EP0834773A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Focusing and tilting adjustment system for lithography aligner, manufacturing apparatus or inspection apparatus
Assignee: Nikon Corp
•
Filing: 1997-10-06
•
Granted: —
•
Expires: 2017-10-06
Abstract
Abstract Improvements in a focusing apparatus having an objective optical system for optically manufacturing a workpiece, forming a desired pattern on a surface of a workpiece or inspecting a pattern on a workpiece and used to adjust the state of focusing between the surface of the workpiece and the objective optical system. The focusing apparatus has a first detection system having a detection area at a first position located outside the field of the objective optical system, a second detection system having a detection area at a second position located outside the field of the objective optical system and spaced apart from the first position, and a third detection system having a detection area at a third position located outside the field of the objective optical system and spaced apart from each of the first and second positions. A calculator calculates a deviation between a first focus position and a target focus position and temporarily stores a second focus position at the time of detection made by the first detection system. A controller controls focusing on the surface of the workpiece on the basis of the calculated deviation, the stored second focus position and a third focus position when the area on the workpiece corresponding to the detection area of the first detection system is positioned in the field of the objective optical system by relative movement of the workpiece and the objective optical system.
Inventors
- 👤 Kyoichi Suwa
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-31 22:44
CPC Classifications
G; G03; G03F; G03F7/00; G03F7/70; G03F7/70483; G03F7/70605; G03F7/70616; G03F7/70641; G03F7/70216; G03F7/70275; G03F7/70341; G03F7/70358; G03F7/70691; G03F7/70716; G03F7/708; G03F7/70808; G03F7/70858; G03F7/70866; G03F7/70875; G03F7/70883; G03F7/70891; G03F9/00; G03F9/70; G03F9/7003; G03F9/7023; G03F9/7026; G03F9/7034; G03F9/7088
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
355 words
A scanning exposure apparatus comprising: (a) an imaging system for projecting an image
of a pattern of a mask onto a substrate at an
Imaging field; (b) a scanning mechanism for moving the mask
and the substrate in a scanning direction relative
to said imaging system; (c) an adjusting system for adjusting a focus
of the projected image on the substrate; (d) a first detection system having a
detection area at a first position located outside
the imaging field of said imaging system and
spaced apart from the imaging field in the
scanning direction, said first detection system
detecting the position of a principal surface of
the substrate in a Z-direction; (e) a second detection system having a
detection area at a second position located
outside the imaging field of said imaging system
and spaced apart from said first position in a
direction intersecting the scanning direction,
said second detection system detecting the
position of the principal surface of the substrate
in the Z-direction; (f) a third detection system having a
detection area at a third position located outside
the imaging field of said imaging system, spaced
apart from the imaging field in a direction
intersecting the scanning direction and also
spaced apart from said second position in the
scanning direction, said third detection system
detecting the position of the principal surface of
the substrate in the Z-direction; (g) a calculator coupled to said first and
second detection systems and calculating a
deviation between the first Z-position detected by
said first detection system and a target Z-position
and storing the second Z-position
detected by said second detection system at the
time of detection by said first detection system;
and (h) a controller coupled to said adjusting
system and to said calculator and to said third
detection system and controlling said adjusting
system on the basis of the calculated deviation,
the stored second Z-position and the third Z-position
detected by said third detection system
when the area on the substrate corresponding to
the detection area of said first detection system
is positioned in the imaging field of said imaging
system by movement of said scanning mechanism.
Claim 2
Dependent Claim
53 words
An exposure apparatus according to Claim 1,
wherein said scanning mechanism includes a mask stage
for holding the mask, a substrate stage for holding the
substrate, and a synchronizing drive system for moving
said mask stage and said substrate stage at a speed
ratio corresponding to a projection magnification of
said imaging system.
Claim 3
Dependent Claim
52 words
An exposure apparatus according to Claim 2,
wherein said substrate stage includes an attraction
portion for attracting a reverse surface of the
substrate, and an auxiliary plate portion surrounding
the substrate at a height approximately equal to the
principal surface of the substrate when the substrate
is supported on said attraction portion.
Claim 4
Dependent Claim
66 words
An exposure apparatus according to Claim 3,
wherein said second detection system and said third
detection system are arranged to detect the position of
a surface of said auxiliary plate portion in the Z-direction
by at least one of the detection areas when a
shot area of the substrate to be exposed by the pattern
of the mask is at a peripheral portion of the
substrate.
Claim 5
Dependent Claim
52 words
An exposure apparatus according to Claim 4,
wherein each of said first, second and third detection
systems generates a Z-direction positional error value
of one of the principal surface of the substrate and
the auxiliary plate portion relative to predetermined
reference Z-positions with respect to said first,
second and third detection systems.
Claim 6
Dependent Claim
38 words
An exposure apparatus according to Claim 5,
wherein, if the predetermined reference Z-positions
with respect to said first, second and third detection
systems differ from each other, the differences between
the reference Z-positions are detected by a
calibration.
Claim 7
Dependent Claim
79 words
An exposure apparatus according to Claim 4,
wherein, if the scanning direction of the substrate is
a Y-direction and if a direction perpendicular to each
of the Y-direction and the Z-direction is an X-direction,
said first detection system includes a first
focus detector of a multi-point type having a plurality
of detection areas in a row along the X-direction on
the substrate over a range of a size of the imaging
field of said imaging system in the X-direction.
Claim 8
Dependent Claim
73 words
An exposure apparatus according to Claim 7,
wherein said second detection system includes a
plurality of second focus detectors having detection
areas on opposite sides of the row of the plurality of
detection areas of said multi-point focus detector in
the X-direction, each of said second focus detectors
separately detecting the Z-direction position of the
principal surface of one of the substrate and the
auxiliary plate portion at each of the detection areas.
Claim 9
Dependent Claim
65 words
An exposure apparatus according to Claim 8,
wherein said third detection system includes a
plurality of third focus detectors on the opposite
sides of the imaging field of said imaging system in
the X-direction, each of said third focus detectors
separately detecting the Z-direction position of the
principal surface of one of the substrate and the
auxiliary plate portion at each of the detection areas.
Claim 10
Dependent Claim
358 words
A projection exposure apparatus comprising: (a) an imaging system for projecting an image
of a mask pattern onto a substrate at a projection
field; (b) a movable stage mechanism for moving in
intersecting X and Y directions to position the
substrate with respect to the image of the
projected mask pattern; (c) an adjusting mechanism for adjusting a
focus of the projected mask pattern image on the
substrate; d) a first detection system having a
detection area at a first position located outside
the projection field of said imaging system and
spaced apart from the projection field in the Y
direction, said first detection system detecting
the position of a principal surface of the
substrate in a Z direction; (e) a second detection system having a
detection area at a second position located
outside the projection field of said imaging
system and spaced apart from said first position
in the X direction, said second detection system
detecting the position of the principal surface of
the substrate in the Z direction; (f) a third detection system having a
detection area at a third position located outside
the projection field of said imaging system,
spaced apart from the projection field in the X
direction and also spaced apart from said second
position in the Y direction, said third detection
system detecting the position of the principal
surface of the substrate in the Z direction; (g) a calculator coupled to said first and
second detection systems, and calculating a
deviation between the first Z-position detected by
said first detection system and a target Z-position
and for storing the second Z-position
detected by said second detection system at the
time of detection made by said first detection
system; and (h) a controller coupled to said adjusting
mechanism and said calculator and said third
detection system, and controlling said adjusting
mechanism on the basis of the calculated
deviation, the stored second Z-position and the
third Z-position detected by said third detection
system when the area on the substrate
corresponding to the detection area of said first
detection system is positioned in the projection
field of said imaging system by said movable stage
mechanism.
Claim 11
Dependent Claim
74 words
An exposure apparatus according to Claim 10,
wherein said first detection system includes a
plurality of first focus detectors having a plurality
of detection areas in a row along the X direction in a
range according to a size of the projection field of
said imaging system in the X direction, each of said
first focus detectors separately detecting the Z-position
of the principal surface of the substrate at
each of the detection areas.
Claim 12
Dependent Claim
63 words
An exposure apparatus according to Claim 11,
wherein said second detection system includes two
second focus detectors having two detection areas
placed on opposite sides of the row of the plurality of
detection areas of said first detection system, each of
said second focus detectors separately detecting the Z-position
of the principal surface of the substrate at
each of the two detection areas.
Claim 13
Dependent Claim
57 words
An exposure apparatus according to Claim 12,
wherein said third detection system includes two third
focus detectors placed on opposite sides of the
projection field of said imaging system in the X
direction, each of said third focus detectors
separately detecting the Z-position of the principal
surface of the substrate at each of the two detection
areas.
Claim 14
Dependent Claim
78 words
An exposure apparatus according to Claim 13,
wherein said movable stage mechanism includes a mount
portion for attracting a reverse surface of the
substrate and an auxiliary plate portion which
surrounds the substrate at a height substantially equal
to the principal surface of the substrate when the
substrate is supported on said mount portion, a surface
of said auxiliary plate being detected by one of said
two second focus detectors and one of said two third
focus detectors.
Claim 15
Dependent Claim
260 words
A scanning exposure method in which a pattern
of a mask is transferred onto a sensitive substrate by
projecting a part of the mask pattern on the sensitive
substrate through a projection system and by moving the
mask and the sensitive substrate relative to a
projection field of the projection system, the method
comprising the steps of: (a) mounting the sensitive substrate on a
holder having an auxiliary plate portion
surrounding the sensitive substrate at a height
substantially equal to a height of a principal
surface of the sensitive substrate; (b) reading a focus error of an exposure area
of the sensitive substrate on which area a part of
the mask pattern is to be projected, the focus
error of the exposure area being read before the
exposure area reaches the projection field of the
projection system during scanning movement of the
holder and the sensitive substrate; (c) detecting a focus error of the principal
surface of a part of one of the sensitive
substrate and the auxiliary plate portion by an
exposure position focus detection system disposed
apart from the projection field of the projection
system in a direction perpendicular to the
direction of said scanning movement when the
exposure area on the sensitive substrate reaches
the projection field; and (d) adjusting the focus between the
projection system and the sensitive substrate on
the basis of the focus errors detected by said
steps (b) and (c) so that the focus error of the
exposure area on the sensitive substrate is
corrected in the projection field of the
projection system.
Claim 16
Dependent Claim
32 words
A method according to Claim 15, applied to a
projection aligner having a projection system having an
effective working distance to the principal surface of
the substrate of 20 mm or less.
Claim 17
Dependent Claim
45 words
A method according to Claim 15, applied to an
immersion projection exposure apparatus in which a
space containing a projection optical path between the
sensitive substrate and a transparent optical element
disposed at an image plane side of the projection
optical system is liquid filled.
Claim 18
Dependent Claim
41 words
A method according to Claim 17, wherein the
projection optical system has a working distance such
that the thickness of the liquid between the sensitive
substrate and the transparent optical element of said
projection optical system is 2 mm or less.
Claim 19
Dependent Claim
41 words
A method according to Claim 15, applied to a
scanning exposure apparatus having a catadioptric
projection system having a refractive optical material
and a reflecting optical material, and in which a
transparent optical element is disposed at an image
plane side.
Claim 20
Dependent Claim
35 words
A method according to Claim 19, wherein the
transparent optical element disposed at the image plane
side is a prism mirror having an emergent surface
substantially parallel to the principal surface of the
sensitive substrate.
Claim 21
Dependent Claim
308 words
A focusing apparatus provided in an apparatus
having an objective optical system to control focusing
between a surface of a workpiece and the objective
optical system, said focusing apparatus comprising: (a) a first detection system having a
detection area at a first position located outside
a field of said objective optical system, said
first detection system detecting a position of the
surface of the workpiece in the focusing
direction; (b) a second detection system having a
detection area at a second position located
outside the field of said objective optical system
and spaced apart from said first position, said
second detection system detecting the position of
the surface of the workpiece in the focusing
direction; (c) a third detection system having a
detection area at a third position located outside
the field of said objective optical system and
spaced apart from each of said first and second
positions, said third detection system detecting
the position of the surface of the workpiece in
the focusing direction; (d) a calculator coupled to said first and
second detection systems, and calculating a
deviation between the first focus position
detected by said first detection system and a
target focus position and for storing the second
focus position detected by said second detection
system at the time of detection made by said first
detection system; and (e) a controller coupled to said calculator
and to said third detection system, and
controlling focusing of the objective optical
system on the surface of the workpiece on the
basis of the calculated deviation, the stored
second focus position and the third focus position
detected by said third detection system when the
area on the workpiece corresponding to the
detection area of said first detection system is
positioned in the field of said objective optical
system by relative movement of the workpiece and
the objective optical system.
Claim 22
Independent Claim
221 words
A method of controlling focusing of an
objective optical system onto a surface of a workpiece
when the workpiece and a field of the objective optical
system are moved relative to each other in X and Y
directions, said method comprising the steps of: (a) mounting the workpiece on a holder having
an auxiliary plate portion surrounding the
workpiece at a height substantially equal to a
height of the surface of the workpiece; (b) reading a focus error of a predetermined
local portion of the surface of the workpiece
before the local portion of the workpiece reaches
the field of the objective optical system during
movement of said holder and the workpiece in a
predetermined moving direction; (c) detecting a focus error of the surface of
a part of one of the workpiece and the auxiliary
plate portion by a first focus detection system
disposed apart from the field of the objective
optical system in a direction perpendicular to the
moving direction when the local portion of the
workpiece reaches the field; and (d) controlling the focusing between the
objective optical system and the workpiece on the
basis of the focus errors detected by said steps
(b) and (c) so that the focus error of the local
portion of the workpiece is corrected in the field
of the objective optical system.
Claim 23
Dependent Claim
61 words
A method according to Claim 22, applied to at
least one of a manufacturing instrument, a lithography
exposure apparatus, a writing apparatus and an
inspection apparatus having a small effective working
distance such that a detecting beam of an oblique
incident light type focus detector cannot be obliquely
led to the surface of the workpiece immediately below
the objective optical system.
Claim 24
Dependent Claim
120 words
A projection exposure apparatus for
projecting a mask pattern image onto a sensitive
substrate through an optical imaging system and a
liquid in a space between the substrate and the imaging
system, said apparatus comprising: an assembly holding a plurality of optical
elements of said imaging system, wherein at least
an end portion of said assembly is immersed in
said liquid; and a distal optical element mounted at the end
portion of said assembly and having a distal
surface which confronts the substrate and contacts
said liquid; wherein the distal surface of said distal
optical element and a surface of the end portion
of said assembly are substantially flush to each
other, thereby suppressing disturbance of flowing
of said liquid.
Claim 25
Independent Claim
144 words
A method for fabricating a feature on a
semiconductor wafer, employing a projection system,
comprising the steps of: (a) mounting the semiconductor wafer on a
holder having a wall portion vertically provided
at a peripheral portion to form a liquid layer on
the wafer for achieving an immersed condition
between a surface of the wafer and said projection
system; (b) scanning said holder along an image plane
of said projection system to perform a scan-exposure
by projecting a feature pattern image
onto the wafer through said projection system and
said liquid layer; and (c) correcting, during said scanning step, at
least one of focus and tilt error between the
surface of the wafer and the image plane of said
projection system by using a focus detecting
system which has a plurality of focus detection
points disposed outside an image field of said
projection system.
Claim 26
Dependent Claim
16 words
The method of Claim 25, wherein the
projection system has a resolution less than 0.5
micrometers
Claim 27
Dependent Claim
267 words
A scanning exposure method to transfer a pattern of a mask onto a substrate through a
imaging system, the method comprising the steps of: providing a first detection system having a first detection area located outside a imaging
field of the imaging system and spaced apart from the imaging field in a scanning
direction, said first detection system detecting the position of a surface of the substrate in a
optical axis direction of the imaging system; providing a second detection system having a second detection area located outside a
imaging field of the imaging system and spaced apart from the first detection area in a
direction intersecting the scanning direction, said second detection system detecting the
position of the surface of the substrate in the optical axis direction; providing a third detection system having a third detection area located outside a
imaging field of the imaging system and spaced apart from the imaging field in a direction
intersecting the scanning direction and also spaced apart from the second detection area in
the scanning direction. said third detection system detecting a deviation between the
position of the surface of the substrate and a target position in the optical axis direction; determining the target position of the third detection system based on the result of
detection of the first and second detection system during an exposure of the substrate ; and adjusting a positional relationship between the surface of the substrate and a imaging
plane of the imaging system based on the result of detection of the first, second and third
detection system during the exposure of the substrate.
References Cited (Backward Citations)
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