U.S. patent application number 16/109137 was filed with the patent office on 2018-12-20 for exposure apparatus, exposure method, method for producing device, and optical part.
This patent application is currently assigned to NIKON CORPORATION. The applicant listed for this patent is NIKON CORPORATION. Invention is credited to Shigeru HIRUKAWA, Ryuichi HOSHIKA, Hitoshi ISHIZAWA, Hiroyuki NAGASAKA, Hiroaki TAKAIWA.
Application Number | 20180364581 16/109137 |
Document ID | / |
Family ID | 34656211 |
Filed Date | 2018-12-20 |
United States Patent
Application |
20180364581 |
Kind Code |
A1 |
NAGASAKA; Hiroyuki ; et
al. |
December 20, 2018 |
EXPOSURE APPARATUS, EXPOSURE METHOD, METHOD FOR PRODUCING DEVICE,
AND OPTICAL PART
Abstract
An exposure apparatus that exposes a substrate with light via
liquid includes a stage which holds the substrate and is movable
relative to a projection system; and a liquid supply system which
supplies liquid onto the substrate held on the stage to form a
liquid immersion area on part of the substrate The stage includes a
substrate holder arranged in a recess of the stage to hold the
substrate inside the recess so that an upper surface of the
substrate is substantially flush with an upper surface of the stage
around the recess; a flow passage connected to an internal space of
the recess to remove liquid from the internal space; and a sensor
which receives light from the projection optical system and is
arranged so that an upper surface of the sensor is substantially
flush with the upper surface of the stage around the recess.
Inventors: |
NAGASAKA; Hiroyuki;
(Kumagaya-shi, JP) ; TAKAIWA; Hiroaki;
(Kumagaya-shi, JP) ; HIRUKAWA; Shigeru; (Kita-ku,
JP) ; HOSHIKA; Ryuichi; (Sagamihara-shi, JP) ;
ISHIZAWA; Hitoshi; (Kawasaki-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
NIKON CORPORATION |
Tokyo |
|
JP |
|
|
Assignee: |
NIKON CORPORATION
Tokyo
JP
|
Family ID: |
34656211 |
Appl. No.: |
16/109137 |
Filed: |
August 22, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
14697374 |
Apr 27, 2015 |
10088760 |
|
|
16109137 |
|
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|
11639245 |
Dec 15, 2006 |
9019469 |
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14697374 |
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|
10581307 |
Sep 29, 2006 |
8054447 |
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PCT/JP2004/018435 |
Dec 3, 2004 |
|
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|
11639245 |
|
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G03F 7/7085 20130101;
G03F 7/707 20130101; G03F 7/70341 20130101; G03F 7/7075
20130101 |
International
Class: |
G03F 7/20 20060101
G03F007/20 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 3, 2003 |
JP |
2003-404384 |
Feb 19, 2004 |
JP |
2004-042496 |
Claims
1. An exposure apparatus which exposes a substrate with light via
liquid, the exposure apparatus comprising: a projection optical
system which projects a pattern image onto a projection region on
an image plane of the projection optical system; a stage which
holds the substrate, the stage being movable relative to the
projection optical system; and a liquid supply system which
supplies the liquid onto the substrate held on the stage to form a
liquid immersion area on a part of the substrate so that the
projection region is located in the liquid immersion area, wherein
the stage comprises: a substrate holder which holds the substrate,
the substrate holder being arranged in a recess of the stage to
hold the substrate inside the recess so that an upper surface of
the substrate is substantially flush with an upper surface of the
stage around the recess; a flow passage connected to an internal
space of the recess to remove liquid from the internal space; and a
sensor which receives light from the projection optical system, the
sensor being arranged so that an upper surface of the sensor is
substantially flush with the upper surface of the stage around the
recess.
2. The exposure apparatus according to claim 1, wherein the liquid
supply system includes a supply port to supply the liquid onto the
substrate, the supply port being arranged to face the upper surface
of the substrate inside the recess via the liquid.
3. The exposure apparatus according to claim 2, further comprising
a liquid recovery system having a recovery port to recover the
liquid from the liquid immersion region, the recovery port being
arranged above the stage so as to face the upper surface of the
substrate inside the recess.
4. The exposure apparatus according to claim 3, wherein the
recovery port is arranged outside the supply port with respect to
an optical axis of the projection optical system.
5. The exposure apparatus according to claim 3, wherein the supply
port is arranged outside the projection region, and the recovery
port is arranged to surround the projection region and the supply
port.
6. The exposure apparatus according to claim 1, wherein the flow
passage is connected to a space between an inner side surface of
the recess and an outer side surface of the substrate holder.
7. The exposure apparatus according to claim 1, wherein the
substrate holder comprises a circumferential wall and a supporting
portion disposed in a space surrounded by the circumferential wall,
and the substrate holder is configured to hold the substrate on the
supporting portion by applying a negative pressure to the space
surrounded by the circumferential wall.
8. The exposure apparatus according to claim 7, wherein the
substrate holder comprises a plurality of suction ports to apply
the negative pressure to the space surrounded by the
circumferential wall.
9. The exposure apparatus according to claim 8, wherein a height of
an upper surface of the circumferential wall is lower than a height
of an upper surface of the supporting portion.
10. The exposure apparatus according to claim 9, wherein the upper
surface of the circumferential wall is liquid repellent.
11. The exposure apparatus according to claim 1, wherein the stage
includes a reference member having a reference mark, of which an
upper surface is substantially flush with the upper surface of the
stage around the recess.
12. The exposure apparatus according to claim 11, wherein at least
a part of the upper surface of the reference member is liquid
repellent.
13. The exposure apparatus according to claim 1, wherein the sensor
includes a light shielding member arranged on at least a part of
the upper surface of the sensor.
14. The exposure apparatus according to claim 13, wherein the light
shielding member forms a light transmissive area in a pinhole shape
or a slit shape.
15. The exposure apparatus according to claim 1, wherein at least a
part of an upper surface of the sensor is liquid repellent.
16. The exposure apparatus according to claim 1, wherein at least a
part of the stage is liquid repellent.
17. An exposure method which exposes a substrate with light via
liquid, the exposure method comprising: exposing the substrate by
use of the exposure apparatus according to claim 1.
18. The exposure method according to claim 17, wherein the method
comprises filling an optical path of the light from the projection
optical system to the substrate being supported on the stage with
the liquid.
19. A device manufacturing method comprising: transferring a
pattern image onto a substrate by exposing the substrate with the
exposure apparatus according to claim 1; and assembling a device on
the substrate onto which the pattern image has been transferred.
Description
[0001] This is a Division of U.S. patent application Ser. No.
14/697,374 filed Apr. 27, 2015, which in turn is a Division of U.S.
patent application Ser. No. 11/639,245 filed Dec. 15, 2006 (now
U.S. Pat. No. 9,019,469), which is a Division of U.S. patent
application Ser. No. 10/581,307 filed Sep. 29, 2006 (now U.S. Pat.
No. 8,054,447), which is the U.S. National Stage of
PCT/JP2004/018435 filed Dec. 3, 2004. The disclosure of each of the
prior applications is hereby incorporated by reference herein in
its entirety.
TECHNICAL FIELD
[0002] The present invention relates to an exposure apparatus, an
exposure method, and a method for producing a device, in which an
exposure light beam is radiated onto a substrate through a liquid
to expose the substrate. The present invention also relates to an
optical part which is usable for a projection exposure apparatus
using the liquid immersion method, and the projection exposure
apparatus using the optical part. Further, the present invention
relates to an optical part which is preferably usable in such an
environment that the optical part makes contact with a liquid or a
vapor.
BACKGROUND ART
[0003] Semiconductor devices and liquid crystal display devices are
produced by means of the so-called photolithography technique in
which a pattern formed on a mask is transferred onto a
photosensitive substrate. The exposure apparatus, which is used in
the photolithography step, includes a mask stage for supporting the
mask and a substrate stage for supporting the substrate. The
pattern on the mask is transferred onto the substrate via a
projection optical system while successively moving the mask stage
and the substrate stage. In recent years, it is demanded to realize
the higher resolution of the projection optical system in order to
respond to the further advance of the higher integration of the
device pattern. As the exposure wavelength to be used is shorter,
the resolution of the projection optical system becomes higher. As
the numerical aperture of the projection optical system is larger,
the resolution of the projection optical system becomes higher.
Therefore, the exposure wavelength, which is used for the exposure
apparatus, is shortened year by year, and the numerical aperture of
the projection optical system is increased as well. The exposure
wavelength, which is dominantly used at present, is 248 nm of the
KrF excimer laser. However, the exposure wavelength of 193 nm of
the ArF excimer laser, which is shorter than the above, is also
practically used in some situations. When the exposure is
performed, the depth of focus (DOF) is also important in the same
manner as the resolution. The resolution R and the depth of focus
.delta. are represented by the following expressions
respectively.
R=k.sub.1.lamda./NA (1)
.delta.=.+-.k.sub.2.lamda./NA.sup.2 (2)
[0004] In the expressions, .lamda. represents the exposure
wavelength, NA represents the numerical aperture of the projection
optical system, and k.sub.1 and k.sub.2 represent the process
coefficients. According to the expressions (1) and (2), the
following fact is appreciated. That is, when 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. is narrowed.
[0005] If the depth of focus .delta. is too narrowed, it is
difficult to match the substrate surface with respect to the image
plane of the projection optical system. It is feared that the
margin is insufficient during the exposure operation. Further, the
optical part material, which is usable for the exposure light beam
that has the increasingly shortened wavelength, is restricted. From
the viewpoints as described above, the liquid immersion method has
been suggested, which is disclosed, for example, in International
Publication No. 99/49504 and Japanese Patent Application Laid-open
No. 10-303114 as a method for substantially shortening the
wavelength of the exposure light beam after passing via the
projection optical system and widening the depth of focus. In this
liquid immersion method, the space between the lower surface of the
projection optical system and the substrate surface is filled with
a liquid such as water or any organic solvent to form a liquid
immersion area so that the resolution is improved and the depth of
focus is magnified about n times by utilizing the fact that the
wavelength of the exposure light beam in the liquid is 1/n as
compared with that in the air (n represents the refractive index of
the liquid, which is about 1.2 to 1.6 in ordinary cases).
[0006] As schematically shown in FIG. 18, an edge area E of a
substrate P is sometimes subjected to the exposure as well in the
case of the exposure apparatus which adopts the liquid immersion
method. In such a situation, a portion of the projection area 100
protrudes to the outside of the substrate P, and the exposure light
beam is also radiated onto a substrate table 120 for holding the
substrate P. In the case of the liquid immersion exposure, the
liquid immersion area of the liquid is formed so that the
projection area 100 is covered therewith. However, when the edge
area E is subjected to the exposure, then a part of the liquid
immersion area of the liquid protrudes to the outside of the
substrate P, and the liquid immersion area is also formed on the
substrate table 120. When various measuring members and/or
measuring sensors are arranged around the substrate P on the
substrate table 120, the liquid immersion area is also formed on
the substrate table 120 in some cases in order to use the measuring
members and/or the measuring sensors. When a portion of the liquid
immersion area is formed on the substrate table 120, then the
liquid may remain on the substrate table 120 highly possibly, and
the following possibility arises.
[0007] That is, for example, the environment (temperature,
humidity), in which the substrate P is placed, may be varied as a
result of the vaporization of the remained liquid, the substrate
table 120 may be thermally deformed, the environment of the optical
paths for various measuring light beams to measure, for example,
the position information about the substrate P may be varied, and
the exposure accuracy may be lowered. Further, the following
possibility arises as well. That is, the water mark (trace of
water) may remain after the vaporization of the remained liquid,
which may result in the factor of the pollution of, for example,
the substrate P and the liquid, and which may result in the factor
of the error concerning various types of measurements.
DISCLOSURE OF THE INVENTION
[0008] The present invention has been made taking the foregoing
circumstances into consideration, a first object of which is to
provide an exposure apparatus, an exposure method, and a method for
producing a device, in which it is possible to prevent the liquid
from remaining, and it is possible to maintain a satisfactory
exposure accuracy and a satisfactory measurement accuracy.
[0009] A second object of the present invention is to provide an
optical part which has a water-repellent film provided with
durability against ultraviolet laser irradiation, and a projection
exposure apparatus which is provided with the optical part.
[0010] In order to achieve the objects as described above, the
present invention adopts the following constructions.
[0011] According to a first aspect of the present invention, there
is provided an exposure apparatus which exposes a substrate by
radiating an exposure light beam onto the substrate through a
liquid; the exposure apparatus comprising a projection optical
system which projects an image of a pattern onto the substrate; and
a substrate table which holds the substrate; wherein a member, at
least a part of a surface of which is liquid-repellent, is provided
exchangeably on the substrate table.
[0012] According to the present invention, there is provided a
method for producing a device, comprising using the exposure
apparatus according to the aspect as described above.
[0013] According to the present invention, the liquid-repellent
member, which is provided on the substrate table, is provided
exchangeably. Therefore, when the liquid repellence of the member
is deteriorated, the member can be exchanged with a new
liquid-repellent member. Therefore, it is possible to suppress the
remaining of the liquid. Even when the liquid remains, the liquid
can be recovered smoothly. Therefore, it is possible to avoid the
deterioration of the exposure accuracy and the measurement accuracy
which would be otherwise caused by the remaining liquid. It is
possible to produce the device which can exhibit desired
performance.
[0014] According to a second aspect of the present invention, there
is provided an exposure method for performing liquid immersion
exposure for a substrate by radiating an exposure light beam onto
the substrate via a projection optical system and a liquid; the
exposure method comprising holding the substrate with a
substrate-holding member, the substrate-holding member having a
flat portion which is disposed around the substrate and which is
substantially flush with a surface of the substrate; loading the
substrate-holding member to a substrate stage, the
substrate-holding member holding the substrate; performing the
liquid immersion exposure for the substrate loaded onto the
substrate stage; and unloading the substrate-holding member with
which the substrate is held from the substrate stage after
completion of the liquid immersion exposure.
[0015] According to the present invention, there is provided a
method for producing a device, comprising using the exposure method
as described above.
[0016] According to the present invention, the substrate-holding
member, which has the flat portion around the substrate, is loaded
and unloaded with respect to the substrate stage together with the
substrate. Accordingly, the substrate-holding member can be easily
exchanged with respect to the substrate stage together with the
substrate. For example, even when the liquid repellence of the
substrate-holding member is deteriorated, it is easy to perform the
exchange. The substrate-holding member has the flat portion around
the substrate. Therefore, when the substrate-holding member is
loaded to the substrate stage together with the substrate, and the
liquid immersion exposure for the edge area of the substrate is
performed, the shape of the liquid immersion area is maintained by
the flat portion, even when a part of the liquid immersion area of
the liquid protrudes to the outside of the substrate. It is
possible to perform the liquid immersion exposure in a state in
which the liquid is satisfactorily retained below the projection
optical system, without causing, for example, the outflow of the
liquid. Therefore, the deterioration of the exposure accuracy is
avoided, and it is possible to produce the device which exhibits
desired performance.
[0017] According to a third aspect of the present invention, there
is provided an exposure apparatus which exposes a substrate by
radiating an exposure light beam onto the substrate through a
liquid; the exposure apparatus comprising a projection optical
system which projects an image of a pattern onto the substrate; and
a movable stage which is movable relative to the projection optical
system; wherein a liquid-repellent member, at least a part of which
is liquid-repellent, is provided on the movable stage, and the
liquid-repellent member is exchangeable.
[0018] In the exposure apparatus according to the third aspect of
the present invention, the liquid-repellent member, which is
provided on the movable stage, is provided exchangeably. Therefore,
when the liquid repellence of the member is deteriorated, the
member can be exchanged with a new member. The movable stage may be
a substrate stage which is movable while holding the substrate, or
a measuring stage which is provided with various reference members
and/or measuring members such as measuring sensors. Alternatively,
the exposure apparatus may include, as the movable stage, both of a
substrate stage and a measuring stage. Further, the exposure
apparatus may include, as the movable stage, a plurality of
substrate stages or a plurality of measuring stages.
According to a fourth aspect of the present invention, there is
provided an exposure method for performing liquid immersion
exposure for a substrate by radiating an exposure light beam onto
the substrate through a liquid; the exposure method comprising
supplying the liquid to at least a part of a surface of the
substrate; and performing the liquid immersion exposure for the
substrate by radiating the exposure light beam onto the substrate
through the liquid; wherein a part of the exposure apparatus, which
is different from the substrate for which the liquid is supplied,
is liquid-repellent, and the liquid-repellent part of the exposure
apparatus is exchanged depending on deterioration of liquid
repellence thereof.
[0019] In the exposure method according to the fourth aspect of the
present invention, even when the liquid-repellent part of the
exposure apparatus is deteriorated by being irradiated with the
ultraviolet light, it is possible to avoid, for example, the
remaining and the leakage of the liquid which would be caused by
the deterioration, because the concerning part is exchanged
depending on the deterioration. The part may be exchanged
periodically. Alternatively, the part may be exchanged on the basis
of the result of the observation or the estimation of the situation
of deterioration for every part.
[0020] rewritten paragraph:
[0021] According to a fifth aspect of the present invention, there
is provided an optical part to be provided on a substrate stage of
a projection exposure apparatus which illuminates a mask with an
exposure light beam and transfers a pattern of the mask through a
liquid onto a substrate held by the substrate stage by using a
projection optical system; the optical part comprising a light
irradiated surface which is irradiated with the exposure light
beam; an adhesive particulate layer which comprises a particulate
layer composed of at least one of silicon dioxide, magnesium
fluoride, and calcium fluoride, and formed on the light irradiated
surface; and a water-repellent film which is composed of an
amorphous fluororesin and formed on a surface of the adhesive
particulate layer.
[0022] The inventors performed analysis about the adhesiveness
between the base material glass and fluoroalkylsilane, and found
that any chemical bond, which is based on, for example, the
hydrogen bond and/or the condensation reaction, cannot be expected
between fluoroalkylsilane and the base material glass, because the
terminal group --CF.sub.3 of fluoroalkylsilane is chemically
stable. Accordingly, the inventors have made the investigation
about the method for increasing the intermolecular attractive force
without depending on the chemical bond. As a result, the inventors
have succeeded in the increase in the adhesion energy in a skillful
manner by increasing the surface area of the adhesive layer which
is to be adhered to the base material glass. According to the
optical part of the present invention, the particulate or fine
particle layer, which is composed of at least one of silicon
dioxide (SiO.sub.2), magnesium fluoride (MgF.sub.2), and calcium
fluoride (CaF.sub.2) for forming the adhesive particulate layer,
has the good affinity for the glass (main component: SiO.sub.2) of
the base material, wherein a proper or appropriate degree of
adhesiveness is obtained. Further, irregularities, which result
from diameters of the particles or particulates, are generated on
the surface. Further, silicon dioxide or the like is such a
material that the ultraviolet transmittance is extremely high.
Therefore, such a material itself has the high durability against
the laser irradiation as well. Therefore, when the particulate
layer, which is composed of at least one of silicon dioxide
(SiO.sub.2), magnesium fluoride (MgF.sub.2), and calcium fluoride
(CaF.sub.2), is formed as a film, and the water-repellent film,
which is composed of the amorphous fluororesin, is formed
thereafter, then the amorphous fluororesin enters voids or
interstices of particulates of silicon dioxide or the like, and the
amorphous fluororesin is subjected to drying and solidification
while effecting embrace and inclusion of the particles. The
mechanical strength of the amorphous fluororesin itself is high.
Therefore, the water-repellent film, which is allowed to make tight
contact with the base material, has the high strength.
[0023] According to a sixth aspect of the present invention, there
is provided an optical part to be provided on a substrate stage of
a projection exposure apparatus for illuminating a mask with an
exposure light beam and transferring a pattern of the mask through
a liquid onto a substrate held by the substrate stage by using a
projection optical system; the optical part comprising a light
irradiated surface which is irradiated with the exposure light
beam; an adhesive surface which is formed on the light irradiated
surface; and a water-repellent film which is composed of an
amorphous fluororesin and formed on the adhesive surface. In the
optical part of this aspect, it is preferable that the adhesive
surface is a surface subjected to etching with hydrogen
fluoride.
[0024] According to the optical part of the sixth aspect, the
adhesive surface, which is constructed of the etching surface
subjected to the etching with hydrogen fluoride, for example, is
provided for the light irradiated surface. Therefore, when the
water-repellent film, which is composed of the amorphous
fluororesin, is formed on the adhesive surface, the amorphous
fluororesin is subjected to drying and solidification while
effecting embrace and inclusion. The mechanical strength of the
amorphous fluororesin itself is high. Therefore, the
water-repellent film, which is allowed to make tight contact with
the base material, has the high strength.
[0025] In the optical part according to the aspect described above,
the light irradiated surface may have a base material glass. In the
optical part according to the aspect described above, the
irradiated surface may have a metal film which is formed on at
least a part or portion of the base material glass. According to
the optical part as described above, the water-repellent film,
which is formed on the light irradiated surface, has the durability
against the laser irradiation. Therefore, it is possible to
maintain the water repellence of the light irradiated surface of
the optical part provided on the substrate stage of the projection
exposure apparatus for a long period of time.
[0026] According to the present invention, there is also provided a
projection exposure apparatus comprising the optical part according
to any one of the aspects described above. According to this
projection exposure apparatus, the optical part, which makes it
possible to maintain the water repellence of the light irradiated
surface for a long period of time, is provided on the substrate
stage. Therefore, even when the liquid immersion exposure is
repeatedly performed, it is possible to reliably discharge water
from the light irradiated surface of the optical part.
[0027] According to a seventh aspect of the present invention,
there is provided a projection exposure apparatus which illuminates
a mask with an exposure light beam and transfers a pattern of the
mask through a liquid onto a substrate held by a substrate stage by
using a projection optical system; the projection exposure
apparatus comprising, on the substrate stage, an optical part
including a light irradiated surface which is irradiated with the
exposure light beam; an adhesive particulate layer which is formed
on the light irradiated surface; and a water-repellent film which
is composed of an amorphous fluororesin and formed on a surface of
the adhesive particulate layer.
[0028] According to the projection exposure apparatus of the
seventh aspect, the optical part, which is provided on the
substrate stage, has the adhesive particulate layer on the light
irradiated surface. Therefore, the water-repellent film, which is
composed of the amorphous fluororesin, makes tight contact with the
adhesive particulate layer. The mechanical strength of the
amorphous fluororesin itself is high. Therefore, the
water-repellent film, which is allowed to make tight contact with
the base material, has the high strength.
[0029] In the projection exposure apparatus of the seventh aspect,
the light irradiated surface may have a base material glass. In the
projection exposure apparatus of the seventh aspect, the light
irradiated surface may have a metal film which is formed on at
least a part or portion of the base material glass. According to
the projection exposure apparatus as described above, the
water-repellent film, which is formed on the light irradiated
surface of the optical part mounted on the substrate stage, has the
durability against the laser irradiation. Therefore, it is possible
to maintain the water repellence of the light irradiated surface of
the optical part mounted on the substrate stage of the projection
exposure apparatus for a long period of time.
[0030] According to an eighth aspect of the present invention,
there is provided an optical part comprising a part body which has
a light irradiated surface; a particulate layer which is formed of
at least one particulate selected from the group consisting of
silicon dioxide, magnesium fluoride, and calcium fluoride, and
formed on the light irradiated surface; and a water-repellent film
which is formed of an amorphous fluororesin, on a surface of the
particulate layer. The water-repellent film is strongly connected
to the light irradiated surface by the aid of the particulate
layer. Therefore, the present invention is extremely useful for the
way of use including, for example, optical sensors and lenses to be
used in the liquid or vapor atmosphere.
[0031] According to a ninth aspect of the present invention, there
is provided an optical part comprising a part body which has a
light irradiated surface; an adhesive surface which is formed by
etching on the light irradiated surface; and a water-repellent film
which is formed of an amorphous fluororesin, on the adhesive
surface. The water-repellent film is strongly connected to the
light irradiated surface by the aid of the particulate layer.
Therefore, the present invention is extremely useful for the way of
use including, for example, optical sensors and lenses to be used
in the liquid or vapor atmosphere.
BRIEF DESCRIPTION OF THE DRAWINGS
[0032] FIG. 1 shows a schematic arrangement illustrating an
embodiment of an exposure apparatus of the present invention.
[0033] FIG. 2 shows a schematic plan view illustrating a liquid
supply mechanism and a liquid recovery mechanism.
[0034] FIG. 3 shows a plan view illustrating a substrate table.
[0035] FIG. 4 shows a plan view illustrating the substrate table in
a state in which a substrate is held.
[0036] FIG. 5 shows a sectional view illustrating the substrate
table.
[0037] FIG. 6 schematically shows that respective members are
detachable with respect to the substrate table.
[0038] FIGS. 7(a) to 7(d) schematically show an example of the
operation of the exposure apparatus of the present invention.
[0039] FIGS. 8(a) to 8(d) schematically show an example of the
operation of the exposure apparatus of the present invention.
[0040] FIG. 9 shows a plan view illustrating a substrate-holding
member transported by a transport unit.
[0041] FIG. 10 shows a sectional view illustrating another
embodiment of a substrate table.
[0042] FIGS. 11(a) and 11(b) show a schematic arrangement
illustrating another embodiment of an exposure apparatus of the
present invention.
[0043] FIGS. 12(a) and 12(b) show another embodiment of a
substrate-holding member.
[0044] FIGS. 13(a) to 13(d) schematically show another example of
the operation of the exposure apparatus of the present
invention.
[0045] FIG. 14 shows a schematic arrangement illustrating another
embodiment of an exposure apparatus of the present invention.
[0046] FIG. 15 shows a schematic arrangement illustrating another
embodiment of an exposure apparatus of the present invention.
[0047] FIG. 16 shows a schematic arrangement illustrating another
embodiment of an exposure apparatus of the present invention.
[0048] FIG. 17 shows a flow chart illustrating exemplary steps of
producing a semiconductor device.
[0049] FIG. 18 schematically explains a problem involved in the
conventional technique.
[0050] FIG. 19 shows optical parts provided on a wafer stage
according to an embodiment.
[0051] FIG. 20 shows a construction of the optical part provided on
the wafer stage according to the embodiment.
[0052] FIG. 21 shows a construction of the optical part provided on
the wafer stage according to the embodiment.
BEST MODE FOR CARRYING OUT THE INVENTION
[0053] An explanation will be made below about the exposure
apparatus according to the present invention with reference to the
drawings. However, the present invention is not limited
thereto.
First Embodiment
[0054] FIG. 1 shows a schematic arrangement illustrating an
embodiment of the exposure apparatus of the present invention. With
reference to FIG. 1, an exposure apparatus EX includes a mask stage
MST which supports a mask M, a substrate stage PST which supports a
substrate P by the aid of a substrate table PT, an illumination
optical system IL which illuminates, with an exposure light beam
EL, the mask M supported by the mask stage MST, a projection
optical system PL which performs projection exposure for the
substrate P supported by the substrate stage PST with an image of a
pattern of the mask M illuminated with the exposure light beam EL,
and a control unit CONT which integrally controls the overall
operation of the exposure apparatus EX.
[0055] The liquid immersion method is applied to the exposure
apparatus EX of the embodiment of the present invention in order
that the exposure wavelength is substantially shortened to improve
the resolution and the depth of focus is substantially widened. The
liquid immersion exposure apparatus includes a liquid supply
mechanism 10 which supplies the liquid 1 onto the substrate P, and
a liquid recovery mechanism 20 which recovers the liquid 1 from the
surface of the substrate P. In embodiment of the present invention,
pure water is used as the liquid 1. The exposure apparatus EX forms
a liquid immersion area AR2 (locally) on at least a part of the
substrate P including a projection area AR1 of the projection
optical system PL by the liquid 1 supplied from the liquid supply
mechanism 10 at least during the period in which the image of the
pattern of the mask M is transferred onto the substrate P.
Specifically, the exposure apparatus EX is operated as follows.
That is, the space between the surface (exposure surface) of the
substrate P and the optical element 2 disposed at the end portion
of the projection optical system PL is filled with the liquid 1.
The image of the pattern of the mask M is projected onto the
substrate P to expose the substrate P therewith via the projection
optical system PL and the liquid 1 disposed between the projection
optical system PL and the substrate P.
[0056] The embodiment of the present invention will now be
explained as exemplified by a case of the use of the scanning type
exposure apparatus (so-called scanning stepper) as the exposure
apparatus EX in which the substrate P is exposed with the pattern
formed on the mask M while synchronously moving the mask M and the
substrate P in mutually different directions (opposite directions)
in the scanning directions. In the following explanation, the Z
axis direction is the direction which is coincident with the
optical axis AX of the projection optical system PL, the X axis
direction is the synchronous movement direction (scanning
direction) for the mask M and the substrate P in the plane
perpendicular to the Z axis direction, and the Y axis direction
(non-scanning direction) is the direction which is perpendicular to
the Z axis direction and the X axis direction. The directions of
rotation (inclination) about the X axis, the Y axis, and the Z axis
are designated as .theta.X, .theta.Y, and .theta.Z directions
respectively. The term "substrate" referred to herein includes
those obtained by coating a semiconductor wafer surface with a
photoresist as a photosensitive material, and the term "mask"
includes a reticle formed with a device pattern to be subjected to
the reduction projection onto the substrate.
[0057] The illumination optical system IL is used so that the mask
M, which is supported on the mask stage MST, is illuminated with
the exposure light beam EL. The illumination optical system IL
includes, for example, an exposure light source, an optical
integrator (homogenizer) which uniformizes the illuminance of the
light flux radiated from the exposure light source, a condenser
lens which collects the exposure light beam EL emitted from the
optical integrator, a relay lens system, and a variable field
diaphragm which sets the illumination area on the mask M
illuminated with the exposure light beam EL to be slit-shaped. The
predetermined illumination area on the mask M is illuminated with
the exposure light beam EL having a uniform illuminance
distribution by the illumination optical system IL. Those usable as
the exposure light beam EL radiated from the illumination optical
system IL include, for example, emission lines (g-ray, h-ray,
i-ray) radiated, for example, from a mercury lamp, far ultraviolet
light beams (DUV light beams) such as the KrF excimer laser beam
(wavelength: 248 nm), and vacuum ultraviolet light beams (VUV light
beams) such as the ArF excimer laser beam (wavelength: 193 nm) and
the F.sub.2 laser beam (wavelength: 157 nm). In this embodiment,
the ArF excimer laser beam is used. As described above, the liquid
1 is pure water in this embodiment, through which the exposure
light beam EL is transmissive even when the exposure light beam EL
is the ArF excimer laser beam. The emission line (g-ray, h-ray,
i-ray) and the far ultraviolet light beam (DUV light beam) such as
the KrF excimer laser beam (wavelength: 248 nm) are also
transmissive through pure water.
[0058] The mask stage MST supports the mask M, while the mask stage
MST 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 it is finely rotatable in the OZ direction. The mask
stage MST is driven by a mask stage-driving unit MSTD such as a
linear motor. The mask stage-driving unit MSTD is controlled by the
control unit CONT. A movement mirror 50 is provided on the mask
stage MST. A laser interferometer 51 is provided at a position
opposed to the movement mirror 50. The position in the
two-dimensional direction and the angle of rotation of the mask M
on the mask stage MST are measured in real-time by the laser
interferometer 51. The result of the measurement is outputted to
the control unit CONT. The control unit CONT drives the mask
stage-driving unit MSTD on the basis of the result of the
measurement obtained by the laser interferometer 51 to thereby
position the mask M supported on the mask stage MST.
[0059] The projection optical system PL projects the pattern on the
mask M onto the substrate P at a predetermined projection
magnification a to perform the exposure. The projection optical
system PL includes a plurality of optical elements including the
optical element (lens) 2 provided at the end portion on the side of
the substrate P. The optical elements are supported by a barrel PK.
In this embodiment, the projection optical system PL is based on
the reduction system having the projection magnification .beta.
which is, for example, 1/4 or 1/5. The projection optical system PL
may be any one of the 1.times. magnification system and the
magnifying system. The projection optical system PL may be any one
of the catoptric system including no dioptric element, the dioptric
system including no catoptric element, and the catadioptric system
including dioptric and catoptric elements. The optical element 2,
which is disposed at the end portion of the projection optical
system PL of this embodiment, is provided detachably (exchangeably)
with respect to the barrel PK. The liquid 1 in the liquid immersion
area AR2 makes contact with the optical element 2.
[0060] The optical element 2 is formed of fluorite. Water has a
high affinity for fluorite. Therefore, the liquid 1 is successfully
allowed to make tight contact with the substantially entire surface
of the liquid contact surface 2a of the optical element 2. That is,
in this embodiment, the water, which has the high affinity for the
liquid contact surface 2a of the optical element 2, is supplied as
the liquid 1. Therefore, the highly tight contact is effected
between the liquid 1 and the liquid contact surface 2a of the
optical element 2. The optical path, which is disposed between the
optical element 2 and the substrate P, can be reliably filled with
the liquid 1. The optical element 2 may be quartz having a high
affinity for water as well. A water-attracting (lyophilic or
liquid-attracting) treatment may be performed to the liquid contact
surface 2a of the optical element 2 to further enhance the affinity
for the liquid 1. The barrel PK makes contact with the liquid
(water) 1 at portions disposed in the vicinity of the end portion.
Therefore, at least the portions disposed in the vicinity of the
end portion are formed of a metal such as Ti (titanium) which has
the resistance against rust.
[0061] The substrate stage PST supports the substrate P. The
substrate stage PST includes a Z stage 52 which holds the substrate
P by the aid of the substrate table PT, an XY stage 53 which
supports the Z stage 52, and a base 54 which supports the XY stage
53. The substrate table PT holds the substrate P. The substrate
table PT is provided on the substrate stage PST (Z stage 52). The
substrate stage PST is driven by a substrate stage-driving unit
PSTD such as a linear motor. The substrate stage-driving unit PSTD
is controlled by the control unit CONT. By driving the Z stage 52,
the substrate P held by the substrate table PT is subjected to the
control of the position in the Z axis direction (focus position)
and the positions in the .theta.X and .theta.Y directions. By
driving the XY stage 53, the substrate P is subjected to the
control of the position in the XY directions (position in the
direction substantially parallel to the image plane of the
projection optical system PL). That is, the Z stage 52 controls the
focus position and the angle of inclination of the substrate P so
that the surface of the substrate P is adjusted to match the image
plane of the projection optical system PL in the auto-focus manner
and the auto-leveling manner, and the XY stage 53 positions the
substrate P in the X axis direction and the Y axis direction. It
goes without saying that the Z stage and the XY stage may be
provided as an integrated body. Those usable for the
auto-focus/auto-leveling detecting system include, for example, an
arrangement disclosed in Japanese Patent Application Laid-open No.
8-37149.
[0062] A movement mirror 55, which is movable together with the
substrate stage PST with respect to the projection optical system
PL, is provided on the substrate stage PST (substrate table PT). A
laser interferometer 56 is provided at a position opposed to the
movement mirror 55. The angle of rotation and the position in the
two-dimensional direction of the substrate P on the substrate stage
PST (substrate table PT) are measured in real-time by the laser
interferometer 56. The result of the measurement is outputted to
the control unit CONT. The control unit CONT drives the substrate
stage-driving unit PSTD on the basis of the result of the
measurement of the laser interferometer 56 to thereby position the
substrate P supported on the substrate stage PST.
[0063] A substrate alignment system 350, which detects the
alignment mark on the substrate P or the reference mark (described
later on) provided on the substrate stage PST (substrate table PT),
is arranged over those disposed in the vicinity of the substrate
stage PST (substrate table PT). A mask alignment system 360, which
detects the reference mark provided on the substrate stage PST
(substrate table PT) via the mask M and the projection optical
system PL by using a light beam having the same wavelength as that
of the exposure light beam EL, is provided in the vicinity of the
mask stage MST. Those usable for the arrangement of the substrate
alignment system 350 include, for example, one disclosed in
Japanese Patent Application Laid-open No. 4-65603 (corresponding to
U.S. Pat. No. 5,493,403). Those usable for the arrangement of the
mask alignment system 360 include, for example, one disclosed in
Japanese Patent Application Laid-open No. 7-176468 (corresponding
to U.S. Pat. No. 5,646,413).
[0064] A plate member 30, which surrounds the substrate P held by
the substrate table PT, is provided on the substrate table PT. The
plate member 30 is a member distinct from the substrate table PT.
The plate member 30 is provided detachably with respect to the
substrate table PT, and the plate member 30 is exchangeable. The
plate member 30 has a flat surface (flat portion) 30A which is
substantially flush with the surface of the substrate P held by the
substrate table PT. The flat surface 30A is arranged around the
substrate P held by the substrate table PT. Further, a second plate
member 32, which has a flat surface 32A substantially flush with
the flat surface 30A of the plate member 30, is provided outside
the plate member 30 on the substrate table PT. The second plate
member 32 is provided detachably with respect to the substrate
table PT as well, and the second plate member 32 is
exchangeable.
[0065] The liquid supply mechanism 10, which supplies the
predetermined liquid 1 onto the substrate P, includes a first
liquid supply section 11 and a second liquid supply section 12
which are capable of supplying the liquid 1, a first supply member
13 which is connected to the first liquid supply section 11 via a
supply tube 11A having a flow passage and which has a supply port
13A for supplying the liquid 1 fed from the first liquid supply
section 11 onto the substrate P, and a second supply member 14
which is connected to the second liquid supply section 12 via a
supply tube 12A having a flow passage and which has a supply port
14A for supplying the liquid 1 fed from the second liquid supply
section 12 onto the substrate P. The first and second supply
members 13, 14 are arranged closely to the surface of the substrate
P, and they are provided at mutually different positions in the
surface direction of the substrate P. Specifically, the first
supply member 13 of the liquid supply mechanism 10 is provided on
one side (-X side) in the scanning direction with respect to the
projection area AR1. The second supply member 14 is provided on the
other side (+X side) in the scanning direction with respect to the
projection area AR1.
[0066] Each of the first and second liquid supply sections 11, 12
includes, for example, a tank for accommodating the liquid 1, and a
pressurizing pump (these components are not shown). The first and
second liquid supply sections 11, 12 supply the liquid 1 onto the
substrate P via the supply tubes 11A, 12A and the supply members
13, 14 respectively. The operation of each of the first and second
liquid supply sections 11, 12 for supplying the liquid is
controlled by the control unit CONT. The control unit CONT is
capable of controlling the liquid supply amounts per unit time onto
the substrate P by the first and second liquid supply sections 11,
12 independently respectively. Each of the first and second liquid
supply sections 11, 12 includes a temperature-adjusting mechanism
for the liquid. The liquid 1, which has approximately the same
temperature (for example, 23.degree. C.) as the temperature in the
chamber for accommodating the apparatus therein, can be supplied
onto the substrate P by the temperature-adjusting mechanism. It is
not necessarily indispensable that the exposure apparatus EX is
provided with the tank, the pressurizing pump, and the
temperature-adjusting mechanism of each of the liquid supply
sections 11, 12 which may be replaced with the equipment of the
factory or the like in which the exposure apparatus EX is
installed.
[0067] The liquid recovery mechanism 20 recovers the liquid 1 from
the surface of the substrate P. The liquid recovery mechanism 20
includes first and second recovery members 23, 24 each of which has
a recovery port 23A, 24A arranged closely to the surface of the
substrate P, and first and second liquid recovery sections 21, 22
which are connected to the first and second recovery members 23, 24
via recovery tubes 21A, 22A having flow passages respectively. Each
of the first and second liquid recovery sections 21, 22 includes,
for example, a vacuum system (sucking unit) such as a vacuum pump,
a gas/liquid separator, and a tank for accommodating the recovered
liquid 1 (these components are not shown). The first and second
liquid recovery sections 21, 22 recover the liquid 1 from the
surface of the substrate P via the first and second recovery
members 23, 24 and the recovery tubes 21A, 22A, respectively. The
operation of each of the first and second liquid recovery sections
21, 22 for recovering the liquid is controlled by the control unit
CONT. The control unit CONT is capable of controlling the liquid
recovery amounts per unit time by the first and second liquid
recovery sections 21, 22 independently respectively. It is not
necessarily indispensable that the exposure apparatus EX is
provided with the vacuum system, the gas/liquid separator, and the
tank of each of the liquid recovery sections 21, 22 which may be
replaced with the equipment of the factory or the like in which the
exposure apparatus EX is installed.
[0068] FIG. 2 shows a plan view illustrating a schematic
arrangement of the liquid supply mechanism 10 and the liquid
recovery mechanism 20. As shown in FIG. 2, the projection area AR1
of the projection optical system PL is designed to have a slit
shape (rectangular shape) in which the Y axis direction
(non-scanning direction) is the longitudinal direction. The liquid
immersion area AR2, which is filled with the liquid 1, is formed on
a part of the substrate P so that the projection area AR1 is
included therein. The first supply member 13 of the liquid supply
mechanism 10, which is used to form the liquid immersion area AR2
of the projection area AR1, is provided on one side (-X side) in
the scanning direction with respect to the projection area AR1, and
the second supply member 14 is provided on the other side (+x
side).
[0069] The first and second supply members 13, 14 are formed to be
substantially circular arc-shaped respectively as viewed in a plan
view. The size in the Y axis direction of the supply port 13A, 14A
is designed to be larger than at least the size in the Y axis
direction of the projection area AR1. The supply ports 13A, 14A,
which are formed to be substantially circular arc-shaped as viewed
in a plan view, are arranged to interpose the projection area AR1
in relation to the scanning direction (X axis direction). The
liquid supply mechanism 10 simultaneously supplies the liquid 1 on
the both sides of the projection area AR1 by the aid of the supply
ports 13A, 14A of the first and second supply members 13, 14.
[0070] Each of the first and second recovery members 23, 24 of the
liquid recovery mechanism 20 has a recovery port 23A, 24A which is
formed continuously to be circular arc-shaped so that the recovery
port 23A, 24A is directed to the surface of the substrate P. A
substantially annular recovery port is formed by the first and
second recovery members 23, 24 which are arranged so that they are
opposed to one another. The recovery ports 23A, 24A of the first
and second recovery members 23, 24 respectively are arranged to
surround the projection area AR1 and the first and second supply
members 13, 14 of the liquid supply mechanism 10.
[0071] The liquid 1, which is supplied onto the substrate P from
the supply ports 13A, 14A of the first and second supply members
13, 14, is supplied so that the liquid 1 is spread while causing
the wetting between the substrate P and the lower end surface of
the end portion (optical element 2) of the projection optical
system PL. The liquid 1, which outflows to the outside of the first
and second supply members 13, 14 with respect to the projection
area AR1, is recovered from the recovery ports 23A, 24A of the
first and second recovery members 23, 24 which are arranged outside
with respect to the projection area AR1 as compared with the first
and second supply members 13, 14.
[0072] In this embodiment, when the substrate P is subjected to the
scanning exposure, the liquid supply amount per unit time, which is
supplied in front of the projection area AR1 in relation to the
scanning direction, is set to be larger than the liquid supply
amount supplied from the side opposite thereto. For example, when
the exposure process is performed while moving the substrate P in
the +X direction, the control unit CONT is operated so that the
liquid amount, which is supplied from the -x side (i.e., from the
supply port 13A) with respect to the projection area AR1, is larger
than the liquid amount which is supplied from the +X side (i.e.,
from the supply port 14A). On the other hand, when the exposure
process is performed while moving the substrate P in the -X
direction, the control unit CONT is operated so that the liquid
amount, which is supplied from the +X side with respect to the
projection area AR1, is larger than the liquid amount which is
supplied from the -X side. The liquid recovery amount per unit
time, which is recovered in front of the projection area AR1 in
relation to the scanning direction, is set to be smaller than the
liquid recovery amount on the side opposite thereto. For example,
when the substrate P is moved in the +X direction, the recovery
amount, which is recovered from the +X side (i.e., from the
recovery port 24A) with respect to the projection area AR1, is
larger than the recovery amount which is recovered from the -X side
(i.e., from the recovery port 23A).
[0073] The mechanism, with which the liquid immersion area AR2 is
locally formed on the substrate P (substrate stage PST), is not
limited to the mechanism as described above. It is also possible to
adopt, for example, mechanisms disclosed in United States Patent
Application Publication No. 2004/020782 and International
Publication No. 2004/055803, the content of which are incorporated
herein by reference within a range of permission of the domestic
laws and ordinances of the state designated or selected in this
international application.
[0074] FIG. 3 shows a plan view illustrating the substrate table PT
as viewed from an upper position. FIG. 4 shows a plan view
illustrating the substrate table PT which holds the substrate P as
viewed from an upper position. With reference to FIGS. 3 and 4,
movement mirrors 55 are arranged at two edge portions of the
substrate table PT which is rectangular as viewed in a plan view,
the two edge portions being perpendicular to one another. A recess
31 is formed at a substantially central portion of the substrate
table PT. The substrate holder PH, which constructs a part of the
substrate table PT, is arranged in the recess 31. The substrate P
is held by the substrate holder PH. The plate member 30, which has
the flat surface 30A having approximately the same height as that
of (being flush with) the surface of the substrate P, is provided
around the substrate P (substrate holder PH). The plate member 30
is an annular member, which is arranged to surround the substrate
holder PH (substrate P). The plate member 30 is formed of a
material having the liquid repellence such as fluoride including,
for example, polytetrafluoroethylene (Teflon (trade name)). The
liquid immersion area AR2 can be satisfactorily formed on the image
plane side of the projection optical system PL even when the edge
area E of the substrate P is subjected to the liquid immersion
exposure, because the plate member 30, which has the flat surface
30A substantially flush with the surface of the substrate P, is
provided around the substrate P.
[0075] It is also allowable that any difference in height is
present between the surface of the substrate P and the flat surface
30A of the plate member 30, on condition that the liquid immersion
area AR2 can be formed to fill the optical path space on the image
plane side of the projection optical system PL with the liquid 1.
For example, the flat surface 30A may be lower than the surface of
the substrate P in relation to the Z direction.
[0076] As shown in FIGS. 1, 3, and 4, the second plate member 32 is
provided outside the plate member 30 (substrate holder PH) on the
substrate table PT. The second plate member 32 has the flat surface
32A which has substantially the same height as that of (is flush
with) the surface of the substrate P and the flat surface 30A of
the plate member 30. The second plate member 32 is provided to
cover the substantially entire region of the upper surface of the
substrate table PT except for the substrate holder PH (substrate P)
and the plate member 30. The second plate member 32 is also formed
of a material having the liquid repellence including, for example,
polytetrafluoroethylene.
[0077] The contact angle of the liquid 1 on the surface of the flat
surface 30A of the plate member 30 and the contact angle of the
liquid 1 on the surface of the flat surface 32A of the second plate
member 32 are not less than 110.degree. respectively in the initial
state before the exposure light beam EL is radiated.
[0078] A plurality of openings 32K, 32L, 32N are formed at
predetermined positions of the second plate member 32. A reference
member 300 is arranged in the opening 32K. A reference mark PFM to
be detected by a substrate alignment system 350 and a reference
mark MFM to be detected by a mask alignment system 360 are provided
in a predetermined positional relationship on the reference member
300. The reference member 300 has an upper surface 301A which is a
substantially flat surface. The upper surface 301A may be used as a
reference plane for the focus/leveling-detecting system as well.
Further, the upper surface 301A of the reference member 300 is
provided to have approximately the same height as those of (be
flush with) the surface of the substrate P, the surface (flat
surface) 30A of the plate member 30, and the surface (flat surface)
32A of the second plate member 32. The reference member 300 is
formed to be rectangular as viewed in a plan view. A gap K is
formed between the second plate member 32 and the reference member
300 arranged in the opening 32K. In this embodiment, the gap K is,
for example, about 0.3 mm.
[0079] An uneven illuminance sensor 400 as an optical sensor is
arranged in the opening 32L. The uneven illuminance sensor is
disclosed, for example, in Japanese Patent Application Laid-open
No. 57-117238 (corresponding to U.S. Pat. No. 4,465,368), the
content of which are incorporated herein by reference within a
range of permission of the domestic laws and ordinances of the
state designated or selected in this international application. An
upper surface 401A of an upper plate 401 of the uneven illuminance
sensor 400 is a substantially flat surface, which is provided to
have approximately the same height as those of (be flush with) the
surface of the substrate P, the surface 30A of the plate member 30,
and the surface 32A of the second plate member 32. A pinhole 470,
through which the light can pass, is provided for the upper surface
401A of the uneven illuminance sensor 400. Portions of the upper
surface 401A of the light-transmissive upper plate 401 except for
the pinhole 470 are covered with a light-shielding material such as
chromium. The uneven illuminance sensor 400 (upper plate 401) is
formed to be rectangular as viewed in a plan view. A gap L is
formed between the second plate member 32 and the uneven
illuminance sensor 400 (upper plate 401) arranged in the opening
32L. In this embodiment, the gap L is, for example, about 0.3
mm.
[0080] A spatial image-measuring sensor 500 as an optical sensor is
arranged in the opening 32N. The spatial image-measuring sensor 500
is disclosed, for example, in Japanese Patent Application Laid-open
No. 2002-14005 (corresponding to United States Patent Application
Publication No. 2002/0041377), the content of which are
incorporated herein by reference within a range of permission of
the domestic laws and ordinances of the state designated or
selected in this international application. An upper surface 501A
of an upper plate 501 of the spatial image-measuring sensor 500 is
a substantially flat surface, which may be used as a reference
plane for the focus/leveling-detecting system as well. The upper
surface 501A is provided to have approximately the same height as
those of (be flush with) the surface of the substrate P, the
surface 30A of the plate member 30, and the surface 32A of the
second plate member 32. A slit 570, through which the light can
pass, is provided for the upper surface 501A of the spatial
image-measuring sensor 500. Portions of the upper surface 501A of
the light-transmissive upper plate 501 except for the slit 570 are
covered with a light-shielding material such as chromium. The
spatial image-measuring sensor 500 (upper plate 501) is formed to
be rectangular as viewed in a plan view. A gap N is formed between
the spatial image-measuring sensor 500 (upper plate 501) and the
opening 32N. In this embodiment, the gap N is in approximately the
same degree as the production tolerance or margin for the outer
shape of the substrate P, for example, about 0.3 mm. As described
above, the substrate table PT, which holds the substrate P, has the
upper surface which is substantially flush over the entire
surface.
[0081] It is also allowable that any mutual difference in height is
present in relation to the flat surface 30A of the plate member 30,
the surface 32A of the second plate member 32, the upper surface
301A of the reference member 300, the upper surface 401A of the
uneven illuminance sensor 400, and the upper surface 501A of the
spatial image-measuring sensor 500, on condition that the liquid
immersion area AR2 can be formed to fill the optical path space on
the image plane side of the projection optical system PL with the
liquid 1.
[0082] Although not shown, the substrate table PT is also provided
with a radiation amount sensor (illuminance sensor) which is
arranged in an opening formed for the second plate member 32. The
radiation amount sensor is disclosed, for example, in Japanese
Patent Application Laid-open No. 11-16816 (corresponding to United
States Patent Application Publication No. 2002/0061469), the
content of which are incorporated herein by reference within a
range of permission of the domestic laws and ordinances of the
state designated or selected in this international application.
[0083] The measuring units, which are provided on the substrate
table PT, are not limited to those described above. Various
measuring units can be provided, if necessary. For example, a wave
front aberration-measuring unit may be arranged on the substrate
table PT. The wave front aberration-measuring unit is disclosed,
for example, in International Publication No. 99/60361
(corresponding to European Patent Publication No. 1,079,223) and
U.S. Pat. No. 6,650,399, the content of which are incorporated
herein by reference within a range of permission of the domestic
laws and ordinances of the state designated or selected in this
international application. Of course, it is also allowable that no
measuring unit is provided on the substrate table PT.
[0084] The flat surface 30A of the plate member 30, which is formed
to have the annular shape, has the width which is formed to be
larger than at least the projection area AR1 (see FIG. 4).
Therefore, when the edge area E of the substrate P is subjected to
the exposure, the exposure light beam EL is not radiated onto the
second plate member 32. Accordingly, it is possible to suppress the
deterioration of the liquid repellence of the second plate member
32 which would be caused by the radiation of the exposure light
beam. The frequency of the exchange of the second plate member 32
can be made smaller than the frequency of the exchange of the plate
member 30. Further, it is preferable that the width of the flat
surface 30A is formed to be larger than the liquid immersion area
AR2 which is formed on the image plane side of the projection
optical system PL. Accordingly, when the edge area E of the
substrate P is subjected to the liquid immersion exposure, then the
liquid immersion area AR2 is arranged on the flat surface 30A of
the plate member 30, and the liquid immersion area AR2 is not
arranged on the second plate member 32. Therefore, it is possible
to avoid the inconvenience which would be otherwise caused such
that the liquid 1 of the liquid immersion area AR2 inflows into the
gap G as the interstice between the plate member 30 and the second
plate member 32. The width of the flat surface 30A of the plate
member 30 is not limited to those described above. It goes without
saying that the width may be smaller than the liquid immersion area
AR2.
[0085] As shown in FIG. 3 and FIG. 5 which is a magnified sectional
view illustrating main parts of the substrate table PT which holds
the substrate P, the substrate holder PH, which constructs a part
of the substrate table PT, includes a substantially annular
circumferential wall portion 33, a plurality of support portions 34
which are provided on a base portion 35 disposed inside the
circumferential wall portion 33 and which support the substrate P,
and a plurality of suction ports 41 which are arranged between the
support portions 34 and which are provided in order to attract and
hold the substrate P. The support portions 34 and the suction ports
41 are arranged uniformly at the inside of the circumferential wall
portion 33. In FIG. 5, the upper end surface of the circumferential
wall portion 33 is depicted to have a relatively wide width.
However, the upper end surface actually has only a width of about 1
to 2 mm. The base portion 35 is provided with holes 71 which are
arranged with lifting members 70 constructed of pin members for
moving the substrate P upwardly and downwardly. In this embodiment,
the lifting members 70 are provided at three positions. The lifting
member 70 is moved upwardly and downwardly by an unillustrated
driving unit. The control unit CONT controls the upward/downward
movement of the lifting member 70 by the aid of the driving
unit.
[0086] As shown in FIG. 5, a plurality of suction holes 72, which
are provided in order to attract and hold the plate member 30 with
respect to the substrate table PT, are disposed at positions of the
upper surface of the substrate table PT opposed to the lower
surface of the plate member 30. Lifting members 74, which are
constructed of pin members for moving the plate member 30 upwardly
and downwardly with respect to the substrate table PT, are provided
at a plurality of positions (three positions in this arrangement)
of the substrate table PT. The lifting member 74 is moved upwardly
and downwardly by an unillustrated driving unit. The control unit
CONT controls the upward and downward movement of the lifting
member 74 by the aid of the driving unit (see FIG. 7(d)). Further,
although not shown, a plurality of suction holes, which are
provided in order to attract and holds the second plate member 32
with respect to the substrate table PT, are disposed at positions
of the upper surface of the substrate table PT opposed to the lower
surface of the second plate member 32. Lifting members, which move
the second plate member 32 upwardly and downwardly with respect to
the substrate table PT, are provided at a plurality of positions of
the substrate table PT.
[0087] The exchange frequency of the second plate member 32 is
small as described above. Therefore, the second plate member 32 may
be fixed by, for example, the screw fastening rather than being
attracted and held with respect to the substrate table PT, and the
exchange operation may be performed manually. It is also allowable
that the second plate member 32 is not exchangeable.
[0088] However, the exposure light beam EL or any light beam having
the same wavelength as that of the exposure light beam is radiated
onto the second plate member 32, for example, when the reference
member 300 and/or the uneven illuminance sensor 400 is used, it is
feared that the liquid repellence of the surface of the second
plate member 32 may be deteriorated. In this case, there is such a
possibility that the exchange frequency equivalent to that of the
plate member 30 may be required.
[0089] As shown in FIGS. 4 and 5, a predetermined gap A is formed
between the plate member 30 and a side surface PB of the substrate
P held by the substrate holder PH (substrate table PT).
[0090] With reference to FIG. 5, the substrate holder PH, which
holds the substrate P, is arranged in the recess 31 of the
substrate table PT. The substrate table PT is formed so that an
upper end surface 34A of the substrate holder PH is higher than the
placing surface PTa of the substrate table PT for the plate member
30 and the second plate member 32, when the substrate holder PH is
arranged in the recess 31. The circumferential wall portion 33 and
the support portions 34 are provided on the substantially
disk-shaped base portion 35 which constructs a part of the
substrate holder PH. Each of the support portions 34 is trapezoidal
as viewed in a sectional view. The back surface PC of the substrate
P is held by the upper end surface 34A of the plurality of support
portions 34. The upper surface 33A of the circumferential wall
portion 33 is a flat surface. The height of the circumferential
wall portion 33 is lower than the height of the support portion 34.
A gap B is formed between the substrate P and the circumferential
wall portion 33. The gap B is smaller than the gap A which is
provided between the plate member 30 and the side surface PB of the
substrate P. A gap C is formed between the inner side surface 36 of
the recess 31 and the side surface 37 of the substrate holder PH
opposed to the inner side surface 36. In this arrangement, the
diameter of the substrate holder PH is formed to be smaller than
the diameter of the substrate P. The gap A is smaller than the gap
C. In this embodiment, any cutout (for example, orientation flat or
notch), which is to be used for the positioning, is not formed for
the substrate P. The substrate P is substantially circular. The gap
A is 0.1 mm to 1.0 mm, which is about 0.3 mm in this embodiment
over the entire circumference of the substrate. Therefore, it is
possible to avoid the inflow of the liquid. When any cutout is
formed for the substrate P, the plate member 30 and the
circumferential wall portion 33 may be allowed to shapes adapted to
the cutout, for example, such that projections are provided for the
plate member 30 and the circumferential wall portion 33 depending
on the cutout. Accordingly, the gap A can be also secured between
the substrate P and the plate member 30 at the cutout of the
substrate P.
[0091] An inner stepped portion 30D is formed at an inner portion
of the plate member 30. A support surface 30S, which is opposed to
the edge portion of the substrate lower surface PC, is formed by
the inner stepped portion 30D. The plate member 30 is capable of
supporting the edge portion of the substrate lower surface PC by
the support surface 30S. In this arrangement, as shown in FIG. 5, a
gap D is formed between the edge portion of the substrate lower
surface PC held by the substrate holder PH and the support surface
30S of the plate member 30 held by the placing surface PTa of the
substrate table PT. Accordingly, it is possible to avoid the
occurrence of the inconvenience which would be otherwise caused
such that the plate member 30 (support surface 30S) abuts against
the edge portion of the substrate lower surface PC, and the edge
portion of the substrate P is warped upwardly.
[0092] An inner stepped portion 32D is formed at an inner portion
of the second plate member 32. An outer stepped portion 30F is
formed at an outer portion of the plate member 30 so that the outer
stepped portion 30F is adapted to the shape of the inner stepped
portion 32D of the second plate member 32. Accordingly, a state is
given, in which a part of the plate member 30 is placed on a part
of the second plate member 32. A predetermined gap G is formed
between the outer side surface of the plate member 30 and the inner
side surface of the second plate member 32. In this embodiment, the
gap G is, for example, about 0.3 mm. The gap G is interposed by the
second plate member 32 and the plate member 30 made of
polytetrafluoroethylene having the liquid-repellent surface.
Therefore, even when the liquid immersion area is formed at the
boundary between the plate member 30 and the second plate member
32, it is possible to avoid the inflow of the liquid into the gap
G.
[0093] The surface PA as the exposure surface of the substrate P is
coated with a photoresist (photosensitive material) 90. In this
embodiment, the photosensitive material 90 is a photosensitive
material for the ArF excimer laser (for example, TARF-P6100
produced by TOKYO OHKA KOGYO CO., LTD.). The photosensitive
material 90 is liquid-repellent (water-repellent), and the contact
angle thereof is about 70.degree. to 80.degree..
[0094] In this embodiment, the side surface PB of the substrate P
is subjected to a liquid-repelling treatment (water-repelling
treatment). Specifically, the side surface PB of the substrate P is
also coated with the photosensitive material 90 having the liquid
repellence. Accordingly, it is possible to avoid the inflow of the
liquid from the gap A between the side surface of the substrate P
and the plate member 30 having the liquid-repellent surface.
Further, the back surface PC of the substrate P is also subjected
to a liquid-repelling treatment by coating the back surface PC with
the photosensitive material 90.
[0095] In this embodiment, the placing surface PTa and the inner
side surface 36 of the substrate table PT have the liquid
repellence. Further, a part of the surface of the substrate holder
PH is also subjected to the liquid-repelling treatment to have the
liquid repellence. In this embodiment, the side surface 37 and the
upper surface 33A of the circumferential wall portion 33 of the
substrate holder PH have the liquid repellence. When the
liquid-repelling treatment is performed for the substrate table PT
and the substrate holder PH, for example, a liquid-repellent
material including, for example, fluorine-based resin materials and
acrylic resin materials is coated, or a thin film composed of the
liquid-repellent material as described above is stuck. A material,
which is insoluble in the liquid 1, is used as the liquid-repellent
material in order to provide the liquid repellence. The entire
substrate table PT and/or the entire substrate holder PH may be
formed of a material having the liquid repellence (for example,
fluorine-based resin).
[0096] A first space 38, which is surrounded by the circumferential
wall portion 33 of the substrate holder PH, is allowed to have the
negative pressure by a sucking unit 40. The sucking unit 40
includes a plurality of suction ports 41 which are provided on the
upper surface of the base portion 35 of the substrate holder PH, a
vacuum section 42 which includes a vacuum pump provided externally
with respect to the substrate table PT, and a flow passage 43 which
is formed in the base portion 35 and which connects the plurality
of suction ports 41 and the vacuum section 42 respectively. The
suction ports 41 are provided at a plurality of predetermined
positions of the upper surface of the base portion 35 except for
the support portions 34 respectively. The sucking unit 40 sucks the
gas (air) contained in the first space 38 formed among the
circumferential wall portion 33, the base portion 35, and the
substrate P supported by the support portions 34 so that the first
space 38 is allowed to have the negative pressure. Accordingly, the
substrate P is attracted and held by the support portions 34. The
gap B, which is formed between the back surface PC of the substrate
P and the upper surface 33A of the circumferential wall portion 33,
is minute. Therefore, the negative pressure of the first space is
maintained.
[0097] The liquid 1, which flows into a second space 39 between the
inner side surface 36 of the recess 31 and the side surface 37 of
the substrate holder PH, is recovered by a recovery section 60. In
this embodiment, the recovery section 60 has a tank 61 which is
capable of accommodating the liquid 1, and a flow passage 62 which
is provided in the substrate table PT and which connects the space
39 and the external tank 61. The liquid-repelling treatment is also
performed to the inner wall surface of the flow passage 62. The
liquid, which flows into the space 39, may be temporarily held on
the substrate stage PST (substrate table PT), and the liquid may be
discharged, for example, to an external tank provided separately
from the substrate stage PST at a predetermined timing.
[0098] The substrate table PT is formed with a flow passage 45
which connects the second space 39 disposed between the inner side
surface 36 of the recess 31 and the side surface 37 of the
substrate holder PH and the space (atmospheric air space) disposed
outside the substrate table PT. The gas (air) is capable of flowing
via the flow passage 45 between the second space 39 and the outside
of the substrate table PT. The second space 39 is approximately set
to have the atmospheric pressure.
[0099] As shown in FIG. 6, the substrate holder PH, the plate
member 30, and the second plate member 32 are independent parts,
and are provided detachably with respect to the substrate table PT.
The contact surface 57, of the substrate table PT, which makes
contact with the substrate holder PH is subjected to the
liquid-repelling treatment to have the liquid repellence. Further,
the back surface 58 of the substrate holder PH, which is the
contact surface with respect to the substrate table PT, is also
subjected to the liquid-repelling treatment to have the liquid
repellence. The liquid-repelling treatment for the contact surface
57 and the back surface 58 can be performed, for example, by
coating the liquid-repellent material such as fluorine-based resin
materials and acrylic resin materials as described above.
[0100] Next, an explanation will be made with reference to
schematic views shown in FIGS. 7 and 8 about the method for
exposing the substrate P by using the exposure apparatus EX
constructed as described above.
[0101] As shown in FIG. 7(a), the plate member 30 is attracted and
held by the placing surface PTa of the substrate table PT, and the
second plate member 32 is also attracted and held by the placing
surface PTa of the substrate table PT. The substrate P as the
exposure process objective is loaded to the substrate table PT by a
transport arm (transport unit) 80. In this situation, the lifting
members 70 are moved upwardly. The transport arm 80 delivers the
substrate P to the lifting members 70 which are moved upwardly. The
lifting members 74 are not moved upwardly. The lifting members 70
are moved downwardly while holding the substrate P delivered from
the transport arm 80. Accordingly, as shown in FIG. 7(b), the
substrate P is arranged inside the plate member 30, and the
substrate P is held by the substrate table PT (substrate holder
PH). As shown in FIG. 7(c), the control unit CONT performs the
supply and the recovery of the liquid 1 by the liquid supply
mechanism 10 and the liquid recovery mechanism 20 to form the
liquid immersion area AR2 of the liquid 1 between the projection
optical system PL and the substrate P held by the substrate table
PT. The control unit CONT radiates the exposure light beam EL onto
the substrate P via the projection optical system PL and the liquid
1 to perform the liquid immersion exposure while moving the
substrate stage PST which supports the substrate P.
[0102] When the edge area E of the substrate P is subjected to the
exposure, the exposure light beam EL is radiated onto the flat
surface 30A of the plate member 30. As a result of the irradiation
with the exposure light beam EL, there is such a possibility that
the liquid repellence of the flat surface 30A may be deteriorated.
If the liquid repellence of the flat surface 30A is deteriorated,
for example, the following inconvenience arises. That is, the
liquid 1 of the liquid immersion area AR2 arranged on the flat
surface 30A tends to remain to cause the variation of the
environment in which the substrate P is placed. Accordingly, the
control unit CONT exchanges the plate member 30 in which the liquid
repellence is deteriorated, with a new plate member 30 (having
sufficient liquid repellence), depending on the deterioration of
the liquid repellence of the plate member 30 (flat surface
30A).
[0103] Specifically, the liquid 1, which remains on the substrate P
and/or the flat surface 30A, is recovered by using, for example,
the liquid recovery mechanism 20 after the completion of the liquid
immersion exposure process. After that, as shown in FIG. 7(d), the
control unit CONT moves the lifting members 74 upwardly after
releasing the plate member 30 from the state of being attracted and
held. In this situation, the substrate P is also released from the
state of being attracted and held by the substrate holder PH. The
lifting members 74 are moved upwardly in a state in which the lower
surface of the plate member 30 is supported. In this situation, the
lifting members 70 are not moved upwardly. Accordingly, the plate
member 30 is separated or away from the substrate table PT. In this
situation, the support surface 30S of the plate member 30 supports
the edge portion of the substrate lower surface PC. Therefore, the
substrate P is moved upwardly together with the plate member 30,
and the substrate P is separated from the substrate table PT. As
described above, the lifting members 74, which construct the
attachment/detachment mechanism for attaching/detaching the plate
member 30 with respect to the substrate table PT, are capable of
detaching the plate member 30 from the substrate table PT together
with the substrate P. The transport arm 80 enters the space between
the substrate table PT and the plate member 30 having been moved
upwardly by the lifting members 74. The transport arm 80 supports
the lower surface of the plate member 30. The transport arm 80
unloads the plate member 30 which holds the substrate P, out of the
substrate table PT (substrate stage PST).
[0104] The unloaded plate member 30 is exchanged with a new plate
member 30. As shown in FIG. 8(a), the control unit CONT loads a new
plate member 30 which holds a substrate P as the exposure process
objective, to the substrate table PT (substrate stage PST) by using
the transport arm 80. In this situation, the lifting members 74 are
moved upwardly, and the transport arm 80 delivers the plate member
30 which holds the substrate P, to the lifting members 74 which are
moved upwardly. The lifting members 70 are not moved upwardly. The
lifting members 74 are moved downwardly while holding the plate
member 30 which has been delivered from the transport arm 80.
Accordingly, as shown in FIG. 8(b), the plate member 30, which
holds the substrate P, is arranged inside the second plate member
32, and the plate member 30 is held by the substrate table PT
(substrate holder PH). As shown in FIG. 8(c), the control unit CONT
performs the supply and the recovery of the liquid 1 by the liquid
supply mechanism 10 and the liquid recovery mechanism 20 to form
the liquid immersion area AR2 of the liquid 1 between the
projection optical system PL and the substrate P held by the
substrate table PT. The control unit CONT radiates the exposure
light beam EL onto the substrate P via the projection optical
system PL and the liquid 1 to perform the liquid immersion exposure
while moving the substrate stage PST which holds the substrate
P.
[0105] When the liquid repellence of the plate member 30 is not
deteriorated yet, the liquid 1, which remains, for example, on the
substrate P and/or on the upper surface 30A of the plate member 30,
is recovered by using, for example, the liquid recovery mechanism
20 after the completion of the liquid immersion exposure. After
that, the control unit CONT releases the substrate P from the state
of being attracted and held. After that, as shown in FIG. 8(d), the
lifting members 70 are moved upwardly. In this situation, the plate
member 30 is attracted and held by the substrate table PT. The
lifting members 70 are moved upwardly in a state in which the lower
surface of the substrate P is supported. In this situation, the
lifting members 74 are not moved upwardly. Accordingly, the
substrate P is separated from the substrate table PT. The transport
arm 80 enters the space between the substrate table PT and the
substrate P having been moved upwardly by the lifting members 70,
and the lower surface of the substrate P is supported thereby. The
transport arm 80 unloads the substrate P from the substrate table
PT (substrate stage PST).
[0106] As for the transport arm 80, it is also allowable that a
transport arm for transporting the plate member 30 and a transport
arm for transporting the substrate P are provided separately.
However, as shown in FIG. 9, the following arrangement is
available. That is, a support surface 80A of a transport arm 80 is
formed to be large so that the transport arm 80 can make contact
with both of the substrate P and the plate member 30. Accordingly,
it is possible to support both of the substrate P and the plate
member 30. Therefore, both of the substrate P and the plate member
30 can be transported with one transport arm 80.
[0107] As explained above, the liquid-repellent plate members 30,
32, which are provided for the substrate table PT, are provided
exchangeably. Therefore, when the liquid repellence of the plate
member 30, 32 is deteriorated, the liquid repellence on the
substrate table PT can be maintained by merely exchange the plate
member 30, 32 with the new plate member 30, 32.
[0108] When the liquid-repellent material is coated, or the plate
member 30, 32 is formed of the liquid-repellent material in order
to provide the liquid repellence of the upper surface of the plate
member 30, 32 on the substrate table PT, then the liquid repellence
thereof is deteriorated in some cases when the exposure light beam
is radiated. In particular, for example, when the fluorine-based
resin is used as the liquid-repellent material, and the ultraviolet
light is used as the exposure light beam, then the liquid
repellence of the plate member 30, 32 tends to be deteriorated
(tends to become lyophilic or liquid-attractive). In such a
situation, the liquid tends to remain on the plate member 30,
32.
[0109] In view of the above, in the embodiment of the present
invention, when the liquid repellence of the plate member 30, 32 is
deteriorated, the plate member 30, 32 is exchanged with the new
plate member 30, 32.
[0110] Therefore, it is possible to suppress the remaining of the
liquid 1 on the substrate table PT. Even when the liquid 1 remains,
the liquid 1 can be smoothly recovered by using, for example, the
liquid recovery mechanism 20. Therefore, the deterioration of the
exposure accuracy, which would be caused by the remaining liquid 1,
can be avoided. It is possible to produce the device which can
exhibit the desired performance.
[0111] The plate member 30, which has the flat portion 30A around
the substrate P, is loaded and unloaded together with the substrate
P with respect to the substrate table PT. Accordingly, the plate
member 30 can be easily exchanged together with the substrate P
with respect to the substrate table PT. Further, the plate member
30 has the flat surface 30A around the substrate P. Therefore, when
the plate member 30 is loaded to the substrate table PT together
with the substrate P and the liquid immersion exposure is performed
for the edge area E of the substrate P, even if a part of the
liquid immersion area AR2 of the liquid 1 protrudes to the outside
of the substrate P, then the shape of the liquid immersion area AR2
is maintained by the flat surface 30A. The liquid immersion
exposure can be performed in such a state that the liquid 1 is
satisfactorily retained on the image plane side of the projection
optical system PL, without causing, for example, the outflow of the
liquid 1.
[0112] The inner stepped portion 30D is provided at the inner
portion of the plate member 30 to form the support surface 30S so
that the edge portion of the substrate lower surface PC can be
supported. Therefore, the substrate P can be moved together with
the plate member 30 by merely effecting the movement while holding
the plate member 30. The corner or turning portion is formed as
viewed in a sectional view between the plate member 30 and the
substrate P by the inner stepped portion 30D. Therefore, even if
the liquid 1 enters the gap A between the plate member 30 and the
substrate P, the corner functions as a seal portion. It is possible
to avoid the inconvenience which would be otherwise caused such
that the liquid 1 inflows into the side of the back surface PC of
the substrate P and the substrate stage PST (substrate table PT).
Further, the side surface PB of the substrate P is also subjected
to the liquid-repelling treatment. Therefore, it is possible to
satisfactorily avoid the inflow of the liquid 1 from the gap A
between the side surface PB of the substrate P and the plate member
30.
[0113] The inconvenience, which would be otherwise caused such that
the liquid 1 inflows into the first space 38 via the gap B, can be
avoided by providing the liquid repellence for the back surface PC
of the substrate P and the upper surface 33A of the circumferential
wall portion 33 opposed to the back surface PC. Therefore, it is
possible to avoid the occurrence of the inconvenience which would
be otherwise caused such that the liquid 1 flows into the suction
ports 41. The exposure process can be performed in such a state
that the substrate P is satisfactorily attracted and held.
[0114] In the embodiment of the present invention, the
liquid-repelling treatment is performed to the back surface 58 of
the substrate holder PH which is detachable with respect to the
substrate table PT, and the contact surface 57, of the substrate
table PT, which makes contact with the substrate holder PH.
Accordingly, even when the liquid 1 flows into the second space 39,
it is possible to suppress the inflow of the liquid 1 into the
space between the back surface 58 of the substrate holder PH and
the contact surface 57 of the z stage 52. Therefore, it is possible
to avoid, for example, the occurrence of any rust on the back
surface 58 of the substrate holder PH and the contact surface 57 of
the substrate table PT. If the liquid 1 inflows into the space
between the back surface 58 of the substrate holder PH and the
contact surface 57 of the substrate table PT, a situation arises
such that the substrate holder PH and the Z stage 52 are adhered to
one another and they are hardly separated from each other. However,
the separation can be effected with ease by providing the liquid
repellence.
[0115] As for the attachment/detachment mechanism for attaching and
detaching the plate member 30 with respect to the substrate table
PT, the lifting members 74 are provided to serve as the lifting
unit, and the suction holes 72 are provided to serve as the
attracting/holding unit for attracting and holding the plate member
30. Therefore, it is possible to smoothly perform the operation for
exchanging the plate member 30. The new plate member 30 after the
exchange can be satisfactorily held on the substrate table PT.
[0116] The inner stepped portion 32D is formed at the inner portion
of the second plate member 32, and the outer stepped portion 30F is
formed at the outer portion of the plate member 30. Accordingly,
the corner is also formed as viewed in a sectional view at the gap
between the plate member 30 and the second plate member 32.
Therefore, even if the liquid 1 inflows from the gap G, the corner
functions as a seal portion. It is possible to avoid the
inconvenience which would be otherwise caused such that the liquid
1 arrives at the inside of the substrate table PT.
[0117] The outer stepped portion 30F of the plate member 30 can be
supported by the inner stepped portion 32D of the second plate
member 32. Therefore, it is not necessarily indispensable that the
plate member 30 is held by the substrate table PT, because the
plate member 30 is supported by the second plate member 32 when the
second plate member 32 is attracted and held by the substrate table
PT. Therefore, as schematically shown in FIG. 10, a space (dent)
130 can be formed in an area of the substrate table PT opposed to
the plate member 30. It is possible to realize a light weight of
the substrate table PT (substrate stage PST).
[0118] In this arrangement, the substrate P is transported by the
transport arm 80 in the state in which the substrate P is held by
the plate member 30. Therefore, a relatively wide area of the
substrate P is supported by the plate member 30. Therefore, for
example, even when the substrate P is large-sized, the flexure
(warpage) of the substrate P can be suppressed by transporting the
substrate P in the state of being held by the plate member 30.
[0119] When the liquid repellence of the flat surface 32A of the
second plate member 32 is deteriorated, and the second plate member
32 is exchanged, then the second plate member 32 may be unloaded
together with the substrate P and the plate member 30 by using the
transport arm 80 after the completion of the liquid immersion
exposure for the substrate P, because the second plate member 32
supports the plate member 30. In this arrangement, lifting members
for moving the second plate member 32 upwardly and downwardly may
be provided in the same manner as the lifting members 74. It is
also allowable that the plate member 30 and the second plate member
32 can be separately unloaded and loaded without providing the
inner stepped portion 32D of the second plate member 32. In this
arrangement, a transport mechanism may be further provided in order
to unload and load the second plate member 32.
[0120] The timing of the exchange of the plate member 30, 32 is
determined depending on the deterioration of the liquid repellence
of the flat surface 30A, 32A as described above. The timing of the
exchange of the plate member 30, 32 includes, for example, every
interval of a predetermined number of pieces of processed
substrates and/or every interval of a predetermined period of time.
The plate members 30, 32 can be exchanged at predetermined
intervals which are previously prescribed. Alternatively, the
relationship between the radiation amount (radiation time,
illuminance) of the exposure light beam EL and the level of the
liquid repellence of the plate member 30, 32 is previously
determined by an experiment or simulation. The timing of the
exchange of the plate member 30, 32 may be set on the basis of the
determined result. The deterioration of the liquid repellence can
be evaluated, for example, such that the flat surface 30A, 32A or
the like is observed visually or under a microscope, a liquid
droplet is dripped onto the surface to be evaluated to observe the
state of the liquid droplet visually or under a microscope, or the
contact angle of the liquid droplet is measured. When the
evaluation as described above is previously recorded in the control
unit CONT while providing the relationship in relation to the
totalized radiation amount of the ultraviolet light such as the
exposure light beam, the control unit CONT can determine the
service life of the plate member 30, 32 or the like, i.e., the
exchange time (timing) in accordance with the relationship.
[0121] The exposure apparatus EX can determine the totalized
radiation amount of the exposure light beam EL radiated onto the
plate member 30, 32 by using an integrator sensor (not shown) which
is capable of measuring the intensity of the exposure light beam EL
radiated onto the image plane side of the projection optical system
PL. The control unit CONT can measure the radiation time (number of
radiation pulses) and the intensity of the exposure light beam EL
radiated onto the plate member 30 and/or the plate member 32 on the
basis of the position information of the substrate stage PST
measured by using the laser interferometer 56 and the intensity
information of the exposure light beam EL measured by using the
integrator sensor. Therefore, it is possible to determine the
totalized radiation amount of the exposure light beam EL radiated
onto the plate member 30 and/or the plate member 32 on the basis of
the result of the measurement. The integrator sensor for measuring
the intensity of the exposure light beam EL is disclosed, for
example, in U.S. Pat. Nos. 5,728,495 and 5,591,958, the content of
which are incorporated herein by reference within a range of
permission of the domestic laws and ordinances of the state
designated or selected in this international application.
[0122] In the embodiment of the present invention, the control unit
CONT judges whether or not the exchange of the plate member 30, 32
is required, on the basis of the contact angle of the liquid on the
upper surface 30A, 32A of the plate member 30, 32. When it is
estimated or predicted that the contact angle of the liquid is
lowered to be not more than a predetermined angle (for example,
1000) on the basis of, for example, the time of use of the plate
member 30, 32 and/or the totalized radiation amount of the
ultraviolet light, it is judged that the exchange of the plate
member 30, 32 is required. Alternatively, when it is estimated that
the contact angle of the liquid 1 on the surface 30A, 32A of the
plate member 30, 32 is lowered by not less than a predetermined
angle (for example, 10.degree.) as compared with the initial state
on the basis of, for example, the time of use of the plate member
30, 32 and/or the totalized radiation amount of the ultraviolet
light, it is judged that the exchange of the plate member 30, 32 is
required.
[0123] It is not necessarily indispensable that the deterioration
of the liquid repellence of the plate member 30, 32 or the like is
judged by the control unit CONT of the exposure apparatus EX. For
example, the exposure apparatus EX may be connected to a host
computer of a factory or the like in which the exposure apparatus
EX is installed so that various data can be exchanged, and the
judgment may be made by the host computer.
[0124] When the liquid recovery mechanism 20 has a high ability to
recover the liquid, there is such a possibility that the liquid can
be sufficiently recovered even when the liquid repellence of the
plate member 30, 32 is deteriorated. Therefore, the exchange timing
of the plate member 30, 32 or the like can be also determined while
considering the relationship between the ability of the liquid
recovery mechanism 20 to recover the liquid and the deterioration
of the liquid repellence (decrease in the contact angle) as
well.
[0125] The speed of the deterioration and the degree of the
deterioration of the liquid repellence differ depending on not only
the radiation time of the exposure light beam EL but also other
factors including, for example, the material for providing the
liquid repellence, the liquid, the exposure wavelength, and the
temperature. Therefore, it is appropriate that the evaluation data
is prepared together with the factors as described above. This fact
also holds in the same manner as described above for the exchange
timings of other members to which the liquid repellence is imparted
as described below.
[0126] In the embodiment of the present invention, the plate member
30, 32 is formed of, for example, polytetrafluoroethylene which is
the liquid-repellent material. However, it is a matter of course
that the plate member 30, 32 may be formed of any other material
having the liquid repellence. Alternatively, for example, the plate
member 30, 32 may be formed of a predetermined metal, and the
surface of the plate member 30, 32 made of metal may be coated with
the liquid-repellent material (fluoride such as
polytetrafluoroethylene) having the liquid repellence. As for the
coating area of the liquid-repellent material, the entire surface
of the plate member 30, 32 may be subjected to the coating, or only
a part of the area including, for example, the flat surface 30A,
which requires the liquid repellence, may be subjected to the
coating.
[0127] It is a matter of course that the plate member 30 and the
second plate member 32 may be formed of separate materials, and the
plate member 30 and the second plate member 32 may be subjected to
the coating by using liquid-repellent materials which are distinct
from each other. It is not necessarily indispensable that all of
the surfaces of the plate member 30 and the second plate member 32
have the liquid repellence at a uniform level. It is also allowable
that a portion having the strong liquid repellence may be partially
provided. It is not necessarily indispensable that all of the
surfaces of the plate member 30 and the second plate member 32 have
the same or equivalent durability against the deterioration of the
liquid repellence. It is also allowable that the durability against
the deterioration of a portion which undergoes a large radiation
amount of the exposure light beam may be strengthened as compared
with other portions. For example, it is preferable that the surface
of the plate member 30 has the durability against the deterioration
which is stronger than that of the surface of the second plate
member 32.
[0128] The embodiment of the present invention has been explained
such that the plate member 30 is unloaded together with the
substrate P when the plate member 30 is exchanged. It is a matter
of course that only the plate member 30 may be loaded and unloaded
with respect to the substrate table PT.
[0129] The plate member 30 can be exchanged by using the lifting
members 74 and the transport arm 80. However, it is not necessarily
indispensable to provide the lifting members 74 and the transport
arm 80 which is capable of transporting the plate member 30. The
plate member 30 may be exchanged manually by an operator. In the
embodiment described above, the plate member 30 and the second
plate member 32 are provided integrally respectively. However, it
is also allowable that the plate member 30 and the second plate
member 32 may be divided respectively so that they can be partially
exchanged. Accordingly, it is also possible to frequently exchange
only a portion at which the deterioration of the liquid repellence
is seriously deteriorated.
[0130] Alternatively, the plate member 30 and the plate member 32
may be formed as one plate member which may be held on the
substrate table PT.
[0131] In the embodiment of the present invention, as appreciated
from FIG. 5, the substrate holder PH and the substrate table PT are
detachable. However, the substrate holder PH may be provided
integrally with the substrate table PT.
[0132] In the embodiment of the present invention, the entire
surfaces of the surface PA, the side surface PB, and the back
surface PC of the substrate P are coated with the photosensitive
material 90 in order to perform the liquid-repelling treatment.
However, another arrangement is also available, in which the
liquid-repelling treatment is performed to only the area for
forming the gap A, i.e., the side surface PB of the substrate P and
the area for forming the gap B, i.e., the area of the back surface
PC of the substrate P opposed to the upper surface 33A of the
circumferential wall portion 33. Further, when the gap A is
sufficiently small, and the material, which is coated to effect the
liquid-repelling treatment, has the sufficiently large liquid
repellence (contact angle), then the possibility of the inflow of
the liquid 1 into the second space 39 via the gap A is further
lowered. Therefore, an arrangement is also available, in which the
liquid-repelling treatment is not performed to the back surface PC
of the substrate P for forming the gap B, and the liquid-repelling
treatment is performed to only the side surface PB of the substrate
P. It is a matter of course that the substrate P, in which the
liquid-repelling treatment is not performed to all of the surface
PA, the side surface PB, and the back surface PC, can be also
used.
[0133] In the embodiment of the present invention, the height of
the circumferential wall portion 33 is lower than the height of the
support portion 34, and the gap B is formed between the back
surface PC of the substrate P and the upper surface 33A of the
circumferential wall portion 33. However, the back surface PC of
the substrate P and the upper surface 33A of the circumferential
wall portion 33 may make contact with each other.
[0134] In the embodiment of the present invention, the
photosensitive material 90 having the liquid repellence is coated
as the liquid-repelling treatment for the side surface PB and the
back surface PC of the substrate P. However, the side surface PB
and the back surface PC may be coated with a predetermined material
having the liquid repellence (water repellence) other than the
photosensitive material 90. For example, a protective layer called
"top coat layer" (film to protect the photosensitive material 90
from the liquid) is coated or formed as the upper layer of the
photosensitive material 90 coated to the surface PA as the exposure
surface of the substrate P in some cases. The material for forming
the top coat layer (for example, fluorine-based resin material) has
the liquid repellence (water repellence) with a contact angle of,
for example, about 110.degree.. Therefore, the side surface PB and
the back surface PC of the substrate P may be coated with the
material for forming the top coat layer. Of course, any material
having the liquid repellence other than the photosensitive material
90 and the material for forming the top coat layer may be
coated.
[0135] In the embodiment of the present invention, for example, the
fluorine-based resin material or the acrylic resin material is
coated as the liquid-repelling treatment for the substrate table PT
and the substrate holder PH. However, the substrate table PT and
the substrate holder PH may be coated with the photosensitive
material or the material for forming the top coat layer. On the
other hand, the side surface PB and the back surface PC of the
substrate P may be coated with the material used for the
liquid-repelling treatment for the substrate stage PST and the
substrate holder PH.
[0136] The top coat layer is provided in order to prevent the
liquid 1 of the liquid immersion area AR2 from the infiltration
into the photosensitive material 90 in many cases. For example,
even when the adhesion trace (so-called "water mark") of the liquid
1 is formed on the top coat layer, a predetermined process
treatment such as the development process can be performed after
removing the water mark together with the top coat layer, by
removing the top coat layer after the liquid immersion exposure. In
this procedure, when the top coat layer is formed of, for example,
a fluorine-based resin material, the top coat layer can be removed
by using a fluorine-based solvent. Accordingly, it is unnecessary
to provide any unit for removing the water mark (for example, a
substrate-washing unit for removing the water mark). The
predetermined process treatment can be satisfactorily performed
after removing the water mark by a simple configuration in which
the top coat layer is removed with the solvent.
[0137] In the embodiment described above, the plate member 30, 32
is held by the substrate table PT in the vacuum-attraction manner.
However, it is also possible to use another chuck mechanism such as
an electromagnetic chuck mechanism.
Second Embodiment
[0138] Next, another embodiment of the present invention will be
explained. In the following description, parts or components, which
are the same as or equivalent to those of the embodiment described
above, are designated by the same reference numerals, any
explanation of which will be simplified or omitted.
[0139] FIG. 11 shows a substrate holder PH which is
attached/detached with respect to the substrate table PT (substrate
stage PST). FIG. 11(a) shows a side sectional view, and FIG. 11(b)
shows a plan view as viewed from an upper position, illustrating
the substrate table PT after the substrate holder PH is
detached.
[0140] As shown in FIG. 11, the substrate table PT includes, on an
upper surface thereof (holding surface for the substrate holder
PH), a recess 157 to which the substrate holder PH is capable of
being fitted, a plurality of vacuum suction holes 158 which are
provided in the recess 157 and which attract and hold the substrate
holder PH arranged in the recess 157, and flow passages 159 which
are provided in the recess 157 as described later on. When the
substrate holder PH is fitted to the recess 157, the substrate
table PT and the substrate holder PH are positioned. The vacuum
suction holes 158 construct a part of the chuck mechanism for
holding the substrate holder PH arranged in the recess 157. The
vacuum suction holes 158 are connected to an unillustrated vacuum
unit. The driving of the vacuum unit is controlled by the control
unit CONT. The control unit CONT controls the vacuum unit to effect
the attraction and the holding as well as the release from the
holding of the substrate table PT with respect to the substrate
holder PH by the aid of the vacuum suction holes 158. When the
substrate table PT is released from the holding, then the substrate
holder PH and the substrate table PT can be separated from each
other, and the substrate holder PH can be exchanged.
[0141] In this embodiment, the explanation has been made such that
the substrate table PT holds the substrate holder PH by the vacuum
attraction. However, the substrate holder PH may be subjected to
the holding and the release from the holding by another chuck
mechanism including, for example, an electromagnetic chuck
mechanism. In this embodiment, the explanation has been made such
that the substrate table PT and the substrate holder PH are
positioned by using the recess 157. However, for example, the
following arrangement is also available. That is, the positional
relationship between the substrate holder PH and the substrate
table PT is optically detected, and the substrate holder PH is
positioned at a predetermined position with respect to the
substrate table PT on the basis of the result of the detection.
[0142] The substrate holder PH has a recess 150 in which the
substrate P is to be arranged, and a flat surface 30A which is
substantially flush with the surface of the substrate P arranged in
the recess 150. The flat surface 30A is provided annularly around
the substrate P. A side wall portion 151, which is higher than the
flat surface 30A, is formed around the flat surface 30A. The side
wall portion 151 is formed continuously and annularly around the
flat surface 30A. The liquid 1 can be retained inside the side wall
portion 151 (on the substrate P and on the flat surface 30A).
[0143] The substrate holder PH is formed of a material having the
liquid repellence including, for example, polytetrafluoroethylene.
The substrate holder PH may be formed of, for example, a
predetermined metal. At least the flat surface 30A of the substrate
holder PH made of metal may be coated with a liquid-repellent
material (for example, polytetrafluoroethylene) having the liquid
repellence. Of course, the entire region of the surface of the
substrate holder PH made of metal may be coated with a
liquid-repellent material.
[0144] The transport arm 80 is capable of transporting the
substrate holder PH detached from the substrate table PT.
[0145] For example, the transport arm 80 can be operated as
follows. That is, the substrate holder PH, which holds the
substrate P after being subjected to the exposure process, is
unloaded from the substrate table PT (substrate stage PST). The
substrate holder PH is exchanged with another substrate holder PH.
After that, the another substrate holder PH is loaded to (loaded
on) the substrate table PT.
[0146] When the substrate holder PH is loaded to the substrate
table PT, then the transport arm 80 can load only the substrate
holder PH, or the transport arm 80 can load the substrate holder PH
which holds the substrate P before being subjected to the exposure
process.
[0147] FIG. 12 shows the substrate holder PH. FIG. 12(a) shows a
side sectional view, and FIG. 12(b) shows a plan view as viewed
from an upper position.
[0148] With reference to FIG. 12, the substrate holder PH includes
a side wall portion 151 which is capable of retaining the liquid 1
as described above, a plurality of projections 161 which are formed
on a bottom surface portion PHT of the recess 150, and vacuum
suction holes 162 which are formed on upper end surfaces of the
projections 161 respectively. The upper end surfaces of the
projections 161 are flat surfaces. The substrate holder PH supports
the substrate P on the upper end surfaces of the plurality of
recesses 161. Further, the substrate holder PH attracts and holds
the substrate P by the aid of the vacuum suction holes 162. In this
embodiment, the projections 161 are provided at a plurality of
predetermined positions of the bottom surface portion PHT of the
recess 150 of the substrate holder PH respectively so that the
supported substrate P is not warped. When the substrate P is
supported by the projections 161, a spacing portion 164 is formed
between the substrate P and the bottom surface portion PHT of the
substrate holder PH. In this embodiment, the shape of the substrate
holder PH, which is viewed in a plan view, is substantially
circular. However, the shape may be rectangular.
[0149] When the substrate table PT and the substrate holder PH are
connected to each other, the vacuum suction holes 162 of the
substrate holder PH are connected to the flow passages 159 (see,
for example, FIG. 11(b)) provided on the upper surface of the
substrate table PT, via flow passages 162A formed in the substrate
holder PH. The flow passages 159 are connected to the vacuum unit.
When the control unit CONT drives the vacuum unit, the substrate P,
which is supported by the projections 161, is attracted and held
via the flow passages 159 of the substrate table PT, the flow
passages 162A of the substrate holder PH, and the vacuum suction
holes 162. Valves 162B, which are constructed of, for example,
solenoid-operated valves to be driven under the control of the
control unit CONT, are provided for the flow passages 162A
respectively. The operation for opening/closing the flow passage
162A can be subjected to the remote control. The control unit CONT
opens the flow passages 162A by controlling the valves 162B when
the vacuum unit is driven, and the control unit CONT closes the
flow passages 162A when the vacuum unit is stopped.
[0150] Therefore, after the attracting operation for the substrate
P by the aid of the vacuum suction holes 162, the driving of the
vacuum unit is stopped, and the flow passages 162A are closed by
the valves 162B. Accordingly, the negative pressure of the flow
passages 162A is maintained.
[0151] Therefore, even when the substrate table PT and the
substrate holder PH are separated from each other, the substrate
holder PH can maintain the attraction and the holding of the
substrate P by allowing the flow passages 162A to have the negative
pressure.
[0152] Next, an explanation will be made with reference to a
schematic view shown in FIG. 13 about the operation of the exposure
apparatus EX constructed as described above.
[0153] As shown in FIG. 13(a), the substrate holder PH, which holds
the substrate P as the exposure process objective, is loaded to the
substrate table PT together with the substrate P by the transport
arm (transport unit) 80. As shown in FIG. 13(b), the substrate
holder PH is arranged so that the substrate holder PH is fitted to
the recess 157 provided for the substrate table PT. The substrate
holder PH is held by the chuck mechanism having the vacuum suction
holes 158 (FIG. 11). The control unit CONT drives the vacuum unit
to vacuum-attract and hold the substrate P by the aid of the flow
passages 159, the flow passages 162A, and the vacuum suction holes
162 (not shown in FIG. 13). In this situation, the valves 162B open
the flow passages 162A. As shown in FIG. 13(c), the control unit
CONT supplies and recovers the liquid 1 by the liquid supply
mechanism 10 and the liquid recovery mechanism 20 to form the
liquid immersion area AR2 of the liquid 1 between the projection
optical system PL and the substrate P held on the substrate table
PT by the aid of the substrate holder PH. The control unit CONT
radiates the exposure light beam EL onto the substrate P via the
projection optical system PL and the liquid 1 to perform the liquid
immersion exposure while moving the substrate P held on the
substrate table PT (substrate stage PST) by the aid of the
substrate holder PH. In this situation, the vacuum suction holes
162 are closed by the substrate P which is attracted and held.
Therefore, even when the liquid 1 is supplied, the liquid 1 does
not inflow into the vacuum suction holes 162. The liquid 1, which
is disposed on the substrate P and on the flat surface 30A, does
not outflow to the outside of the substrate holder PH owing to the
side wall portion 151 of the substrate holder PH as well.
[0154] After the completion of the liquid immersion exposure for
the substrate P, the control unit CONT recovers the liquid 1
remaining on the substrate P and on the flat surface 30A by using,
for example, the liquid recovery mechanism 20 (see FIG. 2).
Subsequently, the control unit CONT releases the holding of the
substrate holder PH having been effected by the chuck mechanism
including the vacuum suction holes 158. Further, the flow passages
162A are closed by using the valves 162B. As shown in FIG. 13(d),
the control unit CONT unloads the substrate holder PH in a state of
holding the substrate P for which the exposure process has been
completed, from the substrate table PT together with the substrate
P by the transport arm 80. When the substrate holder PH is
separated from the substrate table PT, the flow passages 162A,
which are connected to the vacuum suction holes 162 that attract
and hold the substrate P, are closed by the valves 162B to maintain
the negative pressure state as explained with reference to FIG. 12.
Therefore, the attraction and the holding for the substrate P,
which are effected by the upper end surfaces of the projections
161, are maintained.
[0155] When the substrate P is transported together with the
substrate holder PH, even if the liquid 1 remains on the substrate
P and on the flat surface 30A, then the remaining liquid 1 does not
outflow via the flow passages 162A. The remaining liquid 1 is
retained inside the side wall portion 151. Therefore, the remaining
liquid 1 does not outflow to the outside of the substrate holder
PH, and the remaining liquid 1 is not scattered into the transport
passage as well.
[0156] The unloaded substrate holder PH is exchanged with a new
substrate holder PH. The control unit CONT loads the new substrate
holder PH which holds the substrate P as the exposure process
objective, to the substrate table PT (substrate stage PST) by using
the transport arm 80 (see FIG. 13).
[0157] As described above, the substrate holder PH is exchanged in
this embodiment as well. Therefore, it is possible to hold the
substrate P by the substrate holder PH having the surface which is
liquid-repellent.
Third Embodiment
[0158] The foregoing embodiments have been explained such that the
member (plate member 30, second plate member 32, substrate holder
PH), which has the flat surface 30A around the substrate P, is
exchanged depending on the deterioration of the liquid repellence
thereof. However, it is desirable that any member other than the
plate member 30, the second plate member 32, and the substrate
holder PH provided on the substrate table PT has its
liquid-repellent surface. It is appropriate that such a member is
exchangeable depending on the deterioration of the liquid
repellence thereof. In particular, it is desirable that the member,
which makes contact with the liquid 1, has the liquid-repellent
surface. It is appropriate that such a member is exchangeable
depending on the deterioration of the liquid repellence thereof.
Specifically, the constitutive members of the reference member 300
and the constitutive members of the optical sensors 400, 500, which
are used while forming the liquid immersion area on the surface,
may also be exchangeable.
[0159] FIG. 14 shows a sectional view illustrating the reference
member 300 provided on the substrate table PT. With reference to
FIG. 14, the reference member 300 includes an optical member 301
which is formed of glass (CLEARCERAM), and the reference marks MFM,
PFM which are formed on the upper surface 301A of the optical
member 301.
[0160] The reference member 300 is attached onto the substrate
table PT. As described above, the reference member 300 is arranged
in the opening 32K provided for the second plate member 32, and the
upper surface 301A is exposed. The reference member 300 (optical
member 301) is detachable with respect to the substrate table PT,
and the reference member 300 (optical member 301) is exchangeable.
Concave and convex members or male and female members, which are
fitted to one another in order to position the reference member 300
with respect to the substrate table PT when the reference member
300 is reinstalled to a predetermined position of the substrate
table PT, may be provided for the reference member 300 and the
substrate table PT.
[0161] Alternatively, a magnet and a material to be attracted
thereby may be embedded in the reference member 300 and the
substrate table PT so that the reference member 300 can be
positioned with respect to the substrate table PT by the magnetic
force. Further alternatively, it is also allowable that the
reference member can be positioned with respect to the substrate
table PT by the vacuum attractive force. Quartz may be used as the
optical member 301.
[0162] A gap K, which is, for example, about 0.3 mm, is provided
between the reference member 300 and the opening 32K. The upper
surface 301A of the optical member 301 (reference member 300) is a
substantially flat surface which is provided to have approximately
the same height as those of (be flush with) the surface of the
substrate P, the surface 30A of the plate member 30, and the
surface 32A of the second plate member 32.
[0163] Portions of the second plate member 32, which are disposed
in the vicinity of the reference member 300, are thin-walled. An
end of a thin-walled portion 32S, of the thin-walled portion, which
is disposed on the side of the reference member 300, is bent
downwardly to form a bent portion 32T. A wall section 310, which
protrudes upwardly, is formed on the substrate table PT. The wall
section 310 is provided outside the bent portion 32T in relation to
the reference member 300. The wall section 310 is formed
continuously to surround the reference member 300 (bent portion
32T). The outer side surface 32Ta of the bent portion 32T is
opposed to the inner side surface 310A of the wall section 310. The
inner side surface 32Tb of the bent portion 32T is opposed to the
side surface 301B of the optical member 301 (reference member 300).
The side surface 301B of the optical member 301, the inner side
surface 32Tb and the outer side surface 32Ta of the bent portion
32T, and the inner side surface 310A and the upper end surface 310B
of the wall section 310 are flat surfaces respectively. The
thin-walled portion 32S including the bent portion 32T of the
second plate member 32 is slightly separated from the wall section
310, and a predetermined gap (interstice) is formed
therebetween.
[0164] The areas of the upper surface 301A and the side surface
301B of the optical member 301 opposed to at least the bent portion
32T, and the inner side surface 310A and the upper end surface 310B
of the wall section 310 are subjected to the liquid-repelling
treatment to have the liquid repellence. The liquid-repelling
treatment can be performed, for example, by coating the
liquid-repellent material such as the fluorine-based resin material
and the acrylic resin material as described above.
[0165] The liquid 1, which flows into the space 370 between the
reference member 301 and the bent portion 32T of the second plate
member 32 (wall section 310), is recovered by a recovery section
380. In this embodiment, the recovery section 380 includes a vacuum
system 383, a gas/liquid separator 381 which includes a tank
capable of accommodating the liquid 1, and a flow passage 382 which
is provided in the substrate table PT and which connects the space
370 and the gas/liquid separator 381. The liquid-repelling
treatment is also performed to the inner wall surface of the flow
passage 382.
[0166] It is conceived that the reference member 300 described
above may be constructed to perform the operation for detecting the
reference mark, for example, in a state in which the liquid
immersion area AR2 of the liquid 1 is formed on the upper surface
301A of the reference member 300. However, the upper surface 301A
is liquid-repellent. Therefore, the liquid 1 of the liquid
immersion area AR2 on the upper surface 301A can be satisfactorily
recovered after the completion of the operation for detecting the
reference mark. It is possible to avoid the inconvenience which
would be otherwise caused such that the liquid 1 remains. Further,
the side surface 301B of the optical member 301 is
liquid-repellent, and the inner side surface 32Tb of the bent
portion 32T opposed to the side surface 301B is also
liquid-repellent. Therefore, the liquid 1 hardly inflows into the
gap K. Therefore, it is possible to avoid the inconvenience of the
inflow of the liquid 1 into the space 370. Even if the liquid 1
inflows into the space 370, the liquid 1 can be satisfactorily
recovered by the recovery section 380. Further, even if the liquid
1 inflows into the space 370, it is possible to avoid the
inconvenience which would be otherwise caused such that the liquid
1, which inflows into the space 370, rides across the wall section
310, and the liquid 1 inflows into the substrate table PT to cause
the rust or the like, because the inner side surface 310A and the
upper end surface 310B of the wall section 310 are
liquid-repellent, and the second plate member 32 (bent portion 32T)
opposed to the wall section 310 is also liquid-repellent. As
described above, the wall section 310 functions as a liquid
diffusion-preventing wall to avoid the diffusion of the liquid 1. A
corner is formed as viewed in a sectional view by the bent portion
32T at the gap between the second plate member 32 and the wall
section 310. The corner functions as a seal portion. Therefore, it
is possible to reliably avoid the inflow of the liquid 1 into the
substrate table PT.
[0167] Since the reference member 300 (optical member 301) is
exchangeable, when the liquid repellence thereof is deteriorated,
the reference member 300 may be exchanged with a new reference
member 300 (having the sufficient liquid repellence) in the same
manner as the plate member 30.
[0168] When the reference member 300 is used, the measuring light
beam is locally radiated onto the mark portion. Therefore, a
plurality of identical reference marks may be formed on the
reference member 300 beforehand. When the liquid repellence of the
surface of the mark portion is deteriorated, another reference mark
may be used. Alternatively, the marks may be alternately used for
every measurement operation in order to lower the speed of the
deterioration of the liquid repellence. Accordingly, it is possible
to decrease the exchange frequency of the reference member 300.
This procedure is especially effective, because the liquid
repellence is quickly deteriorated at the portion including the
reference mark MFM for which the measuring light beam having the
same wavelength as the exposure wavelength is used.
[0169] FIG. 15 shows a sectional view illustrating the uneven
illuminance sensor 400 provided on the substrate table PT. With
reference to FIG. 15, the uneven illuminance sensor 400 includes an
upper plate 401 which is formed of, for example, quartz glass, and
an optical element 402 which is provided below the upper plate 401
and which is formed of, for example, quartz glass. In this
embodiment, the upper plate 401 and the optical element 402 are
provided as an integrated body. In the following description, the
upper plate 401 and the optical element 402 will be appropriately
referred to as "optical member 404" in combination. The upper plate
401 and the optical element 402 are supported on the substrate
table PT by the aid of a support section 403. The support section
403 has a continuous wall portion which surrounds the optical
member 404. As described above, the uneven illuminance sensor 400
is arranged in the opening 32L provided for the second plate member
32, and the upper surface 401A is exposed. The optical member 404,
which includes the upper plate 401 and the optical element 402, is
detachable with respect to the substrate table PT, and the optical
member 404 is exchangeable. Concave and convex members or male and
female members, which are fitted to one another in order to
position the optical member 404 with respect to the substrate table
PT when the optical member 404 is reinstalled to a predetermined
position of the substrate table PT, may be provided for the optical
member 404 and the substrate table PT. Alternatively, a magnet and
a material to be attracted thereby may be embedded in the optical
member 404 and the substrate table PT so that the optical member
404 can be positioned with respect to the substrate table PT by the
magnetic force. Further alternatively, it is also allowable that
the optical member can be positioned with respect to the substrate
table PT by the vacuum attractive force.
[0170] A pinhole 470, through which the light beam can pass, is
provided on the upper plate 401. A thin film 460, which includes a
light-shielding material such as chromium, is provided at portions
on the upper plate 401 except for the pinhole 470. In this
embodiment, an optical member formed of quartz glass is also
provided in the pinhole 470. Accordingly, the thin film 460 is
flush with the pinhole 470, and the upper surface 401A is a flat
surface.
[0171] An optical sensor 450, which receives the light beam allowed
to pass through the pinhole 470, is arranged below the optical
member 404. The optical sensor 450 is attached onto the substrate
table PT. The optical sensor 450 outputs a light-receiving signal
to the control unit CONT. In this arrangement, a space 405, which
is surrounded by the support section 403, the substrate table PT,
and the optical member 404, is a substantially tightly closed
space. The liquid 1 does not inflow into the space 405. An optical
system (optical element) may be arranged between the optical member
404 and the optical sensor 450.
[0172] A gap L, which is, for example, about 0.3 mm, is provided
between the opening 32L and the uneven illuminance sensor 400
including the optical member 404 and the support section 403. The
upper surface 401A of the uneven illuminance sensor 400 is a
substantially flat surface which is provided to have approximately
the same height as those of (be flush with) the surface of the
substrate P, the surface 30A of the plate member 30, and the
surface 32A of the second plate member 32.
[0173] Portions of the second plate member 32, which are disposed
in the vicinity of the uneven illuminance sensor 400, are
thin-walled. An end of the thin-walled portion 32S, of the
thin-walled portion, which is disposed on the side of the uneven
illuminance sensor 400, is bent downwardly to form a bent portion
32T. A wall section 310, which protrudes upwardly, is formed on the
substrate table PT. The wall section 310 is provided outside the
bent portion 32T in relation to the uneven illuminance sensor 400.
The wall section 310 is formed continuously to surround the uneven
illuminance sensor 400 (bent portion 32T). The outer side surface
32Ta of the bent portion 32T is opposed to the inner side surface
310A of the wall section 310. The inner side surface 32Tb of the
bent portion 32T is opposed to the side surface 401B of the support
section 403 and the optical member 404 of the uneven illuminance
sensor 400. The side surface 401B, the inner side surface 32Tb and
the outer side surface 32Ta of the bent portion 32T, and the inner
side surface 310A and the upper end surface 310B of the wall
section 310 are flat surfaces respectively. The thin-walled portion
32S including the bent portion 32T of the second plate member 32 is
slightly separated from the wall section 310, and a predetermined
gap (interstice) is formed therebetween.
[0174] The areas of the upper surface 401A and the side surface
401B of the uneven illuminance sensor 400 opposed to at least the
bent portion 32T, and the inner side surface 310A and the upper end
surface 310B of the wall section 310 are subjected to the
liquid-repelling treatment to have the liquid repellence. The
liquid-repelling treatment can be performed, for example, by
coating the liquid-repellent material such as the fluorine-based
resin material and the acrylic resin material as described
above.
[0175] The liquid 1i, which flows into a space 470 between the
uneven illuminance sensor 400 and the bent portion 32T of the
second plate member 32 (wall section 310), is recovered by a
recovery section 480. In this embodiment, the recovery section 480
includes a vacuum system 483, a gas/liquid separator 481 which
includes a tank capable of accommodating the liquid 1, and a flow
passage 482 which is provided in the substrate table PT and which
connects the space 470 and the gas/liquid separator 481. The
liquid-repelling treatment is also performed to the inner wall
surface of the flow passage 482.
[0176] As for the uneven illuminance sensor 400 described above,
the pinhole 470 is successively moved to a plurality of positions
in the irradiation area (projection area) onto which the exposure
light beam EL is radiated, for example, in a state in which the
liquid immersion area AR2 of the liquid 1 is formed on the upper
surface 401A of the uneven illuminance sensor 400. The upper
surface 401A is liquid-repellent. Therefore, the liquid 1 of the
liquid immersion area AR2 on the upper surface 401A can be
satisfactorily recovered after the completion of the measurement of
the uneven illuminance. It is possible to avoid the inconvenience
which would be otherwise caused such that the liquid 1 remains.
Further, the side surface 401B of the uneven illuminance sensor 400
(optical member 404, support section 403) is liquid-repellent, and
the inner side surface 32Tb of the bent portion 32T opposed to the
side surface 401B is also liquid-repellent. Therefore, the liquid 1
hardly inflows into the gap L. Therefore, it is possible to avoid
the inconvenience of the inflow of the liquid 1 into the space 470.
Even if the liquid 1 inflows into the space 470, the liquid 1 can
be satisfactorily recovered by the recovery section 480. Further,
even if the liquid 1 inflows into the space 470, it is possible to
avoid the inconvenience which would be otherwise caused such that
the liquid 1, which inflows into the space 470, rides across the
wall section 310, and the liquid 1 inflows into the substrate table
PT to cause the rust or the like, because the inner side surface
310A and the upper end surface 310B of the wall section 310 are
liquid-repellent, and the second plate member 32 (bent portion 32T)
opposed to the wall section 310 is also liquid-repellent. A corner
is formed as viewed in a sectional view by the bent portion 32T at
the gap between the second plate member 32 and the wall section
310. The corner functions as a seal portion. Therefore, it is
possible to reliably avoid the inflow of the liquid 1 into the
substrate table PT.
[0177] Since the optical member 404 is exchangeable, when the
liquid repellence thereof is deteriorated, the optical member 404
may be exchanged with a new optical member 404 (having the
sufficient liquid repellence) in the same manner as the plate
member 30.
[0178] The spatial image-measuring sensor 500 is constructed
substantially equivalently to the uneven illuminance sensor 400.
Therefore, any detailed explanation thereof will be omitted.
However, the spatial image-measuring sensor 500 also has an optical
member constructed of an optical element and an upper plate
supported by the aid of a support section on the substrate table
PT. A slit 570 through which the light beam can pass, and a thin
film which is formed of a light-shielding material to cover
portions other than the slit are provided on an upper surface 501A
of the spatial image-measuring sensor 500. An optical sensor, which
receives the light beam allowed to pass through the slit 570, is
provided below the optical member. The optical member, which has
the slit 570, is exchangeable depending on the deterioration of the
liquid repellence.
[0179] In the embodiment explained with reference to FIGS. 14 and
15, the inflow of the liquid 1 is avoided by providing the liquid
repellence for the surfaces of the members for forming the gaps K,
L. However, the inflow of the liquid 1 into the gap can be avoided
by similarly providing the liquid repellence for the gap existing
on the upper surface of the substrate table PT, without being
limited to the gaps disposed around the measuring member and the
sensor. Alternatively, a seal member, which is formed of a resin or
the like, may be arranged in the gap K, L to avoid the inflow of
the liquid 1. Further alternatively, the gap K, L may be filled
with a liquid (for example, vacuum grease or magnetic fluid) to
provide the liquid seal function so that the inflow of the liquid 1
is avoided. In this arrangement, it is preferable that the sealing
liquid is hardly dissolved or eluted in the liquid 1. Of course, it
goes without saying that the countermeasures to avoid the inflow of
the liquid may be used in combination.
[0180] It is unnecessary that all of the surfaces (liquid contact
surfaces) of the measuring members (for example, the optical member
301 of the reference member 300, the upper plate 401 of the optical
sensor 400, and the upper plate 501 of the optical sensor 500),
which are provided on the substrate stage PST (substrate table PT),
are liquid-repellent. It is also allowable that only a part or
parts of them may have the liquid repellence.
[0181] In the embodiment described above, the exchange is performed
when the liquid repellence of the surface of the member is
deteriorated. However, when a certain member is exchanged, other
members, which will reach the exchange timing soon, may be
simultaneously exchanged.
[0182] In order to recover the liquid (water) more reliably, it is
desirable that the contact angle with respect to the liquid (water)
is larger than about 80.degree., desirably not less than
100.degree. (contact angle of polytetrafluoroethylene described
above with respect to the liquid (water) is about 110.degree.), for
example, for the surface of the substrate table PT, i.e., the
surface of the plate member 30, the surface of the second plate
member 32, and the surface of the reference member 300.
[0183] It is desirable that the photosensitive material (resist for
the ArF exposure light beam) to be used, with which the surface of
the substrate P is coated, has the contact angle with respect to
the liquid (water) that is larger than about 80.degree.. Of course,
when the KrF excimer laser light beam is used as the exposure light
beam, it is desirable to use, as a resist for the KrF exposure
light beam, a material which has the contact angle with respect to
the liquid that is larger than 80.degree..
[0184] The specified embodiment described above is illustrative of
the exemplary substrate stage which is provided with both of the
substrate table and the measuring units or instruments including,
for example, the reference member 300, the uneven illuminance
sensor 400, and the spatial image-measuring sensor 500. However,
the present invention is also applicable to an exposure apparatus
in which a stage for performing the exposure while holding the
substrate is distinct from a stage for the measurement.
[0185] That is, the present invention also intends an exposure
apparatus provided with an exposure stage which is movable while
holding a processing objective substrate such as a wafer, and a
measuring stage which is provided with various reference members
and measuring members such as measuring sensors. In this
arrangement, at least a part or parts of the reference members
and/or the various measuring sensors arranged on the substrate
stage PST in the embodiment described above can be arranged on the
measuring stage. The exposure apparatus, which is provided with the
exposure stage and the measuring stage, is described, for example,
in Japanese Patent Application Laid-open No. 11-135400, the content
of which are incorporated herein by reference within a range of
permission of the domestic laws and ordinances of the state
designated or selected in this international application.
[0186] The embodiment of the present invention is also applicable
to a twin-stage type exposure apparatus which is provided with two
substrate stages (substrate tables) for holding the substrate P.
The structure and the exposure operation of the twin-stage type
exposure apparatus are disclosed, for example, in Japanese Patent
Application Laid-open Nos. 10-163099 and 10-214783 (corresponding
to U.S. Pat. Nos. 6,341,007, 6,400,441, 6,549,269, and 6,590,634),
Published Japanese Translation of PCT International Publication for
Patent Application No. 2000-505958 (corresponding to U.S. Pat. No.
5,969,441), and U.S. Pat. No. 6,208,407, the content of which are
incorporated herein by reference within a range of permission of
the domestic laws and ordinances of the state designated or
selected in this international application.
Fourth Embodiment
[0187] FIG. 16 shows a schematic arrangement of a twin-stage type
exposure apparatus to which the present invention is applied. The
twin-stage type exposure apparatus includes first and second
substrate stages PST1, PST2 which are movable on a common base 54
independently respectively. Each of the first and second substrate
stages PST1, PST2 is a substrate stage which has the structure and
the function as explained in relation to FIGS. 1 to 15. The first
and second substrate stages PST1, PST2 have first and second
substrate tables PT1, PT2 respectively. The plate member 30 and the
second plate member 32 are provided exchangeably on each of the
first and second substrate tables PT1, PT2. The twin-stage type
exposure apparatus includes an exposure station ST1 and a
measuring/exchange station ST2. The exposure station ST1 is
provided with the projection optical system PL. The substrate
alignment system, the focus/leveling-detecting system and the like
are provided on the measuring/exchange station ST2 (not shown in
FIG. 16). The liquid immersion exposure process is performed for a
substrate P held on the first substrate table PT1 in the exposure
station ST1, during which the substrate P is loaded/unloaded with
respect to the second substrate stage PST2 (second substrate table
PT2) together with the plate member 30 in the measuring/exchange
station ST2. In the measuring/exchange station ST2, the measuring
operation (focus-detecting operation, alignment operation) is
performed for a substrate P disposed on the second substrate stage
PST2 concurrently with the liquid immersion exposure in the
exposure station ST1. After the completion of the measuring
operation, the second substrate stage PST2 is moved to the exposure
station ST2, and the liquid immersion exposure process is performed
for the substrate P disposed on the second substrate stage
PST2.
[0188] As described above, in the case of the twin-stage type
exposure apparatus, it is possible to perform not only the
substrate exchange and the measuring process but also the exchange
of the plate member 30 on the other stage during the period in
which the liquid immersion exposure process is performed on one
stage. Therefore, it is possible to improve the throughput of the
exposure process.
[0189] The respective embodiments described above have been
explained such that the plate member 30 or the like is exchanged
depending on the liquid repellence thereof.
[0190] However, it goes without saying that the plate member 30 or
the like can be exchanged for any reason other than the
deterioration of the liquid repellence, for example, when the plate
member 30 or the like is damaged or polluted due to any cause. For
example, when the plate member 30 or the like makes contact with
the liquid 1 for a long period of time, there is such a possibility
that the surface may be deteriorated, any substance may be eluted,
and the liquid 1 may be polluted therewith. Therefore, the exchange
timing may be also determined in consideration of the surface
deterioration of the plate member 30 or the like which accompanies
the elution of the substance.
[0191] In the embodiment described above, the optical element 2 is
formed of fluorite. However, for example, it is possible to use
fluorite in which the crystalline orientation of the fluorite
surface is the (111) plane. Further, magnesium fluoride
(MgF.sub.2), which serves as a dissolution-preventive film
constructed of a single layer film, may be formed by means of the
vacuum vapor deposition method at the end portion 2a of the optical
element 2 shown in FIG. 1, i.e., the portion which makes contact
with the liquid 1.
Fifth Embodiment
[0192] For example, when the optical part for constructing the unit
such as the radiation amount monitor and the uneven illuminance
sensor, the index plate for the spatial image-measuring unit, and
the reference mark (reference member) to be used when the reticle
alignment is performed are provided on the substrate stage PST as
explained in the first embodiment, it is desirable that the light
irradiated surface (liquid contact surface) of the optical part as
described above has the liquid repellence. If water is not
discharged completely from the light irradiated surface of the
radiation amount monitor, the uneven illuminance sensor or the
like, it is feared that the measurement of the light radiation
amount and/or the light illuminance cannot be performed correctly.
If water is not discharged completely from the surface of the index
plate of the spatial image-measuring unit, there is such a
possibility that the surface shape of the index plate may be
changed due to the evaporation of the liquid on the index plate,
and any error may arise in the measurement performed by the spatial
image-measuring unit. If water is not discharged completely from
the surface of the reference mark, there is such a possibility that
the shape of the reference mark may be changed due to the
evaporation of the liquid on the reference mark, and the reticle
alignment cannot be performed correctly. Therefore, it is required
that the surface of the optical part arranged on the substrate
stage has the liquid repellence for a long period of time.
[0193] In such circumstances, it is conceived that an amorphous
fluororesin is coated on the surface of the optical part to form a
thin film so that the liquid-repellent optical thin film having the
high optical performance is prepared thereby. That is, the
amorphous fluororesin is such a material that the amorphous
fluororesin is especially transparent and it has the high
ultraviolet transmittance, as compared with other resins. Further,
the amorphous fluororesin exhibits the smallest surface tension as
compared with any other organic matter, owing to the --CF.sub.3
bond coordinated on the resin surface. Therefore, the amorphous
fluororesin is also a material which has the excellent
water-repelling performance.
[0194] However, in the case of the water-repellent optical thin
film formed on the surface of the optical part, when the
ultraviolet laser, which has the high energy in the liquid
immersion state, is radiated, a minute amount of the light energy
absorbed by the thin film is converted into the temperature. The
thin film is consequently swelled in a relatively short period of
time, and water inflows into the film. In such a situation, the
film is consequently exfoliated if adhesiveness is unsatisfactory
between the fluororesin thin film and the surface of the optical
part. The optical performance is harmfully affected thereby, and
the water-repelling performance is deteriorated. Therefore, it is
feared that any water droplet may remain on the substrate
stage.
[0195] In general, it is known that a thin film, which has the
satisfactory adhesiveness, is obtained by reacting the optical part
surface with a coupling agent such as fluoroalkylsilane to form a
binder layer and forming a fluororesin thin film thereon. However,
the inventors performed investigation and found that the
adhesiveness cannot be obtained after the laser irradiation,
because fluoroalkylsilane absorbs the ultraviolet laser beam to
consequently cause the decomposition.
[0196] In this embodiment, an explanation will be made with
reference to the drawings about an optical part which is capable of
maintaining the liquid repellence for a long period of time and
which is appropriately usable for the liquid immersion type
projection exposure apparatus. FIG. 19 shows optical parts provided
on the wafer stage. FIG. 20 shows an arrangement of the optical
part provided on the wafer stage.
[0197] The optical parts, which include, for example, a
light-entrance window (light irradiated surface) 650 of a radiation
amount monitor for monitoring the radiation amount of the exposure
light beam, and a light-entrance window (light irradiated surface)
652 of an uneven illuminance sensor for detecting the uneven
illuminance of the exposure light beam, are provided on a wafer
stage 609 shown in FIG. 19. Further, the optical parts, which
include, for example, an index plate (light irradiated surface) 654
of a spatial image-measuring unit (AIS system) for measuring, for
example, the optical characteristic of the projection optical
system, and a reference mark (FM) (light irradiated surface) 656 to
be used when the reticle alignment is performed, are provided on
the wafer stage 609. In this arrangement, as shown in FIG. 20, the
light-entrance window (light irradiated surface) 650 of the
radiation amount monitor (as well as the light-entrance window
(light irradiated surface) 652 of the uneven illuminance sensor) is
formed of quartz glass 660. A particulate layer (adhesive
particulate layer) 662, which is formed of silicon dioxide
(SiO.sub.2), is formed as a film on the surface of the quartz glass
660. A water-repellent film 664, which is composed of an amorphous
fluororesin, is formed as a film on the surface of the particulate
layer.
[0198] Each of the index plate 654 of the spatial image-measuring
unit (AIS system) and the reference mark (FM) 656 is composed of
quartz glass and a chromium (metal) pattern formed on the surface
of quartz glass. A particulate layer (adhesive particulate layer),
which is formed of silicon dioxide (SiO.sub.2), is formed as a film
on the surface thereof. A water-repellent film, which is composed
of an amorphous fluororesin, is formed as a film on the surface of
the particulate layer.
[0199] According to the optical part concerning this embodiment,
the particulate layer, which is composed of silicon dioxide
(SiO.sub.2) for forming the adhesive particulate layer, has the
good affinity for the glass (main component: SiO.sub.2) of the base
material. It is possible to obtain an appropriate degree of
adhesiveness with respect to the base material glass. Further,
irregularities, which result from the diameters of particles, are
formed on the surface. Additionally, for example, silicon dioxide
itself has the high durability against the laser irradiation as
well, because silicon dioxide or the like is a material having the
extremely high ultraviolet transmittance. In this embodiment, the
particulate layer composed of silicon dioxide (SiO.sub.2) is formed
as the film, and then the water-repellent film composed of the
amorphous fluororesin is formed on the particulate layer. The
amorphous fluororesin enters voids or interstices of particulates
of silicon dioxide or the like, and the amorphous fluororesin is
subjected to drying and solidification while effecting embrace and
inclusion. The mechanical strength of the amorphous fluororesin
itself is high. Therefore, the water-repellent film, which is
allowed to make tight contact with the base material, has the high
strength.
[0200] The water-repellent film, which is formed on the light
irradiated surface, has the high durability against the laser
irradiation. Therefore, it is possible to maintain, for a long
period of time, the water repellence of the light irradiated
surface of the optical part provided on the substrate stage of the
projection exposure apparatus.
[0201] According to the projection exposure apparatus concerning
this embodiment, the optical part, which makes it possible to
maintain the water repellence of the light irradiated surface for a
long period of time, is provided on the substrate stage. Therefore,
even when the liquid immersion exposure is repeatedly performed, it
is possible to reliably discharge water from the light irradiated
surface of the optical part.
[0202] In the embodiment described above, the adhesive particulate
layer, which is constructed of the particulate layer composed of
silicon dioxide (SiO.sub.2), is formed as the film on the light
irradiated surface of the optical part, on which the
water-repellent film composed of the amorphous fluororesin is
formed as the film. However, an adhesive particulate layer, which
is composed of magnesium fluoride (MgF.sub.2) or calcium fluoride
(CaF.sub.2), may be formed as a film on the light irradiated
surface in place of the silicon dioxide (SiO.sub.2), on which the
water-repellent film composed of the amorphous fluororesin may be
formed as the film. Alternatively, arbitrary two of silicon dioxide
(SiO.sub.2), magnesium fluoride (MgF.sub.2), and calcium fluoride
(CaF.sub.2) may be mixed or laminated to constitute an adhesive
particulate layer. Further alternatively, three of them may be
mixed or laminated to constitute an adhesive particulate layer.
Also in this case, it is possible to obtain the water-repellent
film which is excellent in the durability against the laser
irradiation, in the same manner as in the case in which the
adhesive particulate layer constructed of the particulate layer
composed of silicon dioxide (SiO.sub.2) is formed as the film, on
which the water-repellent film composed of the amorphous
fluororesin is formed as the film.
[0203] In the embodiment described above, the adhesive particulate
layer, which is constructed of the particulate layer composed of
silicon dioxide (SiO.sub.2), is formed as the film on the light
irradiated surface of the optical part (for example, the
light-entrance window 650), on which the water-repellent film
composed of the amorphous fluororesin is formed as the film.
However, as shown in FIG. 21, an adhesive surface (etching surface)
668 may be formed by performing the etching by using hydrogen
fluoride (or hydrofluoric acid obtained by dissolving hydrogen
fluoride in water) on the surface of the light irradiated surface
formed of quartz glass 666. A water-repellent film 670 composed of
an amorphous fluororesin may be formed as a film on the surface of
the adhesive surface 668. In this case, the optical part has, on
the light irradiated surface, the adhesive surface constructed of
the etching surface obtained by performing the etching with
hydrogen fluoride. Therefore, when the water-repellent film
composed of the amorphous fluororesin is formed on the adhesive
surface, then the amorphous fluororesin enters voids or interstices
of the adhesive surface, and the amorphous fluororesin is subjected
to drying and solidification while effecting embrace and inclusion.
The mechanical strength of the amorphous fluororesin itself is
high. Therefore, the water-repellent film, which is allowed to make
tight contact with the base material, has the high strength.
[0204] In this embodiment, the light irradiated surface has the
base material glass and the metal film (chromium film) for forming
the pattern on the part of the base material glass, on which the
water-repellent film composed of the amorphous fluororesin is
formed. However, it is also appropriate that a base material glass
and a metal film formed on the entire surface of the base material
glass are provided, on which the water-repellent film composed of
the amorphous fluororesin is formed. Such an optical part is usable
as a high reflection plate to be employed, for example, when the
transmittance of the projection lens is monitored.
[0205] In this embodiment, quartz glass is used as the base
material glass. However, it is also appropriate that low expansion
glass is used.
[0206] The method for producing the optical part according to the
embodiment of the present invention will be specifically explained
below with reference to Examples.
Example A
[0207] A surface of a light irradiated surface of an optical part
(quartz glass) to be subjected to the film formation is washed to
be extensively clean by washing the surface with an automatic
washing apparatus which radiates the ultrasonic wave or by wiping
the surface with a cloth or the like impregnated with alcohol.
[0208] Subsequently, a coat solution, which is obtained by stably
dispersing fine particles of MgF.sub.2 having an average particle
size of 80 nm in an alkaline solution, is dripped in an appropriate
amount onto the surface of the optical part to perform the spin
coat by using a high speed rotation apparatus. When the coat
solution is dried until it loses the fluidity, the optical part is
detached from the high speed rotation apparatus, followed by being
dried for 1 to 2 hours in a drying furnace at about 150.degree. C.
in order to completely dry the coat solution. A coat solution,
which is obtained by dissolving an amorphous fluororesin ("CYTOP"
produced by Asahi Glass Co., Ltd.), is dripped in an appropriate
amount further onto the optical part having been cooled to room
temperature to perform the spin coat by using the high speed
rotation apparatus. When the coat solution is dried until it loses
the fluidity, the optical part is detached from the high speed
rotation apparatus, followed by being dried for 1 to 2 hours in a
drying furnace at about 100.degree. C. in order to completely dry
the coat solution. According to the steps as described above, the
optical part is produced, which has an MgF.sub.2 film and an
amorphous fluororesin film on the base material glass (quartz
glass).
Example B
[0209] A surface of a light irradiated surface of an optical part
(quartz glass) to be subjected to the film formation is washed to
be extensively clean by washing the surface with an automatic
washing apparatus which radiates the ultrasonic wave or by wiping
the surface with a cloth or the like impregnated with alcohol.
[0210] Subsequently, a coat solution, which is obtained by stably
dispersing fine particles of SiO.sub.2 having an average particle
size of 80 nm in an alkaline solution, is dripped in an appropriate
amount onto the surface of the optical part to perform the spin
coat by using a high speed rotation apparatus. When the coat
solution is dried until it loses the fluidity, the optical part is
detached from the high speed rotation apparatus, followed by being
dried for 1 to 2 hours in a drying furnace at about 150.degree. C.
in order to completely dry the coat solution. A coat solution,
which is obtained by dissolving an amorphous fluororesin ("CYTOP"
produced by Asahi Glass Co., Ltd.), is dripped in an appropriate
amount further onto the optical part having been cooled to room
temperature to perform the spin coat by using the high speed
rotation apparatus. When the coat solution is dried until it loses
the fluidity, the optical part is detached from the high speed
rotation apparatus, followed by being dried for 1 to 2 hours in a
drying furnace at about 100.degree. C. in order to completely dry
the coat solution. According to the steps as described above, the
optical part is produced, which has an SiO.sub.2 film and an
amorphous fluororesin film on the base material glass (quartz
glass).
[0211] A surface of an optical part (quartz glass), which is
polished highly accurately to have a roughness of about 0.2 nm RMS,
is immersed for 5 seconds in hydrofluoric acid diluted to 5%, and
then hydrofluoric acid is rinsed with pure water, followed by being
wiped with a cloth or the like impregnated with alcohol. A coat
solution, which is obtained by dissolving an amorphous fluororesin
("CYTOP" produced by Asahi Glass Co., Ltd.), is dripped in an
appropriate amount onto the surface to perform the spin coat by
using a high speed rotation apparatus. When the coat solution is
dried until it loses the fluidity, the optical part is detached
from the high speed rotation apparatus, followed by being dried for
1 to 2 hours in a drying furnace at about 100.degree. C. in order
to completely dry the coat solution. According to the steps as
described above, the optical part is produced, which has an
amorphous fluororesin film on the base material glass (quartz
glass).
Comparative Example
[0212] A surface of a light irradiated surface of an optical part
(quartz glass) to be subjected to the film formation is washed to
be extensively clean by washing the surface with an automatic
washing apparatus which radiates the ultrasonic wave or by wiping
the surface with a cloth or the like impregnated with alcohol.
Subsequently, a coat solution, which is obtained by dissolving an
amorphous fluororesin ("CYTOP" produced by Asahi Glass Co., Ltd.),
is dripped in an appropriate amount onto the surface to perform the
spin coat by using a high speed rotation apparatus.
[0213] When the coat solution is dried until it loses the fluidity,
the optical part is detached from the high speed rotation
apparatus, followed by being dried for 1 to 2 hours in a drying
furnace at about 100.degree. C. in order to completely dry the coat
solution. According to the steps as described above, the optical
part is produced, which has an amorphous fluororesin film on the
base material glass (quartz glass).
Exfoliation Test
[0214] An exfoliation test (tape test) using the cellophane
adhesive tape was performed for the optical parts obtained in
Examples A to C and Comparative Example as described above. In the
tape test, a cellophane adhesive tape (JIS-468006) produced by
NICHIBAN Co., Ltd. having a width of 18 mm was used. The degree of
exfoliation of the film was judged such that the tape was rubbed
strongly three times with a finger front when the tape was stuck,
and then the tape was quickly peeled off perpendicularly. Three
samples were prepared for each of the optical parts obtained in
respective Examples, and the test was performed for each of
them.
[0215] The following evaluation value criteria were used. That is,
a case, in which the water-repelling coat was exfoliated in an
amount of not less than .PHI.5 mm, was regarded as "occurrence of
exfoliation". The other cases were regarded as "no exfoliation".
The expression "3/3" indicates the fact that all of the three
samples were exfoliated.
Test Results
TABLE-US-00001 [0216] Example A 0/3 samples no exfoliation Example
B 0/3 samples no exfoliation Example C 0/3 samples no exfoliation
Comp. Ex. 3/3 samples occurrence of exfoliation
[0217] As clarified from the test results, the water-repellent film
of each of Examples A to C is strongly adhered to the base material
glass, because the adhesive layer or the etching surface is
provided. Therefore, it is appreciated that the optical part of the
present invention is extremely excellent in the liquid resistance
(water resistance) in the environment in which the optical part
makes contact with the liquid such as in the liquid immersion
exposure.
[0218] The embodiment has been explained as exemplified by the case
in which the water-repellent film is adhered to the base material
glass by way of example. According to the results as described
above, it is appreciated that the present invention is usable for
arbitrary various optical parts. That is, the present invention is
not limited to various sensors and reference members provided on
the substrate stage of the liquid immersion exposure apparatus. The
present invention can be also used for all optical lenses and
optical sensors which are used in such an environment that the
contact is made with the liquid or the vapor. Further, the present
invention is also applicable to the projection optical system to be
used for the exposure apparatus, especially the lens installed to
the end portion disposed on the side of the substrate, the lens to
be used for the illumination optical system, and the sensor.
[0219] The term "contact angle" referred to in the embodiments
described above includes not only the static contact angle but also
the dynamic contact angle.
[0220] In the embodiments of the exposure apparatus described
above, pure water is used as the liquid 1. Pure water is
advantageous in that pure water is available in a large amount with
ease, for example, in the semiconductor production factory, and
pure water exerts no harmful influence, for example, on the optical
element (lens) and the photoresist on the substrate P. Further,
pure water exerts no harmful influence on the environment, and the
content of impurity is extremely low. Therefore, it is also
expected to obtain the function to wash the surface of the
substrate P and the surface of the optical element provided at the
end surface of the projection optical system PL. When the purity of
pure water supplied from the factory or the like is low, it is also
appropriate that the exposure apparatus is provided with an
ultrapure water-producing unit.
[0221] The liquid 1 is water in the respective embodiments
described above. However, the liquid 1 may be any liquid other than
water. For example, when the light source of the exposure light
beam EL is the F.sub.2 laser, the F.sub.2 laser beam is not
transmitted through water. Therefore, in this case, liquids
preferably usable as the liquid 1 may include, for example, a
fluorine-based fluid such as fluorine-based oil and
perfluoropolyether (PFPE) through which the F.sub.2 laser beam is
transmissive. In this case, the portion to make contact with the
liquid 1 is subjected to the liquid-attracting treatment by forming
a thin film, for example, with a substance having a molecular
structure of small polarity including fluorine. Alternatively,
other than the above, it is also possible to use, as the liquid 1,
liquids (for example, cedar oil) which have the transmittance with
respect to the exposure light beam EL, which have the refractive
index as high as possible, and which are stable against the
photoresist coated on the surface of the substrate P and the
projection optical system PL. Also in this case, the surface
treatment is performed depending on the polarity of the liquid 1 to
be used.
[0222] It is approved that the refractive index n of pure water
(water) with respect to the exposure light beam EL having a
wavelength of about 193 nm is approximately in an extent of 1.44.
When the ArF excimer laser beam (wavelength: 193 nm) is used as the
light source of the exposure light beam EL, then the wavelength is
shortened on the substrate P by 1/n, i.e., to about 134 nm, and a
high resolution is obtained. Further, the depth of focus is
magnified about n times, i.e., about 1.44 times as compared with
the value obtained in the air. Therefore, when it is enough to
secure an approximately equivalent depth of focus as compared with
the case of the use in the air, it is possible to further increase
the numerical aperture of the projection optical system PL. Also in
this viewpoint, the resolution is improved.
[0223] When the liquid immersion method is used as described above,
the numerical aperture NA of the projection optical system is 0.9
to 1.3 in some cases. When the numerical aperture NA of the
projection optical system is increased as described above, the
image formation performance is sometimes deteriorated by the
polarization effect with the random polarized light beam having
been hitherto used as the exposure light beam. Therefore, it is
desirable to use the polarized illumination. In this case, the
following procedure is preferred. That is, the linear polarized
illumination is effected, which is adjusted to the longitudinal
direction of the line pattern of the line-and-space pattern of the
mask (reticle) so that a large amount of diffracted light of the
S-polarized component (TE-polarized component), i.e., the component
in the polarization direction along the longitudinal direction of
the line pattern is allowed to outgo from the pattern of the mask
(reticle). When the space between the projection optical system PL
and the resist coated on the surface of the substrate P is filled
with the liquid, the diffracted light of the S-polarized component
(TE-polarized component), which contributes to the improvement in
the contrast, has the transmittance through the resist surface that
is raised to be high as compared with a case in which the space
between the projection optical system PL and the resist coated on
the surface of the substrate P is filled with the air (gas).
Therefore, even when the numerical aperture NA of the projection
optical system exceeds 1.0, it is possible to obtain the high image
formation performance. It is more effective to make appropriate
combination, for example, with the phase shift mask and/or the
oblique incidence illumination method (especially the dipole
illumination method) adjusted to the longitudinal direction of the
line pattern as disclosed in Japanese Patent Application Laid-open
No. 6-188169.
[0224] Further, for example, when the ArF excimer laser beam is
used as the exposure light beam, and the substrate P is exposed
with a fine line-and-space pattern (for example, line-and-space of
about 25 to 50 nm) by using the projection optical system PL having
a reduction magnification of about 1/4, then the mask M functions
as a polarizing plate on account of the Wave Guide effect depending
on the structure of the mask M (for example, the pattern fineness
and the chromium thickness), and a large amount of the diffracted
light beam of the S-polarized component (TE-polarized component) is
radiated from the mask M as compared with the diffracted light beam
of the P-polarized component (TM-component) which lowers the
contrast. In such a situation, it is desirable that the linear
polarized illumination is used as described above. However, the
high resolution performance can be obtained even when the numerical
aperture NA of the projection optical system PL is large, for
example, 0.9 to 1.3 even when the mask M is illuminated with the
random polarized light beam. When the substrate P is exposed with
an extremely fine line-and-space pattern on the mask M, there is
also such a possibility that the P-polarized component
(TM-polarized component) may be larger than the S-polarized
component (TE-polarized component) on account of the Wire Grid
effect. However, for example, when the ArF excimer laser beam is
used as the exposure light beam, and the substrate P is exposed
with a line-and-space pattern larger than 25 nm by using the
projection optical system PL having a reduction magnification of
about 1/4, then a large amount of the diffracted light beam of the
S-polarized component (TE-polarized component) is radiated from the
mask M as compared with the P-polarized component (TM-polarized
component). Therefore, the high resolution performance can be
obtained even when the numerical aperture NA of the projection
optical system PL is large, for example, 0.9 to 1.3.
[0225] Further, it is also effective to use a combination of the
oblique incidence illumination method and the polarized
illumination method in which the linear polarization is effected in
a tangential (circumferential) direction of a circle having a
center of the optical axis as disclosed in Japanese Patent
Application Laid-open No. 6-53120 as well as the linear polarized
illumination (S-polarized illumination) adjusted to the
longitudinal direction of the line pattern of the mask (reticle).
In particular, when the pattern of the mask (reticle) includes not
only the line pattern which extends in a predetermined one
direction but the pattern also includes line patterns which extend
in a plurality of directions in a mixed manner, then the high image
formation performance can be obtained even when the numerical
aperture NA of the projection optical system is large, by using, in
combination, the zonal illumination method and the polarized
illumination method in which the linear polarization is effected in
a tangential direction of a circle having a center of the optical
axis as disclosed in Japanese Patent Application Laid-open No.
6-53120 as well.
[0226] In the respective embodiments described above, the optical
element 2 is attached to the end portion of the projection optical
system PL. The lens can be used to adjust the optical
characteristics of the projection optical system PL, including, for
example, the aberration (for example, spherical aberration and
comatic aberration). The optical element, which is attached to the
end portion of the projection optical system PL, may be an optical
plate to be used to adjust the optical characteristic of the
projection optical system PL. Alternatively, the optical element
may be a plane parallel plate through which the exposure light beam
EL is transmissive. When the optical element which makes contact
with the liquid 1 is the plane parallel plate which is cheaper than
the lens, it is enough that the plane parallel plate is merely
exchanged immediately before supplying the liquid 1 even when any
substance (for example, any silicon-based organic matter), which
deteriorates the transmittance of the projection optical system PL,
the illuminance of the exposure light beam EL on the substrate P,
and the uniformity of the illuminance distribution, is adhered to
the plane parallel plate, for example, during the transport, the
assembling, and/or the adjustment of the exposure apparatus EX. An
advantage is obtained such that the exchange cost is lowered as
compared with the case in which the optical element which makes
contact with the liquid 1 is the lens. That is, the surface of the
optical element to make contact with the liquid 1 is dirtied, for
example, due to the adhesion of scattered particles generated from
the resist by being irradiated with the exposure light beam EL or
any impurity contained in the liquid 1. Therefore, it is necessary
to periodically exchange the optical element.
[0227] However, when the optical element is the cheap plane
parallel plate, then the cost of the exchange part is low as
compared with the lens, and it is possible to shorten the time
required for the exchange. Thus, it is possible to suppress the
increase in the maintenance cost (running cost) and the decrease in
the throughput.
[0228] When the pressure, which is generated by the flow of the
liquid 1, is large between the substrate P and the optical element
disposed at the end portion of the projection optical system PL, it
is also allowable that the optical element is tightly fixed so that
the optical element is not moved by the pressure, rather than
allowing the optical element to be exchangeable.
[0229] Each of the embodiments described above is constructed such
that the space between the projection optical system PL and the
surface of the substrate P is filled with the liquid 1. However,
for example, another arrangement may be adopted such that the space
is filled with the liquid 1 in a state in which a cover glass
constructed of a plane parallel plate is attached to the surface of
the substrate P.
[0230] The exposure apparatus, to which the liquid immersion method
is applied as described above, is constructed such that the optical
path space, which is disposed on the light-outgoing side of the
terminal end optical element 2 of the projection optical system PL,
is filled with the liquid (pure water) to expose the substrate P.
However, as disclosed in International Publication No. 2004/019128,
it is also allowable that the optical path space, which is disposed
on the light-entrance side of the terminal end optical element 2 of
the projection optical system PL, is filled with the liquid (pure
water).
[0231] The substrate P, which is usable in the respective
embodiments described above, is not limited to the semiconductor
wafer for producing the semiconductor device. Those applicable
include, for example, the glass substrate for the display device,
the ceramic wafer for the thin film magnetic head, and the master
plate (synthetic quartz, silicon wafer) for the mask or the reticle
to be used for the exposure apparatus.
[0232] As for the exposure apparatus EX, the present invention is
also applicable to the scanning type exposure apparatus (scanning
stepper) based on the step-and-scan system for performing the
scanning exposure for the pattern of the mask M by synchronously
moving the mask M and the substrate P as well as the projection
exposure apparatus (stepper) based on the step-and-repeat system
for performing the full field exposure for the pattern of the mask
M in a state in which the mask M and the substrate P are allowed to
stand still, while successively step-moving the substrate P. The
present invention is also applicable to the exposure apparatus
based on the step-and-stitch system in which at least two patterns
are partially overlaid and transferred on the substrate P.
[0233] The embodiments described above adopt the exposure apparatus
in which the space between the projection optical system PL and the
substrate P is locally filled with the liquid. However, the present
invention is also applicable to a liquid immersion exposure
apparatus in which the entire surface of the substrate as the
exposure objective is covered with the liquid. The structure and
the exposure operation of the liquid immersion exposure apparatus
in which the entire surface of the substrate as the exposure
objective is covered with the liquid are described in detail, for
example, in Japanese Patent Application Laid-open Nos. 6-124873 and
10-303114 and U.S. Pat. No. 5,825,043, the content of which are
incorporated herein by reference within a range of permission of
the domestic laws and ordinances of the state designated or
selected in this international application.
[0234] As for the type of the exposure apparatus EX, the present
invention is not limited to the exposure apparatus for the
semiconductor device production apparatus for exposing the
substrate P with the semiconductor device pattern. The present
invention is also widely applicable, for example, to the exposure
apparatus for producing the liquid crystal display device or for
producing the display as well as the exposure apparatus for
producing, for example, the thin film magnetic head, the image
pickup device (CCD), the reticle, or the mask.
[0235] When the linear motor is used for the substrate stage PST
(wafer stage 609) and/or the mask stage MST, it is allowable to use
any one of those of the air floating type based on the use of the
air bearing and those of the magnetic floating type based on the
use of the Lorentz's force or the reactance force. Each of the
stages PST (609), MST may be either of the type in which the
movement is effected along the guide or of the guideless type in
which no guide is provided. An example of the use of the linear
motor for the stage is disclosed in U.S. Pat. Nos. 5,623,853 and
5,528,118, the content of which are incorporated herein by
reference within a range of permission of the domestic laws and
ordinances of the state designated or selected in this
international application.
[0236] As for the driving mechanism for each of the stages PST
(690), MST, it is also allowable to use a plane motor in which a
magnet unit provided with two-dimensionally arranged magnets and an
armature unit provided with two-dimensionally arranged coils are
opposed to one another, and each of the stages PST (690), MST is
driven by the electromagnetic force. In this arrangement, any one
of the magnet unit and the armature unit is connected to the stage
PST (690), MST, and the other of the magnet unit and the armature
unit is provided on the side of the movable surface of the stage
PST (690), MST.
[0237] The reaction force, which is generated in accordance with
the movement of the substrate stage PST (690), may be mechanically
released to the floor (ground) by using a frame member so that the
reaction force is not transmitted to the projection optical system
PL. The method for handling the reaction force is disclosed in
detail, for example, in U.S. Pat. No. 5,528,118 (Japanese Patent
Application Laid-open No. 8-166475), the content of which are
incorporated herein by reference within a range of permission of
the domestic laws and ordinances of the state designated or
selected in this international application.
[0238] The reaction force, which is generated in accordance with
the movement of the mask stage MST, may be mechanically released to
the floor (ground) by using a frame member so that the reaction
force is not transmitted to the projection optical system PL. The
method for handling the reaction force is disclosed in detail, for
example, in U.S. Pat. No. 5,874,820 (Japanese Patent Application
Laid-open No. 8-330224), the content of which are incorporated
herein by reference within a range of permission of the domestic
laws and ordinances of the state designated or selected in this
international application.
[0239] As described above, the exposure apparatus EX according to
the embodiment of the present invention is produced by assembling
the various subsystems including the respective constitutive
elements as defined in claims so that the predetermined mechanical
accuracy, the electric accuracy, and the optical accuracy are
maintained. In order to secure the various accuracies, those
performed before and after the assembling include the adjustment
for achieving the optical accuracy for the various optical systems,
the adjustment for achieving the mechanical accuracy for the
various mechanical systems, and the adjustment for achieving the
electric accuracy for the various electric systems. The steps of
assembling the various subsystems into the exposure apparatus
include, for example, the mechanical connection, the wiring
connection of the electric circuits, and the piping connection of
the air pressure circuits in correlation with the various
subsystems. It goes without saying that the steps of assembling the
respective individual subsystems are performed before performing
the steps of assembling the various subsystems into the exposure
apparatus. When the steps of assembling the various subsystems into
the exposure apparatus are completed, the overall adjustment is
performed to secure the various accuracies as the entire exposure
apparatus. It is desirable that the exposure apparatus is produced
in a clean room in which, for example, the temperature and the
cleanness are managed.
[0240] As shown in FIG. 17, the microdevice such as the
semiconductor device is produced by performing, for example, a step
201 of designing the function and the performance of the
microdevice, a step 202 of manufacturing a mask (reticle) based on
the designing step, a step 203 of producing a substrate as a base
material for the device, an exposure process step 204 of exposing
the substrate with a pattern of the mask by using the exposure
apparatus EX of the embodiment described above, a step 205 of
assembling the device (including a dicing step, a bonding step, and
a packaging step), and an inspection step 206.
INDUSTRIAL APPLICABILITY
[0241] According to the exposure apparatus of the present
invention, it is possible to perform the exposure process while
suppressing the outflow of the liquid, and it is possible to avoid
the remaining of the liquid. Therefore, the liquid immersion
exposure can be performed at the high exposure accuracy.
[0242] According to the optical part of the present invention, the
particulate layer, which is composed at least one of silicon
dioxide (SiO.sub.2), magnesium fluoride (MgF.sub.2), and calcium
fluoride (CaF.sub.2) for forming the adhesive particulate layer,
has the satisfactory affinity for the glass (main component:
SiO.sub.2) of the base material. An appropriate degree of
adhesiveness is obtained with respect to the base material glass.
The irregularities, which result from the diameters of the
particles, are formed on the surface. Further, for example, silicon
dioxide itself has the high durability against the laser
irradiation, because silicon dioxide or the like is the material
which has the extremely high ultraviolet transmittance. Therefore,
the particulate layer, which is composed of at least one of silicon
dioxide (SiO.sub.2), magnesium fluoride (MgF.sub.2), and calcium
fluoride (CaF.sub.2), is formed as the film, and then the
water-repellent film, which is composed of the amorphous
fluororesin, is formed. The amorphous fluororesin enters voids or
interstices of particulates of silicon dioxide or the like, and the
amorphous fluororesin is subjected to drying and solidification
while effecting embrace and inclusion. The mechanical strength of
the amorphous fluororesin itself is high. Therefore, the
water-repellent film, which is allowed to make tight contact with
the base material, has the high strength. Therefore, the optical
part is applicable to optical sensors and optical instruments to be
used in a variety of environments in which the optical part makes
contact with the liquid.
[0243] According to the optical part of the present invention, the
adhesive surface, which is constructed of the etching surface
obtained by performing the etching, for example, with hydrogen
fluoride, is provided at the light irradiated surface. Therefore,
when the water-repellent film, which is composed of the amorphous
fluororesin, is formed on the adhesive surface, then the amorphous
fluororesin enters voids or interstices of the adhesive surface,
and the amorphous fluororesin is subjected to drying and
solidification while effecting embrace and inclusion. The
mechanical strength of the amorphous fluororesin itself is high.
Therefore, the water-repellent film, which is allowed to make tight
contact with the base material, has the high strength. Therefore,
the optical part is applicable to optical sensors and optical
instruments to be used in a variety of environments in which the
optical part makes contact with the liquid.
[0244] According to the projection exposure apparatus of the
present invention, the optical part, which makes it possible to
maintain the water repellence of the light irradiated surface for a
long period of time, is provided on the substrate stage. Therefore,
even when the liquid immersion exposure is repeatedly performed, it
is possible to reliably discharge water from the light irradiated
surface of the optical part.
* * * * *