sputtering,
various plasma CVD methods such as direct current (DC) plasma CVD
method, low-frequency plasma CVD method, radio-frequency (RF)
plasma CVD method, pulsed plasma CVD method, microwave plasma CVD
method, atmospheric plasma method (e.g., dielectric-barrier
discharge system), and subatmospheric plasma method, various ion
plating methods using plasma such as direct current (DC) ion
plating method, hollow cathode discharge (HCD) method, and
radio-frequency (RF) excitation method, various ion plating methods
using ion beams such as ion beam deposition (IBD) method, ion beam
assisted deposition (IBAD) method, and ion vapor-deposition film
formation (IVD) method, and combinations of these methods. For
example, in a physical vapor deposition (PVD) method using a solid
Si target, Ti target, Al target, Al.sub.2O.sub.3 target, Zr target,
etc., a substrate of the mesh 16 may be set on a deposition
apparatus wherein a sputtering gas (e.g., an inert gas such as
argon gas) may be introduced at a particular gas pressure and flow
rate in a vacuum environment and the Si target, Ti target, Al
target, Al.sub.2O.sub.3 target, or Zr target may be sputtered to
form on the substrate a thin primer film according to an embodiment
of the present disclosure. By mixing the sputtering gas with oxygen
(O), nitrogen (N), or a mixture thereof, a thin primer film
comprising a product of silicon, titanium, aluminum, aluminum
oxide, or zirconium combined with O or N (e.g., SiO.sub.2,
SiN.sub.2, TiO.sub.2, TiN.sub.2, ZrO.sub.2, etc.) may be formed by
a reactive sputtering method. In a chemical vapor deposition method
(plasma CVD method) using a gas material, a plasma CVD apparatus
having a work placed therein and evacuated with vacuum may form a
primer layer containing Si or Ti by using a main material gas for
Si primer layers such as silane (SiH.sub.4) and tetraethoxysilane
(TEOS) or a main material gas for Ti primer layers such as titanium
chloride (TiCl.sub.4), titanium iodide (TiI.sub.4), titanium
isopropoxide Ti(i-OC.sub.3H.sub.7).sub.4. In an embodiment, a main
material gas such as trimethylaluminum (Al(CH.sub.3)).sub.3) or
aluminum chloride (AlCl.sub.3) may be mixed with oxygen gas or
nitrogen gas as necessary to form a primer layer containing
aluminum and oxygen or nitrogen. Further, a thin primer film
containing at least one of silicon, titanium, aluminum, aluminum
oxide, and zirconium and formed on a substrate may be exposed to
oxygen plasma or nitrogen plasma such that the thin primer film may
contain one or both of oxygen and nitrogen. In the embodiment as
described above, the thin primer film may contain one or both of
oxygen and nitrogen that provide polarity to the thin primer film.
Thus, the chemical adhesion and the physical adhesion (fixity)
between the thin primer film and the fluorine-containing silane
coupling agent may be improved.
[0035] When the primer layer contains zirconium, the surface layer
of the primer layer may be exposed to oxygen plasma, nitrogen
plasma, or both oxygen and nitrogen at high energy by a plasma
process, thereby to activate an oxide layer (passive layer)
produced on the surface layer of the primer layer containing
zirconium. Thus, when the primer layer contains zirconium, a
passive layer formed on the surface layer of the primer layer may
be activated without a hydrothermal process. This method can be
readily applied to a stencil printing plate and a porous sheet
unsuitable for surface activation by a hydrothermal process.
[0036] Further, in an embodiment wherein a thin primer layer
contains one or both of oxygen and nitrogen, the thin film may have
improved wettability for water, and a water-soluble emulsion
(liquid emulsion) applied to a printing screen mesh may have
improved wettability. This may prevent pinholes originating from
bubbles produced on application of the emulsion and improve the
wear resistance of the stencil printing plate as the emulsion
fixity on the screen mesh is improved. After a thin primer film
containing at least one of silicon, titanium, aluminum, aluminum
oxide, and zirconium according to the present disclosure is formed,
and another layer comprising an amorphous carbon film substantially
constituted by carbon, or carbon and hydrogen is formed, oxygen may
be applied by oxygen plasma while a part or all of the layer
comprising the amorphous carbon film is removed by ashing with
oxygen gas. Also, the main material gas may be mixed with a carrier
gas such as argon, hydrogen, nitrogen, etc. as necessary. When the
work on which the primer layer is to be formed by these dry
processes is vulnerable to thermal deformation or damage (e.g., a
stencil printing plate to which an emulsion is applied), heating of
the work may be prevented by using a cooling device or
significantly shortening the film formation time in the dry
processes. The primer layer according to an embodiment of the
present disclosure comprising at least one of silicon, titanium,
aluminum, aluminum oxide, and zirconium may be formed in an
amorphous state as necessary.
[0037] The primer layer according to an embodiment of the present
disclosure comprising at least one of silicon, titanium, aluminum,
aluminum oxide, and zirconium may be formed by a high straightness
plasma (process) and thus have less tendency to spread onto
irrelevant portions such as the bottom surface of the substrate
than do liquid primers. Therefore, in an embodiment of the present
disclosure, the primer layer can be formed selectively on a desired
surface of the substrate (e.g., a printing surface of a stencil to
be provided with water and oil repellence), and can be formed
selectively on a particular portion on the substrate by masking.
For a screen printing mesh #500 having thin wire rods with a
diameter of about 20 .mu.m for example, a high straightness plasma
process can form a primer layer selectively on the side of the wire
rods of the mesh that can be reached by the plasma. Such a process
can prevent spreading of the primer layer onto the back of the wire
rods of the mesh to form the primer layer selectively on the
desired side. For a stencil printing plate, when the surface for
loading a printing paste (squeegee surface) is provided with water
repellence and oil repellence, the loadability of the printing
paste and rollability of the paste by the squeegee (control of
viscoelasticity of the paste) may be inhibited to cause defects
such as blurred printing; in contrast, when a primer layer is
formed by a high straightness plasma process, the primer layer can
be formed selectively on the side opposite to the squeegee surface
to avoid such defects.
[0038] In an embodiment, on the squeegee surface may be formed an
amorphous carbon film substantially comprising carbon only and/or a
conventional amorphous carbon film substantially comprising
hydrogen and carbon only. Such a conventional amorphous carbon film
may have less tendency to bind to a fluorine-containing silane
coupling agent because of its inert surface. Accordingly, a
coupling agent such as a fluorine-containing silane coupling agent
adhered to the squeegee surface can be readily removed. The
conventional amorphous carbon film having an inert surface may be
formed on a desired region where a water-repellent layer or a
water- and oil-repellent layer should preferably not formed, as
well as on the squeegee surface.
[0039] Further, the printing screen mesh may include convex
portions where wires of the mesh lie one over another and concave
portions, as well as fine irregularity in the surface of the mesh;
when a primer layer is formed by a plasma dry process using an
electric field, the primer layer may be formed first on the convex
portions where the electric field is focused and then on the
concave portions. Therefore, the coverage on the mesh by the primer
layer (the proportion of the region where the primer layer is
formed in the surface area of the mesh) can be finely controlled by
controlling the formation time and/or optimizing the positions of
the masking shield, work, and/or electrodes in the electric
field.
[0040] Additionally, in an embodiment of the present disclosure,
when a thin primer film containing at least one of silicon,
titanium, aluminum, aluminum oxide, and zirconium and having
adhesion and ductility is formed on a printing screen mesh, the
intersection points between wires constituting the screen may be
fixed by adhesion to improve the durability of the screen mesh and
prevent the deformation.
[0041] The thin primer film layer according to the present
disclosure may be either formed on the mesh 16 before the emulsion
14 is applied to the mesh 16 or formed on the exposed portion of
the mesh 16 exposed in the printing pattern openings after the
emulsion 14 is applied. In another embodiment, the thin primer film
layer according to the present disclosure may be formed, along with
or in place of the emulsion 14, on the exposed portion of the
plate-like or foil-like printing pattern retainer exposed in its
printing pattern openings 18 after the mesh 16 is placed on the
frame 12. In still another embodiment, a primer composition
according to the present disclosure, and/or a water-repellent layer
and/or a water- and oil-repellent layer may be formed, in place of
the emulsion 14, on the plate-like or foil-like printing pattern
retainer having the printing pattern openings 18 formed therein.
Additionally, various necessary intermediate layers may be formed
between the mesh 16 and the thin primer film layer according to the
present disclosure, unless diverged from the purport of the present
disclosure.
[0042] At the edges of the emulsion formed on the mesh 16
encompassing the printing pattern openings 18, part of the openings
in the mesh 16 may be filled with the emulsion; therefore, the
printing paste is not transferred well. To overcome this problem,
the thin primer film layer of the present disclosure may be formed
on the emulsion 14, as well as on the exposed portion of the mesh
16 exposed in the printing pattern opening 18; and a
water-repellent layer and/or a water- and oil-repellent layer may
be formed on the thin primer film layer. Thus, the transferability
of the printing paste may be further improved.
[0043] A high-energy light beam used for emulsion exposure such as
UV light may be applied to the portions encompassing the printing
pattern openings 18 in the photosensitive emulsion 14 applied on
the mesh 16. In this case, the exposure light may oxidize the thin
primer film of the present disclosure formed on the surface of the
mesh 16 (surface activation). Thus, the silane coupling agent may
be tightly fixed on the surface of the mesh 16.
[0044] A thin coating film 20 including, for example, a
fluorine-containing silane coupling agent may be formed on at least
part of the thin primer film formed as described above on the
surface of the mesh 16. Such a fluorine-containing silane coupling
agent may be "FG-5010Z130-0.2" manufactured by Fluoro Technology
Corporation. In an embodiment, the thin coating film 20 may be
formed so thin as to have substantially no impact on the volume of
printing paste which passes through the printing pattern openings
18; for example, the thickness may be approximately 20 nm. The
thickness of the thin coating film 20 is not limited thereto and
can be appropriately changed depending on types of
fluorine-containing silane coupling agent used; for instance, the
thickness may range from 1 nm to 1 .mu.m.
[0045] The thin coating film 20 formed of the fluorine-containing
silane coupling agent may be formed on the thin primer film by
various methods. For example, the thin coating film 20 may be
applied onto the mesh 16 having formed thereon a thin primer film
by using fabrics such as unwoven fabrics, a sponge, a sponge-like
roller, a brush, and/or other various application tools. Also, the
thin coating film 20 may be formed by spraying the
fluorine-containing silane coupling agent. The thin coating film 20
may be formed by other various methods including dipping,
resistance heating, evaporation, and/or other various methods.
[0046] If a thin coating film comprising the fluorine-containing
silane coupling agent is formed on a printing screen mesh before
the screen mesh is fastened on the stencil printing plate, the
adhesion between the components of the stencil such as emulsion and
the screen mesh may be degraded. Alternatively, the screen mesh
having formed thereon a primer layer only may be adhered to the
components of the stencil before a thin coating film is formed, and
then the coating film comprising the fluorine-containing silane
coupling agent may be formed on the portions of the screen mesh
adhered to the stencil that require water repellence and oil
repellence.
[0047] The silane coupling agent chemically binds to at least one
of silicon, titanium, aluminum, aluminum oxide, and zirconium, or a
hydroxyl group originating from an oxide of these elements (e.g.,
by a bond due to a dehydration condensation reaction or a hydrogen
bond). Therefore, a continuous planar fluorine resin film including
a tight binding bridge layer may be formed on the surface of the
primer layer.
[0048] Additionally, through the above reactive sputtering method
or application of oxygen plasma or nitrogen plasma, the thin primer
film may contain oxygen or nitrogen that may produce electrical
polarity. This electrical polarity may produce a bond between the
thin primer film and the fluorine-containing silane coupling agent
based on the polarity, and this bond may also tightly fix the
fluorine-containing silane coupling agent on the thin primer
film.
[0049] The thin primer film and the coating film formed as above
may be as thin as several tens of nanometers and thus may be
applicable to a mesh and stencil printing plate having fine
structures. That is, even if the thin primer film and the coating
film according to an embodiment of the present disclosure is
adhered to a fine printing pattern opening of the mesh or the
stencil printing plate, there may be almost no change in the shape
of the printing pattern opening, and thus accuracy in printing may
not be degraded.
[0050] An embodiment of the present disclosure may include a
desired fluorine-containing coupling agent or a fluorine coating
agent that can bind, by a dehydration condensation reaction, to a
hydroxyl group originating from at least one of silicon, titanium,
aluminum, aluminum oxide, and zirconium in the primer layer. For
example, the fluorine-containing coupling agent in an embodiment
may include an element M that can form --O-M bonds with a substrate
(M is Ti, Al, or Zr). Further, when a fluorine-silicon compound
such as a liquid coupling agent is introduced in a vacuum
apparatus, a fluorine-containing layer comprising the
fluorine-silicon compound and having water and oil repellence may
be formed on the primer layer of the present disclosure by, e.g.,
resistance heating, a sort of vacuum evaporation method.
[0051] The fluorine-containing coupling agent may refer to a
coupling agent exhibiting water repellence and oil repellence and
including a substituent group of fluorine in the molecular
structure thereof. The fluorine-containing coupling agents that can
be used for the thin film 20 may include the following.
(i) CF3 (CF2)7 CH2 CH2 Si(OCH3)3
(ii) CF3 (CF2)7 CH2 CH2 SiCH3 Cl2
[0052] (iii) CF3 (CF2)7 CH2 CH2 SiCH3 (OCH3)2
(iv) (CH3)3 SiOSO2 CF3
(v) CF3 CON(CH3)SiCH3
(vi) CF3 CH2 CH2 Si(OCH3)3
[0053] (vii) CF3 CH2 SiCl3 (viii) CF3 (CF2)5 CH2 CH2 SiCl3
(ix) CF3 (CF2)5 CH2 CH2 Si(OCH3)3
(x) CF3 (CF2)7 CH2 CH2 SiCl3
[0054] These fluorine-containing coupling agents are non-limiting
examples of fluorine-containing coupling agents applicable to the
present disclosure. The applicable fluorine-containing coupling
agents may include, for example, FG-5010Z130-0.2 (containing
0.02-0.2% fluorine resin and 99.8-99.98% fluorine-based solvent)
from Fluoro Technology Corporation.
[0055] The thin coating film 20 may have two-layer structure
including a first layer composed mainly of a coupling agent and a
second layer composed mainly of a water repellent material or a
water- and oil-repellent material. The first layer may be a thin
film composed of, for example, a coupling agent that can form, with
the primer layer, hydrogen bonds and/or --O-M bonds (M is any one
element selected from the group consisting of Si, Ti, Al, and Zr)
by condensation reaction, on the primer layer of the present
disclosure on the surface of the mesh 16. Such coupling agents may
include, for example, silane coupling agent, titanate-based
coupling agent, aluminate-based coupling agent, and zirconate-based
coupling agent. These coupling agents may be used combinedly with
other coupling agents. The second layer may be a thin film composed
of a water repellent material, for example, alkylchlorosilanes such
as methyltrichlorosilane, octyltrichlorosilane, and
dimethyldichlorosilane, alkylmethoxysilanes such as
dimethyldimethoxysilane and octyltrimethoxysilane,
hexamethyldisilazane, a silylation agent, and silicone. Also, the
thin film composed of the above fluorine-containing silane coupling
agent may be used as the second layer. The water repellent
materials or water- and oil-repellent materials that can be used as
the second layer are not limited to those explicitly described
herein. The material of the thin film 20 may be appropriately
selected in view of various printing conditions such as the opening
width and wire diameter of the used mesh and/or the size of the
printing pattern openings in the stencil printing plate, the
compositions of the printing paste and ink (water-based or
oil-based, the particle size of the contents such as a pigment),
viscosity, thixotropy, and the temperature and humidity in
printing.
[0056] Silane coupling agents are widely used; and this requires no
example to be cited. Various silane coupling agents commercially
available can be used as the first layer of the thin film 20. One
example of the silane coupling agent applicable to the present
disclosure is decyltrimethoxysilane ("KBM-3103" from Shin-Etsu
Chemical Co., Ltd.).
[0057] The titanate-based coupling agents contained in the thin
coating film 20 may include, for example, tetramethoxy titanate,
tetraethoxy titanate, tetrapropoxy titanate, and tetraisopropoxy
titanate. For example, "Plenact 38S" (from Ajinomoto Fine-Techno
Co., Inc.) is commercially available.
[0058] The aluminate-based coupling agents contained in the thin
coating film 20 may include aluminum alkyl acetoacetate
diisopropylate, aluminum ethyl acetoacetate diisopropylate,
aluminum tris(ethyl acetoacetate), and aluminum isopropylate. For
example, "Plenact AL-M" (alkyl acetate aluminum diisopropylate from
Ajinomoto Fine-Techno Co., Inc.) is commercially available.
[0059] The zirconia-based coupling agents contained in the thin
film 20 may include neopentyl(diaryl)oxy, trimethacryl zirconate,
tetra(2,2 diaryloxy methyl)butyl, di(ditridecyl)phosphate
zirconate, and cyclo[dineopentyl(diaryl)]pyrophosphate
dineopentyl(diaryl)zirconate. For example, "Ken-React NZ01" (from
Kenrich Petrochemicals, Inc.) is commercially available.
[0060] Further, as compared to, e.g., an amorphous carbon film
primer layer comprising carbon, the thin primer film containing Si
or Ti according to an embodiment of the present disclosure may have
less tendency to diffuse from the surface layer of the substrate
comprising Ni, Co, Fe, etc. into the substrate and thus can be
formed on the substrate comprising these elements with excellent
fixity. In many cases, the elements Ni, Co, Fe, etc. are present in
the following: the mesh 16 made of a stainless steel which is an
alloy of Fe, Ni, and Cr; an Ni plating film or an Ni--Co alloy
plating film formed on the surface layer of the mesh 16 made of the
stainless steel to fix the intersection points and thus prevent
deformation of the mesh 16; or a substrate used to form the mesh 16
itself of films deposited by Ni plating or Ni--Co alloy plating in
electroforming.
[0061] In the embodiment of the present disclosure as described
above, a fluorine-containing silane coupling agent may be applied
onto a thin primer film formed by a dry process and containing at
least one of silicon, titanium, aluminum, aluminum oxide, and
zirconium; therefore, clogging of fine openings in the mesh 16 may
be inhibited as compared to conventional techniques wherein a
liquid primer is applied onto the mesh 16. Additionally, when a
liquid primer is applied, the thickness of the primer layer may be
uneven because of spreading of the liquid primer to irrelevant
portions, gravity, uneven surface tension distribution on the
surface of the substrate. In contrast, in an embodiment of the
present disclosure, the primer layer may be formed by a dry
process; therefore, the thickness of the primer layer can be
relatively even. The thin primer film thus formed may tightly bind
to, e.g., a fluorine-containing silane coupling agent therefore,
the fluorine-containing silane coupling agent may be applied with
excellent fixity on the portion of the mesh 16 that is exposed from
the printing pattern openings 18.
[0062] Further, when the primer layer of the present disclosure is
coated with a fluorine-containing silane coupling agent, the
fluorine-containing silane coupling agent may enter the defects
such as pinholes in the primer layer by capillarity, and the wall
surface of the pinholes may be coated with the fluorine-containing
silane coupling agent. Thus, the weather resistance of the
substrate may be improved. For example, a solvent that attacks a
substrate and is used as a binder or a solvent of a printing paste
may be prevented from entering the pinholes by reverse capillarity,
thereby to protect the substrate such as an emulsion for a stencil
printing plate that is sensitive to solvents and tends to swell to
be deformed.
[0063] When a coating layer having water repellence and/or water
and oil repellence is formed on a stencil printing plate or a mesh
with a primer layer of the present disclosure therebetween, the
paste can be readily removed from the printing pattern openings and
the mesh openings after printing. This may prevent damage to the
stencil caused by solidification of the paste left unremoved.
[0064] In the use situation, the screen printing plate 10 having
such a configuration is disposed such that the lower surface 26 of
the emulsion 14 faces a recording medium. After the screen printing
plate 10 is disposed at a predetermined position, printing paste,
such as solder paste or metallic paste for forming an inner
electrode of an electronic component, may be applied onto an upper
surface 24, and then a squeegee (not illustrated) may be slid along
the upper surface 24 while the upper surface 24 is pressed by the
squeegee at a certain level of pressure, so that the applied
printing paste passes through the printing pattern opening 18 and
is then transferred to the printing medium. In addition to these
printing pastes, the screen printing plate 10 may be used to
transfer printing ink, dye, paint, antirust, adhesive, reactive
material, slurry for green sheets, resist for lithography,
pressure-sensitive material, temperature-sensitive material, and
adsorbent.
[0065] The mesh 16 may also be applied to a stencil printing plate
that can be used in printing other than screen printing
(transcription). The mesh 16 may be applied to, for example, a
stencil printing plate for pressure printing, in which an ink
forced by a pressure mechanism such as an ink jet mechanism is
transferred to a printing medium, and vacuum printing, in which an
ink is transferred to a printing medium provided with a lower
pressure. The printing methods that can use the stencil printing
plate including the mesh 16 having formed thereon an amorphous
carbon film of the present disclosure are not limited to those
stated herein.
[0066] An example of a method for manufacturing the screen printing
plate 10 will now be described. The first step may be to prepare a
frame 12 comprising an iron casting, a stainless steel, and an
aluminum alloy and a mesh 16 having formed thereon by sputtering,
etc. a thin primer film containing at least one of silicon,
titanium, aluminum, aluminum oxide, and zirconium. The mesh 16 may
be affixed on the frame 12. The mesh 16 may be either directly
attached to the frame 12 or indirectly attached via a support
screen. Then, the sensitive emulsion 14 may be applied to the mesh
16, and the printing pattern opening 18 corresponding to a print
pattern may be formed in the emulsion 14 by a photolithographic
method. Then, the thin coating film 20 of a fluorine-containing
silane coupling agent may be formed on the surface of the mesh 16
exposed in the printing pattern opening 18 and facing toward the
lower surface 26, to complete the screen printing plate 10.
[0067] FIG. 3 is a schematic view illustrating a part of an
adsorbing collet installed on an electronic component conveyor 30
having a porous sheet according to an embodiment of the present
disclosure. The adsorbing collect 32 may be installed on a desired
electronic component conveyor so as to be movable vertically and
horizontally. As shown, the adsorbing collet 32 may be tubularly
shaped with one end thereof being connected to a negative-pressure
source not shown. Near an adsorbing port of the adsorbing collet 32
may be provided a porous sheet 34 according to an embodiment of the
present disclosure. An electronic component 36 may rest on a wafer
sheet 38. When this electronic component 36 is conveyed from the
wafer sheet to another working space, the adsorbing collet 32 may
be positioned on the electronic component 36 and a negative
pressure may be supplied from the negative-pressure source; thus,
the electronic component 36 may be adsorbed near the adsorbing port
of the adsorbing collect 32. Next, the adsorbing collet 32 having
adsorbed thereon the electronic component 36 may be moved to a
working space, where the supply of the negative pressure may be
stopped; thus, the electronic component 36 may be conveyed to the
working space. Such an adsorbing collet 32 is disclosed in, for
example, Japanese Patent Application Publication No. 2011-014582
and is obvious to those skilled in the art as to detailed
configuration and operations thereof. The detailed description of
the above collet 32 will be omitted herein. Additionally, the
adsorbing collet 32 may be used for conveying various components
other than electronic components, such as a green sheet.
[0068] The porous sheet 34 may be composed of, for example, a
synthetic resin such as polypropylene, a metal such as stainless
steel, a ceramic such as zirconia, a breathable fabric such as
bandage, an unwoven fabric, or a combination thereof; and the
porous sheet 34 may include openings as does the above screen
printing mesh 16. On the surface of the porous sheet 34 may be
formed a thin primer layer according to an embodiment of the
present disclosure containing at least one of silicon, titanium,
aluminum, aluminum oxide, and zirconium by a dry process such as
sputtering; and on this thin primer film may be formed a
fluorine-containing silane coupling agent layer. This thin primer
layer may be formed in the same method as the above thin primer
film formed on the mesh 16. Accordingly, the thin primer film
according to an embodiment of the present disclosure can be formed
so as not to clog the openings of the porous sheet 34. The thin
primer film according to an embodiment of the present disclosure
may be formed selectively on the portion of the porous sheet 34
where the electronic component 36 is adsorbed. Thus, no thin primer
film (or fluorine-containing silane coupling agent) may be formed
on the contact portion between the porous sheet 34 and the
adsorbing collet 32; and thus the adhesion between the porous sheet
34 and the adsorbing collet 32 may be ensured.
[0069] The porous sheet 34 can securely retain the
fluorine-containing silane coupling agent as a thin primer film
comprising the primer composition according to an embodiment of the
present disclosure; therefore, the porous sheet 34 may have a
smooth surface and resist wear. Thus, when the electronic component
36 is being conveyed, the electronic component 36 may be inhibited
from being adhered to the porous sheet 34, and the pores in the
porous sheet may be inhibited from being clogged with absorbed dust
and foreign bodies; thus, the electronic component 36 can be
efficiently conveyed. The porous sheet 34 may have unevenness in
the surface thereof. The fluorine-containing silane coupling agent
applied into cavities may be protected from externally exerted
stresses by convexities having a hard silicon film, titanium film,
aluminum oxide film, or zirconia film; and thus the fixity on the
porous sheet 34 is very high.
[0070] The above screen printing mesh and the porous sheet for
electronic component conveyor are mere examples to which the thin
primer film of the present disclosure is applied. The thin primer
film of the present disclosure may be used for any type of works
that may suffer clogging by a liquid primer. For example, the thin
primer film of the present disclosure may be applied to a sieving
mesh, a liquid cleaning mesh (cleaning sieve, cleaning net, etc.),
a mesh for barrel plating apparatuses, filters such as strainer,
and/or any other members in which a liquid primer may clog the
openings.
EXAMPLES
[0071] It was confirmed by the following method that a
fluorine-containing silane coupling agent can be applied with
excellent fixity on a thin primer layer according to an embodiment
of the present disclosure containing at least one of silicon,
titanium, aluminum, aluminum oxide, and zirconium. First, samples
(Examples 1 to 9) were prepared, each comprising a thin primer film
containing at least one of Si, Ti, Al, Al.sub.2O.sub.3, and Zr and
formed on the surface of a stainless steel piece (SUS304), the thin
primer film being provided with a fluorine coating
(fluorine-containing silane coupling agent). Each of the samples
was subjected to measurement of contact angles with water (pure
water) to investigate the fixity of the fluorine coating layer. If
the fluorine-containing silane coupling agent is retained on the
thin primer film, the contact angle with water may be high because
of the water repellence; therefore, it can be confirmed by
measuring the contact angle whether the fluorine-containing silane
coupling agent is retained on the thin primer film.
1. Preparation of Samples
[0072] First, substrates composed of stainless steel (SUS304) were
prepared for each sample. These stainless steel (SUS304) substrates
had a rectangular shape with a side length of 30 mm, a thickness of
1 mm, and a surface roughness Ra of about 0.05 .mu.m and were
subjected to 15 minutes of cleaning using isopropyl alcohol (IPA)
in an ultrasonic cleaning apparatus.
(1) Preparation of Sample for Example 1
[0073] The first step was to place the above stainless steel
(SUS304) substrate and an Si target having a purity of 99.999% and
a size of 101.6 .phi..times.5 t (mm) (from Kojundo Chemical
Laboratory Co., Ltd) mutually opposed and separated at a distance
of about 12 cm in a high-pressure DC pulsed plasma CVD apparatus,
and evacuate the CVD apparatus to 3.times.10.sup.-3 Pa. Next, Ar
gas was introduced into the CVD apparatus at a flow rate of 40 SCCM
and an internal gas pressure of 1.5 Pa; and the sample was
sputtered at an applied voltage of -4.5 kVp, a pulse frequency of
10 kHz, and a pulse width of 10 .mu.s for a total of 30 minutes
thereby to deposit an Si thin film layer on the sample-bearing
surface of the substrate. A solution of a fluorine-containing
silane coupling agent FG-5010Z130-0.2 (from Fluoro Technology
Corporation) (containing 0.02 to 0.2% fluorine resin and 99.8 to
99.98% fluorine-based solvent) was applied through a dip coating
process onto the substrate having formed thereon the Si thin film
layer. The product was dried at room temperature for two days to
yield a sample for Example 1.
(2) Preparation of Sample for Example 2
[0074] As with Example 1, the stainless steel (SUS304) substrate
and an Si target were placed in the high-pressure DC pulsed plasma
CVD apparatus; and the CVD apparatus was evacuated to
3.times.10.sup.-3 Pa. Next, a mixture of Ar gas and oxygen was
introduced into the CVD apparatus at respective flow rates of 20
SCCM and 20 SCCM and an internal gas pressure of 1.5 Pa; and the
sample was sputtered at an applied voltage of -4.5 kVp, a pulse
frequency of 10 kHz, and a pulse width of 10 .mu.s for 30 minutes
using the mixture gas as a sputter gas, thereby to deposit an Si
thin film layer on the sample-bearing surface of the substrate in
an oxygen atmosphere. As with Example 1, a solution of
FG-5010Z130-0.2 was applied through a dip coating process onto the
substrate having formed thereon the Si thin film layer. The product
was dried at room temperature for two days to yield a sample for
Example 2.
(3) Preparation of Sample for Example 3
[0075] The above stainless steel (SUS304) substrate was placed on a
turntable in a reaction container of the SRDS-7000T general-purpose
compact deposition apparatus (from Sanyu Electron Co., Ltd); the
reaction container was evacuated to 1.times.10.sup.-4 Pa; and then
the substrate was reverse-sputtered for one minute at an RF output
of 100 W, clockwise sample table rotations of 10 rpm, and a sample
table temperature equal to a room temperature (without heating or
water cooling) by using Ar gas at flow rate of 100 SCCM and a gas
pressure of 10 Pa. Subsequently, the substrate was sputtered for
three minutes at an output DC of 400 W, a T-S distance of 100 mm,
an offset of 40 mm, clockwise sample table rotations of 10 rpm,
counterclockwise magnetic fluctuation of 5 rpm, a sample table
temperature equal to a room temperature (without heating or water
cooling) by using Ar gas at a flow rate of 100 SCCM and a gas
pressure of 2 Pa. When the substrate was exposed to the atmosphere,
a Ti thin film layer was deposited on the sample-bearing surface of
the substrate under the condition of three minutes of N.sub.2 gas
leak. The Ti target used was that of 2N8 101.6 .phi..times.5 t DB
(from Sony Chemical Information Device Corporation). As with
Example 1, a solution of FG-5010Z130-0.2 was applied through a dip
coating process onto the substrate having formed thereon the Ti
thin film layer. The product was dried at room temperature for two
days to yield a sample for Example 3.
(4) Preparation of Sample for Example 4
[0076] A sample comprising an Si thin film layer formed on the
stainless steel (SUS304) substrate was prepared by the same method
as for Example 1. Next, this sample was placed into the
high-pressure DC pulsed plasma CVD apparatus, which was then
evacuated to 1.times.10.sup.-3 Pa; and oxygen gas was introduced
into the CVD apparatus at a flow rate of 30 SCCM and a gas pressure
of 2 Pa; and the sample surface was exposed to oxygen plasma at an
applied voltage of -2.5 kV, a pulse frequency of 10 kHz, and a
pulse width of 10 .mu.s for 2 minutes, such that the Si thin film
layer contained oxygen. As with Example 1, a solution of
FG-5010Z130-0.2 was applied through a dip coating process onto the
substrate having formed thereon the oxygen-containing Si thin film
layer. The product was dried at room temperature for two days to
yield a sample for Example 4.
(5) Preparation of Sample for Example 5
[0077] A sample comprising an Ti thin film layer formed on the
stainless steel (SUS304) substrate was prepared by the same method
as for Example 3. Next, this sample was placed into the
high-pressure DC pulsed plasma CVD apparatus, which was then
evacuated to 1.times.10.sup.-3 Pa; and oxygen gas was introduced
into the CVD apparatus at a flow rate of 30 SCCM and a gas pressure
of 2 Pa; and the sample surface was exposed to oxygen plasma at an
applied voltage of -2.5 kV, a pulse frequency of 10 kHz, and a
pulse width of 10 .mu.s for 2 minutes, such that the Ti thin film
layer contained oxygen. As with Example 1, a solution of
FG-5010Z130-0.2 was applied through a dip coating process onto the
substrate having formed thereon the oxygen-containing Ti thin film
layer. The product was dried at room temperature for two days to
yield a sample for Example 5.
(6) Preparation of Sample for Example 6
[0078] A sample comprising an Si oxide thin film layer formed on
the stainless steel (SUS304) substrate was prepared by the same
method as for Example 2. Next, this sample was placed into the
high-pressure DC pulsed plasma CVD apparatus, which was then
evacuated to 1.times.10.sup.-3 Pa; and nitrogen gas was introduced
into the CVD apparatus at a flow rate of 30 SCCM and a gas pressure
of 2 Pa; and the sample surface was exposed to nitrogen plasma at
an applied voltage of -2.5 kV, a pulse frequency of 10 kHz, and a
pulse width of 10 .mu.s for 2 minutes, such that the Si oxide layer
contained nitrogen. As with Example 1, a solution of
FG-5010Z130-0.2 was applied through a dip coating process onto the
substrate having formed thereon the nitrogen-containing Si oxide
thin film layer. The product was dried at room temperature for two
days to yield a sample for Example 6.
(7) Preparation of Sample for Example 7
[0079] A sample comprising an Ti thin film layer formed on the
stainless steel (SUS304) substrate was prepared by the same method
as for Example 3. Next, this sample was placed into the
high-pressure DC pulsed plasma CVD apparatus, which was then
evacuated to 1.times.10.sup.-3 Pa; and nitrogen gas was introduced
into the CVD apparatus at a flow rate of 30 SCCM and a gas pressure
of 2 Pa; and the sample surface was exposed to nitrogen plasma at
an applied voltage of -2.5 kV, a pulse frequency of 10 kHz, and a
pulse width of 10 .mu.s for 2 minutes, such that the Ti thin film
layer contained nitrogen. As with Example 1, a solution of
FG-5010Z130-0.2 was applied through a dip coating process onto the
substrate having formed thereon the nitrogen-containing Ti thin
film layer. The product was dried at room temperature for two days
to yield a sample for Example 7.
(8) Preparation of Sample for Example 8
[0080] The stainless steel (SUS304) substrate and an Al target were
placed on the turntable in the reaction container of the SRDS-7000
general-purpose compact deposition apparatus (from Sanyu Electron
Co., Ltd.) so as to be mutually opposed, and the reaction container
was evacuated to 1.times.10.sup.-4 Pa. Subsequently, the substrate
was reverse-sputtered under the same condition as Example 3, and
then was sputtered for five minutes at an output DC of 400 W, a T-S
distance of 100 mm, OFS of 55 mm, and sample table rotations of 10
rpm by using Ar gas as a sputtering gas at a flow rate of 100 SCCM
and a gas pressure of 3 Pa. Thus, an Al thin film layer was formed
on the substrate. As with Example 1, a solution of FG-5010Z130-0.2
was applied through a dip coating process onto the substrate having
formed thereon the Al thin film layer. The product was dried at
room temperature for two days to yield a sample for Example 8. The
Al target used was Al 4N 4'' .phi..times.5 t having a purity of
99.99% from Kojundo Chemical Laboratory Co., Ltd.
(9) Preparation of Sample for Example 9
[0081] The stainless steel (SUS304) substrate and an
Al.sub.2O.sub.3 target were placed on the turntable in the reaction
container of the SRDS-7000 general-purpose compact deposition
apparatus (from Sanyu Electron Co., Ltd.) so as to be mutually
opposed, and the reaction container was evacuated to
1.times.10.sup.-4 Pa. Subsequently, the substrate was
reverse-sputtered under the same condition as Example 3, and then
was sputtered for 70 minutes at an output RF of 400 W, a T-S
distance of 100 mm, OFS of 55 mm, and sample table rotations of 10
rpm by using a mixture sputtering gas of Ar gas and O.sub.2 gas
both at a flow rate of 100 SCCM, the mixture sputtering gas having
a gas pressure of 10 Pa. Thus, an Al.sub.2O.sub.3 thin film layer
was formed on the substrate. As with Example 1, a solution of
FG-5010Z130-0.2 was applied through a dip coating process onto the
substrate having formed thereon the Al.sub.2O.sub.3 thin film
layer. The product was dried at room temperature for two days to
yield a sample for Example 9. The Al.sub.2O.sub.3 target used was
Al.sub.2O.sub.3 4N 4'' .phi..times.5 t having a purity of 99.99%
from Kojundo Chemical Laboratory Co., Ltd.
(8) Preparation of Sample for Comparative Example 1
[0082] As with Example 1, a solution of FG-5010Z130-0.2 was applied
through a dip coating process onto a stainless steel (SUS304)
substrate having no film formed thereon. The product was dried at
room temperature for two days to yield a sample for Comparative
Example 1.
[0083] Measurement of the Contact Angle with Water by an Ultrasonic
Fatigue Acceleration Test
[0084] Next, each of the samples was placed into isopropyl alcohol
(IPA) and time-course degradation of contact angles of the samples
with water through the fatigue acceleration test by ultrasonic
cleaning, thereby to investigate the fixity of the
fluorine-containing silane coupling agent on the thin primer film.
The test was carried out by using US-20KS from SND Co., Ltd. at
oscillation of 38 kHz (BLT self-excitation oscillation) and a
high-frequency output of 480 W. In ultrasonic cleaning, strong
vibrations were locally generated by a piezoelectric vibrator to
generate cavities in IPA. When the cavities crush on the surface of
the substrate, the crushed cavities generate a great physical
impact force on the surface of the substrate; therefore, it is
suitable to determine the adhesion power between the substrate and
a thin film formed thereon. A fluorine-containing silane coupling
agent loosely bound to the thin primer film may be removed from the
surface of the substrate by an impact from the cavities; the
adhesion between the fluorine-containing silane coupling agent and
the thin primer film thereunder can be determined by investigating
the contact angle at the surface of the substrate.
[0085] FIG. 4 is a graph showing a measurement result of contact
angles with water in Examples 1 to 9 subjected to five minutes of
ultrasonic cleaning. The ordinate of FIG. 4 indicates the average
value of the contact angles measured at ten measuring points on the
sample. The measurement of the contact angles was carried out with
a portable contact angle analyzer "PG-X" (mobile contact angle
tester) from FIBRO System AB, at a room temperature of 25.degree.
C. and a humidity of 30%. As shown, each of the samples for
Examples 1 to 9 retained a contact angle of not less than
100.degree.. Each result of the measurement demonstrates that a
sufficient amount of fluorine-containing silane coupling agent was
remaining on a surface of the sample to exhibit a water
repellence.
[0086] In contrast, for Comparative Example 1 subjected to five
minutes of ultrasonic cleaning, the contact angle between the
sample and water was about 95.degree.. The test for Comparative
Example was terminated when it was confirmed that the average
contact angle with water was reduced to about 91.degree. after
further 30 minutes of ultrasonic cleaning. The contact angle of
91.degree. is near the border of "water repellence" and is near the
contact angle of a stainless steel substrate itself with water
before application of the fluorine-containing silane coupling agent
(about 80.degree.). Thus, it was confirmed for Comparative Example
1 that the fluorine-containing silane coupling agent was removed by
as short as about 30 minutes of ultrasonic cleaning.
[0087] FIG. 5 is a graph showing a measurement result of contact
angles with water in Examples 1 to 3 and 8 to 9 subjected to 120
minutes of ultrasonic cleaning. The ordinate of FIG. 4 indicates
the average value of the contact angles measured at ten measuring
points on the sample. As shown, each of the samples for Examples 1
to 3 and 8 to 9 retained a contact angle of not less than
100.degree.. Thus, it was confirmed for Examples 1 to 3 that the
layer comprising a sufficient amount of fluorine-containing silane
coupling agent remained on the surface of the samples to exhibit
water repellence even after 120 minutes of ultrasonic cleaning. For
Examples 4 to 7, the thin primer layers contain oxygen or nitrogen
due to application of oxygen plasma or nitrogen plasma, and thus
were presumably more tightly bound to the fluorine-containing
silane coupling agent therefore, the contact angles were not
measured after 120 minutes of ultrasonic cleaning. As will be
described later, the samples 4 to 7 retained high contact angles
even after 240 minutes of ultrasonic cleaning; therefore, these
samples should also have retained high contact angles after 120
minutes of ultrasonic cleaning.
[0088] FIG. 6 is a graph showing a measurement result of contact
angles with water in Examples 1 to 7 subjected to 240 minutes of
ultrasonic cleaning. The ordinate of FIG. 4 indicates the average
value of the contact angles measured at ten measuring points on the
sample. As shown, each of the samples for Examples 1 to 7 retained
a contact angle of not less than 95.degree.. Particularly, Examples
3 to 7 exhibited high contact angles of not less than 100.degree..
Each result of the measurements for Examples 1 to 7 demonstrates
that the layer comprising a sufficient amount of
fluorine-containing silane coupling agent remained on a surface of
the sample to exhibit water repellence. It was confirmed from the
above experimental results that the fluorine-containing silane
coupling agent was tightly fixed on the substrate in Examples 1 to
9.
[0089] Analysis of Functional Groups in Si, Ti and Al.sub.2O.sub.3
Thin Films
[0090] Next, the functional groups in the thin primer layer
containing Si, Ti, or Al.sub.2O.sub.3 were analyzed in the
following method. First, a stainless steel (SUS304) substrate
having a rectangular shape with a side length of 30 mm, a thickness
of 1 mm, and a surface roughness Ra of 0.034 .mu.m was prepared and
subjected to 15 minutes of ultrasonic cleaning using isopropyl
alcohol (IPA) in an ultrasonic cleaning apparatus.
[0091] A Thin Film Comprising Si
[0092] A sample comprising an Si thin film layer formed on the
stainless steel (SUS304) substrate was prepared by the same method
as for Example 1. Next, PHI TRIFT 2 TOF-SIMS (Ga ion, 25 kV) from
ULVAC-PHI, Inc. was used to carry out qualitative analysis of
hydroxyl groups present in the surface of the sample. As a result
of measurement in the negative ion mode, a sharp peak was detected
in the range of m/z 17.003.+-.0.010, confirming the presence of OH
(hydroxyl groups).
[0093] A Thin Film Comprising Ti
[0094] A sample comprising an Ti thin film layer formed on the
stainless steel (SUS304) substrate was prepared by the same method
as for Example 3. Next, PHI TRIFT 2 TOF-SIMS (Ga ion, 25 kV) from
ULVAC-PHI, Inc. was used to carry out qualitative analysis of
hydroxyl groups present in the surface. As a result of measurement
in the negative ion mode, a sharp peak was detected in the range of
m/z 17.003.+-.0.010, confirming the presence of OH (hydroxyl
groups).
[0095] A Thin Film Comprising Al.sub.2O.sub.3
[0096] A sample comprising an Al.sub.2O.sub.3 thin film layer
formed on the stainless steel (SUS304) substrate was prepared by
the same method as for Example 9. Then, the functional groups were
estimated from the absorption spectrum obtained by
Fourier-transform infrared spectroscopy (FT-IR analysis). The
measurement used HYPERION 3000 from Bruker Corporation. As a result
of 32 time measurements by the micro-ATR method with eight waves in
reflection absorption spectroscopy, it was confirmed that OH
(hydroxyl group) was formed near 3,600 to 3,300 (cm.sup.-1). For Al
thin film (Al thin film layer formed by the same method as Example
8) which is an embodiment of the present disclosure, a passive
layer of aluminum oxide is naturally formed on the surface layer of
aluminum contacting the atmosphere; therefore, it is presumed that
hydroxyl groups were formed as for Al.sub.2O.sub.3 described
above.
[0097] Thus, it was confirmed that the thin primer film layer
according to an embodiment of the present disclosure has hydroxyl
groups formed therein. Further, the hydroxyl groups in the thin
primer film layer form --O-M bonds (M is any one element selected
from the group consisting of Si, Ti, Al, and Zr) by condensation
reaction with the fluorine-containing silane coupling agent;
therefore, it was confirmed that the thin primer film layer in the
present disclosure tightly binds to the fluorine-containing silane
coupling agent.
[0098] A Printing Experiment Using a Screen Mask
[0099] Next, it was confirmed by the following process that the
openings in the mesh for screen printing plate according to an
embodiment of the present disclosure were substantially not clogged
with the printing paste. First, stainless steel pieces were cut to
prepare three meshes (SS325-16) with a size of 300 mm by 300 mm.
The meshes include 325 stainless steel wire rods per one inch
width, and the stainless steel wire rods have a diameter of 16
.mu.m. Next, three stencil printing plate frames having a Tetoron
mesh previously affixed thereon were prepared; and on these Tetoron
meshes, the above meshes (SS325-16) previously prepared were
affixed one on one. Next, each of the meshes (SS325-16) was coated
with an emulsion film composed mainly of 13% vinyl acetate-based
emulsion, 8% polyvinyl alcohol, 14% photopolymerization resin, and
65% water. The emulsion films were formed such that the film
thickness is about 20 .mu.m, the total thickness of the emulsion
screen including the stainless steel mesh is about 48 .mu.m, and
the bias angle of the stainless steel mesh is 30.degree..
[0100] Next, a printing pattern was formed on the emulsion film by
photolithography. More specifically, the printing pattern has a
comb-like shape comprising a straight bus electrode formed in the
middle of the mesh and having a line width of 1,500 .mu.m and a
length of about 10 cm and a plurality of thin lines (finger
electrode wires) extending orthogonally to the bus electrode and
having a length of about 5 cm and a line width of about 70
.mu.m.
[0101] Next, one of the meshes having the printing pattern formed
thereon is placed in a high-pressure DC pulsed plasma CVD
apparatus; then, an Si thin film layer was formed on the mesh (more
specifically, the entirety of areas encompassing the printing
pattern openings in the emulsion screen printing plate, including
the portions of the mesh exposed in the printing pattern openings)
by using an Si target having a purity of 99.999% and a size of
101.6 .phi..times.5 t (mm) (from Kojundo Chemical Laboratory Co.,
Ltd), as for Example 1. More specifically, the CVD apparatus was
evacuated to 3.times.10.sup.-3 Pa; and then the mesh was sputtered
by argon gas plasma for 90 seconds at an applied voltage of -4 kVp,
a pulse frequency of 10 kHz, and a pulse width of 10 .mu.S by using
Ar gas at a flow rate of 30 SCCM and a gas pressure of 1.5 Pa.
Next, the plasma process was stopped to cool the emulsion film and
the mesh, and 15 minutes later the sputtering by argon gas plasma
was resumed and kept for 90 seconds under the same condition such
that an Si thin film layer was deposited on the entirety of
effective printing pattern area on the printing surface of the
screen printing plate including the mesh surface. A solution of a
fluorine-containing silane coupling agent FG-5010Z130-0.2 (from
Fluoro Technology Corporation) (containing 0.02 to 0.2% fluorine
resin and 99.8 to 99.98% fluorine-based solvent) was applied with
an unwoven fabric onto the mesh and the emulsion film having formed
thereon the Si thin film layer. The product was dried at room
temperature for two days to yield a sample for Example 10.
[0102] Next, another of the meshes having the printing pattern
formed thereon was placed in a high-pressure DC pulsed plasma CVD
apparatus; then, an Si thin film layer was formed on the mesh (the
entirety of the effective printing pattern area on the emulsion
screen printing plate, including the portions of the mesh exposed
in the printing pattern openings) by using an Si target having a
purity of 99.999% and a size of 101.6 .phi..times.5 t (mm) (from
Kojundo Chemical Laboratory Co., Ltd), as for Example 10. More
specifically, the CVD apparatus was evacuated to 3.times.10.sup.-3
Pa; and then the mesh was sputtered by argon gas plasma for 90
seconds at an applied voltage of -4 kVp, a pulse frequency of 10
kHz, and a pulse width of 10 .mu.s by using a mixture of Ar gas at
a flow rate of 30 SCCM and oxygen gas at a flow rate of 10 SCCM,
the mixture gas having a gas pressure of 1.5 Pa. Next, the plasma
process was stopped to cool the emulsion film and the mesh, and 15
minutes later the sputtering by argon gas plasma was resumed and
kept for 90 seconds under the same condition such that an Si thin
film layer was deposited on the mesh surface in an oxygen
atmosphere. A solution of a fluorine-containing silane coupling
agent FG-5010Z130-0.2 (from Fluoro Technology Corporation)
(containing 0.02 to 0.2% fluorine resin and 99.8 to 99.98%
fluorine-based solvent) was applied with an unwoven fabric onto the
mesh having formed thereon the Si oxide thin film layer. The
product was dried at room temperature for two days to yield a
sample for Example 11.
[0103] The remaining mesh having the printing pattern formed
thereon (an emulsion screen printing plate not subjected to surface
treatment) was treated as Comparative Example 2.
[0104] Next, the emulsion screen printing plates of Examples 10 and
11 and Comparative Example 2 were set on a printing machine to
perform printing under the following condition. High-viscosity
printing paste: (an equivalent to) X7348S-17 from NAMICS
CORPORATION, Ag paste particle size .phi.: 1 .mu.m, squeegee:
urethane squeegee, squeegee attack angle: 70.degree., squeegee
speed: 110 mm/s, offset 1 mm, squeegee depression: 2 mm, and
printing medium: Pet film "Lumirror" from Toray Industries,
Inc.
[0105] After printing, the printing pattern openings in the
emulsion screen printing plate were observed for each of Examples
10 and 11 and Comparative Example 2 without surface cleaning of the
emulsion pattern openings using a cleaning liquid such as a
thinner. The observation results are shown in FIGS. 7 to 9. FIG. 7
is a photograph of the sample surface of Example 10; FIG. 8 is a
photograph of the sample surface of Example 11; and FIG. 9 is a
photograph of the sample surface of Comparative Example 2. FIGS. 7
and 8 clearly shows the printing pattern openings as black
horizontal lines in the upper and lower portions of the
photographs, indicating that there is no clogging by the printing
paste; and no clogging was observed in the mesh openings. Further,
it was confirmed that the printing paste was transferred to the
printing medium (PET film) in accordance with the printing pattern.
In contrast, FIG. 9 shows the printing pattern openings as gray
horizontal lines in the upper and lower portions of the
photographs, indicating that the printing pattern openings are
clogged with the printing paste. Thus, in Examples 10 and 11, the
fluorine resin layers formed of the fluorine-containing silane
coupling agent were tightly fixed on the mesh surface via a thin
primer layer according to an embodiment of the present disclosure;
and the fluorine resin layers formed of the fluorine-containing
silane coupling agent improved the demoldability of the printing
paste. In contrast, in Comparative Example 2, it is presumed that
the printing paste was adhered to the portion of the mesh where the
base material was exposed and the fluorine resin thin film of the
fluorine-containing silane coupling agent was not formed. Thus, no
mesh opening was clogged with the thin primer film in the screen
printing meshes (Examples 10 and 11) according to an embodiment of
the present disclosure.
[0106] Examples 10 and 11 and Comparative Example were observed
with a CCD camera at the emulsion film surface near the printing
pattern openings and mesh fibers exposed in the printing pattern
openings. The observation results are shown in FIGS. 10 to 12. As
shown in FIGS. 10 and 11, no printing paste was adhered to the
emulsion on the sample surface of Examples 10 and 11 and the mesh
fibers exposed in the printing pattern openings. In contrast, FIG.
12 shows that the printing paste was adhered to the emulsion on the
sample surface of Comparative Example 2 and the mesh fibers exposed
in the printing pattern openings (this printing paste appears white
in the photograph of FIG. 12). Thus, it was confirmed that, in
Examples 10 and 11, the fluorine-containing silane coupling agent
was tightly fixed on the emulsion film as well as on the mesh via
the thin primer film according to an embodiment of the present
disclosure.
[0107] FIGS. 10 to 12 show, in the lower portions, the mesh fibers
exposed in the printing pattern openings. In Comparative Example
shown in FIG. 12, the printing paste was adhered to almost the
entire surface of the mesh fibers and to part of the mesh openings
so as to clog the entirety thereof. That is, Comparative Example 2
indicates poor demoldability of the paste. In contrast, Examples 10
and 11 shown in FIGS. 10 and 11, respectively, indicate that the
printing paste remaining on the mesh fibers was scarce, and no mesh
opening is clogged with the printing paste. That is, Examples 10
and 11 indicate excellent demoldability of the paste.
[0108] Next, the fixity of the fluorine-containing silane coupling
agent on the mesh in a screen printing plate was determined by the
method described in the following paragraph. The mesh, having a
thin primer layer formed thereon by a dry process according to an
embodiment of the present disclosure, was affixed on a frame and
coated with an emulsion, and was exposed again in the printing
pattern openings in the emulsion film formed by exposure
development.
[0109] First, a stainless steel rectangular meshes (#500-19) with a
size of 300 mm by 300 mm was prepared. On the mesh (#500-19) was
formed by the following process a primer layer composed of an
Si-containing amorphous carbon film according to an embodiment of
the present disclosure. First, the prepared mesh (#500-19) was
placed into a high-pressure pulsed plasma CVD apparatus, and a
reaction container of the CVD apparatus was evacuated to
1.times.10.sup.-3 Pa. Next, argon gas was introduced into the
evacuated CVD apparatus at a flow rate of 30 SCCM and a gas
pressure of 2 Pa, and the mesh (#500-19) was cleaned with argon gas
plasma at an applied voltage of -4 kV, a pulse frequency of 10 kHz,
and a pulse width of 10 .mu.s. Next, after argon gas was
discharged, trimethylsilane was introduced into the CVD apparatus
at a flow rate of 30 SCCM and a gas pressure of 2 Pa, and a film
was formed at an applied voltage of -4 kV, a pulse frequency of 10
kHz, and a pulse width of 10 .mu.s for six min. Through this
process, an Si-containing amorphous carbon film was formed on a
surface of the mesh (#500-19).
[0110] Next, acetylene gas was discharged, and then oxygen gas was
introduced into the CVD apparatus at a flow rate of 30 SCCM and a
gas pressure of 2 Pa, and the mesh (#500-19) having formed thereon
the amorphous carbon film was irradiated with oxygen plasma at an
applied voltage of -3 kV, a pulse frequency of 10 kHz, and a pulse
width of 10 .mu.s for 3 min. Thus, an amorphous carbon film (a thin
film primer layer formed by a dry process) containing silicon and
oxygen was obtained.
[0111] Next, the mesh having the amorphous carbon film thus formed
thereon was attached to an iron casting frame with a size of 450 mm
by 450 mm via a polyester mesh. Next, an emulsion was applied to
the mesh having the amorphous film formed thereon and attached to
the frame. The emulsion was applied to a thickness of 5 .mu.m
within a rectangular area having a size of 150 mm by 150 mm in the
middle of the mesh. Roughly, the emulsion used was composed mainly
of 13% vinyl acetate-based emulsion, 8% polyvinyl alcohol, 14%
photopolymerization resin, and 65% water. Next, the emulsion film
formed on the mesh was subjected to exposure development by a known
photolithography method to form a rectangular printing pattern
opening having a size of 30 mm by 30 mm in the rough middle of the
rectangular area (150 mm by 150 mm) coated with the emulsion.
[0112] Next, a fluorine-containing silane coupling agent was
manually applied with an unwoven fabric (BEMCOT CLEAN WIPE-P from
Asahi Kasei Corporation) to the portion of the mesh exposed in the
printing pattern opening. The fluorine-containing silane coupling
agent used was a solution of FG-5010Z130-0.2 from Fluoro Technology
Corporation (fluororesin: 0.02 to 0.2%, fluorine-based solvent
99.8% to 99.98%). Then, the mesh coated with the
fluorine-containing silane coupling agent was dried at a room
temperature and a humidity of about 50% for 180 minutes. Then, the
portion of the mesh exposed in the printing pattern opening was
again coated with the same fluorin-containing silane coupling agent
in the same manner; and the mesh was dried under the same condition
for 180 minutes. Thus, an emulsion screen printing plate was
completed.
[0113] Next, the mesh coated with the fluorine-containing silane
coupling agent was cut off from the complete emulsion screen
printing plate with a cutter knife. Then, the mesh cut off was
placed into an ultrasonic cleaning apparatus filled with isopropyl
alcohol (IPA) and was subjected to ultrasonic cleaning for five
minutes. The ultrasonic cleaning removed excess fluorine-containing
coupling agent not fixed on the mesh. The ultrasonic cleaning was
carried out with an ultrasonic cleaner "US-20KS" from SND Co., Ltd.
(oscillation: 38 kHz (bolt-clamped Langevin type transducer (BLT)
self-oscillation), high-frequency output 480 W).
[0114] Thus prepared mesh coated with the fluorine-containing
silane coupling agent was measured for its contact angle with an
oil (mineral spirit) at different ten points on the mesh being held
in the space. The measurement was carried out with a portable
contact angle analyzer "PG-X" (mobile contact angle tester) from
FIBRO System AB, at a room temperature of 25.degree. C. and a
humidity of 30%. The average of the measured contact angle was
78.degree., confirming that the subject surface of the mesh had
water repellence and oil repellence. Incidentally, the contact
angle of an unprocessed stainless steel mesh (#500-19) with an oil
(mineral spirit) measured under the same condition as above was
about 27.degree.. Thus, it was confirmed that the
fluorine-containing silane coupling agent remains fixed on the
surface of the mesh even after the ultrasonic cleaning.
[0115] As described above, the fluorine-containing coupling agent
can be applied with excellent fixity on the mesh having formed
thereon a primer layer comprising an amorphous carbon film
containing silicon and oxygen in accordance with an embodiment of
the present disclosure.
LIST OF REFERENCE NUMBERS
[0116] 10: Screen printing plate [0117] 12: Frame [0118] 14:
Emulsion [0119] 16: Mesh [0120] 18: Printing pattern opening [0121]
20: Thin coating film [0122] 30: Electronic component conveyor
[0123] 32: Absorbing collet [0124] 34: Porous sheet
* * * * *