U.S. patent application number 15/664319 was filed with the patent office on 2017-11-16 for exposure method, substrate stage, exposure apparatus, and device manufacturing method.
This patent application is currently assigned to NIKON CORPORATION. The applicant listed for this patent is NIKON CORPORATION. Invention is credited to Shigeru HIRUKAWA, Motokatsu IMAI, Jiro INOUE, Hirotaka KOHNO, Yoshihiko KUDO, Nobutaka MAGOME, Hiroyuki NAGASAKA, Masahiro NEI, Yasufumi NISHII, Soichi OWA, Kenichi SHIRAISHI, Hiroaki TAKAIWA.
Application Number | 20170329234 15/664319 |
Document ID | / |
Family ID | 33556144 |
Filed Date | 2017-11-16 |
United States Patent
Application |
20170329234 |
Kind Code |
A1 |
OWA; Soichi ; et
al. |
November 16, 2017 |
EXPOSURE METHOD, SUBSTRATE STAGE, EXPOSURE APPARATUS, AND DEVICE
MANUFACTURING METHOD
Abstract
An exposure apparatus exposes a substrate by projecting a
pattern image onto the substrate through a liquid. The exposure
apparatus includes a projection optical system by which the pattern
image is projected onto the substrate, and a movable member which
is movable relative to the projection optical system. A
liquid-repellent member, at least a part of a surface of which is
liquid-repellent, is provided detachably on the movable member, the
liquid-repellent member being different from the substrate.
Inventors: |
OWA; Soichi; (Kumagaya-shi,
JP) ; MAGOME; Nobutaka; (Kumagaya-shi, JP) ;
HIRUKAWA; Shigeru; (Tokyo, JP) ; KUDO; Yoshihiko;
(Tokyo, JP) ; INOUE; Jiro; (Kumagaya-shi, JP)
; NAGASAKA; Hiroyuki; (Kumagaya-shi, JP) ; KOHNO;
Hirotaka; (Kumagaya-shi, JP) ; NEI; Masahiro;
(Yokohama-shi, JP) ; IMAI; Motokatsu;
(Yokohama-shi, JP) ; SHIRAISHI; Kenichi;
(Saitama-shi, JP) ; NISHII; Yasufumi;
(Kumagaya-shi, JP) ; TAKAIWA; Hiroaki;
(Kumagaya-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
NIKON CORPORATION |
Tokyo |
|
JP |
|
|
Assignee: |
NIKON CORPORATION
Tokyo
JP
|
Family ID: |
33556144 |
Appl. No.: |
15/664319 |
Filed: |
July 31, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14696898 |
Apr 27, 2015 |
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15664319 |
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13753969 |
Jan 30, 2013 |
9019467 |
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14696898 |
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12232064 |
Sep 10, 2008 |
8384880 |
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13753969 |
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11297324 |
Dec 9, 2005 |
7483119 |
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12232064 |
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PCT/JP2004/008578 |
Jun 11, 2004 |
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11297324 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G03F 7/707 20130101;
G03B 27/58 20130101; G03F 7/2041 20130101; G03F 7/70341 20130101;
G03F 7/70716 20130101 |
International
Class: |
G03F 7/20 20060101
G03F007/20; G03F 7/20 20060101 G03F007/20; G03F 7/20 20060101
G03F007/20; G03F 7/20 20060101 G03F007/20; G03B 27/58 20060101
G03B027/58 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 13, 2003 |
JP |
2003-169904 |
Nov 13, 2003 |
JP |
2003-383887 |
Feb 17, 2004 |
JP |
2004-039654 |
Claims
1. An exposure apparatus which exposes a substrate with light via a
liquid immersion region formed with liquid, the exposure apparatus
comprising: a stage which supports the substrate; a projection
optical system which projects a pattern image in a projection
region on the substrate supported on the stage; and a liquid supply
and recovery system which forms the liquid immersion region on a
part of the substrate supported on the stage so that the projection
region is located in the liquid immersion region, wherein the
liquid supply and recovery system comprises a supply port to supply
liquid and a recovery port to recovery liquid, the supply port
being located off the projection region with respect to a direction
perpendicular to an optical axis of the projection optical system,
the recovery port being located away from the projection region
compared to the supply port, the supply port and the recovery port
being arranged above the stage, and wherein the stage comprises a
substrate holder to hold the substrate and a flow channel to
recovery liquid, the substrate holder being disposed in a concave
portion formed on the stage, the flow channel being disposed in the
stage so as to remove liquid from the concave portion.
2. The exposure apparatus according to claim 1, wherein the
substrate holder comprises at least one peripheral wall and
supporting portions disposed in a space surrounded by the
peripheral wall, and the substrate holder is configured to hold the
substrate on the supporting portions by applying a negative
pressure to the space surrounded by the peripheral wall.
3. The exposure apparatus according to claim 2, wherein the
peripheral wall includes a first peripheral wall that faces an
inner surface of the concave portion and a second peripheral wall
that is disposed between the first peripheral wall and the
supporting portion.
4. The exposure apparatus according to claim 2, wherein the flow
channel is connected to a space between the peripheral wall and an
inner surface of the concave portion.
5. The exposure apparatus according to claim 1, wherein the
recovery port is provided to face the surface of the substrate held
by the substrate holder.
6. The exposure apparatus according to claim 1, wherein an upper
surface of the stage around the concave portion is arranged so that
a height of the upper surface of the stage around the concave
portion is substantially the same height as an upper surface of the
substrate supported by the substrate holder.
7. The exposure apparatus according to claim 6, wherein the upper
surface of the stage is arranged so as to contact with the liquid
immersion region.
8. A method for producing a device, comprising using the exposure
apparatus according to claim 1.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This is a continuation of U.S. patent application Ser. No.
14/696,898, filed Apr. 27, 2015, which is a division of U.S. patent
application Ser. No. 13/753,969, filed Jan. 30, 2013, which is a
continuation of U.S. patent application Ser. No. 12/232,064, filed
Sep. 10, 2008, which is a division of U.S. patent application Ser.
No. 11/297,324 filed Dec. 9, 2005, which in turn is a Continuation
of International Application No. PCT/JP2004/008578, filed Jun. 11,
2004, which claims priority to Japanese Patent Application Nos.
2003-169904 (filed on Jun. 13, 2003), 2003-383887 (filed on Nov.
13, 2003), and 2004-039654 (filed on Feb. 17, 2004). The
disclosures of the aforementioned applications are incorporated
herein by reference in their entireties.
BACKGROUND OF THE INVENTION
Field of the Invention
[0002] The present invention relates to an exposure method by which
a pattern image is exposed, via a projection optical system and a
liquid, on a substrate; to a substrate stage that supports a
substrate; to an exposure apparatus; and to a device manufacturing
method.
Description of Related Art
[0003] Semiconductor devices and liquid crystal display devices are
manufactured through the so-called photolithography technique, by
which a pattern formed on a mask is transferred onto a
photosensitive substrate. The exposure apparatus used in the
photolithography process has a mask stage that supports a mask and
a substrate stage that supports a substrate, and while successively
moving the mask stage and the substrate stage, transfers the mask
pattern, via a projection optical system, onto the substrate. In
recent years, to address the increasingly high integration of
device patterns, increasingly high resolution of the projection
optical system has been desired. The shorter the exposure
wavelength used is, and, also, the larger the numerical aperture of
the projection optical system is, the higher the resolution of the
projection optical system becomes. For this reason, the exposure
wavelength used for the exposure apparatus is becoming shorter and
shorter year by year, and the numerical aperture of the projection
optical system is also becoming larger and larger. In this context,
the presently dominant exposure wavelength is 248 nm from a KrF
excimer laser, but a still shorter wavelength of 193 nm from an ArF
excimer laser is now gradually being put to practical use.
[0004] In addition, when performing exposure, the depth of focus
(DOF) is an important factor along with the resolution. The
resolution R and the depth of focus .delta. are respectively
expressed by the following formulas:
R=k.sub.1.lamda./NA, (1)
.delta.=.+-.k.sub.2.lamda./NA.sup.2, (2)
where .lamda. is the exposure wavelength, NA is the numerical
aperture of the projection optical system, and k.sub.1 and k.sub.2
are process coefficients. It can be seen from formulas (1) and (2)
that if, to enhance the resolution R, the wavelength .lamda. is
made shorter and the numerical aperture is made larger, then the
depth of focus .delta. becomes narrower.
[0005] When the depth of focus .delta. becomes too narrow, it
becomes difficult to make the substrate surface coincide with the
image plane of the projection optical system, and thus there occurs
the possibility that the focus margin during the exposure operation
will be insufficient. To address this problem, the liquid immersion
method, which is disclosed in, e.g., PCT International Publication
No. WO 99/49504, has been proposed as a method to make the exposure
wavelength shorter in effect and to make the depth of focus
broader. This liquid immersion method is designed to, by filling
the space between the under surface of the projection optical
system and the substrate surface with a liquid, e.g., water or
organic solvent, to form a liquid immersion region and thus by
taking advantage of the fact that the wavelength of the exposure
light in the liquid becomes 1/n times (n is the refractive index of
the liquid and is generally about 1.2 to 1.6) of that in the air,
improve the resolution and, at the same time, enlarge the depth of
focus by approximately n times.
[0006] By the way, with the above-described related art, there are
problems as described below. The above-described prior art has
adopted the configuration in which the space between the image
plane side end face of the projection optical system and the
substrate (wafer) is locally filled with a liquid, and when
exposing shot areas around the center of the substrate, the liquid
does not flow out to the outside of the substrate. However, when,
as shown by the schematic of FIG. 27, projection area 100 of the
projection optical system is applied to peripheral area (edge area)
E of substrate P for the purpose of exposing edge area E of
substrate P, the liquid flows out to the outside of substrate P,
which leads to the disadvantage that the liquid immersion region is
not formed well, thus deteriorating the pattern image projected.
Furthermore, there also arises the disadvantage that the liquid
that flowed out causes mechanical parts, etc. in the vicinity of
the substrate stage that supports substrate P to rust or causes
electric leakage of the stage drive system, etc. Moreover, if the
liquid that flowed out finds its way over to the underside surface
of the substrate and penetrates into the space between the
substrate and the substrate stage (substrate holder), there also
arises the disadvantage that the substrate stage cannot hold the
substrate well. In addition, air bubbles may come to be mixed in
the liquid due to the height difference or gap between substrate P
and the substrate stage, and, in this case, there arises the
disadvantage, for example, that the exposure light is scattered
under the influence of the air bubbles or that the pattern does not
focus into an image on substrate P because of the bubbles. Besides,
also when the liquid penetrates into the above-mentioned gap, rust
or electric leakage may be induced.
SUMMARY OF THE INVENTION
[0007] The present invention has been made in consideration of such
situations, and its objective is to provide an exposure method, a
substrate stage, an exposure apparatus, and a device manufacturing
method, by which, in the case of performing exposure process with
the space between a projection optical system and a substrate being
filled with a liquid, the exposure can be done in a condition that
a liquid immersion region is formed well, even when exposing edge
areas of the substrate.
[0008] To resolve the above-described problems, the present
invention adopts the following configurations that are illustrated
in the embodiments and correspond to FIGS. 1 to 26.
[0009] An exposure method of the present invention is an exposure
method wherein a substrate is exposed by projecting an image of a
pattern onto the substrate via a projection optical system and a
liquid, the side surface of the substrate is applied with
liquid-repellent treatment.
[0010] In accordance with the present invention, because the side
surface of the substrate is applied with liquid-repellent
treatment, penetration of the liquid into, for example, the space
between a member (substrate stage) disposed so as to surround the
substrate and the side surface of the substrate can be prevented.
Thus, penetration of the liquid to the underside surface side of
the substrate can be prevented. Furthermore, mixing of bubbles with
the liquid, for example, is also prevented, and thus, the edge
areas of the substrate can be exposed in a condition that the
liquid immersion region is formed well.
[0011] An exposure method of the present invention is an exposure
method wherein a substrate is exposed by projecting an image of a
pattern onto the substrate via a projection optical system and a
liquid, the underside surface of the substrate is applied with
liquid-repellent treatment.
[0012] In accordance with the present invention, because the
underside surface of the substrate is applied with liquid-repellent
treatment, penetration of the liquid into, for example, the space
between the substrate holder that holds the underside surface of
the substrate and the underside surface of the substrate can be
prevented. Therefore, the exposure can be performed with the
substrate being held well.
[0013] A substrate stage of the present invention is a substrate
stage that is used in liquid immersion exposure wherein a substrate
is exposed by projecting an image of a pattern onto the substrate
via a projection optical system and a liquid and that is movable
while holding the substrate, at least a part of its surface is
liquid-repellent.
[0014] In accordance with the present invention, by making the
surface of the substrate stage liquid-repellent, while suppressing
scattering of the liquid, flowing out of the liquid to the outside
of the substrate stage, mixing of bubbles with the liquid,
penetration of the liquid into the inside of the substrate stage,
etc., the edge areas of the substrate can be exposed in a condition
that the liquid immersion region is formed well.
[0015] A substrate stage of the present invention is a substrate
stage that is used in liquid immersion exposure wherein a substrate
is exposed by forming a liquid immersion region on a part of the
substrate and by projecting a pattern image onto the substrate via
a projection optical system and a liquid and that holds the
substrate, the substrate stage has around the substrate a flat
portion of which height is substantially equal to that of the
substrate, in that a concave portion in which the substrate is
disposed is formed inside the flat portion, and in that the
exposure of the substrate is performed in a condition that a gap
between the flat portion and the substrate is filled with the
liquid.
[0016] In accordance with the present invention, even when the
liquid immersion region is formed around the edge of the substrate,
not only the liquid immersion region can be maintained in good
condition, but also mixing of bubbles with the liquid of the liquid
immersion region formed on a part of the substrate can be
prevented. As a result, also around the edge of the substrate, good
pattern images can be formed on the substrate.
[0017] An exposure apparatus of the present invention is provided
with any one of the substrate stages described above. A device
manufacturing method of the present invention uses the exposure
method described above or an exposure apparatus described above
provided with the substrate stage.
[0018] In accordance with the present invention, the edge areas of
the substrate can be liquid immersion exposed in a condition that
the liquid immersion region is formed well, and thus devices having
a desired performance can be manufactured.
[0019] A substrate stage of the present invention is a substrate
stage that is movable while holding a substrate as an object to be
exposed, the substrate stage is provided with a first peripheral
wall, a second peripheral wall formed inside the first peripheral
wall, and a supporting portion formed inside the second peripheral
wall and in that by applying a negative pressure to a space
surrounded by the second peripheral wall, the substrate is held by
the supporting portion.
[0020] In accordance with the present invention, because at least
double peripheral walls are provided with around the supporting
portion that supports the substrate, even if a liquid penetrates
into the space between a member disposed so as to surround the
substrate and the side surface of the substrate, penetration of the
liquid to the underside surface side of the substrate or into a
vacuum system for applying the negative pressure to the space can
be prevented.
[0021] A substrate stage of the present invention is a substrate
stage that is movable while holding a substrate as an object to be
exposed, the substrate stage is provided with a supporting portion
that supports the substrate, a flat portion which is disposed
around the substrate supported by the supporting portion and is
substantially coplanar with the surface of the substrate, and a gap
adjustment portion for making the gap between a cut portion of the
substrate supported by the supporting portion and the flat portion
small.
[0022] In accordance with the present invention, by making the gap
between the cut portion of the substrate and the flat portion
surrounding the substrate small by means of the gap adjustment
portion, penetration of the liquid into the space between the cut
portion of the substrate and the flat portion can be suppressed.
Thus, penetration of the liquid to, e.g., the underside surface
side of the substrate can be prevented.
[0023] A substrate stage of the present invention is a substrate
stage that is movable while holding a substrate as an object to be
exposed, the substrate stage is provided with a peripheral wall and
a supporting portion formed inside the peripheral wall, in that the
peripheral wall is formed in accordance with the form or shape of a
cut portion of the substrate, and in that by applying a negative
pressure to a space surrounded the peripheral wall, the substrate
is held by the supporting portion.
[0024] In accordance with the present invention, by forming the
peripheral wall in accordance with the form of the cut portion of
the substrate, the disadvantage that a large gap would be formed
between the substrate and the peripheral wall will be suppressed,
thus allowing the space surrounded by the peripheral wall to have
smoothly a negative pressure. Thus, the substrate can be held well
by the supporting portion, and, further, penetration of the liquid
to the underside surface side of the substrate and/or into the
space can be suppressed.
[0025] A substrate stage of the present invention is a substrate
stage that is movable while holding a substrate as an object to be
exposed, the substrate stage is provided with a supporting portion
for holding the substrate and a plurality of gas-suction ports for
sucking and holding the substrate and in that the gas-sucking force
near a cut portion of the substrate is made to be smaller than the
gas-sucking force therearound.
[0026] In accordance with the present invention, by making the
gas-sucking force via the gas-suction port(s) near the cut portion,
which tends to create a large gap between the substrate and the
substrate stage, smaller (weaker) than the gas-sucking force via
the gas-suction ports therearound, the disadvantage that the liquid
would penetrate into the space between the cut portion of the
substrate and the substrate stage will be suppressed. Thus,
penetration of the liquid to the underside surface side of the
substrate and/or into the gas-suction ports can be prevented.
[0027] An exposure apparatus of the present invention is by
illuminating a substrate held by any one of the substrate stage
described above with an exposure light via a projection optical
system and a liquid, the substrate is liquid immersion exposed. A
device manufacturing method of the present invention uses the
exposure apparatus described above.
[0028] In accordance with the present invention, while suppressing
penetration of the liquid to the underside side of the substrate,
into the inside of the substrate stage, or into the vacuum system,
the substrate can be liquid immersion exposed, and thus devices
having a desired performance can be manufactured.
BRIEF DESCRIPTION OF THE DRAWINGS
[0029] FIG. 1 is a schematic diagram showing an embodiment of an
exposure apparatus of the present invention.
[0030] FIG. 2 is a schematic showing a liquid supply system and a
liquid recovery system.
[0031] FIG. 3 is a plan view of a substrate stage.
[0032] FIG. 4 is a cross sectional view showing a main part of an
embodiment of a substrate stage of the present invention.
[0033] FIG. 5 is a schematic showing a substrate holder attachable
to a substrate stage.
[0034] FIG. 6 is a cross sectional view showing a main part of
another embodiment of a substrate stage of the present
invention.
[0035] FIGS. 7A to 7C are schematics showing an example of a
procedure for disposing a liquid in a space.
[0036] FIG. 8 is a cross sectional view showing a main part of
another embodiment of a substrate stage of the present
invention.
[0037] FIG. 9 is a plan view of a substrate stage related to
another embodiment of the present invention.
[0038] FIG. 10 is a plan view of a substrate stage related to
another embodiment of the present invention.
[0039] FIG. 11 is a plan view of a substrate stage related to
another embodiment of the present invention.
[0040] FIG. 12 is a plan view of a substrate stage related to
another embodiment of the present invention.
[0041] FIG. 13 is a drawing showing an embodiment of a substrate
related to an exposure method of the present invention.
[0042] FIGS. 14A and 14B are plan views of a substrate stage
related to another embodiment of the present invention.
[0043] FIGS. 15A and 15B are plan views of a substrate stage
related to another embodiment of the present invention.
[0044] FIGS. 16A and 16B are drawings showing an embodiment of a
substrate related to an exposure method of the present
invention.
[0045] FIG. 17 is a drawing respectively showing an embodiment of a
substrate related to an exposure method of the present
invention.
[0046] FIG. 18 is a plan view of a substrate stage related to
another embodiment of the present invention.
[0047] FIGS. 19A and 19B are cross sectional views respectively
showing a main part of a substrate stage related to another
embodiment of the present invention.
[0048] FIGS. 20A and 20B are cross sectional views respectively
showing a main part of a substrate stage related to another
embodiment of the present invention.
[0049] FIGS. 21A and 21B are drawings showing another embodiment of
a gap adjustment portion related to the present invention.
[0050] FIG. 22 is a drawing showing another embodiment of a gap
adjustment portion related to the present invention.
[0051] FIG. 23 is a drawing showing another embodiment of a gap
adjustment portion related to the present invention.
[0052] FIG. 24 is a cross sectional view showing a main part of a
substrate stage related to another embodiment of the present
invention.
[0053] FIGS. 25A and 25B are drawings of a substrate stage related
to another embodiment of the present invention.
[0054] FIG. 26 is a flowchart showing an example of a semiconductor
device manufacturing process.
[0055] FIG. 27 is a schematic for explaining problems of a prior
art exposure method.
DETAILED DESCRIPTION OF THE INVENTION
[0056] Now, referring to the drawings, an exposure apparatus
provided with a substrate stage of the present invention will be
described.
[0057] FIG. 1 is a schematic diagram showing an embodiment of an
exposure apparatus of the present invention.
[0058] Referring to FIG. 1, exposure apparatus EX is provided with
mask stage MST that supports mask M, substrate stage PST that
supports substrate P, illumination optical system IL that
illuminates mask M supported by mask stage MST with exposure light
EL, projection optical system PL that projection exposes a pattern
image of mask M illuminated with exposure light EL onto substrate P
supported by substrate stage PST, and controller CONT that controls
the overall operation of exposure apparatus EX.
[0059] Exposure apparatus EX of the embodiment is a liquid
immersion exposure apparatus, to which a liquid immersion method is
applied, with the exposure wavelength being shortened in effect, to
improve the resolution and, at the same time, to widen the depth of
focus. The exposure apparatus EX is provided with liquid supply
system 10 that supply liquid 1 onto substrate P and liquid recovery
system 20 that recover liquid 1 on substrate P. In the embodiment,
purified water is used as liquid 1. Exposure apparatus EX, at least
while transferring the pattern image of mask M onto substrate P,
forms, by liquid 1 supplied from liquid supply system 10, liquid
immersion region AR2 on at least a portion on substrate P, with the
portion including a projection area AR1 of projection optical
system PL. More specifically, exposure apparatus EX fills the space
between optical element 2 located at the end of projection optical
system PL and the surface (exposure surface) of substrate P with
liquid 1, projects the pattern image of mask M onto substrate P via
projection optical system PL and liquid 1 between projection
optical system PL and the substrate P, and thus exposes substrate
P.
[0060] Here, the embodiment will be described assuming, as an
example, the case where as exposure apparatus EX, a scan type
exposure apparatus (the so-called scanning stepper) in which while
synchronously moving mask M and substrate P in mutually different
directions (opposite directions) along the scanning direction, the
pattern formed on mask M is exposed onto substrate P is used. In
the following description, it is assumed that the direction that
coincides with optical axis AX of projection optical system PL is
referred to as the Z-axis direction, that the synchronous movement
direction (the scanning direction), in a plane perpendicular to the
Z-axis direction, of mask M and substrate P is referred to as the
X-axis direction, and that the direction perpendicular to the
Z-direction and to the X-direction is referred to as the
Y-direction (the non-scanning direction). Furthermore, it is
assumed that the direction around the X-axis, the direction around
the Y-axis, and the direction around the Z-axis are respectively
referred to as the .theta.X-direction, the .theta.Y-direction, and
the .theta.Z-direction. It should be noted that a "substrate"
referred to herein comprehends a semiconductor wafer over which a
photoresist, a photosensitive material, is applied and that a
"mask" comprehends a reticle on which a device pattern to be
reduction projected onto a substrate is formed.
[0061] Illumination optical system IL is for illuminating mask M
supported by mask stage MST with exposure light EL and includes an
exposure light source, an optical integrator for uniforming the
illuminace of a light flux emitted from the exposure light source,
a condenser lens for condensing exposure light EL from the optical
integrator, a relay lens system, a variable field stop for setting
an illumination area on mask M formed by exposure light EL to be of
a slit-like shape, etc. A specified illumination area on mask M is
illuminated, by illumination optical system IL, with exposure light
EL having a uniform illuminance distribution. As exposure light EL
emitted from illumination optical system IL, for example, a bright
line of ultraviolet region (g-line, h-line, i-line) emitted from a
mercury lamp, a deep ultraviolet light (DUV light) such as a KrF
excimer laser light (wavelength of 248 nm), and a vacuum
ultraviolet light (VUV light) such as an ArF excimer laser light
(wavelength of 193 nm) or an F.sub.2 excimer laser light
(wavelength of 157 nm) may be used. In the embodiment, an ArF
excimer laser light is used. As described above, liquid 1 of the
embodiment is purified water, and the purified water can transmit
exposure light EL even when the exposure light EL is an ArF excimer
laser light. Purified water can also transmit a bright line of
ultraviolet region (g-line, h-line, or i-line) and a deep
ultraviolet light (DUV light) such as a KrF excimer laser light
(wavelength of 248 nm).
[0062] Mask stage MST is for supporting mask M, is
two-dimensionally movable in a plane perpendicular to optical axis
AX, i.e., in the XY-plane, and is finely rotatable in the
.theta.Z-direction. Mask stage MST is driven by mask stage driver
MSTD such as a linear motor. Mask stage driver MSTD is controlled
by controller CONT. On mask stage MST is provided with moving
mirror 50. Furthermore, laser interferometer 51 is positioned at a
position facing moving mirror 50. The two-dimensional position and
the rotation angle of mask M on mask stage MST are measured by
laser interferometer 51 in real time, and the measurement results
are outputted to controller CONT. By driving mask stage driver MSTD
based on the measurement results from laser interferometer 51,
Controller CONT performs positioning of mask M supported by mask
stage MST.
[0063] Projection optical system PL is for projection exposing the
pattern of mask M onto substrate P at a predetermined projection
magnification of .beta. and is constituted by a plurality of
optical elements, including optical element (lens) 2 disposed at
the substrate P side end portion, and those optical elements are
supported by lens barrel PK. In the embodiment, projection optical
system PL is a reduction system of which projection magnification
.beta. is, e.g., 1/4 or 1/5. It should be noted that projection
optical system PL may also be either a unit magnification system or
a magnifying system. Note that optical element 2 at the end portion
of projection optical system PL of the embodiment is detachably
(exchangeably) disposed relative to lens barrel PK, and liquid 1 of
liquid immersion region AR2 is in contact with optical element
2.
[0064] Optical element 2 is made of fluorite. Since fluorite has a
high affinity for water, liquid 1 can be made to be in tight
contact with substantially the entire surface of liquid contact
surface 2a of optical element 2. More specifically, since, in the
embodiment, it is configured such that liquid (water) 1 having a
high affinity for liquid contact surface 2a of optical element 2 is
supplied, the highly tight contact is effected between liquid
contact surface 2a of optical element 2 and liquid 1, so that the
optical path between optical element 2 and substrate P can be
assuredly filled with liquid 1. It should be noted that optical
element 2 may be made of quartz, which has a high affinity for
water. Furthermore, it may be configured such that liquid contact
surface 2a of optical element 2 is applied with hydrophilic
(lyophilic or liquid-attracting) treatment to enhance the affinity
for liquid 1. In addition, since the portion around the end of lens
barrel PK is to be in contact with liquid 1, at least the portion
around the end is made of a rustproof metal, e.g., Ti
(titanium).
[0065] Substrate stage PST is movable while supporting (holding)
substrate P as an object to be exposed and is provided with Z stage
52 that holds substrate P via substrate holder PH, XY stage 53 that
supports Z stage 52, and base 54 that supports XY stage 53.
Substrate stage PST is driven by substrate stage driver PSTD such
as a linear motor. Substrate stage driver PSTD is controlled by
controller CONT. By driving Z stage 52, the Z-direction position
(focus position) and the .theta.X- and .theta.Y-direction positions
of substrate P held by Z stage 52 are controlled. Furthermore, by
driving XY stage 53, the XY-direction position (the position in the
direction substantially parallel to the image plane of projection
optical system PL) of substrate P is controlled. More specifically,
Z stage 52, by controlling the focus position and inclination angle
of substrate P, makes the surface of substrate P to coincide with
the image plane of projection optical system PL by means of an
autofocus system and an autoleveling system. XY stage 53 performs
positioning of substrate P in the X-axis and Y-axis directions. It
is to be noted that needless to say, the Z stage and the XY stage
may be integrally constructed.
[0066] On substrate stage PST (Z stage 52) is provided with moving
mirror 55. Furthermore, laser interferometer 56 is positioned at a
position facing moving mirror 55. The two-dimensional position and
the rotation angle of substrate P on substrate stage PST are
measured by laser interferometer 56 in real time, and the
measurement results are outputted to controller CONT. By driving
substrate stage driver PSTD based on the measurement results from
laser interferometer 56, controller CONT performs positioning of
substrate P supported by substrate stage PST.
[0067] Furthermore, on substrate stage PST (Z stage 52) is provided
with plate 30 surrounding substrate P. Plate portion 30 is provided
integrally with Z stage 52; and inside plate portion 30 is formed
concave portion 32. It should be noted that plate portion 30 and Z
stage 52 may be separately provided. Substrate holder PH that holds
substrate P is disposed in concave portion 32. Plate portion 30 has
flat surface (flat portion) 31 of which height is substantially
equal to that of the surface of the substrate P held by substrate
holder PH disposed in concave portion 32.
[0068] Liquid supply system 10 is for supplying a predetermined
liquid 1 onto substrate P and is provided with first liquid supply
portion 11 and second liquid supply portion 12 that are capable of
supplying liquid 1, first supply member 13 that has supply port 13A
which is connected to first liquid supply portion 11 via supply
pipe 11A having a flow channel to the supply portion and supplies
onto substrate P liquid 1 delivered from first liquid supply
portion 11, and second supply member 14 that has supply port 14A
which is connected to second liquid supply portion 12 via supply
pipe 12A having a flow channel to the supply portion and supplies
onto substrate P liquid 1 delivered from second liquid supply
portion 12. First supply member 13 and second supply member 14 are
positioned close to the surface of substrate P and are respectively
disposed in different positions in the surface direction of
substrate P. Specifically, first supply member 13 of liquid supply
system 10 is disposed on one scanning direction side (-X side)
relative to projection area AR1, and second supply member 14 is
disposed on the other side (+X side).
[0069] Each of first liquid supply portion 11 and second liquid
supply portion 12 has a tank that stores liquid 1, a pressurizing
pump, etc. and supplies liquid 1 onto substrate P via the pair of
supply pipe 11A and the pair of supply members 13 and supply pipe
12A and supply member 14, respectively. In addition, the liquid
supply operations of first liquid supply portion 11 and second
liquid supply portion 12 are controlled by controller CONT, and
controller CONT can control the per-unit-time liquid supply amounts
onto substrate P by first liquid supply portion 11 and second
liquid supply portion 12 independently of each other. Furthermore,
each of first liquid supply portion 11 and second liquid supply
portion 12 has a temperature adjustment mechanism for the liquid,
and it is configured such that liquid 1 having substantially the
same temperature as that inside a chamber (e.g., 23.degree. C.)
that accommodates the apparatus is supplied onto substrate P.
[0070] Liquid recovery system 20 is for recovering liquid 1 on
substrate P and is provided with first recovery member 23 that has
recovery port 23A positioned close to the surface of substrate P,
second recovery member 24 that has recovery port 24A positioned
close to the surface of substrate P, first liquid recovery portion
21 that is connected to first recovery member 23 via recovery pipe
21A having a flow channel to the recovery member, and second liquid
recovery portion 22 that is connected to second recovery member 24
via recovery pipe 22A having a flow channel to the recovery member.
Each of first liquid recovery portion 21 and second liquid recovery
portion 22 has a suction device such as a vacuum pump, a tank that
stores liquid 1 recovered, etc. and recovers liquid 1 on substrate
P via the pair of first recovery member 23 and recovery pipe 21A
and the pair of second recovery member 24 and recovery pipe 22A,
respectively. The liquid recovery operations of first liquid
recovery portion 21 and second liquid recovery portion 22 are
controlled by controller CONT, and controller CONT can control the
per-unit-time liquid recovery amounts by first liquid recovery
portion 21 and second liquid recovery portion 22.
[0071] With respect to the above-described first supply member 13,
second supply member 14, first recovery member 23, and second
recovery member 24, at least the portions thereof that are in
contact with the liquid are made of a material, which material
includes stainless steels. In the embodiment, first supply member
13, second supply member 14, first recovery member 23, and second
recovery member 24 are made of SUS 316, a stainless steel.
Furthermore, with respect to first supply member 13, second supply
member 14, first recovery member 23, and second recovery member 24,
at least the liquid contact surfaces thereof that are in contact
with the liquid are applied with some surface treatment. As such
surface treatment, for example, "GOLDEP" treatment and "GOLDEP
WHITE" treatment of Shinko Pantec Co., Ltd. can be listed.
[0072] FIG. 2 is a plan view showing the outline configuration of
liquid supply system 10 and liquid recovery system 20. As shown in
FIG. 2, projection area AR1 of projection optical system PL is set
to be slit-shaped (rectangle-shaped) having its longitudinal
direction in the Y-direction (non-scanning direction), and liquid
immersion region AR2 filled with liquid 1 is formed on a part of
substrate P so as to include projection area AR1. Furthermore,
first supply member 13, of liquid supply system 10, for forming
liquid immersion region AR2 of projection area AR1 is disposed on
one scanning direction side (-X side) relative to projection area
AR1, and second supply member 14 is disposed on the other side (+X
side).
[0073] Each of first supply member 13 and second supply member 14
is formed to be substantially arc-shaped when viewed from the top,
and the Y-direction size of their respective supply port 13A and
supply port 14A is set to be, at the least, larger than the
Y-direction size of projection area AR1. Furthermore, supply port
13A and supply port 14A that are formed to be substantially
arc-shaped when viewed from the top are arranged so that projection
area AR1 is located therebetween. Liquid supply system 10
simultaneously supplies liquid 1 on both sides of projection area
AR1 via supply port 13A and supply port 14A of first supply member
13 and second supply member 14.
[0074] Each of first recovery member 23 and second recovery member
24 of liquid recovery system 20 respectively has recovery port 23A
and recovery port 24A that are formed to be continuous, arc-shaped
and to face the surface of substrate P. In addition, a
substantially annular-shaped recovery port is formed by first
recovery member 23 and second recovery member 24 that are disposed
so as to face each other. Recovery port 23A of first recovery
member 23 and recovery port 24A of second recovery member 24 are
disposed so as to surround first supply member 13 and second supply
member 14 of liquid supply system 10, and projection area AR1.
Furthermore, inside the recovery port, which is continuously formed
so as to surround projection area AR1, are provided with a
plurality of partition members 25.
[0075] Liquid 1 that has been supplied onto substrate P from supply
port 13A and supply port 14A of first supply member 13 and second
supply member 14 is then supplied so that liquid 1 is spread while
causing the wetting between the lower end surface of the end
portion (optical element 2) of projection optical system PL and
substrate P. In addition, liquid 1 that has flowed out, relative to
projection area AR1, to the outside of first supply member 13 and
second supply member 14 is recovered by recovery port 23A and
recovery port 24A of first recovery member 23 and second recovery
member 24, which are disposed, relative to projection area AR1,
outside first supply member 13 and second supply member 14.
[0076] In the embodiment, when substrate P is scan-exposed, the
per-unit-time liquid supply amount of the liquid supplied, relative
to the scanning direction, in front of projection area AR1 is set
to be larger than the liquid supply amount of the liquid supplied
in the side opposite thereto. For example, when substrate P is
exposed while substrate P is moved in the +X-direction, controller
CONT makes the liquid amount from the -X side relative to
projection area AR1 (i.e., from supply port 13A) larger than the
liquid amount from the +X side (i.e., from supply port 14A); on the
other hand, when substrate P is exposed while substrate P is moved
in the -X-direction, controller CONT makes the liquid amount from
the +X side relative to projection area AR1 larger than the liquid
amount from the -X side. Furthermore, the per-unit-time liquid
recovery amount of the liquid recovered, relative to the scanning
direction, in front of projection area AR1 is set to be smaller
than the liquid recovery amount of the liquid recovered in the side
opposite thereto. For example, when substrate P is moving in the
+X-direction, the liquid recovery amount at +X side relative to
projection area AR1 (i.e., at recovery port 24A) larger than the
liquid recovery amount at the -X side (i.e., at recovery port
23A).
[0077] FIG. 3 is a plan view of Z stage 52 of substrate stage PST,
when viewed from above. Moving mirrors 55 are disposed on the edge
portions of Z stage 52 that is rectangle-shaped when viewed from
the top, which portions are perpendicular to each other. In
addition, in substantially the center portion of Z stage 52 is
formed concave portion 32; in concave portion 32 is disposed
substrate holder PH that holds substrate P. Around substrate P is
provided with, integrally with Z stage 52, plate portion 30 that
has flat surface (flat portion) 31 of which height is substantially
equal to the surface of substrate P.
[0078] Substrate holder PH has peripheral wall 33 that is
substantially annular-shaped and a plurality of supporting portions
34 that are disposed inside peripheral wall 33 and hold (support)
substrate P. Peripheral wall 33 is disposed around supporting
portions 34, and supporting portions 34 are uniformly arranged
inside peripheral wall 33. Flat surface 31 of plate portion 30 is
disposed around substrate P supported by supporting portions 34 and
is provided so that it is substantially coplanar with the surface
of substrate P supported by supporting portions 34. In addition, a
predetermined gap A is formed between side surface PB of substrate
P supported by supporting portions 34 and plate portion 30. It
should be noted that although, in the drawing, the top surface of
peripheral wall 33 has a relatively wide width, it actually has a
width of only about 1 to 2 mm.
[0079] Two corners of flat surface 31 of plate portion 30 are made
to be wide; and on one of the wide portions is provided with
fiducial mark FM that is used when mask M and substrate P are
aligned with a predetermined position. Also, around substrate P on
substrate stage PST are provided with various kinds of sensors such
as an illuminance sensor. It is to be noted that although, in the
embodiment, fiducial mark FM is provided on plate portion 30, a
fiducial mark member, separate from plate portion 30, for disposing
fiducial mark FM may be provided on substrate stage PST.
[0080] FIG. 4 is an enlarged, cross sectional view showing a main
part of substrate stage PST holding substrate P. In FIG. 4, inside
concave portion 32 of Z stage 52 (plate portion 30) is disposed
substrate holder PH that holds substrate P. Concave portion 32 is
formed inside flat surface 31, and inner side surface 36 of concave
portion 32 is adjacent to flat surface 31. Peripheral wall 33 and
supporting portions 34 formed inside peripheral wall 33 are
provided on the substantially circular disc-shaped base portion 35
that constitutes a portion of substrate holder PH. Each of
supporting portions 34 is trapezoid-shaped as viewed in the cross
section, and substrate P is held, at its underside surface PC, by
top surfaces 34A of the plurality of supporting portions 34. It
should be noted that supporting portions 34 are illustrated in the
drawing as being relatively large, but, actually, a large number of
very small pin-like supporting portions are formed inside
peripheral wall 33.
[0081] Furthermore, top surface 33A of peripheral wall 33 is a flat
surface. The height of peripheral wall 33 is lower than the height
of supporting portions 34, and gap B is formed between substrate P
held by supporting portions 34 and peripheral wall 33. Gap B is
smaller than gap A between inner side surface 36 of concave portion
32 and side surface PB of substrate P. For example, in
consideration of the production tolerance of the outline of
substrate P and of the positioning accuracy of substrate P, gap A
is preferably about 0.1 to 1.0 mm. In contrast, gap B is about 2.0
to 5.0 .mu.m. Furthermore, between inner side surface 36 of concave
portion 32 and substrate holder PH's side surface 37 that faces
inner side surface 36 is formed gap C. Here, the diameter of
substrate holder PH is formed to be smaller than the diameter of
substrate P, and thus gap A is smaller than gap C. It should be
noted that, in the embodiment, no cut portion (orientation flat,
notch, etc.) for aligning is formed on substrate P; substrate P is
substantially circular; gap A is from 0.1 to 1.0 mm around the
entire circumference of substrate P; and thus, penetration of the
liquid can be prevented.
[0082] Surface PA, which is the exposure surface of substrate P, is
applied with a photoresist (photosensitive material) 90.
[0083] In the embodiment, photosensitive material 90 is a
photosensitive material for ArF excimer laser (e.g., TARF-P6100
produced by TOKYO OHKA KOGYO CO., LTD.) and has liquid-repellency
(water-repellency), and its contact angle is about 70 to 80
degrees.
[0084] In addition, in the embodiment, side surface PB of substrate
P is applied with liquid-repellent treatment (water-repellent
treatment). More specifically, over side surface PB of substrate P
is also applied the above-mentioned photosensitive material 90
having liquid-repellency. Furthermore, over underside surface PC of
substrate P is also applied the above-mentioned photosensitive
material 90, and thus the underside surface is applied with
liquid-repellent treatment.
[0085] A part of the surface of Z stage 52 (substrate stage PST) is
applied with liquid-repellent treatment and is thus
liquid-repellent. In the embodiment, flat surface 31 and inner side
surface 36 of Z stage 52 have liquid-repellency. In addition, a
part of substrate holder PH is applied with liquid-repellent
treatment and is thus liquid-repellent. In the embodiment,
peripheral wall 33's top surface 33A and side surface 37 of
substrate holder PH have liquid-repellency. To implement the
liquid-repellent treatment on Z stage 52 and substrate holder PH,
for example, a liquid-repellent material such as a fluoroplastic
material or an acrylic plastic material is applied thereon, or a
thin film made of the above-mentioned liquid-repellent material is
attached thereon. As the liquid-repellent material to realize the
liquid-repellency, a material nonsoluble in liquid 1 is used. It is
to be noted that the entirety of Z stage 52 or substrate holder PH
may be made of a material having liquid-repellency (i.e.,
fluoroplastic).
[0086] Substrate stage PST has suction device 40 for applying a
negative pressure to first space 38 surrounded by peripheral wall
33 of substrate holder PH. Suction device 40 has a plurality of
suction ports 41 provided on the top surface of base portion 35 of
substrate holder PH, vacuum portion 42, provided outside substrate
stage PST, including a vacuum pump, and flow channel 43 that is
formed inside base portion 35 and that connects each of the
plurality of suction ports 41 to vacuum portion 42. Suction ports
41 are provided at predetermined positions of the top surface of
base portion 35 other than the positions occupied by supporting
portions 34. Suction device 40 sucks and holds substrate P on
supporting portions 34, by sucking the gas (air) in first space 38
formed by and between peripheral wall 33, base portion 35, and
substrate P supported by supporting portions 34 and thus by
applying a negative pressure to first space 38. It should be noted
that since gap B between underside surface PC of substrate P and
top surface 33A of peripheral wall 33 is very small, the negative
pressure of first space 38 is maintained.
[0087] Substrate stage PST is provided with recovery section
(recovery means) 60 that recovers liquid 1 that has flowed into
second space 39 between inner side surface 36 of concave portion 32
and side surface 37 of substrate holder PH. In the embodiment,
recovery section 60 has tank 61 that can store liquid 1 and flow
channel 62 that is provided inside Z stage 52 and connects the
space 39 to tank 61. In addition, the internal surface of channel
62 is also applied with liquid-repellent treatment.
[0088] In Z stage 52 is formed flow channel 45 that connects second
space 39 between inner side surface 36 of concave portion 32 and
side surface 37 of substrate holder PH to the space that is outside
Z stage 52 (the atmosphere). The gas (air) can communicate, via
flow channel 45, between second space 39 and the outside of Z stage
52; and second space 39 is set to have a pressure substantially
equal to the atmospheric pressure.
[0089] As shown in FIG. 5, in the embodiment, substrate holder PH
is detachably provided on Z stage 52. Furthermore, contact surface
57 of Z stage 52 that comes into contact with substrate holder PH
is applied with liquid-repellent treatment to have
liquid-repellency; and also, underside surface 58 of substrate
holder PH that comes into contact with Z stage 52 is applied with
liquid-repellent treatment to have liquid-repellency. As described
above, to implement the liquid-repellent treatment on contact
surface 57 and underside surface 58, a liquid-repellent material
such as a fluoroplastic material or an acrylic plastic material may
be applied thereon, for example.
[0090] Next, a method by which edge areas E of substrate P are
liquid immersion exposed by exposure apparatus EX having the
above-described configuration will be described.
[0091] As shown in FIG. 4, when liquid immersion exposing edge
areas E of substrate P, liquid immersion region AR2 of liquid 1 is
formed so as to cover a part of surface PA of substrate P and a
part of flat surface 31 of plate portion 30. In this situation,
since side surface PB of substrate P and inner side surface 36
facing side surface PB are applied with liquid-repellent treatment,
it is hard for liquid 1 of immersion region AR2 to penetrate into
gap A, and liquid 1 hardly flows into gap A because of its surface
tension. Thus, even when exposing edge areas E of substrate P, the
liquid immersion exposure can be done with liquid 1 being
maintained well beneath projection optical system PL. During the
exposure, since flat surface 31 of plate portion 30 is also applied
with liquid-repellent treatment, liquid 1 forming immersion region
AR2 is prevented from excessively wetting and extending to the
outside of plate portion 30; and thus, immersion region AR2 can be
formed well, and the disadvantages such as flowing out or
scattering of liquid 1 can be prevented as well. Also, since
substrate P has no cut portion such as a notch, liquid 1 does not
flow therethrough.
[0092] In addition, even if liquid 1 of immersion region AR2
slightly flows, via gap A, into second space 39, since each of
underside surface PC of substrate P and top surface 33A of
peripheral wall 33 is applied with liquid-repellent treatment and
since gap B is sufficiently small, liquid 1 does not flow into
first space 38 that is set to have a negative pressure in order to
suck and hold substrate P on supporting portions 34. Accordingly,
disadvantages such as the disadvantage that liquid 1 would flow
into suction ports 41 and thus substrate P cannot be suck-and-held
can be prevented.
[0093] Furthermore, liquid 1 that has flowed into second space 39
is recovered by and into tank 61 of recovery section 60 via flow
channel 62, which suppresses flowing out (leakage), scattering, or
the like of liquid 1 toward surrounding devices. Regarding the
recovery process, since inner side surface 36 of concave portion 32
and side surface 37 of substrate holder PH, which surfaces form
second space 39, and flow channel 62 are liquid-repellent, liquid 1
that has flowed into second space 39 flows smoothly through flow
channel 62 and is recovered by and into tank 61, without staying in
second space 39.
[0094] By the way, there can be conceived the possibility that due
to the suction operation of suction device 40, the gas (air) in
second space 39 flows, via gap B, into first space 38, which causes
liquid 1 of immersion region AR2 to penetrate, via gap A, into
second space 39, thus destabilizing the formation of immersion
region AR2.
[0095] However, since gap C between inner side surface 36 of
concave portion 32 and side surface 37 of substrate holder PH is
set to be larger than gap A between side surface PB of substrate P
and inner side surface 36 of concave portion 32 and since second
space 39 is open to the atmosphere, most of the air that passes
through gap B is from the air that has flowed into the space from
the outside via flow channel 45 and has passed through gap C, and
thus the air that passes through gap B includes little of the air
(liquid 1) that has passed through gap A. Therefore, the suction
force exerted on the liquid 1 via gap A can be made smaller than
the surface tension of the liquid 1; and thus, the disadvantage
that liquid 1 of immersion region AR2 would flow, via gap A, into
second space 39 can be suppressed.
[0096] It should be noted that it may be configured such that by
connecting gas (air) supply device 45' to one end portion of the
flow channel opposite to the other end portion to which second
space 39 is connected, thus second space 39 between inner side
surface 36 of concave portion 32 and side surface 37 of substrate
holder PH is made to have a positive pressure: more specifically,
second space 39 is set to have a pressure slightly higher than the
atmospheric pressure. Accordingly, the disadvantage that liquid 1
of immersion region AR2 would flow, via gap A, into second space 39
can be suppressed. In this case if second space 39 is made to have
an excessive positive pressure, since there arises the disadvantage
that the gas (air) in second space 39 flows, via gap A, into liquid
1 of immersion region AR2 and that bubbles come to be mixed in the
liquid 1, second space 39 is preferably set to have a pressure
substantially equal to the atmospheric pressure (i.e., slightly
higher than the atmospheric pressure).
[0097] As described above, since side surface PB of substrate P and
inner side surface 36, facing side surface PB, of concave portion
32 are made to be liquid-repellent, the disadvantage that liquid 1
would penetrate, via gap A, into second space 39 between Z stage 52
and substrate holder PH can be prevented. Thus, when exposing edge
areas E of substrate P, the exposure can be performed in a
condition that the liquid immersion region AR2 is formed well,
while suppressing, for example, mixing of bubbles in liquid 1. In
addition, since penetration of liquid 1 into second space 39 formed
inside substrate stage PST can be prevented, the rusting or
electric leakage of the apparatus can be prevented.
[0098] Furthermore, since underside surface PC of substrate P and
top surface 33A, facing underside surface PC, of peripheral wall 33
are made to be liquid-repellent, the disadvantage that liquid 1
would penetrate, via gap B, into first space 38 can be prevented.
Thus, the disadvantage that liquid 1 would flow into suction ports
41 is avoided, and thus the exposure process can be performed in a
condition that substrate P is suck-and-held well.
[0099] Furthermore, in the embodiment, since underside surface 58
of substrate holder PH attachable to Z stage 52 and contact surface
57 of Z stage 52 that comes into contact with substrate holder PH
are applied with liquid-repellent treatment, even if liquid 1
penetrates into second space 39, penetration of liquid 1 between
underside surface 58 of substrate holder PH and contact surface 57
of Z stage 52 can be suppressed. Thus, occurrence of rust on
underside surface 58 of substrate holder PH and contact surface 57
of Z stage 52 can be prevented. Furthermore, although when liquid 1
penetrates between underside surface 58 of substrate holder PH and
contact surface 57 of Z stage 52, there arises the situation that
substrate holder PH and Z stage 52 adhere to each other and that it
is difficult to separate them, the liquid-repellency of both has
made them to be easily separated.
[0100] It should be noted that although, in the embodiment,
substrate holder PH is attachable to substrate stage PST (Z stage
52), substrate holder PH and substrate stage PST may be integrally
constructed.
[0101] It should be noted that although, in the embodiment, over
the entire surfaces of substrate P's surface PA, side surface PB,
and underside surface PC are applied photosensitive material 90, it
may be configured such that only the region forming gap A, i.e.,
side surface PB of substrate P, and the region forming gap B, i.e.,
the region of underside surface PC of substrate P that faces top
surface 33A of peripheral wall 33 are applied with liquid-repellent
treatment. Furthermore, since when gap A is sufficiently small and
when the liquid-repellency (contact angle) of the material applied
to implement the liquid-repellent treatment is sufficiently large,
the possibility that liquid 1 would penetrate, via gap A, into
second space 39 further decreases, it may be configured such that
without applying liquid-repellent treatment to underside surface PC
of substrate P that forms gap B, only the side surface PB of
substrate P is applied with liquid-repellent treatment.
[0102] Similarly, other than the configuration in which the entire
surface of inner side surface 36 of concave portion 32 of substrate
stage PST is applied with liquid-repellent treatment, it may be
configured such that only the partial region of inner side surface
36 that faces side surface PB of substrate P is applied with
liquid-repellent treatment. Furthermore, other than the
configuration in which the entire surface of top surface 33A of
peripheral wall 33 is applied with liquid-repellent treatment, it
may be configured such that only a partial region of top surface
33A, e.g., an inner side, annular region thereof, is applied with
liquid-repellent treatment. Still further, other than the
configuration in which the entire surface of side surface 37 of
substrate holder PH is applied with liquid-repellent treatment, it
may be configured such that only a partial region thereof is
applied with liquid-repellent treatment.
[0103] Furthermore, although, in the embodiment, both of the side
surface of substrate P and inner side surface 36 that faces the
side surface are applied with liquid-repellent treatment, both of
side surface 37 of substrate holder PH and inner side surface 36
that faces side surface 37 are applied with liquid-repellent
treatment, and both of the underside surface of substrate P and top
surface 33A of peripheral wall 33 are applied with liquid-repellent
treatment, it may be configured such that only one of each of those
paired, facing surfaces is applied with liquid-repellent
treatment.
[0104] Furthermore, in the embodiment, flat surface 31 of plate
portion 30 is applied with liquid-repellent treatment; however,
since, for example, when flat surface 31 of plate portion 30 is
sufficiently wide and/or when the scanning speed of substrate P
relative to liquid 1 is sufficiently low, the possibility that
liquid 1 of immersion region AR2 would flow out to the outside of
plate portion 30 is small, flowing out or scattering of liquid 1
can be prevented, without applying liquid-repellent treatment to
flat surface 31. Furthermore, other than the configuration in which
the entire surface of flat surface 31 is applied with
liquid-repellent treatment, it may be configured such that a
partial region thereof, e.g., an annular region thereof in the
close vicinity of substrate P, is applied with liquid-repellent
treatment.
[0105] Furthermore, the liquid-repellency degree of flat surface 31
of substrate stage PST may differ from that of inner side surface
36. In other words, the contact angle of liquid 1 at flat surface
31 may differ from the contact angle of liquid 1 at inner side
surface 36.
[0106] It should be noted that although, in the embodiment, the
height of peripheral wall 33 is lower than the height of supporting
portions 34, and thus gap B is formed between underside surface PC
of substrate P and top surface 33A of peripheral wall 33, underside
surface PC of substrate P may be in contact with top surface 33A of
peripheral wall 33.
[0107] Although, in the embodiment, to implement the
liquid-repellent treatment on side surface PB and underside surface
PC of substrate P, photosensitive material 90 having
liquid-repellency is applied thereto, side surface PB and/or
underside surface PC may be applied with a predetermined material
having liquid-repellency (water-repellency) other than
photosensitive material 90. For example, while there is the case
where a protective layer (a layer that protects photosensitive
material 90 from the liquid), called topcoat layer, is applied over
photosensitive material 90 that is applied over surface PA of
substrate P, the exposure surface, the topcoat layer forming
material (e.g., fluoroplastic material) has a contact angle of,
e.g., about 110 degrees and thus has liquid-repellency
(water-repellency). Thus, the topcoat layer forming material may
also be applied to side surface PB and/or underside surface PC of
substrate P. Of course, a material having liquid-repellency, other
than photosensitive material 90 and the topcoat layer forming
material, may also be applied.
[0108] Furthermore, although, in the embodiment, to implement
liquid-repellent treatment on substrate stage PST and/or substrate
holder PH, for example, a fluoroplastic material or an acrylic
plastic material is applied thereon, the above-described
photosensitive material or topcoat layer forming material may be
applied to substrate stage PST and/or substrate holder PH, and,
contrariwise, the material used for the liquid-repellent treatment
of substrate stage PST and/or substrate holder PH may be applied to
side surface PB and/or underside surface PC of substrate P.
[0109] While the above-described topcoat layer is often formed to
prevent liquid 1 of immersion region AR2 from infiltrating
photosensitive material 90, even if, for example, an adhesion trace
(so-called water mark) of liquid 1 is formed on the topcoat layer,
by removing the topcoat layer after a liquid immersion exposure, a
predetermined process such as a development process can be
performed, with the water mark being already removed together with
the topcoat layer. Here, when the topcoat layer is formed by, for
example, a fluoroplastic material, the topcoat layer can be removed
by using a fluorinated solvent. By virtue of the process, devices
such as the device for removing the water mark (i.e., a water mark
removing substrate washer) can be dispensed with, and with the
simple configuration in which the topcoat layer is removed by a
solvent, a predetermined process can be performed with the water
mark being already removed.
[0110] Next, referring to FIG. 6, another exposure apparatus
embodiment provided with a substrate stage of the present invention
will be described. Here, in the following description, the same or
equivalent constituent elements as those in the above-described
embodiment are denoted by the same reference numerals, and their
descriptions will be abridged or omitted.
[0111] In substrate stage PST shown in FIG. 6, second space 39
between inner side surface 36 of concave portion 32 and side
surface 37 of substrate holder PH can keep liquid 1. Here, side
surface PB of substrate P of the embodiment is not applied with
liquid-repellent treatment. Furthermore, with respect to underside
surface PC of substrate P, only the partial region thereof that
faces top surface 33A of peripheral wall 33 is applied with
liquid-repellent treatment. It is to be noted that on surface PA of
substrate P, the exposure surface, is applied photosensitive
material 90. Furthermore, in the embodiment, regarding substrate
stage PST, inner side surface 36 and side surface 37 of substrate
holder PH are not applied with liquid-repellent treatment, but only
the top surface 33A of peripheral wall 33 of substrate holder PH is
applied with liquid-repellent treatment.
[0112] Regarding substrate holder PH, inside peripheral wall 33 is
formed second peripheral wall 46.
[0113] Supporting portions 34 that support substrate P are formed
inside second peripheral wall 46. The height of peripheral wall 33
is made to be substantially equal to that of second peripheral wall
46. The height of peripheral wall 33 and the height of second
peripheral wall 46 are lower than that of supporting portions 34.
It should be noted that although, in the drawing, the width of top
surface 46A of second peripheral wall 46 is smaller than the width
of top surface 33A of peripheral wall 33, the two height may be the
same; or the width of top surface 46A of second peripheral wall 46
may be made to be larger than the width of top surface 33A of
peripheral wall 33.
[0114] In addition, the height of top surface 46A of second
peripheral wall 46 may differ from the height of top surface 33A of
peripheral wall 33, and top surface 46A of second peripheral wall
46 may be in contact with the underside surface of substrate P.
[0115] Furthermore, between peripheral wall 33 and second
peripheral wall 46 is formed the annular buffer space 47. Flow
channel 48 is connected to buffer space 47. One end of flow channel
48 is connected to buffer space 47, and the other end is connected
to the space that is outside substrate stage PST (the atmosphere).
Thus, buffer space 47 between peripheral wall 33 and second
peripheral wall 46 is open to the atmosphere, and the pressure of
buffer space 47 is set to be substantially equal to the atmospheric
pressure.
[0116] Furthermore, substrate stage PST is provided with liquid
supply device 70 that can supply the liquid to second space 39.
Liquid supply device 70 has supply portion 71 that can feed the
liquid and flow channel 72 which is formed inside Z stage 52, one
end of which is connected to second space 39, and the other end of
which is connected to supply portion 71. Here, liquid supply device
70 has also the function of recovering liquid 1 in second space
39.
[0117] FIGS. 7A to 7C are the drawings showing the procedure for
filling second space 39 with liquid 1. As shown in FIG. 7A, before
substrate P is loaded (mounted) on substrate stage PST, the water
level (height) of liquid 1 in second space 39 is set to be lower
than the height of peripheral wall 33. It is to be noted that it
may be configured such that, in this stage, liquid 1 has been
removed from second space 39. Next, as shown in FIG. 7B, after
substrate P is loaded on substrate holder PH by a loading device,
not shown, suction device 40 sucks the gas (air) in first space 38
surrounded by second peripheral wall 46 to apply a negative
pressure to first space 38, and thus substrate P is suck-and-held
by supporting portions 34 of substrate holder PH. Next, as shown in
FIG. 7C, liquid 1 is supplied to second space 39 by liquid supply
device 70, and by this, second space 39 is filled with liquid 1.
Here, liquid supply device 70 supplies liquid 1 to second space 39
until the liquid reaches the height (water level) substantially
equal to the height of flat surface 31 of plate portion 30 and of
the surface of substrate P held by substrate holder PH.
[0118] It should be noted that after a liquid immersion exposure is
performed, the operations described with reference to FIGS. 7A to
7C can be performed in reverse order. That is, after the liquid
immersion exposure is performed, liquid supply device 70 combining
the liquid recovery function recovers liquid 1 in second space 39.
Next, suction device 40 stops the sucking and holding of substrate
P by substrate holder PH. Next, an unloading device, not shown,
unloads (carries out) substrate P on substrate holder PH.
[0119] With space 39 being filled with liquid 1, flat surface 31 of
plate portion 30 and surface PA of substrate P are substantially
coplanar with each other via the intervening liquid 1 of space 39.
In other words, the gap between flat surface 31 and substrate P is
filled with liquid 1. For this reason, even when liquid 1 is
disposed on gap A to liquid immersion expose edge areas E of
substrate P, disadvantages such as the disadvantage that bubbles
would come to be mixed in the liquid 1 of immersion region AR2 are
prevented, and the exposure can be performed in a condition that
immersion region AR2 is formed well.
[0120] In this regard, since gap B is sufficiently small and since
top surface 33A of peripheral wall 33 and the partial region,
facing top surface 33A, of underside surface PC of substrate P are
applied with liquid-repellent treatment, liquid 1 in second space
39 does not flow, via gap B, into buffer space 47. Furthermore,
since buffer space 47 is open to the atmosphere and is set to have
substantially the atmospheric pressure, even in a condition that
suction device 40 has applied a negative pressure to first space
38, flowing into buffer space 47 of liquid 1 filling second space
39 can be prevented. Even if the liquid has slightly passed through
gap B, buffer space 47 can capture the liquid that has penetrated
thereto.
[0121] Substrate stage PST of the embodiment has the configuration
in which the stage is provided with liquid supply device 70 that
can supply liquid 1 to second space 39 and can also recover liquid
1 in second space 39. By virtue of this configuration, liquid 1 can
be freely supplied or recovered depending on whether substrate P is
mounted on substrate holder PH, and thus flowing out of liquid 1
toward surrounding devices can be prevented. More specifically,
when filling second space 39 with liquid 1, it is conceivable, for
example, that by arranging liquid 1 of immersion region AR2 on gap
A and by applying a negative pressure to buffer space 47 via flow
channel 48, second space 39 is made to be filled with the liquid
from liquid 1 on gap A; however, in this case, when substrate P is
unloaded after a liquid immersion exposure is performed, since the
water level of liquid 1 of second space 39 is higher than the
height of peripheral wall 33, there arises the disadvantage that
liquid 1 flows to, for example, the side of top surface 33A of
peripheral wall 33 and/or of buffer space 47. However, since liquid
supply device 70, which can supply liquid 1 to second space 39 and
can also recover liquid 1 in second space 39, is provided, when
unloading substrate P, liquid 1 in second space 39 can be
recovered, and thus flowing out of liquid 1 can be prevented.
[0122] It should be noted that it may be configured such that by
connecting gas (air) supply device 48' to one end portion of follow
channel 48 opposite to the other end portion to which buffer space
47 is connected, buffer space 47 is made to have a positive
pressure: more specifically, buffer space 47 is set to have a
pressure slightly higher than the atmospheric pressure. By this
setting, the disadvantage that liquid 1 of second space 39 would
flow, via gap B, into buffer space 47 and furthermore into first
space 38 can be suppressed. It is to be noted that if buffer space
47 is made to have an excessive positive pressure, since there
arises the disadvantage that liquid 1 in second space 39 flows
together with the gas (air) in buffer space 47, via gap A, into
liquid 1 of immersion region AR2 and that bubbles come to be mixed
in the liquid 1, buffer space 47 is preferably set to have a
pressure substantially equal to the atmospheric pressure (i.e.,
slightly higher than the atmospheric pressure). Furthermore, it may
also be configured such that the pressure of buffer space 47 can be
freely adjusted, by making gas supply device 48' have a sucking
function and by setting, by supply device 48', the pressure of
buffer space 47 between peripheral wall 33 and second peripheral
wall 46 to be, for example, slightly lower than the atmospheric
pressure (low negative pressure) and be higher than the pressure of
first space 38.
[0123] It should be noted that although, in the embodiment, it is
configured such that the partial region of underside surface PC of
substrate P is applied with liquid-repellent treatment, the entire
surface of underside surface PC may be applied with
liquid-repellent treatment, and side surface PB may also be applied
with liquid-repellent treatment. Furthermore, side surface 37 of
substrate holder PH and inner side surface 36 of concave portion 32
may be applied with liquid-repellent treatment. Furthermore, only
one of the surfaces of underside surface PC of substrate P and top
surface 33A, facing the underside surface, of peripheral wall 33
may be applied with liquid-repellent treatment. Furthermore, by,
for example, applying with liquid-repellent treatment on top
surface 46A of second peripheral wall 46, the top surface of second
peripheral wall 46 may be made to be liquid-repellent. Of course,
as with the above-described first embodiment and its modifications,
substrate P, substrate holder PH, and substrate stage PST may also
be made to have liquid-repellency.
[0124] FIG. 8 is a drawing showing another embodiment of substrate
stage PST of the present invention. In FIG. 8, substrate stage PST
is provided with second suction device 80 that set the pressure of
second space 39 between inner side surface 36 of concave portion 32
and side surface 37 of substrate holder PH to be lower than the
pressure of first space 38 surrounded by peripheral wall 33. Second
suction device 80 is connected to second space 39 via flow channel
62 and has tank 61 that can store liquid 1 and pump 64 that is
connected to tank 61 via valve 63. The operations of second suction
device 80 and suction device 40 are controlled by controller
CONT.
[0125] In the embodiment, side surface PB and underside surface PC
of substrate P are not applied with liquid-repellent treatment.
Also, inner side surface 36 of concave portion 32, side surface 37
of substrate holder PH, and top surface 33A of peripheral wall 33
are not applied with liquid-repellent treatment. When exposing edge
areas E of substrate P, controller CONT controls the operations of
suction device 40 and second suction device 80 and makes the
pressure of second space 39 lower than the pressure of first space
38. Thus, liquid 1 of immersion region AR2 on gap A, after flowing
into second space 39 via gap A, is recovered by and into tank 61 of
second suction device 80, without flowing to the side of first
space 38 via gap B. Tank 61 has discharge flow channel 61A, and it
is configured such that when liquid 1 has pooled therein up to a
predetermined amount, the liquid is discharged through flow channel
61A.
[0126] As described above, with the pressure of second space 39
being made to be lower than the pressure of first space 38, liquid
1 that has passed through gap A is recovered by and into tank 61 of
second suction device 80, without penetrating to the side of first
space 38. Thus, with liquid 1 being prevented from flowing into
suction ports 41, a liquid immersion exposure can be performed in a
condition that substrate P is suck-and-held well. Furthermore,
since liquid 1 that has passed through gap A is recovered by and
into tank 61, the disadvantages such as flowing out or scattering
to the outside of the device of liquid 1 can be avoided.
[0127] As for the embodiment of FIG. 8 also, as described in
connection with the above-described embodiments and their
modifications, at least a part of each surface of substrate P
(e.g., its side surface), substrate holder PH (e.g., top surface
33A of peripheral wall 33), and substrate stage PST (e.g., flat
surface 31 and inner side surface 36) can be made to be
liquid-repellent.
[0128] Furthermore, although, in the embodiments of FIGS. 1 to 8, a
partial surface(s) of substrate stage PST and a partial surface(s)
of substrate holder PH are applied with liquid-repellent treatment,
all surfaces thereof may be applied with liquid-repellent
treatment.
[0129] For example, top surface 34A of supporting portions 34 of
substrate holder PH may be applied with liquid-repellent treatment.
By this treatment, formation of an adhesion trace (water mark) of
the liquid is suppressed, and thus, the flatness of the supporting
surface defined by the plurality of supporting portions 34 can be
maintained.
[0130] In sum, by applying liquid-repellent treatment to the
surfaces with which the liquid (water) may be in contact or to
which the liquid may adhere, penetration, flowing out, and
scattering of the liquid are suppressed. In addition, even if the
liquid adheres thereto, the liquid can be easily removed.
[0131] By the way, in each of the above-described embodiments,
substrate P is substantially circular, and by disposing the
substantially annular, plate portion 30 around the substrate, gap A
having a width smaller than a predetermined value is formed between
plate portion 30 (inner side surface 36 of concave portion 32) and
side surface PB of substrate P; however, even in the case where
substrate P has a cut portion such as a notch portion or an
orientation flat portion ("orifla" portion), by setting the shape
of plate portion 30 (inner side surface 36 of concave portion 32)
in accordance with the cut portion of substrate P, the width of gap
A at the cut portion also can still be made to be smaller than the
predetermined value.
[0132] FIG. 9 is a plan view of substrate stage PST supporting
substrate P having notch portion NT, when viewed from above. As
shown in FIG. 9, plate portion 30 is provided with protrusion
portion 150 corresponding to the shape of notch portion NT of
substrate P, and on inner side surface 36 of concave portion 32 of
Z stage 52 is formed convex portion 36N so as to form protrusion
portion 150. Protrusion portion 150 has the function, as a gap
adjustment portion, of making the gap between notch portion NT of
substrate P supported by supporting portions 34 and flat surface 31
of plate portion 30 small and is formed integrally with flat
surface 31 (plate portion 30). Gap A is thus formed between notch
portion NT and protrusion portion 150. At the protrusion portion
150, the surface facing substrate P (notch portion NT) and the top
surface of protrusion portion 150 are applied with liquid-repellent
treatment as with the embodiments earlier described; and, the side
surface of notch portion NT of substrate P is also applied with
liquid-repellent treatment. It is to be noted that to implement the
liquid-repellent treatment on protrusion portion 150, for example,
a fluoroplastic material is applied thereon, as described above,
and to implement the liquid-repellent treatment on notch portion
NT, a photosensitive material is applied thereon. Of course, the
above-described topcoat layer forming material (e.g., fluoroplastic
material) may also be applied on notch portion NT.
[0133] Furthermore, on side surface 37 of substrate holder PH is
formed concave portion 37N, corresponding to the shape of notch
portion NT, so as to face convex portion 36N of inner side surface
36 of concave portion 32, with the concave portion and convex
portion being separated by a predetermined gap.
[0134] Furthermore, on the top surface of substrate holder PH that
holds substrate P is provided peripheral wall 33N formed to
correspond to the shape of notch portion NT; and, inside peripheral
wall 33N are provided a plurality of supporting portions 34 and
suction ports 41, as with those in FIG. 3 (the portions and ports
being omitted in FIG. 9). Furthermore, as with the above-described
embodiments, the top surface of peripheral wall 33N is
liquid-repellent. When holding substrate P on supporting portions
34, first space 38 (omitted in FIG. 9) surrounded by peripheral
wall 33N is made to have a negative pressure, with the gas being
sucked via suction ports 41. Since the shape of peripheral wall 33N
of substrate holder PH being also made to correspond to the shape
of notch portion NT as describe above, even if the liquid penetrate
into the stage through gap A of notch portion NT, flowing, of the
liquid penetrated, to the inside of peripheral wall 33N can be
prevented. It is to be noted that although notch portion NT is
exaggerated in FIG. 9, the actual size thereof is about 2 to 3 mm,
and the shape of notch portion NT is not limited to that shown in
FIG. 9.
[0135] FIG. 10 is a plan view of substrate stage PST supporting
substrate P having "orifla" portion OF, when viewed from above. As
shown in FIG. 10, plate portion 30 is provided with flat portion
151 corresponding to the shape of "orifla" portion OF of substrate
P, and on inner side surface 36 of concave portion 32 of Z stage 52
is formed flat portion 36F so as to form flat portion 151. Flat
portion 151 has the function, as a gap adjustment portion, of
making the gap between orifla portion OF of substrate P supported
by supporting portions 34 and flat surface 31 of plate portion 30
small and is formed integrally with flat surface 31 (plate portion
30). Gap A is thus formed between "orifla" portion OF and flat
portion 151. The surface facing substrate P (orifla portion OF) and
the top surface of flat portion 151 are applied with
liquid-repellent treatment; and, "orifla" portion OF is also
applied with liquid-repellent treatment. It is to be noted that to
implement the liquid-repellent treatment on flat portion 151, for
example, a fluoroplastic material is applied thereon, as described
above, and to implement the liquid-repellent treatment on "orifla"
portion OF, a photosensitive material is applied thereon.
[0136] Furthermore, on side surface 37 of substrate holder PH is
formed flat portion 37F, corresponding to the shape of "orifla"
portion OF, so as to face the flat portion of inner side surface 36
of concave portion 32, with flat portion 37F and the flat portion
of inner side surface 36 being separated by a predetermined gap.
Furthermore, on the top surface of substrate holder PH that holds
substrate P is provided peripheral wall 33F formed to correspond to
the shape of orifla portion OF; and, inside peripheral wall 33F are
provided a plurality of supporting portions 34 and suction ports
41, as with those in FIG. 3 (the portions and ports being omitted
in FIG. 10). Since the shape of peripheral wall 33F of substrate
holder PH being also made to correspond to the shape of orifla
portion OF as describe above, even if the liquid penetrate into the
stage through gap A of orifla portion OF, flowing, of the liquid
penetrated, to the inside of peripheral wall 33F can be
prevented.
[0137] As described above, by setting the shape of plate portion 30
in accordance with the cut portion (notch portion or orifla
portion) of substrate P, the width of gap A can still be made to be
smaller than the predetermined value, and thus, penetration of
liquid 1 between substrate P and substrate stage PST (plate portion
30) can be prevented.
[0138] By the way, when multiple substrates P are to be exposed,
the size or shape of the cut portion (notch portion or orifla
portion) may be different from one another, and in such case, there
arises the possibility that gap A between the cut portion of
substrate P and plate portion 30 cannot be kept to be smaller than
the predetermined value. Furthermore, there is also the possibility
that because of the production tolerance of the outline of
substrate P and of the positioning accuracy of substrate P relative
to substrate stage PST, gap A between the cut portion of substrate
P and plate portion 30 cannot be kept to be smaller than the
predetermined value.
[0139] To address the above problems, by movably providing
protrusion member 152 having protrusion portion 152A corresponding
to the shape of notch portion NT and by moving the protrusion
member in the approaching or leaving direction relative to the
substrate P, as shown in FIG. 11, gap A between notch portion NT
and protrusion member 152 can be kept to be smaller than the
predetermined value, even if, for example, the size of notch
portion NT varies. In the embodiment shown in FIG. 11, protrusion
member 152 is disposed in concave portion 30D provided in a portion
of plate portion 30, and it is configured such that the protrusion
member is moved along the XY-plane by a driving mechanism, not
shown. By moving protrusion member 152 via the driving mechanism,
controller CONT forms the predetermined gap A between protrusion
member 152 and notch portion NT. Furthermore, as with the
above-described case, regarding protrusion member 152, the surface
facing substrate P (notch portion NT), the top surface, and the
surface facing concave portion 30D of plate portion 30 are applied
with liquid-repellent treatment; and, notch portion NT is also
applied with liquid-repellent treatment. Here, although gap D is
formed between protrusion member 152 and plate portion 30 (concave
portion 30D), penetration of liquid 1 into gap D is prevented
because gap D is smaller than gap A and because concave portion 30D
of plate portion 30 and the side surface, of protrusion member 152,
facing concave portion 30D of plate portion 30 are
liquid-repellent. Note that description of the same portions as
those of FIG. 9 is omitted.
[0140] FIG. 12 is a drawing showing flat member 153 that is movably
provided and that has flat surface 153A corresponding to the shape
of "orifla" portion OF of substrate P. By moving flat member 153 in
the approaching or leaving direction relative to the substrate P,
gap A between orifla portion OF and flat member 153 can be kept to
be smaller than the predetermined value, even if, for example, the
size of orifla portion OF varies.
[0141] In the embodiment shown in FIG. 12, flat member 153 disposed
in concave portion 30D provided in a portion of plate portion 30,
and it is configured such that the flat member is moved along the
XY-plane by a driving mechanism, not shown. By moving flat member
153 via the driving mechanism, controller CONT forms the
predetermined gap A between flat member 153 and "orifla" portion
OF. Furthermore, as with the above-described case, regarding flat
member 153, the surface facing substrate P (orifla portion OF), the
top surface, and the surface facing concave portion 30D of plate
portion 30 are applied with liquid-repellent treatment; and,
"orifla" portion OF is also applied with liquid-repellent
treatment. Here, although gap D is formed between flat member 153
and plate portion 30 (concave portion 30D), penetration of liquid 1
into gap
[0142] D is prevented because gap D is smaller than gap A and
because concave portion 30D of plate portion 30 and the side
surface, of flat member 153, facing concave portion 30D of plate
portion 30 are liquid-repellent. Note that description of the same
portions as those of FIG. 10 is omitted.
[0143] It should be noted that by replaceably disposing protrusion
member 152 (flat member 153) relative to substrate stage PST, by
stocking beforehand multiple protrusion members 152 (flat members
153) having different shapes or sizes, and by replacing protrusion
member 152 (flat member 153) in accordance with the shape or size
of substrate P mounted on substrate stage PST, gap A can be kept to
be smaller than the predetermined value.
[0144] It should be noted that not only the size or shape of
protrusion member 152 (flat member 153) but also the manner in
which protrusion member 152 (flat member 153) moves, e.g., the
movement direction thereof, are not limited by the above-described
embodiments; in sum, accomplishment of the condition that gap A in
the vicinity of the cut portion of substrate P is smaller than the
predetermined value would suffice.
[0145] It should be noted that while, in the embodiments, it is
configured such that protrusion member 152 (flat member 153) is
moved so that gap A is formed between the cut portion (notch
portion or orifla portion) of substrate P and protrusion member 152
(flat member 153), it may also be configured such that plate
portion 30 to be disposed around substrate P is disposed movably
along the XY-plane to adjust gap A between substrate P and plate
portion 30 to be smaller than the predetermined value. In this
case, for example, the configuration in which plate portion 30 is
divided into multiple parts and each of the divided parts are
moved, along the XY-plane, in the approaching or leaving direction
relative to the substrate P can be adopted. In implementing this
configuration, by setting the each of gaps between the divided
parts to have a gap through which the liquid cannot penetrate, the
disadvantage that the liquid would penetrate to the inside of
substrate stage PST can be avoided.
[0146] Furthermore, it may also be configured such that before
substrate P is carried in (loaded) on substrate stage PST, the size
and/or shape (deformation) of substrate P or the size and/or shape
of the cut portion of substrate P is measured and then based on the
measurement results, each members are moved so that gap A is made
to be smaller than the predetermined value. By this, not only
penetration of the liquid from gap A can be prevented more
certainly, but also damage to the edge of substrate P can be
prevented.
[0147] Furthermore, regarding the above-described embodiment of
FIG. 6, there is the possibility that the liquid flows over top
surface 33A of peripheral wall 33 (46); however, since the liquid
that has flowed beyond top surface 33A of peripheral wall 33 can be
captured by buffer space 47, flowing of the liquid into first space
38 can be prevented. It is to be noted that preparing for such
case, it may be configured such that the liquid that has penetrated
into buffer space 47 is recovered.
[0148] Next, another embodiment of the present invention will be
described. In the embodiments described above with reference to
FIGS. 9 to 12, it is configured such that to prevent liquid 1 from
penetrating between the cut portion (notch portion or orifla
portion) of substrate P supported supporting portions 34 and flat
surface 31 of plate portion 30, protrusion portion 150, flat
portion 151, the movable protrusion member 152, and the movable
flat member 153 are, as gap adjustment portions, provided. On the
other hand, as indicated by reference mark NT' of FIG. 13, by
making notch portion NT' of substrate P small, as far as possible,
to the extent that liquid 1 does not penetrate, penetration of
liquid 1 between the notch portion of substrate P and substrate
stage PST (plate portion 30) can also be prevented. Note that the
not portion shown in FIG. 13 has a rounded shape having no
acutely-angled portion.
[0149] By the way, there is a case where when mounting substrate P
on substrate stage PST, the substrate is mounted on substrate stage
PST, with the position of cut portion being differently positioned
relative to substrate stage PST, in accordance with the process
condition of the circuit and/or with the pattern of mask M. For
example, there is a case where when mounting a first substrate on
substrate stage PST, the substrate is mounted in a condition that
the cut portion is directed to the -Y side and where when mounting
a second substrate on substrate stage PST, the substrate is mounted
in a condition that the cut portion is directed to the +X side. To
address this case, it may be configured such that by movably
providing plate portion 30 having protrusion portion 150, plate
portion 30 is rotated in accordance with the position of cut
portion of substrate P supported by supporting portions 34. For
example, when, as shown in FIG. 14A, making supporting portions 34
support substrate P so that notch portion NT is directed to -Y
side, plate portion 30 is rotated so that protrusion portion 150 is
directed to -Y side in accordance with the position of notch
portion NT; and, when, as shown in FIG. 14B, making supporting
portions 34 support substrate P so that notch portion NT is
directed to +X side, plate portion 30 is rotated so that protrusion
portion 150 is directed to +X side in accordance with the position
of notch portion NT. In this case, although not shown in FIGS. 14A
and 14B, substrate holder PH on which peripheral wall 33N having
concave portion 37N also rotates in accordance with the position of
notch portion NT. It may be, as described above, configured such
that protrusion portion 150 (and convex portion 36N), a gap
adjustment potion, is provided movably in the rotation direction
(.theta.Z-direction). Similarly, plate portion 30 having flat
portion 151 and substrate holder on which peripheral wall 33F
having flat portion 37F is formed may be provided so that they
rotate in accordance with the position of "orifla" portion OF. By
adopting such configurations, penetration of liquid 1 between plate
portion 30 and substrate P (cut portion) can also be prevented,
irrespective of the position of the cut portion of substrate P.
[0150] Also, it may be configured such that the totality of
substrate stage PST is rotated so that protrusion portion 150 of
plate portion 30 is aligned with the position of notch portion NT
of substrate P supported by supporting portions 34.
[0151] In FIG. 15A is shown the condition that notch portion NT is
directed to the -Y side; in FIG. 15B is shown the condition that
notch portion NT is directed to the +X side. Here, when, as shown
in FIGS. 15A and 15B, for example, laser interferometer 56X is
disposed in a position separated, on the +X side, from substrate
stage PST, and laser interferometer 56Y is disposed in a position
separated on the -Y side, by positioning moving mirror 55 on each
of at least three edge portions of substrate stage PST formed in a
rectangle-shape as viewed from the top, each of laser
interferometers 56X and 56Y can be made to face either one of the
moving mirrors 55, also when substrate stage rotates.
[0152] By the way, the cut portion of substrate P is primarily used
during the pre-alignment process, a rough alignment process when
substrate P is mounted on substrate stage PST. More specifically,
with the position of the cut portion being first detected
optically, the pre-alignment process is performed based on the
detection results. Thus, as shown in FIG. 16A, by covering notch
portion (cut portion) NT formed on substrate P with covering member
300 having light transmittance, notch portion NT can be optically
detected via covering member 300, and, at the same time, the
disadvantage that when substrate P is mounted on substrate stage
PST, a large gap would be formed between plate portion 30 and notch
portion NT (covering member 300) can be prevented. Similarly, it
may be configured such that "orifla" portion OF is covered with a
covering member.
[0153] It should be noted that when, as shown in FIG. 16B, notch
portion (cut portion) NT is formed in each of multiple positions of
substrate P, it may be configured such that each of the multiple
notch portions NT is covered with covering member 300. Furthermore,
when notch portion NT is formed in each of multiple positions of
substrate P, it may be configured, instead of covering such notch
portions with covering members 300, such that multiple protrusion
portions 150 are provided on plate portion 30 (substrate stage PST)
in accordance with the multiple notch portions NT. By adopting such
configurations, penetration of liquid 1 between plate portion 30
and substrate P (cut portion) can also be prevented.
[0154] Also, by providing a hole portion in a predetermined
position of substrate P, instead of forming the cut portion on
substrate P, substrate P can be pre-aligned by optically detecting
the hole portion. In this case, the hole portion may be a
through-hole having a small diameter sufficient not to allow liquid
1 to pass through the hole or may a dimple-shaped hole (concave
portion) that does not pierce through substrate P. In FIG. 17 is
shown an embodiment where a group of multiple small through-holes
301 having a diameter of, e.g., about 0.5 mm is formed in a
predetermined position of substrate P.
[0155] FIG. 18 is a plan view illustrating another embodiment of
the present invention. Note that the same members as those of FIG.
4 are denoted by the same reference numerals, and detailed
descriptions thereof are omitted. In FIG. 18, each of protrusion
members 152, as a gap adjustment portion, is provided in each of
the multiple positions in the vicinity of the edge of substrate P
supported by supporting portions 34. In the embodiment shown in
FIG. 18, first protrusion member 152Y is provided in the vicinity
of the -Y side edge of substrate P; second protrusion member 152X
is provided in the vicinity of the +X side edge of substrate P.
Each of protrusion members 152Y and 152X is provided movably in the
Z-axis direction (in the vertical direction). In addition, a single
cut portion (notch portion NT) is formed in the vicinity of the -Y
side edge of substrate P.
[0156] FIG. 19A is a cross sectional view illustrating first
protrusion member 152Y and its vicinity; FIG. 19B is a cross
sectional view illustrating second protrusion member 152X and its
vicinity. As shown in FIGS. 19A and 19B, protrusion members 152
(152Y and 152X) are supported by elastic member 302. In the
embodiment shown in FIGS. 19A and 19B, elastic member 302 is
constituted by a coil spring member, and protrusion members 152 are
supported, via the coil spring member, by the top surface (contact
surface) 57 of Z stage 52. In a state in which notch portion NT, of
substrate P, directed to the -Y side and protrusion member 152Y are
aligned with each other, protrusion member 152Y is disposed, as
shown in FIG. 19A, inside notch portion NT by the upward biasing
force of coil spring member 302 without being pressed by substrate
P. By virtue of protrusion member 152Y, the gap between notch
portion NT of substrate P supported by supporting portions 34 and
flat surface 31 of plate portion 30 can be made to be small. On the
other hand, as shown in FIG. 19B, protrusion member 152X disposed
in the position where notch portion does not exist is pressed from
above by substrate P, and coil spring member 302 shortens. Thus,
protrusion member 152X is disposed under substrate P. In contrast,
when substrate P is supported by supporting portions 34 in a state
in which notch NT is directed to the +X side, protrusion member
152X is disposed inside notch portion NT, and protrusion member
152Y is disposed under substrate P.
[0157] By adopting the configuration just described, the gap
between notch portion NT of substrate P supported by supporting
portions 34 and flat surface 31 of plate portion 30 can be made to
be small. Furthermore, by applying, for example, with
liquid-repellent treatment on the top surface and side surface of
protrusion members 152 to make them liquid-repellent, as with flat
surface 31 and inner side surface 36 of plate portion 30,
penetration of liquid 1 can be prevented more effectively.
[0158] FIGS. 20A and 20B are cross sectional views illustrating
another embodiment of the present invention. The embodiment of
FIGS. 20A and 20B is a modification of the embodiment of FIGS. 19A
and 19B, and the same members of the former as those of the latter
are denoted by the same reference numerals. In FIGS. 20, the under
surface of protrusion member 152 is connected to the top end
portion of the rod-shaped supporting member 303. In a portion of Z
stage 52 is provided through-hole 52K, and supporting member 303 is
disposed, inside through-hole 52K, movably in the Z-direction. The
lower end portion of supporting member 303 protrudes from the under
surface of Z stage 52, and the lower end portion of supporting
member 303 is connected to collar member 304. Furthermore, leaf
spring member 305 attached to the under surface of Z stage 52 is in
contact with the under surface of collar member 304. As with the
embodiment of FIGS. 19A and 19B, in a state in which notch portion
NT of substrate P and protrusion member 152 are aligned with each
other, protrusion member 152 is lifted upward by the biasing force
of leaf spring member 305 and is disposed inside notch portion NT,
as shown in FIG. 20A. On the other hand, in a state in which notch
portion NT of substrate P and protrusion member 152 are not aligned
with each other, protrusion member 152 is pressed by substrate P
and is disposed under substrate P, as shown in FIG. 20B. Also in
this case, by making the top surface and side surface of protrusion
member 152 liquid-repellent, penetration of liquid 1 can be
prevented effectively.
[0159] FIGS. 21A and 21B are cross sectional views illustrating
another embodiment of the present invention. In FIGS. 21A and 21B,
protrusion member 152 is connected, via hinge portion 306, to plate
portion 30 (or a predetermined position of substrate stage PST). In
FIGS. 21A and 21B, hinge portion 306 supports, rotatably in the
.theta.Y-direction, protrusion member 152. Furthermore, hinge
portion 306 has a spring member built-in and supports protrusion
member 152 so as to bias it in the direction of y1 arrow in FIG.
21B. In other words, hinge portion 306 exerts a biasing force upon
protrusion member 152 in the direction such that the top surface of
protrusion member 152 and the surface of substrate P constitute a
single plane. It is to be noted that hinge portion 306 has a
stopper, and the rotation of protrusion member 152 is stopped when
the top surface of protrusion member 152 and the surface of
substrate P substantially constitute a single plane. Thus, in a
state in which notch portion NT of substrate P and protrusion
member 152 are aligned with each other, protrusion member 152 is
disposed inside notch portion NT, as shown in FIG. 21A. On the
other hand, in a state in which notch portion NT of substrate P and
protrusion member 152 are not aligned with each other, protrusion
member 152 is pressed by substrate P and is disposed under
substrate P, as shown in FIG. 21B. Also in this case, by making the
top surface and side surface of protrusion member 152
liquid-repellent, penetration of liquid 1 can be prevented
effectively.
[0160] It should be noted that while, in the above-described
embodiments, it is configured such that protrusion members 152 is
moved by a spring member, it may also be configured such that
protrusion member 152 is moved by using a predetermined actuator.
In this case, for example, before substrate P is mounted on
substrate stage PST, the position information of notch portion NT
is obtained. Furthermore, after substrate P is mounted on substrate
stage PST, a specified protrusion member 152 among the multiple
protrusion members 152 provided on substrate stage PST is driven,
based on the obtained position information, by using the actuator
to dispose the specified protrusion member 152 inside notch portion
NT. Furthermore, it may also be configured such that protrusion
member 152 is detachably provided on substrate stage PST, and an
operator, for example, manually disposes protrusion member 152
inside notch portion NT of substrate P on substrate stage PST,
without using an actuator. Still further, it may also be configured
such that a robot arm that can hold protrusion member 152
detachable relative to substrate stage PST disposes protrusion
member 152 inside notch portion NT of substrate P on substrate
stage PST.
[0161] FIG. 22 illustrates an embodiment in which protrusion member
152 is disposed inside notch portion NT by using an actuator. In
FIG. 22, protrusion member 152 is attached to one end portion (edge
portion) of the rod-shaped supporting member 307, and the other end
portion (base portion) of supporting member 307 is connected to
actuator 308. Actuator 308 can rotate supporting member 307, to
which protrusion member 152 is attached, with the base portion of
supporting member 307 being the rotation center. In FIG. 22,
actuator 308 rotates supporting member 307 in the
.theta.Y-direction. By rotating supporting member 307, actuator 308
can dispose protrusion member 152 attached to the edge portion of
supporting member 307 inside notch portion NT. Also in this case,
by making the top surface and side surface of protrusion member 152
liquid-repellent, penetration of liquid 1 can be prevented
effectively. Furthermore, after a liquid immersion exposure is
performed, actuator 308 can, by rotating supporting member 307 in
the reverse direction, remove protrusion member 152 from notch
portion NT of substrate P.
[0162] Also, by covering notch portion NT with sheet member 309 as
shown in FIG. 23, penetration of liquid 1 between notch portion NT
and plate portion 30 (flat surface 31) can be suppressed. Sheet
member 309 is preferably liquid-repellent; and, for example, a
sheet member made of polytetrafluoroethylene (TEFLON (registered
trademark)) can be used as sheet member 309.
[0163] In addition, it may be configured such that sheet member 309
is formed to be annular-shaped, and such sheet member 309 covers
the entirety of the gap between substrate P and flat surface
31.
[0164] Furthermore, in each of the above-described embodiments,
protrusion member 152 is preferably replaceable. While protrusion
member 152 is preferably liquid-repellent, the liquid-repellency
may deteriorate with time. Thus, by replacing protrusion member 152
when its liquid-repellency has deteriorated, penetration of liquid
1 can be prevented effectively by using another protrusion member
152 having desired liquid-repellency.
[0165] Furthermore, although, in each of the above-described
embodiments, the configuration in which protrusion member 152 is
disposed in notch portion NT was described by way of illustration,
such configuration can also, of course, be applied to a flat member
corresponding to "orifla" portion OF formed on substrate P. In this
case, by using an elastic member (spring member), the flat member
is disposed in a predetermined position; the gap between "orifla"
portion OF of substrate P supported by supporting portions 34 and
flat surface 31 of plate portion 30 is made to be small; and thus,
penetration of liquid 1 can be prevented.
[0166] Furthermore, needless to say, the embodiments described with
reference to FIGS. 1 to 8 and their modifications may be
appropriately combined with the embodiments described with
reference to FIGS. 9 to 23 and their modifications.
[0167] FIG. 24 is a cross sectional view showing another embodiment
of the present invention. Note that description of the same members
as those of FIGS. 4, 6, and 8 is omitted. In FIG. 24, substrate
stage PST is provided with peripheral wall 33, second peripheral
wall 46 formed inside peripheral wall 33, and supporting portions
34 formed inside second peripheral wall 46. Suction device 40
performs the suction operation, via suction ports 41, to apply a
negative pressure to first space 38 surrounded by second peripheral
wall 46, and thus substrate P is suck-and-held by supporting
portions 34.
[0168] Furthermore, the pressure of buffer space 47 between
peripheral wall 33 and second peripheral wall 46 is set to be
higher than the pressure of first space 38 surrounded by second
peripheral wall 46. More specifically, as with the embodiment
described referring to FIG. 6, buffer space 47 is, via flow channel
48, open to the atmosphere, and the pressure of buffer space 47 is
set to be substantially equal to the atmospheric pressure.
Alternatively, by using gas supply device 48' have a pressure
adjustment function, buffer space 47 may be set to have a pressure
slightly higher than the atmospheric pressure, or may be set to
have a pressure lower than the atmospheric pressure and higher than
the pressure of first space 38 (i.e., low negative pressure).
[0169] The height of peripheral wall 33 is set to lower than that
of supporting portions 34. The height of second peripheral wall 46
is also set to lower than that of supporting portions 34.
Furthermore, top surface 33A of peripheral wall 33 is applied with
liquid-repellent treatment to have liquid-repellency, and top
surface 46A of second peripheral wall 46 is also applied with
liquid-repellent treatment to have liquid-repellency.
[0170] It is to be noted that it may also be configured such that
only one of the surfaces of top surface 33A of first peripheral
wall 33 and top surface 46A of second peripheral wall 46 is made to
be liquid-repellent.
[0171] In contrast to FIG. 6, in the embodiment, second space 39
between inner side surface 36 of concave portion 32 and side
surface 37 of substrate holder PH is not filled with liquid 1.
Furthermore, to second space 39 is connected second suction device
80 for adjusting the pressure of second space 39 and, at the same
time, for recovering liquid 1 that has flowed, via gap A, into
second space 39. Second suction device 80 has an configuration
equivalent to the configuration described referring to FIG. 8 and
can make the pressure of second space 39 lower than the pressure of
buffer space 47. By this, even if liquid 1 penetrate slightly from
gap A, penetration, of the liquid 1 having penetrated, into buffer
space 47 through gap B between top surface 33A of first peripheral
wall 33 and substrate P can be suppressed. In addition, second
suction device 80 can recover the liquid that has penetrated into
second space 39.
[0172] It is to be noted that it may also be configured such that,
as shown in FIG. 4, only with tank 61 is provided, without pump 64
and valve 63 being provided. Still further, it may also be
configured such that, as shown in FIG. 4, second space 39 is open
to the atmosphere.
[0173] In this case, the pressure of buffer space 47 is set to be
slightly higher than the atmospheric pressure by using gas supply
device 48'. By this, even if liquid 1 penetrate slightly from gap
A, penetration, of the liquid 1 having penetrated, into buffer
space through gap B between top surface 33A of first peripheral
wall 33 and substrate P can be suppressed. In addition, the liquid
that has penetrated into second space 39 can be recovered.
[0174] When holding substrate P by and on supporting portions 34,
first space 38 is made to have a negative pressure, and, at the
same time, the pressure of buffer space 47 is made to be higher
than that of first space 38. Preferably, the pressure of buffer
space 47 is made to be substantially equal to the atmospheric
pressure or to be higher than the atmospheric pressure. By this
setting, even if liquid 1 has penetrated into second space 39
through gap A, since the pressure of buffer space 47 is set to be
higher, the disadvantage that liquid 1 would penetrate, via buffer
space 47, into first space 38 and furthermore to the underside
surface of substrate P or into suction ports 41 is prevented.
Furthermore, in the embodiment, even when the cut portion of
substrate P is positioned on top surface 33A of peripheral wall 33,
the disadvantage that liquid 1 that has penetrated between the cut
portion and flat surface 31 would penetrate to the side of buffer
space 47 or of first space 38 can be reduced.
[0175] Furthermore, while there is the possibility that the liquid
flows beyond top surface 33A of peripheral wall 33 depending on the
size of the cut portion of substrate P, since the liquid that has
flowed beyond top surface 33A of peripheral wall 33 can be captured
by buffer space 47, penetration of the liquid into first space 38
can be prevented. It is to be noted that preparing for such case,
it may be configured such that the liquid that has penetrated into
buffer space 47 is recovered.
[0176] In addition, although detailed description is omitted, it
may be configured such that, as with the embodiment shown in FIG.
4, side surface PB of substrate P, underside surface PC of
substrate P, flat surface 31 of plate portion 30, and/or inner side
surface 36 of plate portion 30 are made to be liquid-repellent.
[0177] In other words, the liquid-repellent treatments of at least
a part of each surface of substrate P, substrate holder PH, and
substrate stage PST, as described in connection with the embodiment
of FIG. 4 and its modifications, can be appropriately combined with
the embodiment of FIG. 24.
[0178] It should be noted that since, in the embodiment of FIG. 24,
the negative pressure of first space 38 can be maintained by second
peripheral wall 46, a cut portion to communicate buffer space 47
and second space 39 with each other may be provided on a portion of
first peripheral wall 33.
[0179] FIGS. 25A and 25B are drawings illustrating another
embodiment of the present invention; FIG. 25A is a plan view; FIG.
25B is a cross-sectional view taken along the arrow A-A of FIG.
25A. Note that the same members as those of FIG. 3 are denoted by
the same reference numerals, and detailed descriptions thereof are
omitted. In FIGS. 25A and 25B, substrate stage PST is provided with
a plurality of suction ports (air suction ports) 41 for
suck-and-holding substrate P on supporting portions 34.
Furthermore, on an inside portion of peripheral wall 33 is locally
formed second peripheral wall 46'.
[0180] As shown in FIG. 25A, second peripheral wall 46' is provided
in a position corresponding to notch portion NT (or orifla portion)
of substrate P supported by supporting portions 34. Second
peripheral wall 46' has top surface 46A' that is substantially
arc-shaped as viewed from the top, and both ends of the peripheral
wall are connected to peripheral wall 33. Furthermore, between
peripheral wall 33 and second peripheral wall 46' is formed buffer
space 47'. Buffer space 47 is formed in the vicinity of notch
portion NT of substrate P supported by supporting portions 34. In
the embodiment also, each of the heights of peripheral wall 33 and
second peripheral wall 46' is set to be lower than the height of
supporting portions 34, the top surfaces of peripheral wall 33 and
second peripheral wall 46' have liquid-repellency.
[0181] The plurality of suction ports 41 provided in first space 38
are connected, via flow channel 43, to vacuum portion (vacuum
system) 42. On the other hand, suction ports 41' provided in buffer
space 47' located in the vicinity of notch portion NT of substrate
P are connected, via second flow channel 43', to second vacuum
portion (second vacuum system) 42' provided separately from vacuum
portion 42. The suction force (per-unit-time gas suction amount) of
second vacuum portion 42' is set to be weaker than that of vacuum
portion 42. In other words, regarding the multiple suction ports
provided on substrate stage PST, the suction force via suction
ports 41' located in the vicinity of notch portion NT of substrate
P is set to be smaller than the suction force via suction ports 41
surrounding suction ports 41'.
[0182] Since, in this way, the suction force via suction ports 41'
located in the vicinity of notch portion NT of substrate P is made
to be smaller than the suction force via the other suction ports
41, even when it is configured such that the gap between notch
portion NT of substrate P and flat surface 31 (plate portion 30) is
larger than the gap between side surface PB, other than the side
surface of notch portion NT, of substrate P and flat surface 31,
and thus liquid 1 is likely to penetrate, the disadvantage that
liquid 1 would penetrate between notch portion NT and flat surface
31 can be suppressed.
[0183] Furthermore, even if the liquid has penetrated to the
underside surface side of substrate P, with the liquid flowing
through notch portion NT of substrate P and then flowing beyond top
surface 33A of peripheral wall 33, since the liquid can be captured
by buffer space 47', penetration of the liquid into first space 38
can be blocked. It is to be noted that preparing for such case, it
may be configured such that the liquid that has penetrated into
buffer space 47' is recovered.
[0184] It should be noted that it may also be configured such that
without separating the vacuum system connected to suction ports 41'
from the vacuum system connected to the other suction ports 41, the
suction force in the vicinity of notch portion NT of substrate P is
made to be smaller. For example, it may be configured such that the
bore diameter of suction ports 41' in the vicinity of notch portion
NT of substrate P is made to be smaller than that of the other
suction ports 41. Also, it may be configured such that, regarding
the multiple suction ports, the layout density of suction ports in
the vicinity of notch portion NT is made to be smaller than that of
the other suction ports surrounding the suction ports in the
vicinity of notch portion NT. Alternatively, it may be configured
such that no suction ports are provided in the vicinity of notch
portion NT of substrate P. Still further, it may be configured such
that by, for example, closing flow channel 43' connected to suction
ports 41' by using, for example, a valve, gas-suction is not
performed through the suction ports provided in the vicinity of
notch portion NT of substrate P.
[0185] It should be noted that when by making the suction force in
the vicinity of cut portion (notch portion) NT of substrate P
smaller, penetration of the liquid to the underside surface side of
substrate P, it may be configured such that second peripheral wall
46' is not formed.
[0186] Needless to say, also in the embodiment of FIGS. 25A and
25B, it may be configured such that, as with the embodiment shown
in FIG. 4, side surface PB of substrate P, underside surface PC of
substrate P, flat surface 31 of plate portion 30, and/or inner side
surface 36 of plate portion 30 are made to be liquid-repellent.
[0187] In the above-described embodiments, when the pressure of the
liquid forming immersion region AR2 is high, the possibility that
the liquid may penetrate through gaps existing on substrate stage
PST (e.g., the gap around substrate P) increases; and thus, to
address this issue, it may also be configured such that when
immersion region AR2 is formed on such gaps on substrate stage PST,
the pressure of the liquid is lowered. In particular, since there
is the possibility that the pressure of the liquid may be high
underneath supply ports 13A and 14A of liquid supply system 10, by
making the pressure of the liquid smaller when supply ports 13A and
14A of liquid supply system 10 face the gaps on substrate stage
PST, penetration of the liquid through the gaps can be
suppressed.
[0188] Furthermore, needless to say, the embodiments described with
reference to FIGS. 24 and 25 may be appropriately combined with the
embodiments described with reference to FIGS. 9 to 23.
[0189] In each of the above-described embodiments, liquid 1 is
constituted by purified water. Purified water has the advantage
that it is easily available in bulk in, e.g., semiconductor
manufacturing factories and also the advantage that it does not
adversely affect photoresist on substrate P, optical elements
(lenses), etc. Furthermore, purified water does not adversely
affect the environment and contains scarcely any impurities; thus,
the effect that it cleans the surface of substrate P and the
surface of the optical element provided at the end portion of
projection optical system PL can be expected. It should be noted
that when the purity of the purified water supplied from, e.g., the
factory is low, it may be configured such that the exposure
apparatus itself has an ultra-purified water producing system.
[0190] The refractive index n of purified water (water) relative to
exposure light EL having a wavelength of about 193 nm is said to be
approximately 1.44, and when ArF excimer laser light (having 193 nm
wavelength) is used as the light source of exposure light EL, the
wavelength is effectively shortened, on substrate P, as if
multiplied by 1/n, i.e., effectively becomes approximately 134 nm,
and thus, a high resolution can be obtained. Furthermore, since the
depth of focus increases by approximately n times, i.e.,
approximately by 1.44 times, compared with that in the air, when
securing of the depth of focus on par with the depth of focus
realized when the projection optical system is used in the air
suffices, the numerical aperture of the projection optical system
PL can be further increased; which also improves the
resolution.
[0191] When the liquid immersion method is used as described above,
the numerical aperture NA of the projection optical system may
become 0.9 to 1.3. When, in this manner, the numerical aperture NA
of the projection optical system becomes large, random-polarized
light conventionally used as the exposure light may, because of its
polarization effect, adversely affect the imaging performance;
thus, a polarized light illumination method is preferably used. In
this case, it is preferable that by performing linearly polarized
light illumination in which the longitudinal direction of the line
pattern of the line-and-space pattern on the mask (reticle) is
aligned with the polarization direction, a lot of diffraction
lights from S polarization components (TE polarization components),
i.e., the diffraction lights from the polarization components
having the polarization direction in line with the longitudinal
direction of the line pattern are emitted from the pattern of the
mask (reticle). When the space between projection optical system PL
and the resist applied to the surface of substrate P is filled with
the liquid, the transmittance at the resist surface of the
diffraction lights from S polarization components (TE polarization
components), which contribute to the improvement of the contrast,
is higher compared with the case where the space between projection
optical system PL and the resist applied to the surface of
substrate P is filled with the gas (air), a high imaging
performance can be obtained even in the case where the numerical
aperture NA of the projection optical system is over 1.0.
Furthermore, a phase shift mask, an oblique incidence illumination
method (in particular, the dipole illumination method), as
disclosed in Japanese Unexamined Patent Application, First
Publication No. H06-188169, which meets the longitudinal direction
of the line pattern, etc. may be appropriately combined with the
above configuration, which works more effectively.
[0192] It should be noted that, for example, when by using, for
example, ArF excimer laser light as the exposure light and using
projection optical system PL having a reduction magnification of
about 1/4, a fine line-and-space pattern (e.g., line-and-space of
about 25 to 50 nm) is exposed onto substrate P, depending on the
structure of mask M (e.g., the fineness of the pattern or the
thickness of chrome), mask M acts as a polarization plate due to
the wave guide effect, and the emitted amount of the diffraction
lights from S polarization components (TE polarization components)
becomes larger than the emitted amount of the diffraction lights
from P polarization components (TM polarization components), which
lower the contrast, and thus, even when mask M is illuminated with
random-polarized light, a high resolution performance can be
obtained even in the case where the numerical aperture NA of the
projection optical system PL is 0.9 to 1.3, although the
above-described linearly polarized light illumination is preferably
employed. Furthermore, although, for example, when a very fine
line-and-space pattern on mask M is exposed onto substrate P, there
is the possibility that the emitted amount of the diffraction
lights from P polarization components (TM polarization components)
becomes larger than the emitted amount of the diffraction lights
from S polarization components (TE polarization components) due to
the wire grid effect, since, for example, when by using, for
example, ArF excimer laser light as the exposure light and using
projection optical system PL having a reduction magnification of
about 1/4, a line-and-space pattern of more than 25 nm is exposed
onto substrate P, the emitted amount of the diffraction lights from
S polarization components (TE polarization components) is larger
than the emitted amount of the diffraction lights from P
polarization components (TM polarization components), a high
resolution performance can be obtained even in the case where the
numerical aperture NA of the projection optical system is 0.9 to
1.3.
[0193] Furthermore, not only the linearly polarized light
illumination in which the longitudinal direction of the line
pattern on the mask (reticle) is aligned with the polarization
direction, but also the combination, as disclosed in Japanese
Unexamined Patent Application, First Publication No. H06-53120, of
the polarized light illumination method, in which the lights used
are linearly polarized in the tangential directions relative to a
circle, of which center is the optical axis, and an oblique
incidence illumination method is effective. In particular, in the
case where the pattern of the mask (reticle) includes not only line
patterns which extend in a predetermined single direction but also
line patterns which extends in multiple different directions, by
using, as also disclosed in Japanese Unexamined Patent Application,
First Publication No. H06-53120, the polarized light illumination
method, in which the lights used are linearly polarized in the
tangential directions relative to a circle, of which center is the
optical axis, in combination with an annular illumination method, a
high resolution performance can be obtained even in the case where
the numerical aperture NA of the projection optical system is
large.
[0194] In the embodiments, optical element 2 is attached to the end
of projection optical system PL, and by this lens, the optical
characteristics of projection optical system PL (spherical
aberration, coma aberration, etc.) can be adjusted. It should be
noted that as the optical element to be attached to the end of
projection optical system PL, an optical plate used for the
adjustment of the optical characteristics of projection optical
system PL may be utilized. Alternatively, a plane parallel plate
that can transmit exposure light EL may be utilized.
[0195] It should be noted that if the pressure, caused by the flow
of liquid 1, of the space between the optical element located at
the end of projection optical system PL and substrate P is high, it
may be configured such that the optical element is rigidly fixed so
as not to move due to the pressure, instead of making the optical
element replaceable.
[0196] It should be noted that while, in the embodiments, it is
configured such that the space between projection optical system PL
and the surface of substrate P is filled with liquid 1, it may also
be configured, for example, such that the space is filled with
liquid 1 in the condition that a cover glass constituted by a plane
parallel plate is attached to the surface of substrate P.
[0197] It should be noted that while, in the embodiments, liquid 1
is water, liquid 1 may be a liquid other than water. For example,
when the light source of exposure light EL is an F.sub.2 laser, the
F.sub.2 laser light does not transmit through water, and thus, as
liquid 1, a fluorofluid that can transmit the F.sub.2 laser light,
such as perfluoropolyether (PFPE) or fluorochemical oil, may be
used. Furthermore, as liquid 1, a material (e.g., cedar oil) that
can transmit exposure light EL, has a high refractive index as high
as practicable, and does not affect projection optical system and
the photoresist applied to the surface of substrate P can also be
used. Also in this case, the surface treatment is applied in
accordance with the polarity of liquid 1.
[0198] It is to noted that regarding substrate P of each of the
above-described embodiments, not only a semiconductor wafer for
manufacturing a semiconductor device, but also a glass substrate
for a display device, a ceramic wafer for a thin film magnetic
head, a master mask or reticle (synthetic quartz or silicon wafer),
etc. can be used.
[0199] Regarding exposure apparatus EX, in addition to a scan type
exposure apparatus (scanning stepper) in which while synchronously
moving mask M and substrate P, the pattern of mask M is
scan-exposed, a step-and-repeat type projection exposure apparatus
(stepper) in which the pattern of mask M is exposed at one time in
the condition that mask M and substrate P are stationary, and
substrate P is successively moved stepwise can be used. Also, the
present invention can be applied to a step-and-stitch type exposure
apparatus in which at least two patterns are transferred onto
substrate P in a partially overlapping manner.
[0200] Furthermore, the present invention can be applied to a
stitch type one-shot exposure apparatus in which in the state that
a first pattern and substrate P are substantially stationary, the
reduction image of the first pattern is exposed at one time by
using a projection optical system (e.g., a refraction type
projection optical system that has a reduction magnification of 1/8
and includes no reflecting element), and thereafter, in the state
that a second pattern and substrate P are substantially stationary,
the reduction image of the second pattern is exposed at one time
onto substrate P by using the projection optical system in a manner
that the first pattern image and the second pattern image partially
overlap with each other.
[0201] Also, the present invention can be applied to a twin stage
type exposure apparatus, which is disclosed in, e.g., Japanese
Unexamined Patent Application, First Publication No. H10-163099,
Japanese Unexamined Patent Application, First Publication No.
H10-214783, and Published Japanese Translation No. 2000-505958.
[0202] Regarding the type of exposure apparatus EX, the present
invention is not limited to an exposure apparatus, which exposes a
semiconductor pattern onto substrate P, for manufacturing
semiconductor devices, but can also be applied to a variety of
exposure apparatuses, e.g., an exposure apparatus for manufacturing
liquid crystal display devices or a displays, an exposure apparatus
for manufacturing thin film magnetic heads, an exposure apparatus
for manufacturing image pickup devices, and an exposure apparatus
for manufacturing reticles or masks.
[0203] When using a linear motor (see U.S. Pat. No. 5,623,853 or
U.S. Pat. No. 5,528,118) in substrate stage PST or mask stage MST,
either air-cushion type linear motor using an air bearing or a
magnetic levitation type linear motor using a Lorentz force or
reactance force may be used. Furthermore, each of substrate stage
PST and mask stage MST may be either of a type moving along a guide
or of a guideless type having no guide.
[0204] As the driving mechanism for each of substrate stage PST and
mask stage MST, a planar motor in which by making a magnet unit in
which magnets are two-dimensionally arranged and an armature unit
in which coils are two-dimensionally arranged face each other, each
of substrate stage PST and mask stage MST is driven by an
electromagnetic force may be used. In this case, either one of the
magnet unit and the armature unit is attached to stage PST or stage
MST, and the other unit is attached to the moving surface side of
stage PST or stage MST.
[0205] A reaction force generated by the movement of substrate
stage PST may be, as described in Japanese Unexamined Patent
Application, First Publication No. H08-166475 (U.S. Pat. No.
5,528,118), mechanically released to the floor (earth) by use of a
frame member so that the force does not transmit to projection
optical system PL. A reaction force generated by the movement of
mask stage MST may be, as described in Japanese Unexamined Patent
Application, First Publication No. H08-330224 (U.S. Pat. No.
5,874,820), mechanically released to the floor (earth) by use of a
frame member so that the force does not transmit to projection
optical system PL.
[0206] Exposure apparatus EX according to the embodiments of the
present application is built by assembling various subsystems,
including each element listed in the claims of the present
application, in such a manner that prescribed mechanical accuracy,
electrical accuracy, and optical accuracy are maintained. In order
to ensure the various accuracies, prior to and after the assembly,
every optical system is adjusted to achieve its optical accuracy,
every mechanical system is adjusted to achieve its mechanical
accuracy, and every electrical system is adjusted to achieve its
electrical accuracy. The process of assembling each subsystem into
the exposure apparatus includes mechanical interfaces, electrical
circuit wiring connections, and air pressure plumbing connections
between each subsystem. Needless to say, there is also a process
where each subsystem is assembled prior to the assembling of the
exposure apparatus from the various subsystems. On completion of
the process of assembling the various subsystems in the exposure
apparatus, overall adjustment is performed to make sure that every
accuracy is maintained in the complete exposure apparatus.
Additionally, it is desirable to manufacture the exposure apparatus
in a clean room, in which the temperature, purity, etc. are
controlled.
[0207] As shown in FIG. 26, micro devices such as semiconductor
devices are manufactured by a series of steps, including: step 201
in which the micro device's function and performance design is
performed; step 202 in which a mask (reticle) is manufactured based
on the design step; step 203 in which a substrate, the device's
base material, is manufactured; step 204 in which the mask pattern
is exposed onto the substrate by exposure apparatus EX according to
the above-described embodiments; device assembly step 205
(including the dicing process, bonding process, and packaging
process); inspection step 206.
[0208] In accordance with the present invention, even when exposing
edge areas of a substrate, the exposure can be performed in a
condition that a liquid immersion region is formed well and that
penetration of the liquid and flowing out of the liquid to the
outside of a substrate stage are prevented, and devices having a
desired performance can be manufactured.
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