U.S. patent application number 12/159387 was filed with the patent office on 2010-08-26 for stage device and plasma treatment apparatus.
This patent application is currently assigned to SHARP KABUSHIKI KAISHA. Invention is credited to Satoshi Mayumi, Setsuo Nakajima, Yoshinori Nakano, Takashi Satoh, Keiichi Tanaka, Tamaki Wakasaki.
Application Number | 20100212832 12/159387 |
Document ID | / |
Family ID | 38228120 |
Filed Date | 2010-08-26 |
United States Patent
Application |
20100212832 |
Kind Code |
A1 |
Wakasaki; Tamaki ; et
al. |
August 26, 2010 |
STAGE DEVICE AND PLASMA TREATMENT APPARATUS
Abstract
The present invention provides a stage device which does not
generate the difference in level between an upper end of a lift pin
and a setting surface of a stage in a state where a substrate to be
treated is set on the setting surface of the stage, and provides a
plasma treatment apparatus which suppresses the occurrence of
uneven treatment by using the stage device as an electrode stage.
At the center of an electrode stage (2), a spring type lift pin
(20) having elasticity in a direction where the pin moves is
provided. When the spring type lift pin (20) is at a storage
position, a pin upper end (20a) of the spring type lift pin (20)
protrudes above the setting surface (11) of the electrode stage
(2). When the substrate (4) to be treated is set and adsorbed on
the setting surface (11), the upper end of the lift pin is pressed
down to the position that is at the same level as that of the
setting surface (11) by a load applied by the substrate (4).
Inventors: |
Wakasaki; Tamaki;
(Ikoma-shi, JP) ; Satoh; Takashi; (Kizugawa-shi,
JP) ; Tanaka; Keiichi; (Tsu-shi, JP) ;
Nakajima; Setsuo; (Tsukuba-shi, JP) ; Mayumi;
Satoshi; (Kyoto-shi, JP) ; Nakano; Yoshinori;
(Kyoto-shi, JP) |
Correspondence
Address: |
BIRCH STEWART KOLASCH & BIRCH
PO BOX 747
FALLS CHURCH
VA
22040-0747
US
|
Assignee: |
SHARP KABUSHIKI KAISHA
Osaka-shi ,Osaka
JP
SEKISUI CHEMICAL CO., LTD.
Osaka-shi, Osaka
JP
|
Family ID: |
38228120 |
Appl. No.: |
12/159387 |
Filed: |
December 22, 2006 |
PCT Filed: |
December 22, 2006 |
PCT NO: |
PCT/JP2006/325627 |
371 Date: |
August 19, 2008 |
Current U.S.
Class: |
156/345.43 ;
156/345.51 |
Current CPC
Class: |
B65G 49/064 20130101;
H01J 2237/20 20130101; H01J 37/32431 20130101; B65G 2249/045
20130101; H01L 21/68742 20130101; B65G 2249/04 20130101; B65G
2249/02 20130101; H01L 21/68778 20130101; B65G 49/065 20130101 |
Class at
Publication: |
156/345.43 ;
156/345.51 |
International
Class: |
C23F 1/08 20060101
C23F001/08 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 28, 2005 |
JP |
2005-379021 |
Claims
1. A stage device comprising: a stage having a setting surface on
which a substrate to be treated is set; and a lift pin mechanism
having first pins, provided in the stage, each capable of emerging
from the setting surface, the first pins being protruded so that
the substrate is detached from the setting surface, wherein the
lift pin mechanism includes contact adjusting means that brings an
upper end of the first pin being withdrawn in the stage into
contact with the substrate on the setting surface without lifting
the substrate above the setting surface.
2. The stage device according to claim 1, wherein the contact
adjusting means comprises elasticity function imparting means that
imparts to the first pin a function having elasticity in a
direction where the first pin moves, and the upper end of the first
pin is brought into contact with the substrate by the elasticity
imparted by the elasticity function imparting means.
3. The stage device according to claim 2, wherein the elasticity
function imparting means is an elastic body being provided to the
first pin and having elasticity in the direction where the first
pin moves.
4. The stage device according to claim 2, wherein when each of the
first pins is at a storage position where the first pin is
withdrawn in the stage, the upper end of the first pin is protruded
above the setting surface in a state where the substrate is not set
on the setting surface, and the upper end of the first pin is
positioned at the same level as the setting surface by a load
applied by the substrate in a state where the substrate is set on
the setting surface.
5. The stage device according to claim 2, wherein when each of the
first pins is at a storage position where the first pin is
withdrawn in the stage, the upper end of the first pin is
positioned below the setting surface in a state where the substrate
is not set on the setting surface, and after the substrate is set
on the setting surface, the first pin moves upward so that the
upper end thereof comes into contact with the substrate.
6. The stage device according to claim 1, wherein the stage is
provided with an adsorption mechanism that adsorptively holds the
substrate on the setting surface.
7. The stage device according to claim 6, wherein the adsorption
mechanism has a stronger adsorption force in the vicinity of the
first pin to which the function having elasticity is imparted than
an adsorption force in other area.
8. The stage device according to claim 2, wherein the lift pin
mechanism has second pins, provided in an outer region of the
stage, each capable of emerging from the setting surface and having
no elasticity in a direction where the second pin moves, and an
upper end of the second pin is positioned below the setting surface
in a state where the second pin is withdrawn in the stage.
9. A plasma treatment apparatus which generates plasma in between
an electrode stage and a counter electrode at near atmospheric
pressure so as to subject a substrate to be treated set on the
electrode stage to plasma treatment, the plasma treatment apparatus
including a stage device according to claim 1 as the electrode
stage.
10. A display panel substrate for use in manufacturing a display
panel, the display panel substrate being subjected to surface
treatment by means of a plasma treatment apparatus according to
claim 9.
Description
TECHNICAL FIELD
[0001] The present invention relates to a plasma treatment
apparatus which performs plasma treatment at near atmospheric
pressure, and a stage device which can be suitably used in a
treatment apparatus, such as the plasma treatment apparatus, and
allows a substrate to be treated to be set thereon.
BACKGROUND ART
[0002] Conventionally, surface treatment of a substrate made from,
for example, glass, plastic, or other material by means of glow
discharge plasma at a low pressure ranging from appropriately 0.1
Torr to 10 Torr is widely known and industrially applied. Surface
treatment at such a vacuum-level low pressure prevents a shift from
discharge to arc discharge, and therefore can be performed even on
the substrate made from plastic or other material having a high
heat resistance.
[0003] However, surface treatment by low-pressure glow discharge
plasma requires an expensive vacuum chamber as a treatment
container, and an evacuation unit. In addition, upsizing of
substrates, typified by the so-called upsizing of a screen for a
liquid crystal television or the like, has been developed in some
fields. Surface treatment in such fields requires larger vacuum
chamber and evacuation unit. This inevitably increases production
cost of an apparatus and increases a footprint of the apparatus.
Moreover, surface treatment on a substrate having a high water
absorption requires a long time to form a vacuum inside the vacuum
chamber, which increases treatment cost itself.
[0004] In order to overcome the above various kinds of problems,
there has been proposed an apparatus which subjects a substrate to
surface treatment at an atmospheric pressure while generating glow
discharge plasma (for example, see Patent document 1).
[0005] Such a plasma treatment apparatus, as illustrated in FIG.
24, includes: an electrode stage 102 that holds a substrate 104 to
be treated; and a counter electrode 103 that is disposed to face
the electrode stage 102. The counter electrode 103 has a plurality
of gas supply holes (not shown) from which a treatment gas is
flown. To the counter electrode 103, a power source section 110 for
applying a voltage is connected. The electrode stage 102 includes:
a lift pin mechanism 120 that holds the substrate 104 by pushing
it; and an adsorption groove 106 which allows the substrate 104 to
be adsorbed on the surface of the electrode stage 102. The
electrode stage 102 is grounded.
[0006] The adsorption groove 106 has a gap 108 between the
substrate 104 and the electrode stage 102. In the gap 108 plasma
easily occurs since a pressure inside the gap 108 is low.
Therefore, a voltage drop in the adsorption groove 106 is
relatively small.
[0007] As illustrated in FIG. 25 showing an equivalent circuit, a
circuit configuration in which a resistor 131, a capacitor 132, and
a resistor 130 are connected in series can be considered as a
circuit configuration between the power source section 110 and a
ground 112 in the vicinity of the adsorption groove 106. The
resistor 131 shows the occurrence of a voltage drop due to plasma
generated in between the counter electrode 103 and the substrate
104. The capacitor 132 is an electrical capacity in the substrate
104. The resistor 130 shows a voltage drop in the adsorption groove
106. A voltage drop in the capacitor 132 is relatively large, but
voltage drops in the resistors 132 and 130 are relatively small.
Thus, since a voltage drop in the gap 108 of the adsorption groove
106 is small, uneven treatment on the substrate 104 does not
actually occur.
[0008] Patent document 2 discloses, which does not disclose a
plasma treatment apparatus only, the technique of independently
controlling the level of lift pins at their upward movement, which
pins cause a wafer set on a setting table to be floated above the
setting surface of the setting table.
[Patent document 1]
[0009] Japanese Unexamined Patent Publication No. 118857/1995
(Tokukaihei 7-118857; published on May 9, 1995)
[Patent document 2]
[0010] Japanese Unexamined Patent Publication No. 64132/2002
(Tokukai 2002-64132; published on Feb. 28, 2002)
DISCLOSURE OF INVENTION
[0011] Even though an upper end 120a of the pin (lift pin) at the
downward movement of the lift pin mechanism 120 is set so as to be
positioned at the same level as the adsorption surface 102a of the
electrode stage 102, the upper end 120a cannot be positioned
according to the setting. This is because mechanical precision of
the lift pin mechanism 120 is limited. That is, the upper end 120a
sinks below the adsorption surface 102a as illustrated in FIG. 24,
or protrudes above the adsorption surface 102a as illustrated in
FIG. 26.
[0012] When the upper end 120a of the pin is positioned below the
adsorption surface 102a of the electrode stage 102, a gap 109
occurs due to difference in level between the upper end 120a of the
pin and the substrate 104, as illustrated in FIG. 24.
On the other hand, when the upper end 120a of the pin is positioned
above the adsorption surface 102a of the electrode stage 102, a gap
111 occurs due to difference in level between the adsorption
surface 102a and the substrate 104, as illustrated in FIG. 26.
[0013] As different from the case of the adsorption groove 106,
pressures in the gaps 109 and 111 caused by difference in level are
atmospheric pressures, and no plasma therefore occurs even when a
voltage is applied. As a result, a voltage drop in the gaps 109 and
111 increases.
[0014] More specifically, as illustrated in FIG. 27 showing an
equivalent circuit, a circuit configuration in which the resistor
131, the capacitor 132, and the resistor 130 are connected in
series can be considered as a circuit configuration between the
power source section 110 and the ground 112 in the vicinity of the
lift pin mechanism 120. The capacitor 133 is an electrical capacity
in the gaps 109 and 111 that occur due to difference in level
between the pin and the adsorption surface 102a. Thus, it is
inevitable that a voltage drop is relatively large in the gaps 109
and 111 caused by the difference in level since no plasma is
generated in the gaps 109 and 111. As a result, uneven treatment
and/or the so-called incomplete treatment occur in the substrate
104.
[0015] The present invention has been attained in view of the above
problems, and an object of the present invention is to provide a
stage device which does not cause difference in level between the
upper end of a pin in the lift pin mechanism and the setting
surface in a state where a substrate is set on the setting surface
of a stage, and a plasma treatment apparatus which includes such a
stage device and thereby suppresses the occurrence of uneven
treatment.
[0016] In order to achieve the object, a stage device of the
present invention includes: a stage having a setting surface on
which a substrate to be treated is set; and a lift pin mechanism
having first pins, provided in the stage, each capable of emerging
from the setting surface, the first pins being protruded so that
the substrate is detached from the setting surface, wherein the
lift pin mechanism includes contact adjusting means that brings an
upper end of the first pin being withdrawn in the stage into
contact with the substrate on the setting surface without lifting
the substrate above the setting surface.
[0017] A plasma treatment apparatus of the present invention is a
plasma treatment apparatus which generates plasma in between an
electrode stage and a counter electrode at near atmospheric
pressure so as to subject a substrate to be treated being set on
the electrode stage to plasma treatment, the plasma treatment
apparatus including the above stage device as the electrode
stage.
[0018] According to the arrangement of the stage device of the
present invention, the contact adjusting means included in the lift
pin mechanism brings the upper end of the first pin being withdrawn
in the stage into contact with the substrate set on the setting
surface without lifting the substrate above the setting surface
(corresponding to adsorption surface). This makes it possible to
make the upper end of the first pin positioned at the same level as
the setting surface through the use of the substrate.
[0019] That is, through the use of the substrate, the stage device
is realized in which there is no difference in level between the
upper end of the first pin and the setting surface in a state where
the substrate is set on the setting surface.
[0020] In the plasma treatment apparatus of the present invention,
such a stage device of the present invention is used as the
electrode stage. This allows the substrate to come into contact
with both the setting surface and the first pin even in the
vicinity of the first pin.
[0021] This arrangement is free from a gap caused by difference in
level between the above-described lift pin (first pin) and the
setting surface, i.e. a gap between the substrate and lift pin
(first pin) or a gap between the substrate and the setting surface,
where no plasma is generated and a great voltage drop occurs. This
makes it possible to reduce the occurrence of uneven treatment and
incomplete treatment on the substrate.
[0022] Therefore, it is possible to provide a stage device and a
plasma treatment apparatus both of which are arranged such that no
difference in level occurs between the upper end of the first pin
and the setting surface in a state where the substrate is set on
the setting surface.
[0023] A display panel substrate of the present invention is a
display panel substrate for use in manufacturing a display panel,
and the display panel substrate is subjected to surface treatment
by means of the above plasma treatment apparatus of the present
invention capable of effectively reducing the occurrence of uneven
treatment. By manufacturing a display panel including such a
display panel substrate, it is possible to provide a display device
having an excellent display quality without display
irregularity.
BRIEF DESCRIPTION OF DRAWINGS
[0024] FIG. 1 is a view illustrating an embodiment of the present
invention and a cross-sectional view schematically illustrating the
structure of a plasma treatment apparatus of First Embodiment.
[0025] FIG. 2 is a plan view illustrating an appearance of an
electrode stage installed in the plasma treatment apparatus
illustrated in FIG. 1.
[0026] FIG. 3 is a cross-sectional view taken along a line B-B' of
FIG. 2.
[0027] FIG. 4 is a cross-sectional view taken along a line A-A' of
FIG. 2, illustrating the state where a lift pin is at a storage
position and a substrate is not set on the electrode stage.
[0028] FIG. 5 is a cross-sectional view taken along a line A-A' of
FIG. 2, illustrating the state where the lift pin is at the storage
position and the substrate is set on the electrode stage.
[0029] FIG. 6 is a cross-sectional view taken along a line A-A' of
FIG. 2, illustrating the state where the lift pin is at the storage
position and the substrate set on the electrode stage is
adsorbed.
[0030] FIG. 7 is a cross-sectional view taken along a line A-A' of
FIG. 2, illustrating the state where the lift pin is at a
protrusion position and the substrate is detached from the
electrode stage.
[0031] FIG. 8(a) is a cross-sectional view schematically
illustrating an essential part in the vicinity of the lift pin in
the plasma treatment apparatus illustrated in FIG. 1, and FIG. 8(b)
is an equivalent circuit diagram of FIG. 8(a).
[0032] FIG. 9 is an explanatory view of the problem that can occur
in a case where a spring type pin is disposed in the outer region
of the electrode stage.
[0033] FIG. 10 is an explanatory view illustrating that abnormal
electrical discharge occurs when an electrode surface in the outer
region of the electrode stage is exposed, wherein FIG. 10(a) is a
cross-sectional view schematically illustrating an essential part
of a plasma treatment apparatus having an exposed electrode
surface, and FIG. 10(b) is an equivalent circuit diagram of FIG.
10(a).
[0034] FIG. 11 is an explanatory view illustrating that abnormal
electrical discharge does not occur when an insulating section is
provided in the outer region of the electrode stage, wherein FIG.
11(a) is a cross-sectional view schematically illustrating an
essential part of the plasma treatment apparatus illustrated in
FIG. 1, and FIG. 11(b) is an equivalent circuit diagram of FIG.
11(a).
[0035] FIG. 12 is a plan view illustrating an appearance of another
electrode stage that can be installed in the plasma treatment
apparatus illustrated in FIG. 1.
[0036] FIGS. 13(a) through 13(e) are cross-sectional views
illustrating the structure of an electrode stage installed in a
plasma treatment apparatus of another embodiment of the present
invention, wherein an insulating section provided in the outer
region of the electrode stage is movable.
[0037] FIG. 14 is a cross-sectional view schematically illustrating
an essential part in the vicinity of the lift pin in a modified
example of the plasma treatment apparatus illustrated in FIG.
1.
[0038] FIG. 15 is a cross-sectional view schematically illustrating
an essential part in the vicinity of the lift pin in a modified
example of the plasma treatment apparatus illustrated in FIG.
1.
[0039] FIG. 16 is a cross-sectional view illustrating the structure
of an electrode stage installed in a plasma treatment apparatus of
another embodiment of the present invention, wherein the spring
type lift pin moves up and down in different manner.
[0040] FIG. 17 is a view illustrating another embodiment of the
present invention and a plan view illustrating an appearance of an
electrode stage installed in a plasma treatment apparatus of Second
Embodiment.
[0041] FIG. 18 is a cross-sectional view taken along a line C-C' of
FIG. 17, illustrating the state where the lift pin is at the
storage position and a substrate set on the electrode stage is
adsorbed.
[0042] FIG. 19 is a plan view illustrating an appearance of an
electrode stage installed in the plasma treatment apparatus
illustrated in FIG. 1.
[0043] FIG. 20 is a cross-sectional view taken along a line D-D' of
FIG. 19, illustrating the state where the lift pin is at the
storage position and a substrate set on the electrode stage is
adsorbed.
[0044] FIGS. 21(a) through (d) are cross-sectional views
illustrating the procedural steps for manufacturing a liquid
crystal panel in which a color filter is formed on the substrate
with the use of the plasma treatment apparatus illustrated in FIG.
1 or 17.
[0045] FIGS. 22(a) and 22(b) are plan views illustrating examples
of a pattern of black matrices for use in formation of a color
filter.
[0046] FIG. 23 is a plan view illustrating the state after the ink
delivery illustrated in FIG. 21(b).
[0047] FIG. 24 is a cross-sectional and enlarged view of a
conventional plasma treatment apparatus.
[0048] FIG. 25 is a circuit diagram illustrating an equivalent
circuit of an adsorption groove in the conventional plasma
treatment apparatus.
[0049] FIG. 26 is a cross-sectional and enlarged view of another
conventional plasma treatment apparatus.
[0050] FIG. 27 is a circuit diagram illustrating an equivalent
circuit of a part in the vicinity of a lift pin in the conventional
plasma treatment apparatus.
EXPLANATIONS OF REFERENCE NUMERALS
[0051] S plasma treatment apparatus [0052] 2 electrode stage [0053]
3 counter electrode [0054] 4 substrate to be treated [0055] 6
adsorption mechanism [0056] 6a adsorption holes [0057] 7 lift pin
mechanism [0058] 11 adsorption surface [0059] 18a treatment region
[0060] 18b non-treatment region [0061] 20 spring type lift pin
(first pin) [0062] 28 fixed type lift pin (second pin)
BEST MODE FOR CARRYING OUT THE INVENTION
First Embodiment of the Present Invention
[0063] FIGS. 1 through 11 illustrate First Embodiment of the
present invention. As illustrated in a cross-sectional view of FIG.
1, a plasma treatment apparatus S of the present embodiment is
arranged such that an electrode stage device (stage device) 35 and
a counter electrode 3 are provided in a chamber 1. A substrate 4 to
be treated (hereinafter simply referred to as "substrate 4"), such
as a glass substrate, held on an electrode stage 2 of the electrode
stage device 35 is subjected to plasma treatment at near
atmospheric pressure.
[0064] The counter electrode 3 is realized by an electrically
conductive member and is disposed so as to face the electrode stage
2. To the counter electrode 3, a power source section 10 is
connected, and electrical discharge can occur between the counter
electrode 3 and the electrode stage 2. The counter electrode 3 is
located inside the chamber 1 at an upper position thereof, and the
counter electrode 3 is connected to the gas injection pipe 9,
through which a treatment gas is injected into the counter
electrode 3. One end of the gas injection pipe 9 is connected to
the surface of the counter electrode 3 opposite to the surface
thereof facing the electrode stage 2. Further, the counter
electrode 3 has a plurality of gas injection holes 8, through which
the treatment gas supplied from the gas injection pipe 9 to the
counter electrode 3 is supplied toward the substrate 4.
[0065] The structure of the counter electrode 3 is not limited to
the above structure. The counter electrode 3 may be of any
structure as long as gas is evenly injected in between the counter
electrode 3 and the electrode stage 2.
[0066] The other end of the gas injection pipe 9 extends to the
outside of the chamber 1 and is connected to a gas supply source.
The bottom of the chamber 1 is connected to a discharge pipe 5,
through which an exhaust gas in the chamber 1 is discharged.
[0067] The electrode stage device 35 has the electrode stage 2, and
an adsorption mechanism 6 and a lift pin mechanism 7, both of which
are provided in the electrode stage 2.
[0068] The electrode stage 2 is the one on which the substrate 4 is
set. The electrode stage 2 has an electrode section 2a and an
insulating section 2b. The electrode section 2a is realized by a
electrically conductive member in the form of plate. The insulating
section 2b is realized by insulators arranged around the electrode
section 2a. The top surfaces of the electrode section 2a and the
insulating section 2b are a setting surface 11, on which the
substrate 4 is set. The electrode section 2a is grounded.
[0069] As illustrated in FIG. 2, the area on the setting surface 11
is divided into: a treatment region 18a in which plasma treatment
is performed, and a non-treatment region 18b in which plasma
treatment is not performed (or in which a predetermined quality of
treatment is not exhibited). In FIG. 2, the area surrounded by a
dashed-dotted line is the treatment region 18a, and the area
including the insulating section 2b outside the dashed-dotted line
is the non-treatment region 18b. The non-treatment region 18b is
set so that a non-pixel region of the substrate 4 set on the
setting surface 11 is positioned on the non-treatment region 18b.
In consideration of measurement of the non-pixel region of the
substrate 4, a width of the insulating section 2b is preferably 5
mm or greater, more preferably 5 mm to 10 mm.
[0070] The insulating section 2b has the function of preventing the
occurrence of abnormal electrical discharge. More specifically, if
the electrode section 2a was exposed toward the side surface of the
electrode stage 2 on the assumption that the substrate 4 is of the
same size as the electrode stage 2, electrical discharge between
the electrode stage 2 and the counter electrode 3 due to their
electrodes exposed, i.e. abnormal electrical discharge would occur
at the point A illustrated in FIG. 10(a) without the intervention
of a capacitor of the substrate 4. FIG. 10(b) is an equivalent
circuit diagram of FIG. 10(a). The resistor 33 shows the occurrence
of a voltage drop due to direct electrical discharge between the
counter electrode 3 and the electrode stage 2.
[0071] On the contrary, the electrode stage 2 is surrounded by the
insulating section 2b in the present embodiment. With this
arrangement, no abnormal electrical discharge occurs as illustrated
in FIG. 11(a) and FIG. 11(b), which is an equivalent circuit
diagram of FIG. 11(a), and electrical discharge (normal electrical
discharge) occurs by way of a capacitor 32 of the substrate 4. Note
that the resistor 31 shows the occurrence of a voltage drop between
the counter electrode 3 and the substrate 4.
[0072] As illustrated in FIG. 1, an adsorption mechanism 6 causes
the substrate 4 to be adsorbed onto the setting surface 11 of the
electrode stage 2. In the present embodiment, the adsorption
mechanism 6 is made up of a plurality of adsorption holes 6a, each
of which is a vertically long hole being circular in cross section
and formed in the setting surface 11.
[0073] As illustrated in FIG. 3, a plurality of exhaust passages 19
on the rear surface side of the electrode stage 2. Each of the
adsorption holes 6a is connected to a vacuum pump 50 via the
exhaust passage 19. The exhaust passages 19 are depressurized by
the vacuum pump 50 when driven, thereby generating vacuum force
(negative pressure) in the adsorption holes 6a. That is, when the
vacuum pump 50 is driven with the substrate 4 set on the setting
surface 11, vacuum force occurs in the adsorption holes 6a. This
makes it possible to adsorptively hold the substrate 4 on the
setting surface 11.
[0074] As illustrated in FIG. 2, the adsorption holes 6a are evenly
arranged in a matrix manner in the setting surface 11 of the
electrode stage 2. The adsorption holes 6a are formed so as to be
dispersed across the setting surface 11, whereby the substrate 4
can be adsorptively held evenly over the entire setting surface
11.
[0075] As illustrated in FIG. 3, the adsorption holes 6a are
connected in groups of at least two to each of the exhaust passages
19. This arrangement realizes a simpler structure than the
arrangement in which the adsorption holes 6a are connected to the
respectively corresponding exhaust passages 19.
[0076] Although there is a gap between the substrate 4 and the
electrode stage 2, the problem of uneven treatment occurs less
frequently. This is because internal pressures of the adsorption
holes 6a are depressurized by vacuuming, which facilitates plasma
generation and causes a relatively small voltage drop. However, if
the diameter of the adsorption holes 6a is large, uneven treatment
may occur even when the gap is at a negative pressure. Therefore,
it is desirable that the diameter of the adsorption holes 6a is not
greater than 0.5 mm.
[0077] If the pitch between the adsorption holes 6a is not greater
than 100 mm, it complicates working on the electrode stage 2 and
the insulating section 2b. This results in high production cost. On
the other hand, if the pitch is too large, it affects the
capability of the adsorption holes 6a in adsorbing the substrate 4
onto the setting surface 11. This requires negative pressure to be
increased. In view of this, the pitch between the adsorption holes
6a is preferably in the range from 100 mm to 200 mm.
[0078] Apart from the above arrangement, the adsorption mechanism 6
may be made up of a plurality of adsorption grooves which are
formed in the electrode stage 2 and concentrically aligned in a
rectangular ring manner (square-shaped-frame manner) in planar
view. In this case, the adsorption grooves may be connected to a
vacuum pump or the like via exhaust passages formed at the bottoms
of the respective adsorption grooves. Also in this case, it is
desirable that a width of the adsorption groove is not greater than
0.5 mm.
[0079] The lift pin mechanism 7 sets the substrate 4 on the
electrode stage 2 and detaches the substrate 4 from the electrode
stage 2, by means of lift pins which are arranged capable of
emerging from the setting surface 11 of the electrode stage 2. In
the present embodiment, contact adjusting means is provided that
brings the upper end of the lift pin being withdrawn in the
electrode stage 2 into contact with the substrate 4 on the setting
surface 11 without lifting the substrate 4 above the setting
surface 11, although details thereof will be described later. With
this arrangement, it is possible to reduce the occurrence of the
previously described uneven treatment during the plasma
treatment.
[0080] In the plasma treatment apparatus S having such an
arrangement, plasma is generated in between the counter electrode 3
and the electrode stage 2 when the power source section 10a applies
a voltage ranging, for example, from 1 kV through several tens of
kV in between the counter electrode 3 and the electrode stage 2
while a treatment gas is supplied in between the counter electrode
and the electrode stage 2. With this plasma, the substrate 4 is
subjected to plasma treatment.
[0081] For example, in order to perform etching with respect to a
thin film formed on the substrate 4 (thin film having chemical,
mechanical, optical, or electrical properties), the treatment gas
is preferably a mixed gas of CF4, and He or Ar. In order to perform
treatment for making the substrate 4 water repellent (liquid
repellent), the treatment gas can be a fluorine-containing gas such
as CF4, C2F6, or SF6. In order to form a thin film of a metal oxide
film made from SiO2, TiO2, SnO2, or the like on the surface of the
substrate 4, thereby making the substrate 4 hydrophilic, the
treatment gas can be a metal hydride gas (hydrogenated metal gas),
a halogenated metal gas, a gas of an organic metal compound such as
metallic alcoholate, or water vapor.
[0082] Next, the lift pin mechanism 7 installed in the electrode
stage device 35 of the plasma treatment apparatus S will be
described in detail with reference to FIGS. 4 through 7. FIGS. 4
through 7 are cross-sectional views taken along a line A-A' of FIG.
2.
[0083] As described previously, the lift pin mechanism 7 is
provided with lift pins that are arranged capable of emerging from
the setting surface 11 of the electrode stage 2. In this case, the
lift pin mechanism 7 is provided with two types lift pins, spring
type lift pins (first pins) 20 and fixed type lift pins (second
pins) 28. Each of the spring type lift pins 20 is provided with a
coil spring (elastic body) 23 having elasticity in a direction
where the pin moves. Each of the fixed type lift pins 28 is not
provided with the spring 23. As illustrated in FIG. 2, the spring
type lift pins 20 are disposed in the electrode section 2a, which
is located in the center of the electrode stage 2. The fixed type
lift pins 28 are disposed in the insulating section 2b, which is
located in the periphery of the electrode stage 2.
[0084] As illustrated in FIG. 4, the spring type lift pins 20 and
the fixed type lift pins 28 are each provided in a cylinder 26,
which is formed in the electrode stage 2. The cylinder 26 is
realized by a cylindrical hole opened in the setting surface 11.
The spring type lift pins 20 and the fixed type lift pins 28 are
each arranged to be movable in a direction along the length of the
cylinder 26 (i.e. up and down), and they move from a storage
position shown in FIG. 4 to a protrusion position shown in FIG. 7,
and vice versa.
[0085] The storage position is such a position that upper ends 20a
of the spring type lift pins 20 and upper ends 28a of the fixed
type lift pins 28 are positioned near the setting surface 11. The
protrusion position is such a position that the upper ends 20a of
the spring type lift pins 20 and the upper ends 28a of the fixed
type lift pins 28 are protruded above the setting surface 11, so
that the substrate 4 set on the setting surface 11 can be detached
from the setting surface 11. These spring type lift pins 20 and
fixed type lift pins 28 are electrically grounded as in the
electrode stage 2.
[0086] Each of the spring type lift pins 20 is arranged such that a
piston section 21 formed in the form of a column along the inner
walls of the cylinder 26 is coupled via the coil spring (elastic
body) 23 to a pin upper section 22 formed in the form of a bolt so
as to be flat on top. The coil spring 23 is the contact adjusting
means that brings the upper end 20a into contact with the substrate
4 on the setting surface 11 without lifting the substrate 4 above
the setting surface 11, and the coil spring 23 is also elasticity
function imparting means that imparts to the spring type lift pin
20 the function having elasticity in the direction where the pin 20
moves. The spring type lift pin 20 is imparted the function having
elasticity by the coil spring 23, thereby having elasticity in the
length direction, i.e. in the direction where the pin moves.
[0087] That is, with the arrangement in which the spring type lift
pin 20 has elasticity in the direction where the pin moves, the
upper end 20a of the spring type lift pin being withdrawn in the
electrode stage 2 can be brought into contact with the substrate 4
on the setting surface 11 by means of elasticity of the spring type
lift pin 20, without lifting the substrate 4 above the setting
surface 11, even if the upper end 20a of the spring type lift pin
20 cannot be stopped accurately at the position that is at the same
level as the setting surface 11a.
[0088] In the present embodiment, as illustrated in FIG. 4, in a
state where the spring type lift pin 20 is at the storage position,
and the substrate 4 is not set on the setting surface 11 so that no
load is applied onto the pin upper section 22, the upper end 20a of
the spring type lift pin 20 is protruded slightly above the setting
surface 11. The amount of protrusion by which the upper end 20a of
the spring type lift pin 20 is protruded above the setting surface
11 under no load, is the amount by which the upper end 20a can be
pressed down to the same level as the setting surface 11 by the
self weight of the substrate 4 that exceeds spring force of the
spring type lift pin 20. The amount of protrusion, which can be set
appropriately, is, for example, in the range from 0.3 mm to 0.8
mm.
[0089] As illustrated in FIG. 6, the spring type lift pin 20 is
completely pressed down into the cylinder 26 when the substrate 4
is set on the setting surface 11 and the substrate 4 is adsorbed by
the action of the adsorption mechanism 6. Since the pin upper end
20a of the spring type lift pin 20 being pressed down into the
cylinder 26 is pushed to the substrate 4 by the force with which
the coil spring 23 returns to its original state, the substrate 4
comes into contact with both the setting surface 11 and the lift
pins even in the vicinity of the lift pins.
[0090] With this arrangement, the plasma treatment apparatus S of
the present embodiment is free from the previously-described gap
that occurs during the plasma treatment due to the difference in
level between the upper end 20a of the spring type lift pin 20 and
the setting surface 11. This makes it possible to reduce the
occurrence of uneven treatment.
[0091] Incidentally, in order to completely press down the spring
type lift pin 20 into the cylinder 26 by the force (load) with
which the substrate 4 adsorbed by the adsorption mechanism 6
applies to the pin upper section 22, the upper end 20a needs to be
positioned below the setting surface 11 in a state where the force
(load) with which the substrate 4 applies to the pin upper end 22
is proportional to the force with which the coil spring 23 returns
to its original state. Such a design is easily made since a load
applied by the substrate to be treated can be increased by means of
the adsorption action of the adsorption mechanism 6.
[0092] However, as a matter of course, the present embodiment
permits a design that can be made considering only a load applied
by the self weight of the substrate 4, without considering the
adsorption action of the adsorption mechanism 6. In this case, a
load applied to one spring type lift pin 20 varies depending upon
the weight of the substrate 4, the number of the spring type lift
pins 20 disposed, warpage of the substrate, and other factors.
Therefore, assuming that spring forces of the coil springs 23 are
identical with each other, the position of the upper end 20a in a
state where the load applied by the substrate 4 is proportional to
the force with which the coil spring 23 returns to its original
state is varied by the load applied by the substrate 4. This may
cause the upper end 20a to be positioned above the setting surface
11 in the periphery of the setting surface 11 to which a light load
is applied. If the upper end 20a in such a proportional state comes
above the setting surface 11, the spring type lift pin 20 holds
itself with the upper end 20a protruding above the setting surface
11 even when the substrate 4 is set on the setting surface 11.
[0093] On the contrary, the substrate 4 is adsorptively held on the
setting surface 11 in the present embodiment. This ensures the
substrate 4 to be brought into contact with the setting surface 11
even if the substrate 4 is lightweight. In addition, the spring
force of the coil spring 23 can be set in accordance with a load
applied to the pin upper section 22 in the state where the
substrate 4 is adsorbed. This makes it possible to make the spring
force stronger than a spring force set in accordance with only a
load applied by the self weight of the substrate 4, thus allowing
the coil spring 23 to be easily designed, and allowing the coil
spring 23 to have a longer life span.
[0094] Further, the spring type lift pin 20 is arranged such that a
cylindrical member 24 is provided between the piston section 21 and
the pin upper section 22 so as to surround the coil spring 23. The
lower end of the cylindrical member 24 is fixed to the piston
section 21, and the upper end thereof is free. At the shaft of the
pin upper section 22, a sword-guard-like stopper 25 is provided so
as to come into contact with the cylindrical member 24.
[0095] The cylindrical member 24 and the stopper 25 are the ones
that restrict the constriction of the coil spring 23. That is, the
coil spring 23 constricts when the pin upper section 22 moves
downward by being pressed, but the constriction is stopped when the
stopper 25 comes into contact with the cylindrical member 24.
[0096] In such a manner, the constriction of the coil spring is
restricted. This defines a minimum length measurement of the spring
type lift pin 20, thus suppressing the deterioration of the coil
spring 23 without a pressure more than necessary applied to the
coil spring 23. At the step of detaching the substrate 4 from the
electrode stage 2, the coil spring 23 is made function as a
columnar member by the cylindrical member 24 and the stopper 25.
This allows the coil spring 23 to function in the same manner as
the fixed type lift pin 28, thus ensuring the substrate 4 to be
stably detached.
[0097] In this case, the coil spring 23 needs to be constricted
until the upper end 20a of the spring type lift pin 20 comes down
to the position that is at the same level as the setting surface
11. In view of this, a distance between the cylindrical member 24
and the stopper 25, i.e. a distance traveled by the stopper 25
until the stopper 25 comes into contact with the cylindrical member
24 needs to be set longer than the amount by which the upper end
20a is protruded above the setting surface 11 at the storage
position.
[0098] Meanwhile, the fixed type lift pin 28 is formed in the form
of a column along the inner walls of the cylinder 26, and the
diameter of the fixed type lift pin 28 on the rear surface side of
the electrode stage 2 (underside in FIG. 4) is greater than the
diameter on the setting surface 11 side (topside in FIG. 4). The
fixed type lift pin 28 is designed in such a manner that, as
illustrated in FIGS. 4 through 6, the upper end of the fixed type
lift pin 28 is positioned below the setting surface 11 in a state
where the fixed type lift pin 28 is moved downward to the storage
position, and that, as illustrated in FIG. 7, the upper end 28a is
positioned at the same level of the upper end 20a of the spring
type lift pin 20 that lifts up the substrate 4 in a state where the
fixed type lift pin 28 is at the protrusion position.
[0099] When the upper end of the fixed type lift pin 28 is
positioned below the setting surface 11, a gap 49 occurs between
the upper end 28a of the fixed type lift pin 28 and the substrate
104. This causes a voltage drop. However, the voltage drop does not
affect the quality of treatment on the substrate 4 since the fixed
type lift pins 28 are disposed in the non-treatment region 18b.
[0100] Next, the following will describe how to subject the
substrate 4 to plasma treatment by means of the above plasma
treatment apparatus S.
[0101] First of all, in a substrate adsorbing step, the substrate 4
is set on the electrode stage 2 in a state where the spring type
lift pin 20 and the fixed type lift pin 28 in the lift pin
mechanism 7 are moved to the respective storage positions, as
illustrated in FIG. 4. In the state where the substrate 4 is set on
the electrode stage 2, the upper end 20a of the spring type lift
pin 20 is protruded above the setting surface 11, as illustrated in
FIG. 5. With this, the substrate 4 slightly floats away from the
electrode stage 2 in an area corresponding to the center of the
electrode stage 2.
[0102] Then, the vacuum pump 50 is driven so that the adsorption
holes 6a are depressurized, which makes the substrate 4
adsorptively held on the setting surface 11, as illustrated in FIG.
6. At this moment, the upper end 20a of the spring type lift pin 20
is completely pressed down into the cylinder 26, which brings the
substrate 4 into contact with the electrode stage 2. Further, the
upper end 20a is brought into contact with the substrate 4 by the
spring force of the spring type lift pin 20.
[0103] Then, in a plasma generating step, the treatment gas is
injected into the counter electrode 3 and evenly supplied from the
gas injection holes 8 to the area between the counter electrode 3
and the electrode stage 2. In this state, a predetermined magnitude
of voltage is applied from the power source section 10 to the
counter electrode 3, so that plasma is generated in the area
between the counter electrode 3 and the substrate 4 on the
electrode stage 2 at near atmospheric pressure. With the generated
plasma, the substrate 4 is subjected to plasma treatment such as
etching. The exhaust gas in the chamber 1 is discharged via the
discharge pipe 5.
[0104] Next, in the substrate detaching step, after the plasma
treatment performed, application of a voltage by the power source
section 10 and gas supply from the gas injection pipe 9 are
stopped. Thereafter, the operation of the vacuum pump 50 is
stopped, which moves the spring type lift pin 20 and the fixed type
lift pin 28 in the lift pin mechanism 7 from the respective storage
positions to the protrusion position. This causes the substrate 4
to be detached from the setting surface 11 for carrying.
[0105] Through the above steps, the substrate 4 is subjected to
plasma treatment in the plasma treatment apparatus S.
[0106] Thus, according to the present embodiment, the setting
surface 11 of the electrode stage 2 can be made at the same level
as the upper end 20a of the spring type lift pin 20 in the lift pin
mechanism 7 during the plasma treatment, and the substrate 4 can be
brought into contact with both the electrode stage 2 and the spring
type lift pin 20. Therefore, plasma is generated without a gap
between the substrate 4 and the electrode stage 2 or between the
substrate 4 and the upper end 20a of the spring type lift pin 20,
in the vicinity of the spring type lift pin 20. As a result of
this, it is possible to subject the whole area of the substrate 4
to even plasma treatment while suppressing a voltage drop caused by
the gap. This makes it possible to reduce the occurrence of uneven
plasma treatment and incomplete plasma treatment at near
atmospheric pressure.
[0107] FIG. 8(a) is a cross-sectional view schematically
illustrating an essential part of the plasma treatment apparatus S,
and FIG. 8(b) illustrates an equivalent circuit diagram of FIG.
8(a). In FIG. 8(b), a circuit configuration in which the resistor
31 and the capacitor 32 are connected in series can be considered
as a circuit configuration between the power source section 10 and
a ground 12 in the vicinity of the spring type lift pin 20. The
resistor 31 shows the occurrence of a voltage drop due to plasma 14
generated in between the counter electrode 3 and the substrate 4.
The capacitor 32 is an electrical capacity in the substrate 4.
[0108] As is apparent from comparison between the equivalent
circuit in FIG. 8(b) and the equivalent circuit of the conventional
plasma treatment apparatus described previously in BACKGROUND ART
and illustrated in FIG. 25, an electrical capacity of a gap caused
by difference in level between the lift pin of the lift pin
mechanism and the setting surface 11 does not exist in the
arrangement in First Embodiment, which suppresses a voltage
drop.
[0109] In the present embodiment, the fixed type lift pins 28 are
disposed in the outer region of the electrode stage 2, and the
upper end 28a of the fixed type lift pin 28 at the storage position
is positioned below the setting surface 11. However, as a matter of
course, all of the lift pins, including the lift pins disposed in
the outer region of the electrode stage 2, can be changed to the
spring type lift pins 20.
[0110] However, this case may give rise to the problem illustrated
in FIG. 9. That is, the spring type lift pin 20 disposed in the
outer region of the setting surface 11 interferes with the contact
between the substrate 4 and the electrode stage 2 because a load
applied by the self weight of the substrate 4 is low, while the
spring type lift pin 20 disposed in the center of the setting
surface 11 comes down to a desired position because a load applied
by the self weight of the substrate 4 is high. This problem may be
improved to some extent by means of sucking force of the adsorption
mechanism 6. However, if the spring force of the spring type lift
pin 20 is strong, there is the possibility that the substrate 4
cannot contact with the electrode stage 2 even by means of sucking
force. Therefore, as adopted in the present embodiment, the fixed
type lift pins 28 are preferably used as the lift pins disposed in
the outer region of the electrode stage 2. The outer region of the
electrode stage 2 is normally non-treatment region 18b, on which
the region other than display region of the substrate 4, i.e. a
non-pixel region of the substrate 4 is set. Therefore, the
occurrence of uneven treatment in the vicinity of the lift pins is
not serious problem.
[0111] In the present embodiment, as illustrated in FIG. 2, the
fixed type lift pins 28 are provided in the insulating section 2b
of the non-treatment region 18b. However, the fixed type lift pins
28 may be provided in the electrode section 2a of the non-treatment
region 18b, as illustrated in FIG. 12. In short, the present
embodiment only needs to has an arrangement in which the fixed type
lift pins 16 are disposed in the non-treatment region 18b, and all
of the lift pins in the treatment region 18a are the spring type
lift pins 20.
[0112] Further, in the present embodiment, the fixed type lift pins
28 are disposed in the insulating section 2b of the electrode stage
2, and the cylinders 26 are formed in the insulating section 2b.
However, in a case where it is difficult to form holes or the like
as the cylinders 26 in the insulating section 2b, a mechanism for
detaching an insulating section 39, which is employed instead of
the insulating section 2b, from the electrode stage 2 may be
provided separately as illustrated in FIGS. 13(a) through 13(e). In
this case, the fixed type lift pins 28 are provided below the
insulating section 39, and at the rise of the fixed type lift pin
28, the insulating section 39 above the fixed type lift pins 28
retracts, so that the substrate 4 is set on the fixed type lift
pins 28. In this case, a cylinder 30 in which the fixed type lift
pin 28 moves is formed separately.
[0113] Still further, as illustrated in FIG. 8(a), which is a
cross-sectional view schematically illustrating the essential part,
the present embodiment makes it possible to eliminate a gap between
the substrate 4 and the electrode stage 2 and a gap between the
substrate 4 and the spring type lift pin 20, which gaps occur due
to difference in level between the upper end 20a of the spring type
lift pin 20 and the setting surface 11, in the vicinity of the
spring type lift pin 20 disposed in the treatment region 18a.
However, a small gap 15 remains between the cylinder 26 formed in
the electrode stage 2 and the spring type lift pin 20.
[0114] In a case where unevenness caused by such a small gap 15 is
detected after the plasma treatment, it is more preferable that
films 34 of different dielectric constants are formed respectively
on the upper end 20a of the spring type lift pin 20, as illustrated
in FIG. 14, and on the surface of the electrode stage 2 in the
vicinity of the spring type lift pin 20, as illustrated in FIG. 15.
With this arrangement, it is possible to make invisible and less
noticeable unevenness that would occur corresponding to the
position where the spring type lift pin 20 is located. In FIGS. 14
and 15, Reference numeral 14 indicates plasma that is generated in
between the counter electrode 3 and the substrate 4.
[0115] Yet further, in the present embodiment, the spring type lift
pin 20 holds its position in the storage position, which is a state
in which the spring type lift pin 20 is withdrawn underneath the
setting surface 11, in such a manner that the upper end 20a is
protruded above the setting surface 11 in a state where the
substrate 4 is not set on the setting surface 11.
[0116] However, the spring type lift pin 20 does not necessarily
holds its position in the storage position in such a manner that
the upper end 20a is protruded above the setting surface 11.
Alternatively, as illustrated in FIG. 16(a), the spring type lift
pin 20 may hold its position in such a manner that the upper end
20a is located below the setting surface 11. In this case, after
the substrate 4 is set on the setting surface 11, the spring type
lift pin 20 moves upwards to such a position that the substrate 4
does not float away from the setting surface, as illustrated in
FIG. 16(b).
[0117] Also in such an arrangement, variations of stop positions of
the lift pins are compensated for by means of the elasticity given
to the spring type lift pins 20 in the direction where the pins
move, so that the whole area of the substrate 4 can be subjected to
even plasma treatment. This makes it possible to reduce the
occurrence of uneven plasma treatment and the so-called incomplete
treatment at near atmospheric pressure.
[0118] Note that in the arrangement illustrated in FIG. 2, eight
spring type lift pins 20 are disposed in the center of the setting
surface 11. However, the number of spring type lift pins 20
disposed and the spacing between the spring type lift pins 20 may
be set in a manner which does not interfere with the detachment of
the substrate 4. Ditto with the fixed type lift pins 28 disposed in
the outer region of the electrode stage 2.
[0119] Further, in the present embodiment, the coil spring 23,
which makes up part of the spring type lift pin 20, is taken as an
example of the elasticity function imparting means. In short, the
elasticity function imparting means only needs to impart to the
lift pin the function having elasticity in a direction where the
pin moves. For example, a lift pin having no elasticity in its
movement direction, like the fixed type lift pin 28, may be
supported by a coil spring, a blade spring, or a rubber material,
which is provided separately from the lift pin, so that the lift
pin is imparted the function having elasticity in the movement
direction.
Second Embodiment
[0120] FIGS. 17 through 20 illustrate Second Embodiment of the
present invention. In the following descriptions of embodiments,
for convenience of explanation, members having the same functions
as those described in First Embodiment are given the same reference
numerals and explanations thereof are omitted here.
[0121] The apparatus in Second Embodiment is different from that in
First Embodiment illustrated in FIG. 2 in that a plurality of
adsorption holes 6a, which makes up an adsorption mechanism 6
formed in the setting surface 11 of the electrode stage 2 in the
plasma treatment apparatus S, are arranged as illustrated in FIG.
17.
[0122] That is, the arrangement in which the adsorption holes 6a
are arranged evenly beneath the setting surface 11 of the electrode
stage 2, as illustrated in FIG. 19, may cause the problem as
illustrated in FIG. 20, depending upon the magnitude of spring
force exerted by the coil spring 23 of the spring type lift pin 20.
That is, the substrate 4 cannot be attracted and adsorbed to the
electrode stage 2 by means of sucking force exerted by the
adsorption mechanism 6. FIG. 20 is a cross-sectional view taken
along a line D-D' of FIG. 19. Even in a case where the adsorption
holes 6a are arranged evenly, adsorption force can be increased by
decreasing a pitch between the adsorption holes 6a. This avoids the
adsorption force from becoming weaker than the spring force of the
coil spring 23 in the spring type lift pin 20, but inevitably
causes a high production cost.
[0123] In order to solve the above problem, the apparatus in Second
Embodiment is arranged as illustrated in FIG. 17. That is, in the
center of the setting surface 11, the adsorption holes 6a are more
densely disposed in the area where the spring type lift pins 20 of
the lift pin mechanism 7 are disposed than in the other area. A
pitch between the adsorption holes 6a is preferably in the range
from 20 mm to 100 mm in the area where the spring type lift pins 20
are disposed. In an area other than the area where the spring type
lift pins 20 are disposed, a pitch between the adsorption holes 6a
may be set in a manner which does not interfere with the adsorption
force. In this case, a pitch between the adsorption holes 6a is
designed to be 100 mm in the high-density area and 200 mm in the
other area.
[0124] With the electrode stage 2 arranged in this manner, it is
possible to obtain the same effect as obtained in First Embodiment,
and it is possible to reliably attract and adsorb the substrate 4
to the electrode stage 2, as illustrated in FIG. 18, even if spring
force of the coil spring 23 in the spring type lift pin 20 is
strong. That is, a pitch between the adsorption holes 6a is changed
according to the type of lift pins in the lift pin mechanism 7
beneath the setting surface 11. This brings a plasma treatment
apparatus that can improve the occurrence of uneven treatment while
suppressing an increase in production cost. FIG. 18 is a
cross-sectional view taken along a line C-C' of FIG. 17.
[0125] In First and Second Embodiments, the spring type lift pins
20 having elasticity in a direction of their movement are disposed
so that no gap occurs between the substrate 4 and the electrode
stage 2 and between the substrate 4 and the upper end of the lift
pin in the vicinity of the lift pin. However, First and Second
Embodiments are not limited to this. Alternatively, other
arrangement may be adopted as long as it enables the substrate 4 in
the vicinity of the lift pin to contact with both the electrode
stage 2 and the lift pin.
[0126] Next, with reference to FIGS. 21 through 23, the following
will describe the procedural steps for manufacturing a liquid
crystal panel in which the surface of a substrate is subjected to
plasma treatment so that a color filter is formed on the substrate,
with the use of the plasma treatment apparatus described in First
and Second Embodiments.
[0127] First of all, as illustrated in FIG. 21(a), black matrices
41 are formed on a substrate 40 so that concavities 42 are
formed.
[0128] As the substrate 40, a glass substrate or a plastic
substrate is preferably used. However, type of the substrate 40 is
not particularly limited as long as it has essential properties of
a color filter, such as transparency and mechanical strength.
Generally, examples of a pattern of the black matrices 41 include,
but are not particularly limited to, a matrix pattern illustrated
in FIG. 22(a) and a stripe pattern illustrated in FIG. 22(b). In
the following description, the matrix pattern illustrated in FIG.
22(a) is taken as an example.
[0129] The black matrices 41 form the concavity 42 for receiving
ink, and function as a barrier (wall) for preventing inks of
different colors in the adjacent concavities 42 from being mixed. A
method for forming the black matrices 41 is not particularly
limited, and the black matrices 41 may be formed by a known method.
For example, it is possible to form the black matrices 41 by
performing patterning with a black resin by photolithography or the
like method. The thickness of the black matrix is preferably in the
range from 0.5 .mu.m to 3.0 .mu.m, particularly preferably 1.0
.mu.m to 2.0 .mu.m.
[0130] Then, the substrate 40 on which the black matrices 41 are
formed is set on the electrode stage 2 of the plasma treatment
apparatus S of First and Second Embodiments so that the black
matrices 41 are subjected to water repellent treatment (water
repellency step).
[0131] The treatment gas is preferably a fluorine-containing gas
such as CF4, C2F6, or SF6. However, the treatment gas is not
limited to a fluorine-containing gas and may be a gas that gives
the black matrices 41 water repellency that can prevent mixture of
inks.
[0132] In a case where it is necessary to improve water repellency
of the concavities 42, UV treatment or plasma treatment using Ar,
He, or O2 as a treatment gas may be performed before the above
water repellency step (hydrophilicity step).
[0133] Next, as illustrated in FIG. 21(b), ink 44 is delivered from
a nozzle 43 of an inkjet device (ink delivery step).
[0134] The ink 44 is selectively delivered to only the concavities
42 provided between the black matrices 41 while the nozzle 43 goes
over the black matrices 41. The delivered ink 44 is preferably
thermosetting ink having pigment dispersed therein. The ink 44 can
be delivered by a known method.
[0135] FIG. 23 is a plan view of a color filter in a state where
the ink 44 is delivered, when viewed from above the substrate 40.
In FIG. 23, the inks 44, 45, 46 are inks in which red, blue, green
pigments are dispersed, respectively. Since FIG. 21 is a
cross-sectional view, only the ink 44, i.e. ink of red color is
shown in FIG. 21.
[0136] Thereafter, the ink 44 is dried so as to form a color layer
48. For example, the color layer 48 can be formed by evaporating a
solvent in the ink 44 and then burning the ink 44 for thermal
polymerization of the ink 44. A method for evaporating a solvent of
ink and a burning method may be selected appropriately from known
methods according to the states of the ink 44 and the substrate
40.
[0137] Through the improvement of the problem of unevenness
occurring in the vicinity of a lift pin in the plasma treatment
apparatus, a color filter manufactured by the above manufacturing
method has an excellent display quality without unevenness. A
liquid crystal display device having the thus manufactured color
filter provides high-performance, high-quality display and offers a
comfortable viewing environment to the user.
[0138] Now, taking an example, the following will more specifically
describe the procedural steps for manufacturing a liquid crystal
panel in which the surface of a substrate is subjected to plasma
treatment so that a color filter is formed on the substrate, with
the use of the plasma treatment apparatus described in First and
Second Embodiments. The present example will be also described with
reference to FIG. 21.
[0139] First of all, as illustrated in FIG. 21(a), the black
matrices 41 were formed on the substrate 40 so that the concavities
42 were formed. In the present example, the substrate 40 was a 0.7
mm-thick glass substrate. The black matrices 41 were formed with a
resin black and formed 1.5 .mu.m thick by spin coating and photo
process.
[0140] Next, the substrate 40 on which the black matrices were
formed was subjected to UV treatment for hydrophilic treatment of
the concavities. Then, in the present example, plasma treatment was
performed with a fluorine-containing gas by means of the plasma
treatment apparatus S of First and Second Embodiments, so that
water-repellent treatment was performed on the black matrices 41.
In the present example, a contact angle of the hydrophilic
concavity 42 with respect to pure water was approximately
10.degree., and a contact angle of the black matrix 41 with respect
to pure water was approximately 90.degree. to 100.degree..
[0141] Next, the ink 44 was delivered from the nozzle 43 as
illustrated in FIG. 21(b). As illustrated in FIG. 23, the ink is
selectively delivered to only the concavities 42 provided between
the black matrices 41 while the nozzle goes over the black matrices
41. In the present example, ink delivery was performed at
25.degree. C. by means of an inkjet device, and inks of three
colors R, G, B were delivered at the same time by 5 pl per drop.
The ink 44 (ditto for ink 45 and ink 46) after delivered was convex
in the concavity 42, as illustrated in FIG. 21(c).
[0142] Next, a solvent was evaporated at 100.degree. C. for 10
minutes by means of a hot plate. Then, the ink 44 was burned in an
oven at 220.degree. C. for 30 minutes for thermal polymerization of
the ink 44. As a result, the colored layer 48 was formed as
illustrated in FIG. 21(d).
[0143] As described above, a stage device of the present invention
includes: a stage having a setting surface on which a substrate to
be treated is set; and a lift pin mechanism having first pins,
provided in the stage, each capable of emerging from the setting
surface, the first pins being protruded so that the substrate is
detached from the setting surface, wherein the lift pin mechanism
includes contact adjusting means that brings an upper end of the
first pin being withdrawn in the stage into contact with the
substrate on the setting surface without lifting the substrate
above the setting surface.
[0144] A plasma treatment apparatus of the present invention is a
plasma treatment apparatus which generates plasma in between an
electrode stage and a counter electrode at near atmospheric
pressure so as to subject a substrate to be treated being set on
the electrode stage to plasma treatment, the plasma treatment
apparatus including the above stage device as the electrode
stage.
[0145] According to the arrangement of the stage device of the
present invention, the contact adjusting means included in the lift
pin mechanism brings the upper end of the first pin being withdrawn
in the stage into contact with the substrate set on the setting
surface without lifting the substrate above the setting surface
(corresponding to adsorption surface). This makes it possible to
make the upper end of the first pin positioned at the same level as
the setting surface through the use of the substrate.
[0146] That is, through the use of the substrate, the stage device
is realized in which there is no difference in level between the
upper end of the first pin and the setting surface in a state where
the substrate is set on the setting surface.
[0147] In the plasma treatment apparatus of the present invention,
such a stage device of the present invention is used as the
electrode stage. This allows the substrate to come into contact
with both the setting surface and the first pin even in the
vicinity of the first pin.
[0148] This arrangement is free from a gap caused by difference in
level between the above-described lift pin (first pin) and the
setting surface, i.e. a gap between the substrate and lift pin
(first pin) or a gap between the substrate and the setting surface,
where no plasma is generated and a great voltage drop occurs. This
makes it possible to reduce the occurrence of uneven treatment and
incomplete treatment on the substrate.
[0149] In the stage device of the present invention and the plasma
treatment apparatus of the present invention, the contact adjusting
means includes elasticity function imparting means that imparts to
the first pin a function having elasticity in a direction where the
first pin moves, and the upper end of the first pin is brought into
contact with the substrate by the elasticity imparted by the
elasticity function imparting means.
[0150] With this arrangement, the contact adjusting means is
realized by elasticity function imparting means that imparts to the
first pin the function having elasticity in a direction where the
first pin moves, and the upper end of the first pin is brought into
contact with the substrate by the elasticity imparted by the
elasticity function imparting means. That is, even in the event
when the first pin cannot be stopped at such a position that the
upper end of the first pin is at the same level as the setting
surface due to the limitation of the lift pin mechanism in terms of
mechanical precision, the event can be compensated for by a simple
arrangement using elasticity. This makes it possible to make the
upper end of the first pin bring into contact with the substrate
without floating the substrate above the setting surface.
[0151] The elasticity function imparting means is realized by, for
example, an elastic body being provided to the first pin and having
elasticity in the direction where the first pin moves.
[0152] The stage device and the plasma treatment apparatus of the
present invention can be arranged such that when each of the first
pins is at a storage position where the first pin is withdrawn in
the stage, the upper end of the first pin is protruded above the
setting surface in a state where the substrate is not set on the
setting surface, and the upper end of the first pin is positioned
at the same level as the setting surface by a load applied by the
substrate in a state where the substrate is set on the setting
surface.
[0153] The stage device and the plasma treatment apparatus of the
present invention can be also arranged such that when each of the
first pins is at a storage position where the first pin is
withdrawn in the stage, the upper end of the first pin is
positioned below the setting surface in a state where the substrate
is not set on the setting surface, and after the substrate is set
on the setting surface, the first pin moves upward so that the
upper end thereof comes into contact with the substrate.
[0154] Further, the stage device and the plasma treatment apparatus
of the present invention is preferably arranged such that the stage
is provided with an adsorption mechanism that adsorptively holds
the substrate on the setting surface.
[0155] Provision of the adsorption mechanism allows the substrate
to be adsorptively held on the setting surface. This makes it
possible to securely fix the substrate as compared with the
arrangement in which the substrate is just set on the setting
surface. In addition, a load exerted on the first pin becomes
stronger than a load caused only by the self weight of the
substrate. This makes it easy to impart elasticity in the direction
where the first pin moves and make the upper end of the first pin
brought into contact with the substrate without lifting the
substrate above the setting surface.
[0156] That is, in order to make the upper end of the first pin
brought into contact with the substrate without floating the
substrate above the setting surface by means of the elasticity of
the first pin, the upper end of the first pin needs to be
positioned below the setting surface in a state where a load
received from the substrate being set is proportional to a force
with which the first pin deformed by the load is returned to its
original state.
[0157] With this arrangement, it is possible to easily make such a
design that the upper end of the first pin is positioned below the
setting surface in a state where a load received from the substrate
is proportional to the force with which the first pin is returned
to its original state.
[0158] In this case, it is preferable that the adsorption mechanism
has a stronger adsorption force in the vicinity of the first pin to
which the function having elasticity is imparted than an adsorption
force in other area. This makes it possible to more effectively
obtain the above action caused by using adsorption force.
[0159] Further, the stage device and the plasma treatment apparatus
of the present invention can be arranged such that the lift pin
mechanism has second pins, provided in the outer region of the
stage, each capable of emerging from the setting surface and having
no elasticity in a direction where the second pin moves, and an
upper end of the second pin is positioned below the setting surface
in a state where the second pin is withdrawn in the stage.
[0160] As described previously, in order to make the upper end of
the first pin brought into contact with the substrate without
floating the substrate above the setting surface by means of the
elasticity of the first pin, the upper end of the first pin needs
to be positioned below the setting surface in a state where a load
received from the substrate is proportional to a restoring force.
However, since a load received from the substrate is low in the
outer region of the stage, the upper end of the first pin may be
positioned above the setting surface in a state where both of the
forces are proportional to each other. As a result, the substrate
may float in an area corresponding to the outer region of the
stage.
[0161] On the contrary, in the above arrangement, the second pins
each of which is capable of emerging from the setting surface and
has no elasticity in the direction where the second pin moves are
disposed in the outer region of the stage, and the upper end of the
second pin is positioned below the setting surface in a state where
the second pin is withdrawn in the stage. This prevents the
substrate from being floated in an area corresponding to the outer
region of the stage.
[0162] A display panel substrate of the present invention is a
display panel substrate for use in manufacturing a display panel,
and the display panel substrate is subjected to surface treatment
by means of the above plasma treatment apparatus of the present
invention capable of effectively reducing the occurrence of uneven
treatment. By manufacturing a display panel including such a
display panel substrate, it is possible to provide a display device
having an excellent display quality without display
irregularity.
INDUSTRIAL APPLICABILITY
[0163] The present invention can be applied to the manufacture of a
display panel substrate and the like, for example.
* * * * *