WO2006025408A1

WO2006025408A1 - Exposure apparatus and device manufacturing method

Info

Publication number: WO2006025408A1
Application number: PCT/JP2005/015800
Authority: WO
Inventors: Yusaku Uehara
Original assignee: Nikon Corporation
Priority date: 2004-08-31
Filing date: 2005-08-30
Publication date: 2006-03-09
Also published as: TW200619865A; JPWO2006025408A1; TWI315452B; JP5266641B2

Abstract

An exposure apparatus or the like which efficiently corrects a rotation asymmetrical aberration component generated in a projection optical system. The exposure apparatus is provided with adjusting mechanisms (40, etc.) for adjusting dynamic rotation asymmetrical optical characteristics of the projection optical system (PL) and adjusting mechanisms (22, etc.) for adjusting static rotation asymmetrical optical characteristics of the projection optical system (PL). A main control system (20) changes an adjusting quantity of the adjusting mechanisms (40, etc.) which adjust the optical characteristics of the projection optical system (PL) in accordance with the cross section shape and sizes of exposure light (IL) on a plane coupled to an image plane of the projection optical system (PL).

Description

Specification

Exposure apparatus and device manufacturing method

Technical field

The present invention relates to an exposure apparatus that transfers a mask pattern onto a substrate via a projection optical system, and a device manufacturing method for manufacturing a device using the exposure apparatus.

This application claims priority based on Japanese Patent Application No. 2004-251877 filed on August 31, 2004, the contents of which are incorporated herein by reference.

Background art

[0002] When manufacturing devices such as semiconductor elements, liquid crystal display elements, imaging devices (CCD (Charge Coupled Device), etc.), thin film magnetic heads, etc., a reticle pattern as a mask is coated with a photoresist as a substrate. A projection exposure apparatus such as a stepper is used to transfer to each shot area on the wafer (or glass plate or the like). In the projection exposure apparatus, the imaging characteristics of the projection optical system change depending on the exposure light irradiation amount and the ambient pressure change. For this reason, in order to maintain the imaging characteristics in a desired state, the projection exposure apparatus controls the position or posture (tilt) of some optical members constituting the projection optical system, for example. An imaging characteristic correction mechanism for correcting the imaging characteristics is provided. The imaging characteristics that can be corrected by the conventional imaging characteristics correction mechanism are low-order and low-order components such as distortion and magnification.

[0003] By the way, in recent exposure apparatuses, in order to increase the resolution for a specific pattern, so-called annular illumination, quadrupole illumination (2 regions on the pupil plane of the illumination optical system are divided into 2 regions). There are many occasions where illumination conditions are used in which the exposure light does not pass through a region including the optical axis on the pupil plane of the illumination optical system, such as an illumination method as a next light source. When using powerful illumination conditions, the exposure light is illuminated with the optical member near the pupil plane in the projection optical system being substantially hollow. In addition, in order to increase the area of a pattern that can be transferred without increasing the size of the projection optical system, a scanning exposure type projection exposure apparatus such as a scanning stepper has recently been widely used. In the case of the scanning exposure type, the reticle is illuminated in a rectangular illumination area whose scanning direction is the short side direction, for example, so that the reticle is optically close to the reticle and wafer in the projection optical system. In the member, a non-rotationally symmetric region is mainly illuminated by the exposure light.

In such an exposure apparatus, there is a possibility that fluctuations in higher-order components such as higher-order spherical aberration and non-rotationally symmetric aberrations in the imaging characteristics of the projection optical system may occur. A projection exposure apparatus that suppresses aberration fluctuations has been proposed in Patent Document 1 and Patent Document 2 below.

Patent Document 1: Japanese Patent Laid-Open No. 10-64790

Patent Document 2: Japanese Patent Laid-Open No. 10-50585

Disclosure of the invention

Problems to be solved by the invention

Recently, for example, when transferring a reticle pattern mainly including a predetermined line 'and' space pattern, only two regions sandwiching the optical axis on the pupil plane of the illumination optical system are used. Dipole illumination (bipolar illumination) may be used as a secondary light source. Since this dipole illumination has a large light amount distribution and non-rotation symmetry compared to quadrupole illumination, astigmatism on the optical axis, which is a non-rotationally symmetric aberration component in the projected image (hereinafter referred to as “center-astigma”). "Taism") occurs. Dipole illumination also causes non-rotationally symmetric aberration fluctuations other than center astigmatism.

[0006] Furthermore, in recent years, devices with different shapes and sizes have been often produced with a single exposure apparatus, and the size and shape of the illumination area on the reticle have been significantly changed. Opportunities for performing exposure processing are increasing, and depending on the size and shape of the illumination area on the reticle, a situation may occur in which the optical characteristics of the projection optical system exceed a predetermined allowable range.

[0007] The present invention has been made in view of the above circumstances, and an object thereof is to provide an exposure apparatus that can maintain the optical characteristics of a projection optical system in a desired state, and a device manufacturing method using the exposure apparatus. To do. In particular, it is an object of the present invention to provide an exposure apparatus capable of efficiently correcting non-rotationally symmetric aberration components generated in a projection optical system, and a device manufacturing method for manufacturing a device using the exposure apparatus.

Means for solving the problem

[0008] The present invention employs the following configurations associated with the respective drawings shown in the embodiments.伹 The parenthesized symbols attached to each element are merely examples of the element and do not limit each element.

In order to solve the above problems, an exposure apparatus of the present invention includes an illumination optical system (ILS) that irradiates illumination light (IL) onto a mask (R), and an image of the mask pattern on a substrate (W). In an exposure apparatus comprising a projection optical system (PL) for projection, an adjustment device (14, 22, 40) for adjusting the optical characteristics of the projection optical system and a conjugate plane of the image plane of the projection optical system A setting device (9) for setting at least one of the cross-sectional shape and size of the illumination light, and the projection by the adjusting device according to the cross-sectional shape and size of the illumination light set by the setting device And a control device (20) for controlling the adjustment of the optical characteristics of the optical system.

According to the present invention, the optical characteristics of the projection optical system are adjusted according to the cross-sectional shape and size of the illumination light in the conjugate plane with the image plane of the projection optical system.

In order to solve the above problems, the exposure apparatus of the present invention includes an illumination optical system (ILS) that irradiates the mask (R) with illumination light (IL), and an image of the mask pattern on the substrate (W). A first optical adjustment mechanism (22) for adjusting non-rotationally symmetric static optical characteristics in the projection optical system, and a non-rotation in the projection optical system. And a second adjustment mechanism (40) for adjusting symmetric dynamic optical characteristics.

According to the present invention, the first adjustment mechanism adjusts the non-rotationally symmetric static optical characteristic in the projection optical system, and the second adjustment mechanism adjusts the non-rotationally symmetric dynamic optical characteristic in the projection optical system. Is done.

The device manufacturing method of the present invention is characterized by including a step (S46) of transferring a device pattern onto the object (W) using the above exposure apparatus.

The invention's effect

According to the present invention, the optical characteristics of the projection optical system can be maintained in a desired state. Further, by using an exposure apparatus that can maintain the optical characteristics of the projection optical system in a desired state, it is possible to manufacture a device with a high yield.

Brief Description of Drawings FIG. 1 is a view showing the schematic arrangement of an exposure apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating an example of an imaging characteristic correction mechanism.

FIG. 3A is a cross-sectional view showing a configuration example of an adjustment mechanism.

FIG. 3B is a top view showing a configuration example of an adjustment mechanism.

FIG. 4 is a diagram showing another configuration example of the temperature regulator.

FIG. 5 is a diagram showing a configuration example of a temperature regulator using a heat transport mechanism.

FIG. 6A is a front view with a section of a part of the projection optical system.

FIG. 6B is a front view showing a cross section of a part of the projection optical system.

FIG. 7A is a diagram for explaining a lens shape change that occurs when dipole illumination is performed.

FIG. 7B is a diagram for explaining a lens shape change that occurs when dipole illumination is performed.

FIG. 7C is a diagram for explaining the lens shape change that occurs when dipole illumination is performed.

FIG. 7D is a diagram for explaining a lens shape change that occurs when dipole illumination is performed.

FIG. 8A is a diagram for explaining a change in the shape of a lens that occurs when dipole illumination is performed.

FIG. 8B is a diagram for explaining the lens shape change that occurs when dipole illumination is performed.

FIG. 9 is a diagram showing center astigmatism caused by dipole illumination.

FIG. 10A is a diagram for explaining an example of a method for correcting non-rotationally symmetric aberration of a projection optical system using a non-exposure light irradiation mechanism.

FIG. 10B is a diagram for explaining an example of a method for correcting non-rotationally symmetric aberration of the projection optical system using the non-exposure light irradiation mechanism.

FIG. 11 is a block diagram showing an internal configuration of the main control system and an apparatus for exchanging various signals with the main control system.

FIG. 12 is a diagram showing a typical transfer function with respect to the focus fluctuation amount. FIG. 13 is a diagram for explaining an example of a table stored in a memory.

FIG. 14 is a flowchart showing a part of a manufacturing process for manufacturing a semiconductor element as a micro device.

FIG. 15 is a diagram showing an example of a detailed flow of step S 13 in FIG.

Explanation of symbols

[0011] 9 Field stop 14 Imaging characteristic correction mechanism 20 Main control system 22 Adjustment mechanism 37 Memory 40 Non-exposure light irradiation mechanism IL Exposure light (illumination light) ILS illumination optical system PL Projection optical system R Reticle (mask) W Wafer ( Substrate, object)

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[Exposure apparatus]

FIG. 1 is a view showing the schematic arrangement of an exposure apparatus according to an embodiment of the present invention. The exposure apparatus shown in FIG. 1 sequentially moves the pattern formed on the reticle R onto the wafer W while moving the reticle R as a mask and the wafer W as a substrate relative to the projection optical system PL. This is a scanning exposure type exposure apparatus of the next “and” scanning method for transferring.

In the following description, if necessary, an XYZ orthogonal coordinate system is set in the drawing, and the positional relationship of each member will be described with reference to this XYZ orthogonal coordinate system. The XYZ Cartesian coordinate system shown in Fig. 1 is set so that the X-axis and Y-axis are almost parallel to the wafer W surface, and the Z-axis is set in a direction almost perpendicular to the wafer W surface. Yes. In the XYZ coordinate system in the figure, the XY plane is actually set parallel to the horizontal plane, and the Z axis is set vertically. In this embodiment, the direction in which the reticle R and the wafer W are moved synchronously (scanning direction) is set to the Y direction.

The exposure apparatus shown in FIG. 1 includes an exposure light source 1, an illumination optical system ILS, a reticle stage RST, a projection optical system PL, a wafer stage WST, and a main control system 20. The exposure light source 1 is, for example, a KrF excimer laser light source (wavelength 247 nm). As the exposure light source 1, ArF excimer laser light source (wavelength 193 nm), F laser light source (wavelength 157 nm), Kr laser light source (

twenty two

UV laser light source such as Ar laser light source (wavelength 126nm), YAG laser

2

Harmonic generator, solid-state laser (semiconductor laser, etc.) harmonic generator, or mercury run (I-line etc.) can also be used.

[0016] The exposure light IL pulsed from the exposure light source 1 at the time of exposure is shaped into a predetermined shape through a beam shaping optical system (not shown) and the like as an optical integrator (a homogenizer or a homogenizer). The light is incident on the first fly-eye lens 2 and the illuminance distribution is made uniform. The exposure light IL emitted from the first fly-eye lens 2 is incident on the second fly-eye 4 as an optical integrator through a relay lens (not shown) and the vibrating mirror 3, and the illuminance distribution is further uniformized. . The vibrating mirror 3 is used for reducing speckles of the exposure light IL that is laser light and reducing interference fringes by a fly-eye lens. Instead of the fly-eye lenses 2 and 4, a diffractive optical element (DOE: Dilfractive Optical Element) or an internal reflection type integrator (rod lens or the like) can be used.

[0017] On the focal plane on the exit side of the second fly-eye lens 4 (the pupil plane of the illumination optical system ILS), the exposure light intensity distribution (secondary light source) has a small circle (small σ illumination), a normal circle, Illumination system aperture stop member 5 for determining illumination conditions by setting to any one of multiple eccentric regions (dipole and quadrupole illumination) and ring-shaped zones, etc., is rotatably arranged by drive motor 5c Has been. The main control system 20 composed of a computer that controls the overall operation of the apparatus controls the rotation angle of the illumination system aperture stop member 5 via the drive motor 5c to set the illumination conditions. In the state shown in FIG. 1, of the plurality of aperture stops (σ stops) of the illumination system aperture stop member 5, the first dipole illumination (two-pole illumination) in which two circular apertures are formed symmetrically about the optical axis. ), And a second dipole illumination aperture stop 5b obtained by rotating the aperture stop 5a by 90 °. On the focal plane on the exit side of the second fly's eye lens 4, an aperture stop 5a for the first dipole illumination is installed. In this example, the light distribution on the pupil plane of the illumination optical system ILS is adjusted using the illumination system aperture stop member 5, but as disclosed in US Pat. No. 6,563,567. The light amount distribution on the pupil plane of the illumination optical system ILS may be adjusted using another optical member.

The exposure light IL that has passed through the aperture stop 5a in the illumination system aperture stop member 5 is incident on the beam splitter 6 having a low reflectance. The exposure light reflected by the beam splitter 6 is received by the integrator sensor 7 via a condenser lens (not shown). The detection signal of the integrator sensor 7 is supplied to the main control system 20. Based on this detection signal, the main control system 20 The output of the light source 1 is controlled, and the pulse energy of the exposure light IL is controlled step by step using a dimming mechanism (not shown) as necessary.

The exposure light IL that has passed through the beam splitter 6 is incident on the aperture of the field stop 9 via a relay lens (not shown). The field stop 9 is actually composed of a fixed field stop (fixed blind) and a movable field stop (movable blind) force. The latter movable field stop is arranged on a plane almost conjugate with the pattern surface (reticle surface) of the reticle R, and the former fixed field stop is arranged on a plane defocused slightly with a conjugate surface force with the reticle plane. Has been. The fixed field stop is used to define the shape of the illumination area on the reticle R. Here, the case where the fixed field stop is defocused slightly with respect to the reticle surface will be described as an example, but it may be arranged on the conjugate surface. The movable field stop moves in synchronization with reticle R (or wafer W) so that unnecessary portions are not exposed at the start and end of scanning exposure to each shot area to be exposed. Used to block the lighting area. Although the fixed field stop does not move in synchronization with the reticle R (or wafer W), it is also used to define the center and width of the illumination area in the scanning direction and non-scanning direction as required. The main control system 20 controls the operations of the fixed field stop and the movable field stop.

[0020] The exposure light IL that has passed through the aperture of the field stop 9 passes through a condenser lens (not shown), a mirror 10 for bending the optical path, and a condenser lens 11, so that the illumination area of the reticle surface of the reticle R is made uniform. Illuminate with illumination distribution. The normal shape of the aperture of the field stop 9 (fixed field stop) is a rectangle with an aspect ratio of about 1: 3 to 1: 4. Therefore, the normal shape of the illumination area on the reticle R that is almost conjugate with the aperture of the field stop 9 is also rectangular. The main control system 20 changes the shape of the aperture of the field stop 9 so that the distribution of the exposure light IL irradiated onto the reticle R, that is, the cross-sectional shape and size of the exposure light IL (the image plane of the projection optical system). The cross-sectional shape and size of the illumination light at the conjugate plane changes. In addition, if the reticle R on the reticle stage RST is replaced, the distribution (density) of apertures and patterns defined by the light shielding area around the reticle R (area formed to shield unnecessary light) is increased. Even when it changes, the shape and size of the illumination light on the conjugate plane with the image plane of the projection optical system change.

[0021] Under the exposure light IL, the pattern in the illumination area of the reticle R is coated with a photoresist with a projection magnification of | 8 (j8 is 1Z4, 1Z5, etc.) via the telecentric projection optical system PL. Is projected onto an exposure area on one shot area on the wafer w. The exposure area is a rectangular area conjugate with the illumination area on the reticle R with respect to the projection optical system PL. The wafer W is a disk-shaped substrate having a diameter of about 200 to 300 mm, such as a semiconductor (silicon etc.) or SOI (silicon on insulator).

[0022] A part of the exposure light IL is reflected by the wafer W, and the reflected light passes through the projection optical system PL, the reticle R, the condenser lens 11, the mirror 10, and the field stop 9 in this order and returns to the beam splitter 6 to return to the beam splitter. The light further reflected by 6 is received by a reflection amount sensor (reflectance monitor) 8 through a condenser lens (not shown). The detection signal of the reflection amount sensor 8 is supplied to the main control system 20. In addition, environmental sensors 12 for measuring atmospheric pressure and temperature are arranged outside the projection optical system PL (for example, a total of four locations on the ± X side and the Y side of the projection optical system PL). Measurement data measured by the environmental sensor 12 is also supplied to the main control system 20.

An illumination optical system ILS is composed of the exposure light source 1, fly-eye lenses 2 and 4, mirrors 3 and 10, illumination system aperture stop member 5, field stop 9, condenser lens 11, and the like. The illumination optical system IL S is further covered with a sub-chamber (not shown) as an airtight chamber. In order to maintain a high transmittance in the optical path space for the exposure light IL, dry air from which impurities are highly removed (in the case where the exposure light is an ArF excimer laser) is placed in the subchamber and in the lens barrel of the projection optical system PL. Nitrogen gas, helium gas, etc. are also used.

In addition, the projection optical system PL of the present embodiment is a refractive system, and the plurality of optical members constituting the projection optical system PL are quartz that is rotationally symmetric about the optical axis AX (exposure light is ArF excimer). In the case of ZA, it includes a plurality of lenses made of fluorite, etc., and a flat aberration correction plate made of quartz. An aperture stop 13 is disposed on the pupil plane PP of the projection optical system PL (a plane conjugate with the pupil plane of the illumination optical system ILS), and lenses L1 and L2 are disposed near the pupil plane PP.

In the lens L1, in order to adjust dynamic optical characteristics (particularly non-rotationally symmetric aberration) of the projection optical system PL, illumination light having a wavelength region different from that of the exposure light IL is applied. It is irradiated by. The lens L2 is subjected to a predetermined adjustment by the adjusting mechanism 22 in order to adjust the static optical characteristics (particularly non-rotationally symmetric aberration) of the projection optical system PL. Adjustment of the optical characteristics of the projection optical system PL by the adjustment mechanism 22 and the non-exposure light irradiation mechanism 40 is controlled by the main control system 20. To do. Details of the adjustment mechanism 22 and the non-exposure light irradiation mechanism 40 will be described later. The main control system 20 controls the operation of the imaging characteristic correction mechanism 14 for adjusting the optical characteristics (particularly rotationally symmetric aberration) of the projection optical system PL via the control unit 15. The static optical characteristics of the projection optical system PL are the optical characteristics when the projection optical system PL is in the initial state, that is, when the projection optical system PL is not affected by the irradiation of the exposure light IL. The dynamic optical characteristics of the system PL are optical characteristics that change when the projection optical system PL is irradiated with the exposure light IL.

[0026] Reticle R is attracted and held on reticle stage RST. Reticle stage RST moves at a constant speed in the Y direction on a reticle base (not shown), and X direction, Y direction, The reticle R is scanned by slightly moving in the rotation direction. The position and rotation angle of reticle stage RST in the X and Y directions are measured by a movable mirror (not shown) and a laser interferometer (not shown) provided on reticle stage RST. It is supplied to the control system 20.

[0027] On the upper side surface of the projection optical system PL, a slit image is projected obliquely onto the pattern surface (reticle surface) of the reticle R, the reflected light of the reticle surface force is received, and the slit image is re-imaged. An oblique-incidence focus sensor (hereinafter referred to as “reticle-side AF sensor”) 16 that detects the displacement of the reticle surface in the Z direction from the amount of lateral displacement of the slit image is disposed. Information detected by the reticle side AF sensor 16 is supplied to the main control system 20. A reticle alignment microscope (not shown) for reticle alignment is disposed above the periphery of the reticle R.

On the other hand, the wafer W is sucked and held on the Z tilt stage 17 via a wafer holder (not shown). The Z tilt stage 17 is fixed on the wafer stage WST, and the wafer stage WST can be moved at a constant speed in the Y direction on a wafer base (not shown) and can be moved stepwise in the X direction and the Y direction. The Z tilt stage 17 controls the position of the wafer W in the Z direction and the tilt angles around the X and Y axes. The position and rotation angle in the X and Y directions of wafer stage WST are measured by a laser interferometer (not shown), and the measured values are supplied to main control system 20. The main control system 20 controls the position and speed of the wafer stage WST based on the measurement values and various control information. [0029] On the lower side surface of the projection optical system PL, a plurality of slit images are projected obliquely onto the surface of the wafer W (wafer surface), and reflected light from the wafer surface is received to reconstruct the slit images. An oblique-incidence focus sensor (hereinafter referred to as the "wafer-side AF sensor") that forms an image and detects the displacement (defocus amount) and tilt angle of the wafer surface in the Z direction from the lateral displacement of the slit images. 18 is arranged. Information detected by the wafer side AF sensor 18 is supplied to the main control system 20. The main control system 20 constantly projects the wafer surface based on the detection information of the reticle side AF sensor 16 and the wafer side AF sensor 18. The Z tilt stage 17 is driven so as to be focused on the image plane of the optical system PL.

[0030] Further, near the wafer W on the Z tilt stage 17, a dose sensor 19 including a photoelectric sensor having a light receiving surface covering the entire exposure area of the exposure light IL is fixed, and the dose sensor 19 The detection signal is supplied to the main control system 20. Before the exposure starts or periodically, the exposure light IL is irradiated with the light receiving surface of the irradiation sensor 19 moved to the exposure area of the projection optical system PL, and the detection signal of the irradiation sensor 19 is detected as the detection signal of the integrator sensor 7. By dividing by, the main control system 20 calculates and stores the transmittance of the optical system from the beam splitter 6 to the dose sensor 19 (wafer W). On the Z tilt stage 17, an aberration measuring device 21 for measuring the aberration of the projection optical system PL is provided. The measurement result of the aberration measuring device 21 is supplied to the main control system 20. As the aberration measuring device 21, for example, an aerial image sensor as disclosed in Japanese Patent Application Laid-Open No. 2002-14005 (corresponding US Patent Publication 2002Z0041377) can be used.

[0031] Further, an off-axis alignment sensor (not shown) for wafer alignment is arranged above wafer stage WST, and the above-mentioned reticle alignment microscope and the detection result of the alignment sensor are arranged. Based on the above, the main control system 20 performs the reticle R alignment and the wafer W alignment. During exposure, the reticle stage RST and wafer stage WST are driven while the illumination area on the reticle R is irradiated with the exposure light IL, and the reticle R and one shot area on the wafer W are synchronously scanned in the Y direction. And the operation of stepping the wafer W in the X and Y directions by driving the wafer stage WST are repeated. By this operation, the pattern image of the reticle R is exposed to each shot area on the wafer W by the step “and” scanning method. The overall configuration of the exposure apparatus according to the embodiment of the present invention has been described above. Next, the imaging characteristic correction mechanism 14 and the adjustment mechanism 22 provided for adjusting the optical characteristics of the projection optical system PL are described. The non-exposure light irradiation mechanism 40 will be described in order.

[0033] [Image formation characteristic correction mechanism 14]

FIG. 2 is a diagram illustrating an example of the imaging characteristic correction mechanism 14. In FIG. 2, for example, five lenses Ll l, L12, L13, L14, and L15 selected from a plurality of optical members are independently expanded and contracted in the direction of the three optical axes in the lens barrel of the projection optical system PL. It is held via free drive elements 14a, 14b, 14c, 14d, 14e. Fixed lenses (not shown) and aberration correction plates are also arranged before and after the lenses L11 to L15. In this case, the three drive elements 14a (only two are shown in FIG. 2) are arranged in a positional relationship that is approximately the apex of a regular triangle, and each of the other three drive elements is similarly driven. The elements 14b to 14e are also arranged in a positional relationship that is almost the vertex of an equilateral triangle.

[0034] As the extendable drive elements 14a to 14e, for example, piezoelectric elements such as piezoelectric elements, magnetostrictive elements, or electric micrometers can be used. The control unit 15 independently controls the expansion / contraction amounts of the drive elements 14a to 14e based on the control information from the main control system 20, whereby the position of each of the five lenses L11 to L15 in the optical axis direction and the light The tilt angle around two perpendicular axes perpendicular to the axis can be controlled independently. As a result, a predetermined rotationally symmetric aberration in the imaging characteristics of the projection optical system PL can be corrected. Note that the rotationally symmetric optical characteristics (aberration) of the projection optical system PL adjusted by the imaging characteristic correction mechanism 14 are: focus error, projection magnification error, curvature of field aberration, distortion (distortion), coma aberration, spherical Including at least one of the aberrations.

For example, distortion aberration (including magnification error) and the like can be corrected by controlling the position in the optical axis direction and the tilt angle of the lenses Ll l and L15 located near the reticle or wafer. Further, for example, spherical aberration or the like can be corrected by controlling the position in the optical axis direction of the lens L13 at a position close to the pupil plane of the projection optical system PL. 2 may be the same as the lens L1 irradiated with the illumination light for aberration correction in the projection optical system PL of FIG.

As for the mechanism for driving the lens or the like in the projection optical system PL as described above, for example, It is also disclosed in Japanese Patent Laid-Open No. 4-134813. Further, instead of or together with the optical member in the projection optical system PL, the position in the optical axis direction of the reticle R in FIG. 1 may be controlled to correct a predetermined rotationally symmetric aberration. . Further, as the imaging characteristic correction mechanism 14 in FIG. 1, as disclosed in, for example, Japanese Patent Laid-Open No. 60-78454, a sealed space between two predetermined lenses in the projection optical system PL is used. A mechanism for controlling the pressure of the gas may be used.

[0037] [Adjustment mechanism 22]

3A is a cross-sectional view illustrating a configuration example of the adjustment mechanism 22, and FIG. 3B is a top view illustrating a configuration example of the adjustment mechanism 22. 3A and 3B, only the configuration of the adjustment mechanism 22 is shown for the sake of simplicity, and the configuration other than the adjustment mechanism 22 (for example, a lens barrel or the like) is not shown. As shown in FIG. 3A, the adjustment mechanism 22 includes a holding member 22a, a temperature adjuster 22b, an adjustment screw 22c, and the like.

[0038] The holding member 22a is formed of a material having a high thermal conductivity such as aluminum, and holds the lens L2 in contact with one end around the lens L2. The temperature adjuster 22b includes a heating element such as a heater or a heating and cooling element such as a Peltier element, and heats or cools the lens L2 in order to adjust the optical characteristics of the projection optical system PL. The temperature adjuster 22b is mounted on the holding member 22a, and heats or cools the lens L2 via the holding member 22a having high thermal conductivity. The temperature adjustment of the lens L2 performed through the holding member 22a is controlled by the control unit 23 under the control of the main control system 20. The temperature adjuster 22b may be directly attached to the lens L2 to adjust the temperature of the lens L2.

[0039] Further, the holding member 22a is formed with a screw hole penetrating from the contact surface to the lens L2 to one side surface (a surface facing the contact surface), and the adjustment screw 22c is fitted into the screw hole. Combined. The adjusting screw 22c is arranged so that its axis is substantially parallel to a plane perpendicular to the optical axis of the lens L2. The adjustment screw 22c is used to pressurize or depressurize the lens L2 in order to adjust the optical characteristics of the projection optical system PL. By rotating the adjustment screw 22c in the direction of the directional force toward the center of the lens L2, the lens L2 can be pressurized (increasing the force to press the lens L2), and conversely in the direction of the directional force from the center of the lens L2 Rotate the adjustment screw 22c to move the lens L2 Reduce the pressure (reduce or eliminate the force pushing the lens L2). Since this adjusting screw 22c is a member for pressing the lens L2, it is desirable to form it with a highly rigid material. Further, the temperature adjuster 22b is capable of heating or cooling the lens L2 efficiently. It is highly conductive and is preferably made of a material.

[0040] A lens barrel (not shown) provided in the projection optical system PL is provided with an operation hole (not shown) for operating the adjustment screw 22c. The operator is formed in the lens barrel from the outside of the lens barrel. The adjusting screw 22c can be adjusted through the operation hole. Note that the inside of the projection optical system PL is temperature-controlled to suppress fluctuations in optical characteristics. For this reason, for example, it is usually desirable to remove the lid so that the operation hole appears only when the adjustment screw 22c is operated.

[0041] A plurality of adjustment mechanisms 22 are provided around the lens L2. In the example shown in FIG. 3B, eight adjustment mechanisms 22 are provided so as to form an angle of 45 ° with respect to the center of the lens L2. As shown in FIGS. 3A and 3B, the temperature regulator 22b provided in the adjustment mechanism 22 is connected to the control unit 23, and which temperature regulator 22b is to be temperature-adjusted and how many times are to be adjusted? It is controlled by the controller 2 3.

In the present embodiment, the static optical characteristics (non-rotationally symmetric aberration) of the projection optical system PL can be adjusted by either the temperature regulator 22b or the adjustment screw 22c. . The adjustment by the temperature adjuster 22b can be controlled by the control unit 23, but the response is relatively slow. In contrast, adjustment with the adjusting screw 22c is relatively responsive, but requires manual operation by the operator. Therefore, in this embodiment, the adjustment with the adjustment screw 22c is performed at the time of manufacturing the projection optical system or the exposure apparatus, and the adjustment by the temperature adjuster 22b is projected at the time of regular or irregular maintenance of the exposure apparatus. This is done to correct for changes in the static optical characteristics of the optical system PL over time. In the present embodiment, the adjusting mechanism 22 adjusts the static non-rotationally symmetric aberration of the projection optical system PL, but may be used to adjust the rotationally symmetric aberration of the projection optical system PL. .

[0043] In the above example, the force described in the configuration in which the adjustment screw 22c applies pressure in the direction from the periphery to the center of the lens L2 to pressurize and depressurize the lens L2. In addition to this configuration, for example, the lens L2 The periphery of the lens is sandwiched in the vertical direction (Z direction), and the lens is You may use the mechanism which produces the stress which acts in the surface of L2. Further, in the above example, the case where the operator manually adjusts the adjustment screw 22c has been described as an example. However, an actuator for rotating the adjustment screw 22c is provided to control the rotation angle of the adjustment screw 22c. It may be configured to control via the

Furthermore, in the above example, the case where the temperature regulator 22b includes a heating element such as a heater or a heating and cooling element such as a Peltier element has been described as an example, but a heating and cooling source is provided outside the projection optical system PL. The heating / cooling source and the holding member 22a or the vicinity of the end of the lens L2 may be connected by a heat transport mechanism such as a heat nove. FIG. 4 is a diagram showing a configuration example of the temperature regulator 22b using the heat transport mechanism. As shown in FIG. 4, a plurality of heating / cooling sources 24 controlled by the control unit 23 are provided outside the projection optical system PL, and heat pipes from the heating / cooling sources 24 toward the end of the lens L2 are provided. 25 is arranged!

Note that in FIG. 4, there are eight power heating / cooling sources 24 and heat pipes 25 that are simplified in illustration, and each end of the heat pipe 25 is 8 around the lens L2 as in FIG. 3B. Placed in place. With the above configuration, the control unit 23 controls the heating / cooling source 24, so that the optical characteristics of the projection optical system PL can be adjusted in the same manner as the temperature adjuster 22b. In FIG. 4, the configuration including the plurality of heating / cooling sources 24 is described as an example, but the configuration including one heating / cooling source in which eight heat pipes are connected to the outside of the projection optical system PL. It is also good. In the case of a powerful configuration, for example, the heating or cooling part of the lens L2 is changed by controlling the opening and closing of the flow path of each heat pipe.

In the present embodiment, eight adjustment mechanisms 22 are provided at equal intervals around the lens L2, but the number and positions of the adjustment mechanisms 22 can be arbitrarily set. In the present embodiment, the temperature regulator 22b and the adjusting screw 22c are arranged at the same position around the lens L2, and they may be arranged at different positions around the lens L2. The number of may be different. Furthermore, one of the temperature adjuster 22b and the adjustment screw 22c may be arranged around another lens different from the lens L2 in the vicinity of the pupil plane of the projection optical system PL. In addition, in order to adjust the static optical characteristics of the projection optical system PL, the adjusting mechanism 22 can include only one of the forces including both the temperature adjuster 22b and the adjusting screw 22c. [0047] [Non-exposure light irradiation mechanism 40]

Next, the non-exposure light irradiation mechanism 40 for adjusting the dynamic optical characteristics (non-rotationally symmetric aberration) of the projection optical system PL will be described. The non-exposure light irradiation mechanism 40 shown in FIG. 1 corrects non-rotationally symmetric aberration such as center astigmatism that occurs in the projection optical system PL when dipole illumination is performed, for example. In order to correct the non-rotationally symmetric aberration of the projection optical system PL, the non-exposure light irradiation mechanism 40 is used for correcting aberrations in a wavelength region different from the exposure light IL on the lens L1 near the pupil plane PP of the projection optical system PL. Illumination light (hereinafter referred to as “non-exposure light”) LB is irradiated.

In the present embodiment, light in a wavelength region that hardly senses the photoresist applied to the wafer W is used as the non-exposure light LB. Therefore, as the non-exposure light LB, for example, infrared light having a wavelength of 10. emitted from a carbon dioxide laser (CO laser) is used as an example.

2

The Note that continuous light may be used as the CO laser. This infrared light with a wavelength of 10.6 / z m

2

Projection optical system with high absorptivity in the UK Since almost all (preferably 90% or more) is absorbed by one lens in the PL, aberration is controlled without affecting other lenses. Therefore, there is an advantage that it is easy to use. In addition, the non-exposure light LB irradiated to the lens L1 of the present embodiment is set so that 90% or more is absorbed.

[0049] As the non-exposure light LB, in addition to the above-mentioned infrared light, near-infrared light having a wavelength of about 1 μm emitted from a solid-state laser light such as a YAG laser, or a wavelength emitted from a semiconductor laser Infrared light of several meters can also be used. That is, as the light source that generates the non-exposure light LB, an optimum light source can be employed according to the material of the optical member (lens or the like) irradiated with the non-exposure light LB. In FIG. 1 and the like, the lens L1 may be a force-concave lens drawn like a convex lens.

In the non-exposure light irradiation mechanism 40 of FIG. 1, the non-exposure light LB emitted from the light source system 41 is directed to a plurality (eight in this embodiment) of optical paths and photoelectric sensors 43 by the mirror optical system 42. It is branched into another optical path. A detection signal corresponding to the light amount of the non-exposure light LB detected by the photoelectric sensor 43 is fed back to the light source system 41. In addition, the non-exposure light LB force of the two optical paths out of the plurality of optical paths LB force as the non-exposure light LBa and LBb via the two irradiation mechanisms 44a and 44b arranged so as to sandwich the projection optical system PL in the X direction. Lens L1 Irradiated.

FIG. 5 is a top view showing a detailed configuration example of the non-exposure light irradiation mechanism 40. In FIG. 5, the light source system 41 of FIG. 1 includes a light source 41a and a control unit 41b. The non-exposure light LB emitted from the light source 41a is either in a state in which the optical path of the non-exposure light LB is bent by 90 ° (closed state) or in a state in which the non-exposure light LB passes through as it is (open state). Galvano mirrors 45g, 45c, 45e, 45a, 45h, 45d, 45f, and 45b as movable mirrors that can be switched at high speed to the photoelectric sensor 43, and the detection signal of the photoelectric sensor 43 is supplied to the control unit 41b ing. Galvano mirrors 45a to 45h correspond to the mirror optical system 42 in FIG. The control unit 41b controls the light emission timing and output of the light source 41a and the opening and closing of the galvano mirrors 45a to 45h according to control information from the main control system 20.

[0052] In addition, the non-exposure light LB whose optical path is sequentially bent by the eight galvanometer mirrors 45a to 45h is irradiated through the bundle of optical fibers 46a to 46h (or a metal tube or the like can be used). It is guided to ~ 44h. Eight irradiation mechanisms 44a to 44h have the same configuration. Among them, the irradiation mechanisms 44a and 44b are a condensing lens 47, a beam splitter 48 having a predetermined low reflectance, and a bundle of optical fibers or a relay lens system. A light guide unit 49 having equal force, a condensing lens 51, and a holding frame 50 for fixing the condensing lens 47 and the light guide unit 49 to the beam splitter 48 are provided.

The non-exposure light LB is irradiated to the lens L1 in the projection optical system PL as non-exposure light LBa and LBb from the irradiation mechanisms 44a and 44b, respectively. In this case, the first pair of irradiation mechanisms 44a and 44b and the second pair of irradiation mechanisms 44c and 44d are arranged to face each other so as to sandwich the projection optical system PL in the X direction and the Y direction, respectively. . The third pair of irradiation mechanisms 44e and 44f and the fourth pair of irradiation mechanisms 44g and 44h are respectively arranged such that the irradiation mechanisms 44a and 44b and the irradiation mechanisms 44c and 44d are centered on the optical axis of the projection optical system PL. It is arranged at an angle rotated 45 ° clockwise. Then, the non-exposure light LB is irradiated from the irradiation mechanisms 44c to 44h to the lens L1 in the projection optical system PL as non-exposure light LBc to LBh, respectively. Note that the position, shape and size of the optical member irradiated with the non-exposure light LBa to L Bh and the irradiation area of the non-exposure light LBa to LBh on the optical member are as non-rotationally symmetric as possible through experiments and simulations. Aberrations (center astigmatism, etc.) are determined to be reduced. [0054] In addition, photoelectric sensors 52a to 52h that respectively receive part of the non-exposure light reflected by the beam splitters 48 of the irradiation mechanisms 44a to 44h are provided, and detection of the eight photoelectric sensors 52a to 52h is provided. The signal is also supplied to the control unit 41b. The control unit 41b can accurately monitor the light amounts of the non-exposure light LBa to LBh immediately before being irradiated from the irradiation mechanisms 44a to 44h to the lens L1 in the projection optical system PL by the detection signals of the photoelectric sensors 52a to 52h. Based on the monitoring result, each of the irradiation amounts of the non-exposure light LBa to LBh is controlled to a value instructed by the main control system 20, for example. Even if the length (optical path length) of the bundle of optical fibers 46a to 46h varies by measuring the irradiation amount of the non-exposure light LB by the photoelectric sensors 52a to 52h immediately before the projection optical system PL, The amount of non-exposure light LBa to LBh irradiated to the lens L1 can be accurately monitored without being affected by changes over time of the optical system or the like.

6A and 6B are front views in which a part of the projection optical system PL is taken as a cross section. As shown in FIG. 6A, the irradiation mechanisms 44a and 44b are inclined slightly diagonally downward in the openings Fa and Fb provided in the flange portion F of the lens barrel of the projection optical system PL, respectively, by directing the lens L1. It is arranged to do. Then, the non-exposure lights LBa and LBb emitted from the irradiation mechanisms 44a and 44b enter the lens L1 in a direction obliquely intersecting the optical path of the exposure light IL. Similarly, the other irradiation mechanisms 44c to 44h in FIG. 5 are arranged at the same inclination angle in the opening in the flange portion F in FIG. 6A, and the non-exposure light LBc to LBh from these is also the optical path of the exposure light IL. Incident to lens L1 in a direction that crosses diagonally.

[0056] This increases the optical path of the non-exposure light LBa to LBh in the lens L1, and most of the non-exposure light L Ba to LBh is absorbed in the lens L1, and the projection optical system PL force is also almost all. No longer injected. Further, the lens surface of a part of the optical member (lens L1) of the projection optical system PL, that is, the region where the exposure light IL can enter (or exit) is not inserted without passing through other optical members of the projection optical system PL. Since the exposure light LB is irradiated, the temperature distribution of the lens L1 can be adjusted efficiently, and as a result, the non-rotationally symmetric aberration of the projection optical system PL can be adjusted accurately in a short time.

FIG. 6B is a modification of FIG. 6A. As shown in FIG. 6B, the irradiation mechanisms 44a and 44b (the same applies to the other irradiation mechanisms 44c to 44h) are respectively provided for the lens barrels of the projection optical system PL. In the openings Fc and Fd provided in the flange part F, tilt slightly upward toward the lens L1. The bottom surface of the lens L1 may be illuminated with non-exposure light LBa, LBb. In this case, it is possible to further reduce the amount of leakage of the non-exposure light LBa to LBh from the wafer W side force of the projection optical system PL.

Returning to FIG. 5, the non-exposure light irradiation mechanism 40 includes the light source 41a, the control unit 41b, the galvanometer mirrors 45a to 45h, the bundle of optical fibers 46a to 46h, the irradiation mechanisms 44a to 44h, the photoelectric sensors 52a to 52h, and the like. Is configured. For example, when the lens L1 is irradiated with only two non-exposure lights LBa and LBb in the X direction, the galvano mirrors 45a to 45h are all opened and opened (the state where the non-exposure light LB is allowed to pass). The operation of closing the mirror 45a for a predetermined time (non-exposure light reflecting LB) and the operation of closing the galvano mirror 45b for a predetermined time may be repeated alternately! /. There is no effect on the aberration !, it is short enough! By switching the galvano mirror in time (for example, lmsec), the effect on the aberration can be eliminated. Further, since the non-exposure light LB is pulse light, the opening / closing operation of the galvanometer mirrors 45a to 45h may be performed in units of a predetermined number of pulses. Similarly, when only the two non-exposure light beams LBc and LBd in the Y direction are irradiated onto the lens L1, the operation of closing the galvano mirror 45c for a predetermined time and the operation of closing the galvano mirror 45d for a predetermined time are alternately repeated. That's fine. Thus, by using the galvanometer mirrors 45a to 45h, the lens L1 can be efficiently irradiated with almost no light loss of the non-exposure light LB.

In the configuration example of FIG. 5, eight regions on the lens L1 can be illuminated with the non-exposure light LB. For example, four regions on the lens L1 in the X direction and the Y direction are used. Even if only this area can be illuminated with non-exposure light LB, most of the aberrations that occur in normal applications can be corrected. Also, instead of using the galvanometer mirrors 45a to 45h, for example, a fixed mirror and a beam splitter are combined to divide the non-exposure light LB into 8 light beams, and the optical path of these light bundles is opened and closed using a shatter. Also good. In this configuration, a plurality of locations can be irradiated with non-exposure light LB simultaneously. In addition, when a carbon dioxide laser or a semiconductor laser is used as a light source, for example, only the number of necessary irradiation areas on the lens L1 (eight in FIG. 5) is prepared, and light emission of these light sources is turned on. 'The irradiation area on the lens L1 may be directly controlled by turning off or using a shirt. As described above, the non-exposure light irradiation mechanism 40 is a non-rotating pair of the projection optical system PL generated when the exposure light IL is irradiated onto the projection optical system PL. It is possible to adjust the characteristic aberration (dynamic optical characteristics).

[0060] The image formation characteristic correction mechanism 14, the adjustment mechanism 22, and the non-exposure light irradiation mechanism 40 provided for adjusting the optical characteristics of the projection optical system PL have been described above. Next, projection is performed using these. A method for adjusting the optical characteristics of the optical system PL will be described. Note that a method for adjusting the optical characteristics of the projection optical system PL using the imaging characteristic correction mechanism 14 is also disclosed in, for example, the above-mentioned Japanese Patent Laid-Open No. 4-134813. A method for adjusting the optical characteristics of the projection optical system PL by the non-exposure light irradiation mechanism 40 will be described.

[Method for correcting non-rotationally symmetric aberration component]

If the illumination condition is changed by the illumination system aperture stop member 5 or the shape and size of the illumination area on the reticle R is changed by the field stop 9, a non-rotationally symmetric aberration component is generated in the projection optical system PL. there is a possibility. Here, adjustment of non-rotationally symmetric aberration components that occur in the projection optical system when dipole illumination is performed will be described.

[0062] FIGS. 7A, 7B, 7C, 8A, and 8B are diagrams for explaining the change in the shape of the lens that occurs when dipole illumination is performed. First, when the aperture stop 5a having two apertures separated in the direction corresponding to the X direction is disposed on the focal plane on the exit side of the second fly-eye lens 4, the main aperture formed on the reticle R As an example, the pattern for transfer is shown in an enlarged view in Fig. 7A. Line patterns that are elongated in the Y direction are arranged in the X direction (non-scanning direction) at a pitch that is approximately the resolution limit of the projection optical system PL. Directional line 'and' space pattern (hereinafter referred to as “L & S pattern”) PV. At this time, on the reticle R, a plurality of L & S patterns or the like which are usually larger than the L & S pattern PV and whose arrangement direction is the X direction and the Y direction (scanning direction) at the arrangement pitch are also formed.

[0063] In the dipole illumination in the X direction using the aperture stop 5a, assuming that there is no reticle, as shown in FIG. 7B, the pupil plane PP of the projection optical system PL is symmetrical with respect to the X direction across the optical axis AX. Illumination light IL illuminates two circular areas IRx. In addition, when various reticle patterns are arranged in the optical path of the exposure light IL, the exposure light IL is usually low because the 0th-order light intensity is larger than the diffracted light intensity and the diffraction angle is small. Most of the (imaging beam) passes through the circular area IRx or its vicinity. Therefore, if the exposure is continued, the record near the pupil plane PP The temperature distribution of the lens LI is the highest in the two circular regions IRx that sandwich the optical axis in the X direction, and gradually decreases toward the surrounding region, and the lens L1 has a thermal expansion ( Heat deformation).

[0064] In this case, side views exaggerating the change of the lens L1 when viewed in the Y direction and the X direction are as shown in FIGS. 7C and 7D, respectively. In these figures, if the surface shape of the lens L1 before the exposure light absorption is plane A, the thermally expanded surface B after the exposure light absorption is in a wide range in the direction along the X axis (Fig. 7C). Since two convex parts sandwiching the optical axis are formed, the refractive power decreases. In the direction along the Y axis (Fig. 7D), one refractive part is locally formed in the central part, and the refractive power increases. Thus, if there is a difference in the refractive power between the X direction and the Y direction, non-rotationally symmetric aberrations such as center astigmatism occur. Figure 9 shows the center astigmatism caused by dipole illumination. As shown in Fig. 9, the image plane of the projection optical system PL becomes a lower (one Z direction) image plane IV because the refractive power decreases with respect to the light beam opened in the X direction, and the light beam opened in the Y direction. Since the refractive power increases, the upper (+ Z) image plane is IH. Accordingly, center astigmatism Δ で that is astigmatism on the optical axis is generated.

[0065] With center astigmatism occurring, in addition to the L & S pattern PV in the X direction on the reticle R, a predetermined pitch in the Y direction (this pitch is usually larger than the pitch of the L & S pattern PV) ), The exposure light that has passed through the X-direction L & S pattern PV spreads in the X-direction, and the exposure light that has passed through the Y-direction L & S pattern. Expands in the Y direction. Therefore, the image of the L & S pattern PV in the X direction is formed on the lower image plane IV in FIG. 9, and the image of the L & S pattern in the Y direction is formed on the upper image plane IH in FIG. When aligned with surface IV, the image of the L and S pattern PV in the X direction is transferred with high resolution. The image of the L and S pattern in the Y direction will be blurred due to defocus.

[0066] On the other hand, as shown in an enlarged view in FIG. 8A, line patterns elongated mainly in the X direction are arranged on the reticle R in the Y direction (scanning direction) at a pitch substantially close to the resolution limit of the projection optical system PL. The Y direction L & S pattern PH is assumed to be formed. In this case, the aperture stop 5b having a shape obtained by rotating the aperture stop 5a by 90 ° is set on the pupil plane of the illumination optical system ILS in FIG. The In dipole illumination in the Y direction using this aperture stop 5b, assuming that there is no reticle, as shown in Fig. 8 (b), the pupil plane ΡΡ of the projection optical system PL is symmetrical in the Y direction across the optical axis AX. The exposure light IL illuminates two circular areas IRy. At this time, even if various reticle patterns are arranged in the optical path of the exposure light IL, usually most of the exposure light IL (imaging light beam) passes through the circular region IRy and the vicinity thereof. When the reticle R in FIG. 8A is arranged in the optical path of the exposure light IL, ± 1st-order diffracted light from the L & S pattern PH having a pitch close to the resolution limit also passes through the circular region IRy or the vicinity thereof. The image of the L & S pattern PH is projected onto the wafer W with high resolution.

In this case, the light amount distribution of the exposure light IL incident on the lens L1 in the vicinity of the pupil plane PP of the projection optical system PL of FIG. 1 is also substantially the light amount distribution of FIG. 8B. Therefore, when the exposure is continued, the temperature distribution of the lens L1 near the pupil plane PP becomes the highest in the two circular areas IRy that sandwich the optical axis in the Y direction, and gradually decreases toward the surrounding area. Depending on the distribution, the lens L1 expands thermally. Therefore, the image plane of the projection optical system PL is almost opposite to the case of FIGS. 7A, 7B, and 7C, and is close to the upper image plane IH because the refractive power increases for the light beam opened in the X direction. Since the refractive power of the light beam that opens in the Y direction decreases, it is near the lower image plane IV, and a center astigmatism with the same sign as in the case of Fig. 9 is generated. . Since reticle R is illuminated by a rectangular illumination area whose longitudinal direction is the X direction (non-scanning direction), the center astigmatism resulting from the illumination area is the same as the center astigmatism of FIG. It always occurs slightly in the code. On the other hand, the center astigmatism generated by the dipole illumination in FIG. 8B is opposite in sign to the center astigmatism caused by the rectangular illumination area, and the center astigmatism as a whole is The ism is slightly smaller than with the dipole illumination in Figure 7B.

[0068] These center astigmatisms are non-rotationally symmetric aberrations, and other non-rotationally symmetric aberrations by dipole illumination (for example, orthogonal in a plane perpendicular to the optical axis of the projection optical system PL). However, these non-rotationally symmetric aberrations cannot be substantially corrected by the imaging characteristic correction mechanism 14 in FIG. In this embodiment, the dynamic non-rotation symmetry of the projection optical system PL generated by the exposure light IL irradiation. In order to correct various aberrations, a non-exposure light irradiation mechanism 40 is provided.

FIGS. 10A and 10B are diagrams for explaining an example of a method for correcting non-rotationally symmetric aberration of the projection optical system using the non-exposure light irradiation mechanism. As shown in Fig. 7B, the optical axis AX on the pupil plane PP of the projection optical system PL is sandwiched symmetrically in the X direction. When the exposure light IL is irradiated to the two circular areas IRx, this is the optical axis on the lens L1. The exposure light IL is irradiated to the region IRx that sandwiches the AX symmetrically in the X direction and the adjacent region. As shown in FIG. 10A, in this embodiment, the region IRx is a region obtained by rotating the region IRx by 90 ° around the optical axis AX. Circular regions LRc and LRd that sandwich the optical axis AX symmetrically in the Y direction on the lens L1. Are respectively irradiated with the non-exposure light LBc and LBd shown in FIG. Note that the shape and size of the irradiation region of the non-exposure light LBc, LBd (and other non-exposure light as well) is, for example, the position of the condensing lens 51 in the irradiation mechanisms 44c, 44d in FIG. It is also possible to change by making it movable in the axial direction.

[0070] By irradiating the exposure light IL irradiation area by 90 ° with the non-exposure light LBc and LBd, the temperature distribution of the lens L1 becomes higher in the area IRx and the areas LRc and LRd, and gradually increases as the distance from the temperature distribution increases. The distribution becomes lower. 10A and 10B, where the origin of the X and Y axes is the optical axis AX, a cross-sectional view along the non-scanning direction in the plane including the optical axes AX and X of the lens L1, and the optical axes AX and Y axes. The cross-sectional view along the scanning direction in the plane including is shown exaggeratedly in FIG. 10B. As shown in FIG. 10B, the thermal expansion of the lens L1 is almost the same as the cross-sectional shape in the non-scanning direction and the scanning direction, and the shape in which the refractive index distribution is in the central part and its left and right. It changes much more than other areas. As a result, the deformation state of the lens L1 irradiated with the exposure light IL and the non-exposure light LBc, LBd is different in the non-scanning direction and the scanning direction compared to the deformation in FIGS. 7C and 7D when only the exposure light IL is illuminated. Since they are in a similar state, they are opened in the X and Y directions, and the focus positions for the luminous flux are almost equal to each other, so that center astigmatism hardly occurs. That is, non-rotationally symmetric aberration is changed to rotation-symmetric aberration. Since the rotationally symmetric aberration can be corrected by the imaging characteristic correction mechanism 14 shown in FIG. 2, the imaging characteristic of the projection optical system PL can be strictly controlled.

[0071] If the lens that irradiates the non-exposure light is a lens in the vicinity of the pupil plane of the projection optical system PL that is conjugate with the pupil plane of the illumination optical system ILS, such as the lens L1, the compensation of center astigmatism is achieved. The positive effect is increased. At this time, a plurality of lenses near the pupil plane may be irradiated with non-exposure light. Further, it is effective that the irradiation region including the exposure light IL and the non-exposure light LB on the optical member (L1) to be irradiated is as close to rotational symmetry as possible. However, regardless of the position of the optical member (lens, etc.) in the projection optical system PL that is irradiated with non-exposure light, by controlling the amount of irradiation, the effect of correcting center astigmatism can be achieved within a desired range. Obtainable. Further, by irradiating the lens L1 with the exposure light and the non-exposure light LB, non-rotationally symmetric aberrations other than the center astigmatism are also reduced. As described above, the method for correcting the non-rotationally symmetric aberration that occurs when dipole illumination is performed has been described.However, not only dipole illumination but also the setting of the illumination system aperture stop member 5 can be changed to achieve other illumination conditions. Non-rotationally symmetric aberrations can also occur when illuminating reticle R.

[0072] In addition to the change of the illumination system aperture stop 5a, the position, shape, and size of the illumination area on the reticle R are changed by the field stop 9 to perform exposure on a plane conjugate with the image plane of the projection optical system PL. Non-rotationally symmetric aberration may also occur when the position, cross-sectional shape, and size of the light IL are changed. In addition, even if the position, shape, and size of the reticle R aperture change, the distribution (density) of the reticle R pattern changes, and the distribution of the exposure light IL changes on the plane conjugate with the image plane of the projection optical system PL. Non-rotationally symmetric aberrations may occur. Such aberration can also be corrected by the non-exposure light irradiation mechanism 40 described above. That is, in the present embodiment, the static optical characteristics (non-rotationally symmetric optical characteristics) in the initial state of the projection optical system PL are adjusted using the adjusting mechanism 22, and the projection caused by the irradiation of the exposure light IL is performed. The dynamic optical characteristics (non-rotationally symmetric aberration) of the optical system PL are applied to the illumination conditions specified by the illumination system aperture stop member 5 and the distribution of the exposure light IL on the plane conjugate with the image plane of the projection optical system PL. Adjust using the non-exposure light irradiation mechanism 40 accordingly.

[Internal configuration of main control system]

FIG. 11 is a block diagram showing an internal configuration of the main control system 20 and a device that exchanges various signals with the main control system 20. As shown in FIGS. 3A and 3B, the main control system 20 includes an imaging characteristic calculation unit 31, an imaging characteristic control unit 32, an exposure amount control unit 33, a stage control unit 34, a Z tilt stage control unit 35, a controller 36, and a memory. Consists of 37. The imaging characteristic calculation unit 31 uses the detection signals of the integrator sensor 7 and the reflection amount sensor 8 to detect from the reticle scale. The integrated energy of the exposure light IL incident on the projection optical system PL and the integrated energy of the exposure light IL reflected by the wafer W and returning to the projection optical system PL are calculated.

[0074] This imaging characteristic calculation unit 31 receives information about the illumination conditions during exposure, information indicating the shape and size of the aperture of the field stop 9 from the controller 36, and characteristics of the reticle R (the size of the aperture and Information indicating the pattern distribution is also supplied. In addition, the imaging characteristic calculation unit 31 uses information such as illumination conditions, accumulated energy of the exposure light IL, and ambient atmospheric pressure and temperature supplied from the environmental sensor 12 in the imaging characteristics of the projection optical system PL. The amount of fluctuation of the rotationally symmetric aberration component and the non-rotationally symmetric aberration component is calculated. Here, when the imaging characteristic calculation unit 31 calculates the fluctuation amount of the non-rotationally symmetric aberration component in the imaging characteristic of the projection optical system PL, the transfer function read from the memory 37 by the controller 36. (Details will be described later).

Based on the dynamic aberration component variation amount of the projection optical system PL calculated by the imaging characteristic calculation unit 31, the imaging characteristic control unit 32 performs the imaging characteristic correction mechanism 14 via the control unit 15. Further, by controlling the operation of the non-exposure light irradiation mechanism 40, the optical characteristics of the projection optical system PL are adjusted to a desired state. Here, when the imaging characteristic of the projection optical system PL is corrected by the imaging characteristic correction mechanism 14, the control unit 15 3 is controlled based on the control information from the imaging characteristic control unit 32 in the main control system 20. By independently controlling the amount of expansion / contraction of each of the drive elements 14a to 14e, the position of each of the five lenses L11 to L15 in the direction of the optical axis and about two orthogonal axes perpendicular to the optical axis Independently control the inclination angle. This corrects a predetermined rotationally symmetric aberration in the imaging characteristics of the projection optical system PL.

In addition, when adjusting the optical characteristics of the projection optical system PL by the non-exposure light irradiation mechanism 40, the irradiation or non-irradiation of the non-exposure light LBa to LBh to the lens L1 is controlled. By controlling the non-exposure light irradiation mechanism 40, a predetermined non-rotationally symmetric aberration in the imaging characteristics of the projection optical system PL is corrected.

[0077] The exposure amount control unit 33 indirectly controls the exposure energy on the wafer W by using the detection signal of the integrator sensor 7 and the optical transmittance of the optical system from the beam splitter 6 to the wafer W measured in advance. Calculate automatically. Here, the transmittance of the optical system from the beam splitter 6 to the wafer W is calculated by projecting the light receiving surface of the dose sensor 19 before the exposure is started or periodically. It is obtained by irradiating the exposure light IL while moving to the exposure area of L, and dividing the detection signal of the dose sensor 19 by the detection signal of the integrator sensor 7. The exposure control unit 33 controls the output of the exposure light source 1 so that the integrated exposure energy on the wafer W falls within the target range, and uses a dimming mechanism (not shown) as necessary. The pulse energy of exposure light IL is controlled stepwise. Further, the rotation angle of the drive motor 5c that rotates the illumination system aperture stop member 5 is controlled by the control signal from the controller 36, and the size of the aperture of the field stop 9 is further controlled.

The stage control unit 34 controls the position and speed of the reticle stage RST based on measurement values of a laser interferometer (not shown) provided on the reticle stage RST and various control information. In addition, the position and speed of wafer stage WST are controlled based on the measurement values of a laser interferometer (not shown) provided on wafer stage WST and various control information. Also, the Z tilt stage control unit 35 is configured so that the wafer surface is always focused on the image plane of the projection optical system PL based on the detection information of the reticle side AF sensor 16 and the wafer side AF sensor 18. Drive 17

[0079] The controller 36 controls all of the exposure apparatus by controlling the imaging characteristic calculation unit 31, the imaging characteristic control unit 32, the exposure amount control unit 33, the stage control unit 34, and the Z tilt stage control unit 35. Control physical movements. The memory 37 stores a transfer function indicating the relationship between the energy of light incident on the projection optical system PL and the amount of variation in the optical characteristics of the projection optical system PL.

[0080] The general expression of the transfer function stored in the memory 37 is expressed by, for example, the following expression (1).

However,

F: Focus change amount due to exposure light absorption

At: Calculation interval of focus change due to exposure light absorption

T: Focus change time constant due to exposure light absorption

K

F: Focus change time constant before time A t due to exposure light absorption C: Time constant of focus change rate with respect to exposure light absorption

K

R

W: Uha reflectance

: Wafer reflectivity dependence

Q: Incident energy of exposure light

[0081] The transfer function shown in (1) above is a transfer function indicating the amount of force fluctuation when the projection optical system PL is irradiated with the exposure light IL. Change the variable Q in the above equation (1) according to the illumination conditions defined by the illumination system aperture stop member 5 and the cross-sectional shape and size of the exposure light IL in the conjugate plane of the image plane of the projection optical system PL. Thus, the focus fluctuation amount of the projection optical system PL can be obtained. FIG. 12 is a diagram showing a typical transfer function with respect to the focus fluctuation amount. As shown in FIG. 12, the focus fluctuation amount greatly fluctuates with the start of exposure light IL irradiation, but as the exposure light IL irradiation time becomes longer, the change rate of the fluctuation amount gradually becomes closer to the fluctuation amount. Change. Here, regarding the transfer function for the focus fluctuation amount, the same transfer function is used to calculate the amount of fluctuation for the rotationally symmetric aberration such as force magnification and the non-rotationally symmetric aberration such as center astigmatism. Can be sought.

Next, an example of an operation when the wafer W is exposed by the exposure apparatus described above will be described. Note that the static optical characteristics (non-rotationally symmetric aberration) of the projection optical system PL are already adjusted within a predetermined allowable range using at least one of the temperature adjuster 22b and the adjusting screw 22c of the adjusting mechanism 22. . In this case, the static optical characteristics of the projection optical system PL can be measured using the aberration measuring device 21 and the like, and adjustment by the adjusting mechanism 22 can be performed based on the result. When the exposure operation is started, first, the controller 36 in the main control system 20 outputs a control signal to the exposure amount control unit 33, drives the motor 5c, and controls the aperture stop formed in the illumination system aperture stop member 5. Either one is placed on the focal plane on the exit side of the second fly-eye lens 4 and the field stop 9 is driven to set the shape and size of the aperture. Here, it is assumed that the aperture stop 5a is arranged on the focal plane on the exit side of the second fly eye 4. Thereby, the illumination condition and the shape and size of the illumination area on the reticle R are set. At the same time, the controller 36 outputs information on the illumination conditions set for the imaging characteristic calculation unit 31, information on the shape and size of the aperture of the field stop 9, and information on the characteristics of the reticle R. . [0083] Next, in a state where the light receiving surface of the irradiation amount sensor 19 is disposed in the exposure region of the projection optical system PL, the exposure amount control unit 33 outputs a control signal to the exposure light source 1 to generate the exposure light IL. The detection signal of the dose sensor 19 and the detection signal of the integrator sensor 7 are obtained, and the transmittance of the optical system from the beam splitter 6 to the wafer W is obtained from these detection signals. Next, the controller 36 outputs a control signal to a reticle loader (not shown) to convey a predetermined reticle R and hold it on the reticle stage RST, and outputs a control signal to a wafer loader (not shown) to convey the wafer W. And hold it on the wafer stage WST.

[0084] When the above initial processing is completed, stage control unit 34 outputs a control signal to each of reticle stage RST and wafer stage WST, for example, starts acceleration of reticle stage RST in the + Y direction, and at the same time, wafer stage Start accelerating WST in the Y direction. When the reticle stage RST, Ueno, and stage WST start accelerating and the force has also passed for a predetermined time, and each of these stages reaches a constant speed, the controller 36 controls the exposure control 33 to expose from the exposure light source 1. Light IL is emitted.

[0085] The exposure light emitted from the exposure light source 1 passes through the first fly-eye lens 2, the vibrating mirror 3, the second fly-eye lens 4 and the like in order, and then the opening formed in the illumination system aperture stop member 5 It passes through the aperture 5a. The exposure light IL transmitted through the aperture stop 5a is shaped into a slit by the field stop 9 through the beam splitter 6, deflected in the Z direction by the mirror 10, and then irradiated onto the reticle R through the condenser lens 11. Is done. The exposure light IL is shaped by the aperture stop 5a, and the irradiation area on the reticle R is long in the X direction and has a slit shape.

[0086] The exposure light transmitted through the reticle R is irradiated onto the shot area to be exposed on the wafer W via the projection optical system PL, whereby a part of the pattern formed on the reticle R is wafered. W is transferred to a part of the shot area to be exposed. In this way, each shot area on the wafer W is sequentially exposed. While the exposure light IL is irradiated, detection signals are output from the integrator sensor 7 and the reflection amount sensor 8, and the imaging characteristic calculation unit 31 uses the detection signals of the integrator sensor 7 and the reflection amount sensor 8 to Calculate the integrated energy of the exposure light IL that is incident on the projection optical system PL from the reticle scale, and the integrated energy of the exposure light IL that is reflected by the wafer W and returns to the projection optical system PL.

[0087] As described above, the imaging characteristic calculation unit 31 receives the illumination condition under exposure from the controller 36. Information, information indicating the state of the field stop 9, and information indicating the characteristics of the reticle R are supplied, and a transfer function stored in the memory 37 is read and supplied. The image characteristic calculation unit 31 includes information on the above illumination conditions, information indicating the state of the field stop 9, information indicating the characteristics of the reticle R, accumulated energy of the exposure light IL, and surroundings supplied from the environment sensor 12. Using information such as atmospheric pressure and temperature and the transfer function, the amount of fluctuation of the rotationally symmetric aberration component and the non-rotationally symmetric aberration component in the imaging characteristics of the projection optical system PL is calculated. The variation amount of the aberration component of the projection optical system PL is calculated using the above-described equation (1). This calculation result is output from the imaging characteristic calculation unit 31 to the controller 36.

The controller 36 outputs the calculation result of the imaging characteristic calculation unit 31 to the imaging characteristic control unit 32. The imaging characteristic control unit 32 controls the operation of the imaging characteristic correction mechanism 14 via the control unit 15 based on the calculation result output from the controller 36 so that a desired imaging characteristic is always obtained. In addition, the fluctuation of the rotationally symmetric aberration of the projection optical system PL is suppressed. Further, the correction of the non-rotationally symmetric aberration of the projection optical system PL by the irradiation of the exposure light IL is performed by the non-exposure light irradiation mechanism 40. Since the above control is repeatedly executed while the exposure operation is performed, the rotational symmetric aberration and the non-rotation symmetric aberration of the projection optical system PL are applied to the illumination condition and the exposure on the conjugate plane of the image plane of the projection optical system PL. It can be precisely controlled according to the distribution of light IL.

In the above description, the case where the optical characteristic of the projection optical system PL is adjusted using the transfer function has been described as an example. However, when adjusting the optical characteristic of the projection optical system PL, a memory is used. The optical characteristics of the projection optical system PL may be adjusted using the adjustment amount set in the table stored in 37. FIG. 13 is a diagram for explaining an example of a table stored in the memory 37. Under certain illumination conditions, the adjustment amount of the optical characteristics of the projection optical system PL changes according to the size (area) of the aperture of the field stop 9 provided in the illumination optical system ILS. For this reason, the relationship between the aperture size of the field stop 9 and the adjustment amount of the optical characteristics of the projection optical system PL is shown as a curve AJ in FIG. The relationship between the size of the aperture of the field stop 9 shown in FIG. 13 and the adjustment amount of the optical characteristics of the projection optical system PL is merely an example, and may be a straight line!

[0090] In the present embodiment, the size of the aperture of the field stop 9 is divided into a plurality of areas, a representative adjustment amount in each section is set, and information indicating the size of the aperture of the field stop 9 and a representative Adjustment The quantity is stored in association with the table. In the example shown in FIG. 13, the size of the aperture of the field stop 9 is divided into five sections R1 to R5, and typical adjustments g [l to J5 are set for each of the sections R1 to R5. Therefore, for example, the maximum value and the minimum value of each of the sections R1 to R5 and the adjustments 1 to J5 are stored in the table in association with each other. As a typical adjustment amount in each of the sections R1 to R5, for example, an average value of the curve AJ included in each of the sections R1 to R5 is used. In addition, the average value when the curve AJ included in each section R1 to R5 is close to a straight line, or the intermediate value between the maximum and minimum values of the curve AJ included in each section R1 to R5 may be used. it can. Further, the size of the aperture size of the field stop 9 is not limited to five, and can be appropriately determined in consideration of a change in the size of the aperture of the field stop 9.

[0091] When the above table is used, the controller 36 reads the table from the memory 37, reads the adjustment amount of the optical characteristic of the projection optical system PL corresponding to the setting, and controls the adjustment amount to the imaging characteristic control. Output to part 32. The imaging characteristic control unit 32 outputs a control signal for adjusting the optical characteristics of the projection optical system PL according to the adjustment amount output from the controller 36 to the control unit 15 and the non-exposure light irradiation mechanism 40 to output the projection optical system. Adjust the optical characteristics of the PL. With the above processing, the optical characteristics (rotationally symmetric aberration and non-rotationally symmetric aberration) with respect to the projection optical system PL are adjusted according to the cross-sectional shape and size of the exposure light IL.

[0092] In the above description, the force described in the table of the adjustment amount of the optical characteristics of the projection optical system PL corresponding to the size (area) of the aperture of the field stop 9 is only the size of the aperture of the field stop 9 Instead, a table corresponding to the position and shape of the aperture of the field stop 9 may be provided. For example, a table corresponding to the length of the aperture of the field stop 9 in the longitudinal direction or the length of the aperture in the direction corresponding to the X direction and the length in the direction corresponding to the Y direction may be provided. In other words, the adjustment amount table stored in the memory 37 can be prepared for each of various conditions determined by the setting of the field stop 9, the setting of the illumination system aperture stop member 5, the characteristics of the reticle R, etc. wear.

As described above, in the exposure apparatus according to the present embodiment, the adjustment mechanism 22 for adjusting the static optical characteristics (non-rotationally symmetric aberration) of the projection optical system PL, and the dynamics of the projection optical system PL The non-exposure light irradiation mechanism 40 that adjusts the optical characteristics (rotationally symmetric aberration) is provided, so that the amount of dynamic non-rotationally symmetric aberration adjustment by the non-exposure light irradiation mechanism 40 can be reduced. Therefore, the dynamic non-rotation aberration of the projection optical system PL can be adjusted more precisely. Furthermore, in the exposure apparatus of the present embodiment, in consideration of the distribution of the exposure light IL (the position, the cross-sectional shape, and the size of the exposure light IL) in the plane conjugate with the image plane of the projection optical system PL, that is, Since the optical characteristics of the projection optical system PL are adjusted in consideration of at least one of the setting state of the aperture of the field stop 9 and the characteristics of the reticle, the optical characteristics of the projection optical system PL are controlled to a desired state. The pattern of reticle R can be accurately projected.

The exposure apparatus and method according to the embodiment of the present invention have been described above. However, the present invention is not limited to the above embodiment, and can be freely changed within the scope of the present invention. For example, the exposure apparatus of the above-described embodiment includes an adjustment mechanism that adjusts the static non-rotation symmetric aberration of the projection optical system PL and an adjustment mechanism that adjusts the dynamic non-rotation symmetric aberration, and a projection optical system. The power that is used to adjust both the optical characteristics of the projection optical system PL in consideration of the distribution of the exposure light IL in the plane conjugate with the image plane of the system PL. Chisaru

In the above-described embodiment, in consideration of the distribution of the exposure light IL in the plane conjugate with the image plane of the projection optical system PL, the aberration to be rotated of the projection optical system PL is not rotationally symmetric. You can adjust the difference, but you can also adjust either one. In the above-described embodiment, the case where the optical characteristic of the projection optical system PL is adjusted using a transfer function or a table has been described. However, the non-rotation of the PL of the projection optical system is performed using the aberration measuring device 21 shown in FIG. It is also possible to measure the symmetric aberration and adjust the optical characteristics of the projection optical system PL using the measurement result. Further, in the above-described embodiment, the adjustment mechanism 22 and the non-exposure light irradiation mechanism 40 perform the predetermined adjustment on different lenses, but the same adjustment may be performed on the same lens. .

Further, in the above-described embodiment, the force non-rotationally symmetric difference described above is mainly used for correcting the center astigmatism as the non-rotationally symmetric aberration of the projection optical system. In addition to astigmatism, other non-rotationally symmetric aberrations such as orthogonal projection magnification difference (XY magnification difference) and image shift may occur. Therefore, the optical member to be adjusted by the adjusting mechanism 22 can be determined to have an optimum experiment or simulation power according to the type of non-rotationally symmetric aberration. Similarly, non-exposure light irradiation mechanism The optical member to be adjusted 40 and the irradiation position, shape, and size of the non-exposure light LB on the optical member can be set as appropriate according to the type of aberration that is not rotated. For example, in the case of adjusting the non-rotationally symmetric XY magnification difference described above, the optical element relatively close to the reticle R among the plurality of optical members of the projection optical system PL, or an optical element close to Weno or W Is preferably selected. The non-exposure light irradiation mechanism 40 may be used for adjusting the rotationally symmetric aberration of the projection optical system PL. For example, a higher-order that is likely to occur when using a small σ illumination method that reduces the σ value that represents the ratio between the numerical aperture of the projection optical system PL and the numerical aperture of the illumination optical system ILS (for example, less than 0.4). The rotationally symmetric aberration can be corrected satisfactorily using the non-exposure light irradiation mechanism 40.

In the above embodiment, the adjustment mechanism 22 adjusts the static optical characteristics of the projection optical system PL, and the non-exposure light irradiation mechanism 40 adjusts the dynamic optical characteristics of the projection optical system PL. Although the adjustment mechanism 22 may adjust the dynamic optical characteristics of the projection optical system PL, the non-exposure light irradiation mechanism 40 may adjust the static optical characteristics of the projection optical system PL. You may do it. That is, the adjustment mechanism for adjusting the static non-rotation symmetric aberration of the projection optical system PL and the adjustment mechanism for adjusting the dynamic non-rotation symmetric aberration are not limited to the above-described embodiments, and the heating action, the cooling action, Various methods using an external force action or the like can be appropriately selected or combined.

Further, in the above-described embodiment, the step “and” repeat that collectively transfers the pattern of the force reticle described as an example in which the present invention is applied to the exposure apparatus of the step “and” scan method. The present invention can also be applied to an exposure apparatus of a type (so-called stepper). Further, in the above-described embodiment, the present invention is applied to the projection optical system including the force refraction system and the reflection system described using the projection optical system PL of the refraction system, and the projection optical system having only the power of the reflection system. Can do. Further, the shape of the illumination area (exposure area) of the exposure light IL is not limited to a rectangle, and may be, for example, an arc.

In addition, the exposure apparatus of the present invention is an exposure apparatus that is used for manufacturing a semiconductor element to transfer a device pattern onto a semiconductor substrate, and is used for manufacturing a liquid crystal display element to transfer a circuit pattern onto a glass plate. Exposure apparatus used to manufacture thin film magnetic heads, exposure apparatuses that transfer device patterns onto ceramic wafers, and image sensors such as CCDs The present invention can also be applied to an exposure apparatus or the like used for manufacturing the above.

[Device manufacturing method]

Next, a method for manufacturing a semiconductor element using the exposure apparatus will be described in which the exposure apparatus according to the embodiment of the present invention is applied to an exposure apparatus for manufacturing a semiconductor element. FIG. 14 is a flow chart showing a part of a manufacturing process for manufacturing a semiconductor device as a micro device. As shown in Fig. 14, first, in step S10 (design step), the function design of the function of the semiconductor element is performed, and the pattern design for realizing the function is performed. Subsequently, in step S 11 (mask manufacturing step), a mask (reticle) having the designed pattern is manufactured. On the other hand, in step S 12 (wafer manufacturing step), a wafer is manufactured using a material such as silicon.

[0101] Next, in step S13 (wafer processing step), using the mask and wafer prepared in steps S10 to S12, as will be described later, the wafer is actually processed on the wafer by lithography technology or the like. A circuit or the like is formed. Next, in step S 14 (device assembly step), device assembly is performed using the wafer processed in step S 13. This step S14 includes a dicing process, a bonding process, a packaging process (chip encapsulation), and the like as necessary. Finally, in step S 15 (inspection step), inspections such as an operation confirmation test and a durability test of the microdevice fabricated in step S 14 are performed. After these steps, the microdevice is completed and shipped.

FIG. 15 is a diagram showing an example of a detailed flow of step S13 in FIG. In FIG. 15, in step S21 (oxidation step), the wafer surface is oxidized. In step S2 2 (CVD step), an insulating film is formed on the wafer surface. In step S23 (electrode formation step), an electrode is formed on the wafer by vapor deposition. In step S 24 (ion implantation step), ions are implanted into the wafer. Each of the above steps S21 to S24 constitutes a pre-processing step in each stage of wafer processing, and is selected and executed in accordance with necessary processing in each stage.

[0103] At each stage of the wafer process, when the above-described pre-processing step is completed, the post-processing step is executed as follows. In this post-processing process, first, in step S25 (resist formation step), a photosensitive agent is applied to the wafer. Continue with step S26 (Exposure In step (2), the mask pattern is transferred to the wafer by the lithography system (exposure apparatus) and exposure method described above. Next, in step S27 (development process), the exposed wafer is developed, and in step S28 (etching step), the exposed members other than the part where the resist remains are removed by etching. In step S29 (resist removal step), the resist that has become unnecessary after the etching is removed. By repeatedly performing these pre-processing and post-processing steps, multiple patterns are formed on the wafer.

When the device manufacturing method of the present embodiment described above is used, in the exposure step (step S26), the optical characteristics of the projection optical system PL provided in the exposure apparatus are adjusted, and formed on the reticle R. The pattern is transferred onto Ueno, W. Therefore, the optical characteristics of the projection optical system PL are adjusted according to the cross-sectional shape and size of the exposure light IL incident on the plane conjugate with the image plane of the projection optical system PL. As a result, manufacturing defects can be reduced and devices can be manufactured with high yield.

Note that the present invention relates to an immersion exposure apparatus that locally fills a space between the projection optical system PL and the wafer W as disclosed in, for example, International Publication (WO) No. 99Z49504. An immersion exposure apparatus for moving a stage holding a substrate to be exposed as disclosed in Japanese Patent Laid-Open No. 6-124873 in a liquid tank, a stage as disclosed in Japanese Patent Laid-Open No. 10-303114 The present invention can be applied to any exposure apparatus of a liquid immersion optical apparatus in which a liquid tank having a predetermined depth is formed thereon and a substrate is held therein.

Claims

The scope of the claims

[1] An exposure apparatus comprising: an illumination optical system that irradiates a mask with illumination light; and a projection optical system that projects an image of the mask pattern onto a substrate.

An adjusting device for adjusting the optical characteristics of the projection optical system;

A setting device for setting at least one of a cross-sectional shape and a size of the illumination light in a conjugate plane with the image plane of the projection optical system;

An exposure apparatus comprising: a control device that controls adjustment of optical characteristics of the projection optical system by the adjusting device according to a cross-sectional shape and size of the illumination light set by the setting device.

[2] The control device generates a transfer function indicating a relationship between energy of light incident on the projection optical system and a variation amount of optical characteristics of the projection optical system according to a cross-sectional shape and size of the illumination light. 2. The exposure apparatus according to claim 1, further comprising a storage unit that stores data, wherein the adjustment of the optical characteristics of the projection optical system by the adjustment device is controlled using a transfer function stored in the storage unit.

[3] The control device includes a storage unit that stores a table in which a plurality of adjustment amounts of optical characteristics with respect to the projection optical system are set according to a cross-sectional shape and a size of the illumination light. 2. The exposure apparatus according to claim 1, wherein the adjustment of the optical characteristics of the projection optical system by the adjustment device is controlled by using the stored table.

4. The exposure apparatus according to any one of claims 1 to 3, wherein the optical characteristics of the projection optical system include non-rotationally symmetric aberration.

5. The exposure apparatus according to claim 4, wherein the optical characteristics of the projection optical system include rotationally symmetric aberration.

[6] An exposure apparatus comprising: an illumination optical system that irradiates a mask with illumination light; and a projection optical system that projects an image of the mask pattern onto a substrate.

A first adjustment mechanism for adjusting a static optical property of non-rotation symmetry in the projection optical system;

A second adjustment mechanism for adjusting non-rotationally symmetric dynamic optical characteristics in the projection optical system; An exposure apparatus comprising:

[7] The static optical characteristic is an optical characteristic that the projection optical system has in an initial state,

The dynamic optical characteristic is an optical characteristic that changes according to an illumination condition of the illumination light when the illumination light is incident on the projection optical system.

The exposure apparatus according to claim 6, wherein:

8. The first adjustment mechanism includes a mechanism that performs at least one of heating, cooling, pressurization, and decompression on at least one optical element included in the projection optical system. The exposure apparatus according to claim 6 or 7.

9. The second adjustment mechanism includes a mechanism for irradiating at least a part of the projection optical system with a light beam having a wavelength different from the wavelength of the illumination light. The exposure apparatus according to any one of the above.

[10] A device manufacturing method comprising a step of transferring a device pattern onto an object using the exposure apparatus according to any one of [1] to [9].