U.S. patent application number 15/703427 was filed with the patent office on 2018-01-04 for stage apparatus, exposure apparatus, and exposure method.
This patent application is currently assigned to NIKON CORPORATION. The applicant listed for this patent is NIKON CORPORATION. Invention is credited to Hirotaka KOHNO, Yasufumi NISHII, Kenichi SHIRAISHI.
Application Number | 20180004096 15/703427 |
Document ID | / |
Family ID | 34675168 |
Filed Date | 2018-01-04 |
United States Patent
Application |
20180004096 |
Kind Code |
A1 |
NISHII; Yasufumi ; et
al. |
January 4, 2018 |
STAGE APPARATUS, EXPOSURE APPARATUS, AND EXPOSURE METHOD
Abstract
An exposure apparatus has a stage having a substrate holder and
a plate member around the substrate holder to surround a substrate
on the substrate holder. A liquid supply mechanism includes a
supply port above the stage at a more outward position than an
optical path of light from a projection system and supplies liquid
onto the stage from the supply port. A liquid recovery mechanism
includes a recovery port above the stage at a more outward position
than the supply port and recovers the liquid supplied from the
supply port. The liquid supply and recovery mechanisms form a
liquid immersion region that includes the optical path on part of
the stage with the liquid supplied from the supply port. The stage
has a passageway below the plate member and recovers the liquid
from the liquid immersion region that infiltrates a gap between the
plate member and the substrate.
Inventors: |
NISHII; Yasufumi;
(Kumagaya-shi, JP) ; SHIRAISHI; Kenichi;
(Saitama-shi, JP) ; KOHNO; Hirotaka; (Ageo-shi,
JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
NIKON CORPORATION |
Tokyo |
|
JP |
|
|
Assignee: |
NIKON CORPORATION
Tokyo
JP
|
Family ID: |
34675168 |
Appl. No.: |
15/703427 |
Filed: |
September 13, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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12926763 |
Dec 8, 2010 |
9798245 |
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15703427 |
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10582268 |
Jun 9, 2006 |
7982857 |
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PCT/JP2004/018702 |
Dec 15, 2004 |
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12926763 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G03F 7/70341
20130101 |
International
Class: |
G03F 7/20 20060101
G03F007/20 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 15, 2003 |
JP |
2003-416712 |
Claims
1. An exposure apparatus that exposes a substrate through a liquid
with a light from a projection optical system, the exposure
apparatus comprising: a stage which has a substrate holder that
holds the substrate and a plate member provided around the
substrate holder so as to surround the substrate on the substrate
holder and which is movable relative to the projection optical
system; a liquid supply mechanism which includes a supply port
arranged above the stage so as to be face-to-face with the stage at
a more outward position than an optical path of the light from the
projection optical system with respect to an optical axis of the
projection optical system and which supplies the liquid onto the
stage from the supply port; and a liquid recovery mechanism which
includes a recovery port arranged above the stage so as to be
face-to-face with the stage at a more outward position than the
supply port with respect to the optical axis and which recovers,
from the recovery port, a liquid supplied from the supply port,
wherein the liquid supply mechanism and the liquid recovery
mechanism form a liquid immersion region so as to include the
optical path on part of the stage with a liquid supplied from the
supply port, and the stage has a passageway provided below the
plate member and recovers, by the passageway, the liquid that
infiltrates a gap between the plate member and the substrate by
moving with respect to the liquid immersion region in a state where
the substrate is held by the substrate holder.
2. The exposure apparatus according to claim 1, wherein the stage
has a facing surface provided below the gap so as to be
face-to-face with the gap and recovers the liquid that infiltrates
the gap via the facing surface by the passageway.
3. The exposure apparatus according to claim 2, wherein part of the
facing surface is face-to-face with a rear surface of the plate
member.
4. The exposure apparatus according to claim 2, wherein an opening
of the passageway is provided below the plate member.
5. The exposure apparatus according to claim 2, wherein an opening
of the passageway is provided so as to be face-to-face with a rear
surface of the plate member.
6. The exposure apparatus according to claim 2, wherein an opening
of the passageway is provided at a more outward position than the
facing surface with respect to the substrate holder.
7. The exposure apparatus according to claim 1, wherein the
substrate holder is arranged in a recessed part formed on the
stage, and an opening of the passageway is provided at a higher
position than a bottom surface of the recessed part.
8. The exposure apparatus according to claim 1, wherein the
substrate holder holds the substrate such that an upper surface of
the plate member is at a same height as an upper surface of the
substrate.
9. The exposure apparatus according to claim 1, wherein the plate
member is formed in a ring shape so as to surround the substrate
holder.
10. The exposure apparatus according to claim 1, wherein the plate
member is liquid repellent.
11. The exposure apparatus according to claim 1, wherein the
projection optical system includes a lens provided at a tip part on
the stage side so as to come into contact with the liquid immersion
region.
12. The exposure apparatus according to claim 11, wherein a contact
surface, which comes into contact with the liquid immersion region,
of a surface of the lens is lyophilic.
13. A device manufacturing method that forms a device on a
substrate, the method comprising: exposing the substrate using the
exposure apparatus according to claim 1; and developing the
substrate exposed using the exposure apparatus.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This is a continuation of U.S. patent application Ser. No.
12/926,763 filed Dec. 8, 2010, which in turn is a continuation of
U.S. patent application Ser. No. 10/582,268 filed Jun. 9, 2016 (now
U.S. Pat. No. 7,982,857), which is the U.S. National Stage of
International Application No. PCT/JP2004/018702 filed Dec. 15,
2004, which claims priority to Japanese Patent Application No.
2003-416712 filed Dec. 15, 2003. The disclosure of each of the
above-identified applications is incorporated herein by reference
in its entireties.
BACKGROUND OF THE INVENTION
1. Field of the Invention
[0002] The present invention relates to a stage apparatus having a
holder that holds a substrate as well as a stage that supports and
moves the holder, an exposure apparatus comprising the stage
apparatus, and an exposure method; more particularly, the present
invention relates to a stage apparatus, an exposure apparatus, and
an exposure method suited for use when exposing a substrate with an
image of a pattern through a projection optical system and a
liquid. In addition, the disclosure of the following priority
application is hereby incorporated by reference in its entirety:
Japanese Patent Application No. 2003-416712, filed on Dec. 15,
2003.
2. Description of the Related Art
[0003] Semiconductor devices and liquid crystal display devices are
fabricated by a so-called photolithography technique, wherein a
pattern formed on a mask is transferred onto a photosensitive
substrate.
[0004] An exposure apparatus used in this photolithographic process
comprises a mask stage that supports the mask, as well as a
substrate stage that supports the substrate, and transfers the
pattern of the mask onto the substrate through a projection optical
system while successively moving the mask stage and the substrate
stage.
[0005] There has been demand in recent years for higher resolution
projection optical systems in order to handle the much higher
levels of integration of device patterns. The shorter the exposure
wavelength used and the larger the numerical aperture of the
projection optical system, the higher the resolution of the
projection optical system becomes. Consequently, the exposure
wavelength used in exposure apparatuses has shortened year by year,
and the numerical aperture of projection optical systems has
increased. Furthermore, the mainstream exposure wavelength
currently is the 248 nm KrF excimer laser, but an even shorter
wavelength 193 nm ArF excimer laser is also being commercialized.
In addition, as with resolution, the depth of focus (DOF) is
important when performing an exposure. The following equations
express the resolution R and the depth of focus .delta.,
respectively.
R=k.sub.1.lamda./NA (1)
.delta.=.+-.k.sub.2.lamda./NA.sup.2 (2)
[0006] Therein, .lamda. is the exposure wavelength, NA is the
numerical aperture of the projection optical system, and k.sub.1
and k.sub.2 are the process coefficients. Equations (1) and (2)
teach that if the exposure wavelength .lamda. is shortened and the
numerical aperture NA is increased in order to enhance the
resolution R, then the depth of focus .delta. narrows.
[0007] At this time, if the depth of focus .delta. becomes
excessively narrow, then it will become difficult to align the
front surface of the substrate with the image plane of the
projection optical system, and there will be a risk of insufficient
margin during the exposure operation.
[0008] Accordingly, a liquid immersion method has been proposed, as
disclosed in, for example, Patent Document 1 below, as a method to
substantially shorten the exposure wavelength and increase the
depth of focus. This liquid immersion method forms an immersion
area by filling a liquid, such as water or an organic solvent,
between the lower surface of the projection optical system and the
front surface of the substrate, thus taking advantage of the fact
that the wavelength of the exposure light in a liquid is 1/n of
that in the air (where n is the refractive index of the liquid,
normally about 1.2-1.6), thereby improving the resolution as well
as increasing the depth of focus by approximately n times.
[0009] Nevertheless, the related art discussed above has the
following types of problems.
[0010] The abovementioned related art is constituted so that the
liquid locally fills the space between the substrate (wafer) and
the end surface on the image plane side of the projection optical
system, and so that the liquid does not flow out to the outer side
of the substrate when exposing a shot region in the vicinity of the
center of the substrate. Nevertheless, if an attempt is made to set
the projection area 100 of the projection optical system to a
peripheral area (edge area) E of a substrate P and then expose the
edge area E of the substrate P, as depicted by the schematic
diagram of FIG. 10, there is a problem in that the liquid flows out
to the outer side of the substrate P, and therefore the immersion
area does not form satisfactorily, which degrades the projected
pattern image. In addition, the liquid that flows out can also
cause problems such as rusting of mechanical parts and the like
around the substrate stage that supports the substrate P, as well
as electrical leakage of the stage drive system and the like.
[0011] Furthermore, if the liquid that flows out to the outer side
of the substrate P travels around to the rear surface of the
substrate P and infiltrates the space between the substrate P and
the substrate stage (substrate holder), then it will also cause a
problem wherein the substrate stage cannot satisfactorily hold the
substrate P. In addition, if the liquid infiltrates the step or the
gap between the substrate P and the substrate stage, then in this
case as well there is a possibility that the liquid will cause rust
or electric leakage. Particularly if a positioning notched part,
such as a notched part and an orientation flat part (orientation
flat), is formed in the substrate P, then the gap between the outer
circumference of the substrate P and the table part at the
periphery thereof will increase, which will consequently make it
easy for the liquid to travel around through this gap.
[0012] The present invention was made considering the
abovementioned problems, and it is an object of the present
invention to provide a stage apparatus, an exposure apparatus, and
an exposure method that can prevent the infiltration of a liquid
into the space between a substrate and a holder, and that can
perform exposure in a state wherein an immersion area is
satisfactorily formed, even when exposing an edge area of the
substrate.
SUMMARY OF THE INVENTION
[0013] To achieve the abovementioned objects, the present invention
adopts the following constitution.
[0014] The stage apparatus of the present invention comprises a
holder, which has a substrate holding surface that holds a
substrate, and a stage, which supports and moves the holder,
comprising: a recovery apparatus, which is disposed in the vicinity
of the holder, that has a lyophilic part, of which at least a part
is lyophilic, and that recovers a liquid using the lyophilic
part.
[0015] Accordingly, because the lyophilic parts of the stage
apparatus of the present invention have an affinity for the liquid,
it is possible to guide the liquid that infiltrates the vicinity of
the holder in a direction away from the substrate holding surface,
and then recover the liquid. Consequently, it is possible to
prevent the infiltration of the liquid between the substrate
holding surface and the rear surface of the substrate, and thereby
to expose the edge area of the substrate in a state wherein the
immersion area is satisfactorily formed.
[0016] In addition, an exposure apparatus of the present invention
comprises a stage apparatus as described in the claims.
Furthermore, an exposure method of the present invention is to
transfer a mask pattern through a projection optical system onto a
substrate on a holder while filling the liquid between the
projection optical system and the substrate and performing an
exposure while preventing the infiltration of the liquid into the
space between the substrate holding surface and the rear surface of
the substrate.
[0017] With the exposure apparatus and the exposure method of the
present invention, it is possible to prevent the infiltration of
the liquid into the space between the substrate holding surface and
the rear surface of the substrate, even when filling the liquid
between the projection optical system and the substrate and
exposing the edge area of the substrate. Accordingly, it is
possible to perform an exposure while satisfactorily holding the
substrate.
[0018] With the present invention, the liquid can be prevented from
traveling around to the space between the substrate and the holder,
even when exposing the edge area of the substrate, and it is
thereby possible to perform an immersion exposure while
satisfactorily holding the liquid below the projection optical
system.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] FIG. 1 is a schematic block diagram that depicts one
embodiment of an exposure apparatus according to the present
invention.
[0020] FIG. 2 is a schematic block diagram that depicts a liquid
supply mechanism and a liquid recovery mechanism.
[0021] FIG. 3 is a plan view of a substrate stage.
[0022] FIG. 4 is a cross sectional view of principle parts of the
substrate stage according to the first embodiment.
[0023] FIG. 5 is a cross sectional view of principle parts of the
substrate stage according to the second embodiment.
[0024] FIG. 6 is an enlarged plan view of the substrate stage
according to the second embodiment.
[0025] FIG. 7 is a cross sectional view of principle parts of the
substrate stage according to the third embodiment.
[0026] FIG. 8 is a cross sectional view of principle parts of the
substrate stage according to another embodiment.
[0027] FIG. 9 is a flow chart diagram that depicts one example of a
process of fabricating a semiconductor device.
[0028] FIG. 10 is a schematic diagram for explaining the problems
with the conventional exposure method.
DETAILED DESCRIPTION OF THE INVENTION
[0029] The following explains the embodiments of the stage
apparatus and the exposure apparatus of the present invention,
referencing FIG. 1 through FIG. 9. FIG. 1 is a schematic block
diagram that depicts one embodiment of the exposure apparatus
according to the present invention.
First Embodiment
[0030] In FIG. 1, an exposure apparatus EX comprises: a mask stage
MST that supports a mask M; a substrate stage PST that supports a
substrate P; an illumination optical system IL that illuminates the
mask M, which is supported by the mask stage MST, with an exposure
light EL; a projection optical system PL that projects and exposes
a pattern image of the mask M illuminated by the exposure light EL
onto the substrate P supported by the substrate stage PST, which
functions as the stage apparatus; and a control apparatus CONT that
provides overall control of the operation of the entire exposure
apparatus EX.
[0031] The exposure apparatus EX of the present embodiment is a
liquid immersion type exposure apparatus that applies the liquid
immersion method to substantially shorten the exposure wavelength,
improve the resolution, as well as substantially increase the depth
of focus, and comprises a liquid supply mechanism 10 that supplies
a liquid 1 between the projection optical system PL and the
substrate P, and a liquid recovery mechanism 20 that recovers the
liquid 1 on the substrate P. In the present embodiment, pure water
is used as the liquid 1. At least during the transfer of the
pattern image of the mask M onto the substrate P, the exposure
apparatus EX forms an immersion area AR2 with the liquid 1, which
is supplied by the liquid supply mechanism 10, in at least one part
on the substrate P that includes a projection area AR1 of the
projection optical system PL. Specifically, the exposure apparatus
EX exposes the substrate P by filling the liquid 1 between an
optical element 2 at the tip part of the projection optical system
PL and the front surface (exposure surface) PA (refer to FIG. 4) of
the substrate P, and then projecting the pattern image of the mask
M onto the substrate P through the projection optical system PL and
the liquid 1 which is provided between this projection optical
system PL and the substrate P.
[0032] The present embodiment will now be explained as exemplified
by a case of using a scanning type exposure apparatus (a so-called
scanning stepper) as the exposure apparatus EX that exposes the
substrate P with the pattern formed on the mask M while
synchronously moving the mask M and the substrate P in their
respective scanning directions in mutually different orientations
(reverse directions). In the following explanations, the direction
that coincides with an optical axis AX of the projection optical
system PL is the Z axial direction, the direction in which the mask
M and the substrate P synchronously move (in the scanning
directions) within the plane perpendicular to the Z axial direction
is the X axial direction, and the direction perpendicular to the Z
axial direction and the X axial direction (non-scanning direction)
is the Y axial direction. In addition, the directions around the X,
Y, and Z axes are the .theta.X, .theta.Y, and .theta.Z directions,
respectively. Furthermore, "substrate" herein includes a
semiconductor wafer coated with a photoresist, which is a
photosensitive material, and "mask" includes a reticle wherein a
device pattern, which is reduction projected onto the substrate, is
formed.
[0033] The illumination optical system IL illuminates the mask M,
which is supported by the mask stage MST, with the exposure light
EL, and comprises: an exposure light source; an optical integrator
that uniformizes the illuminance of the luminous flux emitted from
the exposure light source; a condenser lens that condenses the
exposure light EL from the optical integrator; a relay lens system;
and a variable field stop that sets an illumination region on the
mask M illuminated by the exposure light EL to be slit shaped; and
the like. The illumination optical system IL illuminates the
prescribed illumination region on the mask M with the exposure
light EL, which has a uniform illuminance distribution. Examples of
light that can be used as the exposure light EL emitted from the
illumination optical system IL include: deep ultraviolet light (DUV
light), such as the bright lines (g, h, and i lines) in the
ultraviolet region emitted from a mercury lamp for example, and KrF
excimer laser light (248 nm wavelength); and vacuum ultraviolet
light (VUV light), such as ArF excimer laser light (193 nm
wavelength) and F.sub.2 laser light (157 nm wavelength). ArF
excimer laser light is used in the present embodiment. As discussed
above, the liquid 1 in the present embodiment is pure water, and
the exposure light EL can transmit therethrough even if it is light
from an ArF excimer laser. In addition, deep ultraviolet light (DUV
light), such as KrF excimer laser light (248 nm wavelength) and the
bright lines (g, h, and i lines) in the ultraviolet region, can
also transmit through pure water.
[0034] The mask stage MST supports the mask M and is two
dimensionally movable in the plane perpendicular to the optical
axis AX of the projection optical system PL, i.e., in the XY plane,
and is finely rotatable in the .theta.Z direction. A mask stage
drive apparatus MSTD, such as a linear motor, drives the mask stage
MST. The control apparatus CONT controls the mask stage drive
apparatus MSTD. A movable mirror 50 is provided on the mask stage
MST. In addition, a laser interferometer 51 is provided at a
position opposing the movable mirror 50. The laser interferometer
51 measures in real time the position in the two dimensional
direction as well as the rotational angle of the mask M on the mask
stage MST, and outputs these measurement results to the control
apparatus CONT. The control apparatus CONT drives the mask stage
drive apparatus MSTD based on the measurement results of the laser
interferometer 51, thereby positioning the mask M, which is
supported by the mask stage MST.
[0035] The projection optical system PL projects and exposes the
pattern of the mask M onto the substrate P at a prescribed
projection magnification .beta., and comprises a plurality of
optical elements, which includes the optical element (lens) 2
provided at the tip part on the substrate P side, that is supported
by a lens barrel PK. In the present embodiment, the projection
optical system PL is a reduction system that has a projection
magnification .beta. for example, 1/4 or 1/5. Furthermore, the
projection optical system PL may be a unity magnification system or
an enlargement system. In addition, the optical element 2 at the
tip part of the projection optical system PL of the present
embodiment is detachably (replaceably) provided to the lens barrel
PK, and the liquid 1 of the immersion area AR2 contacts the optical
element 2.
[0036] The optical element 2 is made of fluorite. Because fluorite
has a strong affinity for water, the liquid 1 can adhere to
substantially the entire surface of a liquid contact surface 2a of
the optical element 2. Namely, because the liquid (water) 1
supplied in the present embodiment has a strong affinity for the
liquid contact surface 2a of the optical element 2, the liquid
contact surface 2a of the optical element 2 and the liquid 1 have
strong adhesion, and therefore the optical path between the optical
element 2 and the substrate P can be reliably filled with the
liquid 1. Furthermore, the optical element 2 may be made of quartz,
which also has a strong affinity (hydrophilic) for water. In
addition, the liquid contact surface 2a of the optical element 2
may be given hydrophilic (lyophilic) treatment in order to further
raise its affinity for the liquid 1. In addition, because the
vicinity of the tip of the lens barrel PK contacts the liquid
(water) 1, at least the vicinity of the tip is made of a metal that
is rust resistant, such as Ti (titanium).
[0037] The substrate stage PST supports the substrate P and
comprises: a substrate table (stage) 52 that holds the substrate P
via a substrate holder PH; an XY stage 53 that supports the
substrate table 52; and a base 54 that supports the XY stage 53. A
substrate stage drive apparatus PSTD, such as a linear motor,
drives the substrate stage PST. The substrate stage drive apparatus
PSTD is controlled by the control apparatus CONT. The position in
the Z axial direction (the focus position) and in the .theta.X and
.theta.Y directions of the substrate P held on the substrate table
52 is controlled by driving the substrate table 52. In addition,
the position of the substrate P in the X and Y directions (the
position in the directions substantially parallel to the image
plane of the projection optical system PL) is controlled by driving
the XY stage 53. In other words, the substrate table 52 functions
as a Z stage that controls the focus position and the inclination
angle of the substrate P, and aligns the front surface of the
substrate P with the image plane of the projection optical system
PL by an auto focus system and an auto leveling system; further,
the XY stage 53 positions the substrate P in the X axial direction
and Y axial direction. Furthermore, the substrate table 52 and the
XY stage 53 may of course be integrally provided.
[0038] Movable mirrors 55 are provided on the substrate stage PST
(the substrate table 52). In addition, a laser interferometer 56 is
provided at a position opposing each movable mirror 55. The laser
interferometers 56 measure in real time the position in the two
dimensional directions as well as the rotational angle of the
substrate P on the substrate stage PST, and output these
measurement results to the control apparatus CONT. The control
apparatus CONT drives the substrate stage drive apparatus PSTD
based on the measurement results of the laser interferometers 56,
and thereby positions the substrate P supported on the substrate
stage PST.
[0039] In addition, a ring shaped plate part 30 is provided on the
substrate stage PST (substrate table 52) so that it surrounds the
substrate P. The plate part 30 is fixed in a state that the outer
circumference of the plate part 30 is mated to the substrate table
52, and a recessed part 32 is formed on the inner side of the plate
part 30. Furthermore, the plate part 30 and the substrate table 52
may be provided integrally. The substrate holder PH that holds the
substrate P is disposed in the recessed part 32 (refer to FIG. 4).
The plate part 30 has a flat surface that is at a height
substantially the same as the front surface PA of the substrate P,
which is held by the substrate holder PH disposed in the recessed
part 32. Furthermore, the details of the plate part 30 and the
substrate holder PH will be discussed later.
[0040] The liquid supply mechanism 10 supplies the prescribed
liquid 1 onto the substrate P, and comprises: a first liquid supply
part 11 and a second liquid supply part 12 that are capable of
supplying the liquid 1; a first supply member 13, which is
connected to the first liquid supply part 11 via a supply pipe 11A
having a passageway, that comprises a supply port 13A that supplies
the liquid 1 fed from this first liquid supply part 11 onto the
substrate P; and a second supply member 14, which is connected to
the second liquid supply part 12 via a supply pipe 12A having a
passageway, that comprises a supply port 14A that supplies the
liquid 1 fed from this second liquid supply part 12 onto the
substrate P. The first and second supply members 13, 14 are
disposed proximate to the front surface of the substrate P, and are
provided at mutually different positions in the surface directions
of the substrate P. Specifically, the first supply member 13 of the
liquid supply mechanism 10 is provided on one side (the -X side) of
the projection area AR1 in the scanning direction, and the second
supply member 14 is provided on the other side (the +X side).
[0041] Each of the first and second liquid supply parts 11, 12
comprises a tank, which stores the liquid 1, a pressure pump, and
the like, and supplies the liquid 1 onto the substrate P through
the supply pipes 11A, 12A and the supply members 13, 14. In
addition, the liquid supply operation of the first and second
liquid supply parts 11, 12 is controlled by the control apparatus
CONT, which is capable of independently controlling the amount of
liquid 1 supplied per unit of time by the first and second liquid
supply parts 11, 12 onto the substrate P. In addition, each of the
first and second liquid supply parts 11, 12 comprises a liquid
temperature adjusting mechanism, and supplies the liquid 1 of a
temperature substantially the same as that inside the chamber
wherein the apparatus is housed (e.g., 23.degree. C.) onto the
substrate P.
[0042] The liquid recovery mechanism 20 recovers the liquid 1 on
the substrate P, and comprises: first and second recovery members
23, 24, which comprise recovery ports 23A, 24A disposed proximate
to the front surface of the substrate P; and first and second
liquid recovery parts 21, 22, which are respectively connected to
these first and second recovery members 23, 24 via recovery pipes
21A, 22A, which have passageways. Each of the first and second
liquid recovery parts 21, 22 comprises: a suction apparatus, such
as a vacuum pump; a tank that stores the recovered liquid 1; and
the like; further, these first and second liquid recovery parts 21,
22 recover the liquid 1 on the substrate P via the first and second
recovery members 23, 24 and the recovery pipes 21A, 22A. The liquid
recovery operation of the first and second liquid recovery parts
21, 22 is controlled by the control apparatus CONT, which is
capable of controlling the amount of liquid recovered by the first
and second liquid recovery parts 21, 22 per unit of time.
[0043] FIG. 2 is a plan view that schematically depicts the
constitution of the liquid supply mechanism 10 and the liquid
recovery mechanism 20. As depicted in FIG. 2, the projection area
AR1 of the projection optical system PL is set to a slit shape
(rectangular shape), wherein the longitudinal direction is in the Y
axial direction (the non-scanning direction), and is formed on a
part of the substrate P so that the immersion area AR2, which is
filled with the liquid 1, includes the projection area AR1.
Furthermore, the first supply member 13 of the liquid supply
mechanism 10 for forming the immersion area AR2 ,which includes the
projection area AR1, is provided on one side (the -X side) of the
projection area AR1 in the scanning direction, and the second
supply member 14 is provided on the other side (the +X side).
[0044] The first and second supply members 13, 14 are formed
substantially arcuately in a plan view, and are set so that their
supply ports 13A, 14A in the Y axial direction are at least larger
than the projection area AR1 in the Y axial direction. Furthermore,
the supply ports 13A, 14A, which are formed substantially arcuately
in a plan view, are disposed so that the projection area AR1 is
interposed therebetween in the scanning direction (the X axial
direction). The liquid supply mechanism 10 simultaneously supplies
the liquid 1 to both sides of the projection area AR1 via the
supply ports 13A, 14A of the first and second supply members 13,
14.
[0045] The first and second recovery members 23, 24 of the liquid
recovery mechanism 20 respectively comprise recovery ports 23A,
24A, which are arcuately and continuously formed so that they face
the front surface of the substrate P. Furthermore, the first and
second recovery members 23, 24, which are disposed so that they
face one another, form a substantially annular recovery port. The
recovery ports 23A, 24A of the first and second recovery members
23, 24 are disposed so that they surround the first and second
supply members 13, 14 of the liquid supply mechanism 10 as well as
the projection area AR1. In addition, a plurality of partition
members 25 is provided inside the recovery port, which is
continuously formed so that it surrounds the projection area
AR1.
[0046] The liquid 1 supplied onto the substrate P from the supply
ports 13A, 14A of the first and second supply members 13, 14 is
supplied so that it spreads between the substrate P and the lower
end surface at the tip part (optical element 2) of the projection
optical system PL. In addition, the liquid 1 that flows out to the
outer side of the first and second supply members 13, 14 with
respect to the projection area AR1 is recovered by the recovery
ports 23A, 24A of the first and second recovery members 23, 24,
which are disposed on the outer side of the first and second supply
members 13, 14 with respect to the projection area AR1.
[0047] When performing a scanning exposure of the substrate P in
the present embodiment, the amount of liquid 1 supplied per unit of
time from the near side of the projection area AR1 in the scanning
direction is set larger than that on the opposite side thereof. For
example, if performing the exposure process while moving the
substrate P in the +X direction, the control apparatus CONT sets
the amount of liquid 1 supplied from the -X side of the projection
area AR1 (i.e., the supply port 13A) greater than that from the +X
side (i.e., the supply port 14A); on the other hand, when
performing the exposure process while moving the substrate P in the
-X direction, the amount of liquid 1 supplied from the +X side of
the projection area AR1 is set greater than that from the -X side.
In addition, the amount of liquid 1 recovered per unit of time on
the near side of the projection area AR1 with respect to the
scanning direction is set less than that on the opposite side. For
example, when moving the substrate P in the +X direction, the
amount of liquid 1 recovered from the +X side of the projection
area AR1 (i.e., the recovery port 24A) is greater than that from
the -X side (i.e., the recovery port 23A).
[0048] FIG. 3 is a plan view of the substrate table 52 of the
substrate stage PST, viewed from above. A movable mirror 55 is
disposed at each of two mutually perpendicular edge parts of the
substrate table 52, which is rectangularly shaped in a plan view. A
fiduciary mark FM, which is used when aligning the mask M and the
substrate P with respect to a prescribed position, is provided in
the vicinity of the intersection part of the movable mirrors 55,
55. In addition, although not shown, various sensors, such as
illuminance sensors and the like, are provided around the substrate
P on the substrate stage PST.
[0049] In addition, a recessed part 32 is circularly formed, in a
plan view, at the substantially center part of the substrate table
52, and a support part 52a is protrudingly provided to this
recessed part 32 for supporting the substrate holder PH (refer to
FIG. 4). Furthermore, the substrate holder PH, which holds the
substrate P, is disposed inside the recessed part 32 in a state
wherein the substrate holder PH is supported by the support part
52a, and wherein there is a gap between the substrate holder PH and
the substrate table 52, as depicted in FIG. 4. Furthermore, the
pressure in the gap between the substrate table 52 and the
substrate holder PH is set to atmospheric pressure (open).
Furthermore, the plate part 30, which has a flat surface 31 that is
at a height substantially the same as the front surface of the
substrate P, is provided around the substrate P.
[0050] The substrate holder PH comprises a substantially annular
circumferential wall part 33, which holds a rear surface PC of the
substrate P on the inner side of the outer circumference of the
substrate P, and a plurality of support parts 34, which are
disposed on the inner side of the circumferential wall part 33,
that hold the substrate P. The circumferential wall part 33 and the
support parts 34 are provided on a substantially discoid base part
35, which constitutes part of the substrate holder PH. The support
parts 34 are each trapezoidal in a cross sectional view, and the
rear surface PC of the substrate P is held on an upper end surface
(substrate holding surface) 33A of the circumferential wall part 33
and an upper end surface (substrate holding surface) 34A of each of
the plurality of support parts 34. The support parts 34 are evenly
disposed on the inner side of the circumferential wall part 33. In
the present embodiment, among the surfaces of the substrate holder
PH, the upper end surface 33A of the circumferential wall part 33
and a side surface 37 are liquid repellent. Liquid repellency
treatments used on the substrate holder PH include coating it with
a fluororesin material or a liquid repellent material, such as
acrylic resin material, or adhering a thin film consisting of the
abovementioned liquid repellent material. Liquid repellent
materials used to impart liquid repellency include materials that
are insoluble in the liquid 1.
[0051] FIG. 4 is an enlarged cross sectional view of principle
parts of the substrate stage PST, which holds the substrate P.
[0052] The ring shaped plate part 30 is installed inside the
recessed part 32 so that its outer circumference mates with the
substrate table 52, and comprises an inner circumferential surface
3, which is formed thinner than the thickness of the substrate P
and opposes a side surface (outer circumferential part) PB of the
substrate P, and an inclined surface (inclined part) 5, which has a
starting point at a lower end part 4 (first portion) of the inner
circumferential surface 3 and slopes gradually downward toward the
outer side. The upper end part 4 (i.e., the lower end part of the
inner circumferential surface 3) of the inclined surface 5 is
disposed at a position higher than the upper end surface 33A of the
circumferential wall part 33 and the upper end surfaces 34A of the
support parts 34.
[0053] In the present embodiment, the flat surface 31 of the plate
part 30 is liquid repellent with respect to the liquid 1, and the
inner circumferential surface 3 and the inclined surface 5 of the
plate part 30 are lyophilic with respect to the liquid 1. The same
processes used in the substrate holder PH discussed above can be
adopted for the liquid repellency treatment of the flat surface 31.
In addition, the inner circumferential surface 3 and the inclined
surface 5 can be lyophilically treated by, for example, ultraviolet
light irradiation, plasma treatment that uses oxygen as the
reaction gas and exposure to an ozone atmosphere. Furthermore, the
plate part 30 may be made of a liquid repellent material
(fluororesin and the like), and the inner circumferential surface 3
and the inclined surface 5 may be given the abovementioned
lyophilic treatment, or provided with a lyophilic metal (or metal
film) adhered thereto (or formed by film deposition).
[0054] In addition, a suction apparatus 60 is provided to the plate
part 30 that suctions the liquid that flows into a space 39, which
is formed between the plate part 30 and the side surface PB of the
substrate P. In the present embodiment, the suction apparatus 60
comprises: a tank 61 that is capable of storing the liquid 1; a
passageway 62, which is provided inside the plate part 30 and the
substrate table 52, that connects the space 39 and the tank 61; and
a pump 64 that is connected to the tank 61 via a valve 63.
Furthermore, this passageway 62 is open to the space 39 in the
vicinity of (below) a lower end part of the inclined surface 5, and
the inner wall surface of the passageway 62 is also given the
abovementioned liquid repellency treatment.
[0055] The recovery apparatus according to the present invention
comprises the suction apparatus 60, as well as the lyophilic inner
circumferential surface 3 and the inclined surface 5 of the plate
part 30.
[0056] Furthermore, the front surface PA, which is the exposure
surface of the substrate P, is coated with a photoresist
(photosensitive material) 90. In the present embodiment, the
photosensitive material 90 is a photosensitive material (e.g.,
TARF-P6100 manufactured by Tokyo Ohka Kogyo Co., Ltd.) for ArF
excimer laser light, is liquid repellent (water repellent), and has
a contact angle of approximately 70-80.degree.. In addition, in the
present embodiment, the side surface PB of the substrate P is given
liquid repellency treatment (water repellency treatment).
Specifically, the side surface PB of the substrate P is also coated
with the abovementioned liquid repellent photosensitive material
90. Furthermore, the rear surface PC of the substrate P is also
given liquid repellency treatment by coating it with the
abovementioned photosensitive material 90.
[0057] In addition, a V shaped notched part PV is formed in the
outer circumference of the substrate P for aligning the substrate P
(refer to FIG. 3). Furthermore, a cross section of the notched part
PV is depicted in FIG. 4, and the outer circumference of the
substrate beyond the notched part PV is depicted by a chain
double-dashed line. In this case, the gap between the substrate
outer circumference beyond the notched part PV and the inner
circumferential surface 3 of the plate part 30 is, for example,
0.3-0.5 mm, and the gap between the substrate outer circumference
of the notched part PV and the inner circumferential surface 3 of
the plate part 30 is, for example, 1.5-2.0 mm.
[0058] On the other hand, the substrate stage PST comprises a
suction apparatus 40 that supplies negative pressure to a space 38,
which is surrounded by the circumferential wall part 33 of the
substrate holder PH. The suction apparatus 40 comprises: a
plurality of suction ports 41, which are provided to the upper
surface of the base part 35 of the substrate holder PH; a vacuum
part 42, which includes a vacuum pump provided outside of the
substrate stage PST; and a passageway 43, which is formed inside
the base part 35 and connects the vacuum part 42 to each of the
plurality of suction ports 41. The suction ports 41 are provided at
a plurality of prescribed locations different from the support
parts 34 on the upper surface of the base part 35. The suction
apparatus 40 suctions the gas (air) inside the space 38 formed
between the circumferential wall part 33, the base part 35, and the
substrate P, which is held by the support parts 34, and holds the
substrate P by suction to the circumferential wall part 33 and the
support parts 34 by creating a negative pressure in the space 38.
The control apparatus CONT controls the operation of the recovery
apparatus (suction apparatus 60) and the suction apparatus 40.
[0059] The following explains the method by which the exposure
apparatus EX, having the constitution discussed above, performs
immersion exposure of an edge area E of the substrate P.
[0060] When performing immersion exposure of the edge area E of the
substrate P as depicted in FIG. 4, the liquid 1 of the immersion
area AR2 is disposed at part of the front surface PA of the
substrate P and part of the flat surface 31 of the plate part 30.
At this time, if the edge area E to be exposed is at a position
where the notched part PV of the substrate P is not provided, then,
because the front surface PA of the substrate P and the flat
surface 31 of the plate part 30 are given liquid repellency
treatment, and because a gap (hereinbelow, referred to as gap A)
therebetween is not large, it is difficult for the liquid 1 of the
immersion area AR2 to infiltrate the gap A and virtually no liquid
1 flows therein due to the surface tension of the liquid 1.
[0061] On the other hand, if the edge area E to be exposed is at
the notched part PV of the substrate P, then there is a possibility
that the liquid 1 will infiltrate the space 39 depicted in FIG. 4
because the gap between the outer circumference PB of the substrate
P and the inner circumferential surface 3 of the plate part 30
increases to, for example, approximately 2 mm.
[0062] Here, because the outer circumference PB of the substrate P
is liquid repellent and the inner circumferential surface 3 and the
inclined surface 5 of the plate part 30 are lyophilic, the liquid 1
that flows into the space 39 moves (travels) from the inner
circumferential surface 3 to the inclined surface 5 due to its own
weight and the force of the affinity with the inner circumferential
surface 3, and arrives at the opening part of the passageway 62. By
continuously operating the pump 64 of the suction apparatus 60, the
negative pressure increases when the liquid 1 blocks the passageway
62, and the liquid 1 that arrives at the opening part thereof can
consequently be suctioned into and recovered in the tank 61 through
the passageway 62. The tank 61 is provided with a discharge
passageway 61A, which discharges the liquid 1 when a prescribed
amount has accumulated.
[0063] Furthermore, even in the event that the liquid 1 travels
around to the rear surface PC of the substrate P, it is possible to
prevent the infiltration of the liquid 1 into the space 38 from the
gap between the rear surface PC and the circumferential wall part
33 because the rear surface PC and the upper end surface 33A of the
circumferential wall part 33 are liquid repellent.
[0064] In addition, the inside of the recessed part 32 is open to
atmospheric pressure; consequently, the pressure therein is held at
a constant level in the state wherein the liquid 1 does not block
the passageway 62, vibrations attendant with the suction operation
are not transmitted to the substrate P, and it is therefore
possible to prevent adverse effects due to those vibrations.
[0065] In addition, a gap is formed in the plate part 30 between
the recovery members 23, 24 of the liquid recovery mechanism 20,
but the flat surface 31 is liquid repellent and it is therefore
possible to prevent the liquid 1 from flowing out of this gap and
to avoid hindering the exposure process.
[0066] Thus, the present embodiment prevents the liquid 1 from
traveling around to the space between the substrate P and the
holder PH (the circumferential wall part 33), even when exposing
the edge area E of the substrate P, and it is therefore possible to
perform immersion exposure while satisfactorily holding the liquid
1 below the projection optical system PL. Particularly, with the
present embodiment, the liquid 1 that flows into the space 39 can
be easily recovered using the inner circumferential surface 3 and
the inclined surface 5, which are lyophilic parts, to guide the
liquid 1 to the passageway 62 of the suction apparatus 60, which is
at a position spaced apart from the substrate P, and it is
therefore possible to prevent the liquid 1 from traveling around
the notched part PV and to satisfactorily perform immersion
exposure, even if using a substrate P wherein a notched part PV for
alignment is formed. Furthermore, with the present embodiment, the
upper end part 4 of the inclined surface 5 is positioned higher
than the upper end surface 33A, which is the substrate holding
surface, and it is consequently possible to guide the liquid 1 that
flows into the space 39 to the inclined surface 5 before it reaches
the upper end surface 33A, thereby making the suctioning and
recovery of the liquid 1 more reliable.
[0067] In addition, with the present embodiment, the side surface
37 and the upper end surface 33A of the circumferential wall part
33 of the substrate holder PH are liquid repellent, and it is
therefore possible to prevent the infiltration of the liquid 1 into
the space 38, even if the liquid 1 travels around to the rear
surface side of the substrate P. In addition, because the flat
surface 31 of the plate part 30 is given liquid repellency
treatment, the liquid 1 that forms the immersion area AR2 is
prevented from excessively spreading to the outer side of the plate
part 30, which makes it possible to satisfactorily form the
immersion area AR2 and prevent problems such as the outflow,
dispersion, and the like of the liquid 1.
Second Embodiment
[0068] FIG. 5 and FIG. 6 depict the second embodiment of the stage
apparatus of the present invention.
[0069] With the first embodiment, the liquid 1 travels to the
inclined surface of the plate part 30 due to its own weight, and is
guided in a direction away from the substrate P; however, the
second embodiment adopts a constitution wherein the liquid 1 is
suctioned using the capillary phenomenon.
[0070] The following explanation is made referencing FIG. 5 and
FIG. 6.
[0071] Furthermore, constituent elements in FIG. 5 and FIG. 6 that
are identical to those in the first embodiment, which is depicted
in FIG. 4 and the like, are assigned the identical symbols, and the
explanations thereof are omitted.
[0072] As depicted in FIG. 5, the plate part 30 in the present
embodiment comprises a rear surface 7 extending in the horizontal
direction (substantially parallel to the substrate holding surface
33A) from the lower end part 4, which serves as a base end, of the
inner circumferential surface 3. A plurality of slits (recessed
parts) 8 is provided to the rear surface 7, wherein one end of each
slit 8 is open to the space 39 formed between the side surface PB
of the substrate P and the inner circumferential surface 3.
[0073] As depicted in the partial enlarged plan view of FIG. 6,
each slit 8 has a minute width, and the slits 8 are radially formed
at prescribed intervals around the entire circumference of the
inner circumferential surface 3. Furthermore, the opening part of
the passageway 62 of the suction apparatus 60 is disposed at the
tip parts of the slits 8. The bottom surface 7 that includes the
slits 8 is given the abovementioned lyophilic treatment, and is
therefore lyophilic.
[0074] Furthermore, to facilitate understanding, FIG. 6 depicts a
state wherein the number of slits 8 is reduced, but actually
numerous slits 8 are formed at a micropitch so that the liquid 1
can be effectively suctioned.
[0075] Other aspects of the constitution of the present embodiment
are the same as the abovementioned first embodiment.
[0076] With the present embodiment, the liquid 1 that flows into
the space 39 is sucked into the slits 8 by the force of its
affinity therewith and by the capillary phenomenon, and is
suctioned and recovered from the end parts of the slits 8 through
the passageway 62; consequently, the liquid 1 can be prevented from
traveling around to the rear surface side of the substrate P, and
an immersion exposure can be satisfactorily performed.
[0077] Furthermore, a constitution wherein the slits of the present
embodiment are adapted to the inclined surface 5 in the first
embodiment would also be suitable. In this case, the suction force
due to the capillary phenomenon is added to the self weight of the
liquid 1, which raises the suction force and enables more reliable
suctioning and recovery thereof.
Third Embodiment
[0078] FIG. 7 depicts the third embodiment of the stage apparatus
of the present invention.
[0079] With the present embodiment, the liquid 1 is suctioned and
recovered using the lyophilic parts and the suction pressure
differential with respect to the plate part 30 and the substrate
P.
[0080] The following explanation is made referencing FIG. 7.
[0081] Furthermore, in FIG. 7, constituent elements that are
identical to those in the first embodiment, which is depicted in
FIG. 4 and the like, are assigned the identical symbols, and the
explanations thereof are omitted.
[0082] As depicted in FIG. 7, the plate part 30 in the present
embodiment is formed in a ring plate shape, and is mounted and
fixed onto the substrate table 52. A groove 9, which is upwardly
open, is formed in the substrate table 52 around its entire
circumference at a position wherein it is covered by the plate part
30. Furthermore, the passageway 62 of the suction apparatus 60 is
provided to the substrate table 52, and connects the groove 9 and
the tank 61. In addition, a step part 52A, which forms a micro gap
between the substrate table 52 and the rear surface 7 of the plate
part 30, is formed on the inner circumferential side of the groove
9 in the substrate table 52, and the groove 9 and the space 39 are
in communication through this gap. The step part 52A and the rear
surface 7 of the plate part 30 are lyophilic parts that have been
given the lyophilic treatment discussed above.
[0083] With the exposure apparatus EX constituted as mentioned
above, the control apparatus CONT controls the suction apparatuses
40, 60 so that the negative pressure suction force that applies
suction to the interior of the groove 9 is greater than the
negative pressure suction force that suctions the space 38 in order
to hold the substrate P to the substrate holder PH. Accordingly, if
the liquid 1 flows into the space 39, the negative pressure in the
groove 9 (the plate part 30 side) is greater than the negative
pressure in the space 38 (the substrate holder PH side), and
consequently the liquid 1 is suctioned into the groove 9 through
the gap between the rear surface 7 of the plate part 30 and the
step part 52A of the substrate table 52, and is further suctioned
into and recovered in the tank 61 through the passageway 62.
Particularly, with the present embodiment, the rear surface PC of
the substrate P and the upper end surface 33A of the substrate
holder PH (the circumferential wall part 33) are liquid repellent,
whereas the rear surface 7 of the plate part 30 and the step part
52A of the substrate table 52 are lyophilic, and it is consequently
possible to easily suction and reliably recover the liquid 1 to the
plate part 30 side by the force of their affinity to the liquid
1.
[0084] Furthermore, with the abovementioned first embodiment, the
plate part 30 comprises the lyophilic inner circumferential surface
3 and the inclined surface 5, but the present invention is not
limited thereto; as depicted in FIG. 8, the inner circumferential
surface 3 may be formed across the entire thickness of the plate
part 30, without forming the inclined surface. In this case, the
inner circumferential surface 3 is given lyophilic treatment, and
may be provided with the opening part of the passageway 62 of the
suction apparatus 60.
[0085] With the abovementioned constitution, the liquid 1 that
flows into the space 39 travels to the inner circumferential
surface 3 due to its own weight and its lyophilicity with the inner
circumferential surface 3, and is suctioned into and recovered in
the tank 61 through the passageway 62, consequently the same
effects as those in the abovementioned first embodiment are
obtained.
[0086] Furthermore, the entire surface of the flat surface 31 of
the plate part 30 in the abovementioned embodiments does not need
to be liquid repellent, but at least the position opposing the
first and second recovery members 23, 24 of the liquid recovery
mechanism 20 should be liquid repellent. In addition, the entire
surface of the substrate holder PH as well does not need to be
liquid repellent, but the upper end surface 33A of the
circumferential wall part 33 that opposes the rear surface PC of
the substrate P as well as the side surface 37 that opposes the
plate part 30 (space 39) should be liquid repellent.
[0087] Likewise for hydrophilicity, the slits 8 in the second
embodiment, for example, should be lyophilic, but the rear surface
7 does not necessarily need to be so.
[0088] In addition, the entire surfaces of the front surface PA,
the side surface PB, and the rear surface PC of the substrate P in
the abovementioned embodiments is coated with the photosensitive
material 90 in order to give them liquid repellency treatment, but
a constitution may be adopted wherein only the side surface PB of
the substrate P and the area of the rear surface PC of the
substrate P that opposes the circumferential wall part 33 are given
liquid repellency treatment.
[0089] The side surface PB and the rear surface PC of the substrate
P are coated with a liquid repellent photosensitive material 90 as
the liquid repellency treatment, but they may be coated with a
liquid repellent (water repellent) prescribed material other than
the photosensitive material 90. For example, there are cases
wherein the upper layer of the photosensitive material 90, which is
coated on the front surface PA that is the exposure surface of the
substrate P, is coated with, for example, a protective layer (a
film that protects the photosensitive material 90 from the liquid)
called a topcoat layer, and the material that forms this topcoat
layer (e.g., fluororesin material) is liquid repellent (water
repellent) at a contact angle of, for example, approximately
110.degree.. Accordingly, the side surface PB, the rear surface PC
of the substrate P are coated with this topcoat layer forming
material. Of course, they may be coated with a liquid repellent
material other than the photosensitive material 90 and the topcoat
layer forming material.
[0090] Likewise, it was explained that, as the liquid repellency
treatment, the substrate stage PST and the substrate holder PH may
be coated with a fluororesin material or an acrylic resin material
but they may be coated with the abovementioned photosensitive
material or the topcoat layer forming material; conversely, the
side surface PB and the rear surface PC of the substrate P may be
coated with the material used in the liquid repellency treatment of
the substrate stage PST and the substrate holder PH.
[0091] It is often the case that the abovementioned topcoat layer
is provided in order to prevent the infiltration of the liquid 1 of
the immersion area AR2 into the photosensitive material 90;
however, even if an adhered residue (a so-called watermark) of the
liquid 1 is formed, for example, on the topcoat layer, eliminating
the topcoat layer after the immersion exposure can eliminate the
watermark together with the topcoat layer, and the subsequent
prescribed process, such as the development process, can then be
performed. Here, if the topcoat layer is made of, for example, a
fluororesin material, then it can be eliminated using a fluorine
based solvent. Thereby, there is no longer a need for apparatuses
and the like (e.g., a substrate cleaning apparatus for removing
watermarks) in order to eliminate the watermark, and the prescribed
processes can be satisfactorily performed after the watermark has
been eliminated by a simple constitution that eliminates the
topcoat layer with a solvent.
[0092] In addition, the abovementioned embodiments explained that a
notched part, which is V shaped in a plan view, is provided for
aligning the substrate P, but the present invention can also be
adapted to a substrate provided with a so-called orientation flat,
wherein the substrate P is notched in a direction orthogonal to the
radial direction, and of course can also be adapted to a substrate
wherein a notched part for alignment is not formed.
[0093] The liquid 1 in each of the abovementioned embodiments
comprises pure water. Pure water is advantageous because it can be
easily obtained in large quantities at a semiconductor fabrication
plant and the like, and because pure water has no adverse impact on
the optical elements (lenses), the photoresist on the substrate P,
and the like. In addition, because pure water has no adverse impact
on the environment and has an extremely low impurity content, it
can also be expected to have the effect of cleaning the surface of
the substrate P and the surface of the optical element provided on
the tip surface of the projection optical system PL. Furthermore,
PFPE (fluoropolyether) may be used as the liquid 1.
[0094] Further, because the refractive index n of pure water
(water) for the exposure light EL that has a wavelength of
approximately 193 nm is substantially 1.44, the use of ArF excimer
laser light (193 nm wavelength) as the light source of the exposure
light EL would shorten the wavelength on the substrate P to 1/n,
i.e., approximately 134 nm, thereby obtaining a high resolution.
Furthermore, because the depth of focus will increase approximately
n times, i.e., approximately 1.44 times, that of in air, the
numerical aperture of the projection optical system PL can be
further increased if it is preferable to ensure a depth of focus
approximately the same as that when used in air, and the resolution
is also improved from this standpoint.
[0095] In the present embodiment, the optical element 2 is attached
to the tip of the projection optical system PL, and this lens can
adjust the optical characteristics, e.g., aberrations (spherical
aberration, coma aberration, and the like), of the projection
optical system PL. Furthermore, the optical element attached to the
tip of the projection optical system PL may be the optical plate
used to adjust the optical characteristics of the projection
optical system PL. Alternatively, it may be a parallel plate
capable of transmitting the exposure light EL.
[0096] Furthermore, if the pressure generated by the flow of the
liquid 1 between the optical element 2 at the tip of the projection
optical system PL and the substrate P is high, then the optical
element 2 may be rigidly fixed so that it does not move by that
pressure, instead of making that optical element 2
exchangeable.
[0097] In addition, the present embodiment is constituted so that
the liquid 1 is filled between the projection optical system PL and
the surface of the substrate P, but it may be constituted so that,
for example, the liquid 1 is filled in a state wherein a cover
glass, comprising a parallel plate, is attached to the surface of
the substrate P.
[0098] Furthermore, although the liquid 1 in the present embodiment
is water, it may be a liquid other than water. For example, if the
light source of the exposure light EL is an F.sub.2 laser, then the
F.sub.2 laser light will not transmit through water, so it would be
acceptable to use as the liquid 1 a fluorine based fluid, such as
fluorine based oil, that is capable of transmitting F.sub.2 laser
light. In addition, it is also possible to use as the liquid 1 a
liquid (e.g., cedar oil) that is transparent to the exposure light
EL, has the highest possible refractive index, and is stable with
respect to the projection optical system PL and to the photoresist
coated on the surface of the substrate P. In this case as well, the
surface treatment is performed in accordance with the polarity of
the liquid 1 used.
[0099] Furthermore, the substrate P in each of the abovementioned
embodiments is not limited to a semiconductor wafer for fabricating
semiconductor devices, and is also applicable to a glass substrate
for a display device, a ceramic wafer for a thin film magnetic
head, or a mask or original plate of a reticle (synthetic quartz,
silicon wafer) used by an exposure apparatus, and the like.
[0100] In addition to a step-and-scan system scanning type exposure
apparatus (scanning stepper) that scans and exposes the pattern of
the mask M by synchronously moving the mask M and the substrate P,
a step-and-repeat system projection exposure apparatus (stepper)
that exposes the full pattern of the mask M, with the mask M and
the substrate P in a stationary state, and sequentially steps the
substrate P is also applicable as the exposure apparatus EX. In
addition, the present invention is also applicable to a
step-and-stitch system exposure apparatus that transfers at least
two patterns partially and superimposingly onto the substrate
P.
[0101] In addition, the present invention is also applicable to the
twin stage type scanning steppers disclosed in Japanese Unexamined
Patent Application, First Publication No. H10-163099, Japanese
Unexamined Patent Application, First Publication No. H10-214783,
Published Japanese Translation No. 2000-505958 of the PCT
International Publication, and the like.
[0102] The type of exposure apparatus EX is not limited to
semiconductor device fabrication exposure apparatuses that expose
the pattern of a semiconductor device on the substrate P, but is
also widely applicable to exposure apparatuses for fabricating
liquid crystal display devices or displays, for fabricating thin
film magnetic heads, imaging devices (CCDs), reticles and masks,
and the like.
[0103] If a linear motor (refer to U.S. Pat. No. 5,623,853 and U.S.
Pat. No. 5,528,118) is used in the substrate stage PST or the mask
stage MST, then either an air levitation type, which uses an air
bearing, or a magnetic levitation type, which uses Lorentz's force
or reactance force, may be used. In addition, each of the stages
PST, MST may be a type that moves along a guide or may be a
guideless type.
[0104] For the drive mechanism of each of the stages PST, MST, a
planar motor may be used that opposes a magnet unit, wherein
magnets are disposed two dimensionally, to an armature unit,
wherein coils are disposed two dimensionally, and drives each of
the stages PST, MST by electromagnetic force. In this case, either
the magnet unit or the armature unit is connected to the stages
PST, MST and the other one, which is either the magnet unit or the
armature unit, should be provided on the moving surface side of the
stages PST, MST.
[0105] The reaction force generated by the movement of the
substrate stage PST may be mechanically discharged to the floor
(ground) using a frame member so that it is not transmitted to the
projection optical system PL, as recited in Japanese Unexamined
Patent Application, First Publication No. H08-166475 (U.S. Pat. No.
5,528,118).
[0106] The reaction force generated by the movement of the mask
stage MST may be mechanically discharged to the floor (ground)
using a frame member so that it is not transmitted to the
projection optical system PL, as recited in Japanese Unexamined
Patent Application, First Publication No. H08-330224 (U.S. Pat. No.
5,874,820). In addition, the reaction force may be eliminated by
using the law of the conversation of momentum, as recited in
Japanese Unexamined Patent Application, First Publication No.
8-63231 (U.S. Pat. No. 6,255,796).
[0107] The exposure apparatus EX of the embodiments in the present
application is manufactured by assembling various subsystems,
including each constituent element recited in the claims of the
present application, so that prescribed mechanical, electrical, and
optical accuracies are maintained. To ensure these various
accuracies, adjustments are performed before and after this
assembly, including an adjustment to achieve optical accuracy for
the various optical systems, an adjustment to achieve mechanical
accuracy for the various mechanical systems, and an adjustment to
achieve electrical accuracy for the various electrical systems. The
process of assembling the exposure apparatus from the various
subsystems includes the mutual mechanical connection of the various
subsystems, the wiring and connection of electrical circuits, the
piping and connection of the pneumatic circuit, and the like.
Naturally, before process of assembling the exposure apparatus from
these various subsystems, there are also the processes of
assembling each individual subsystem. When the process of
assembling the exposure apparatus from the various subsystems is
finished, a comprehensive adjustment is performed to ensure the
various accuracies of the exposure apparatus as a whole.
Furthermore, it is preferable to manufacture the exposure apparatus
in a clean room wherein the temperature, the cleanliness level, and
the like are controlled.
[0108] As shown in FIG. 9, a micro-device, such as a semiconductor
device is manufactured by: a step 201 that designs the functions
and performance of the micro-device; a step 202 that fabricates a
mask (reticle) based on this design step; a step 203 that
fabricates a substrate, which is the base material of the device;
an exposure processing step 204 wherein the exposure apparatus EX
of the embodiments discussed above exposes a pattern of the mask
onto the substrate; a device assembling step 205 (comprising a
dicing process, a bonding process, and a packaging process); an
inspecting step 206; and the like.
[0109] While preferred embodiments of the invention have been
described and illustrated above, it should be understood that these
are exemplary of the invention and are not to be considered as
limiting. Additions, omissions, substitutions, and other
modifications can be made without departing from the spirit or
scope of the present invention. Accordingly, the invention is not
to be considered as being limited by the foregoing description, and
is only limited by the scope of the appended claims.
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