WO2011049004A1

WO2011049004A1 - Spatial light modulator, optical apparatus, and exposure apparatus

Info

Publication number: WO2011049004A1
Application number: PCT/JP2010/068096
Authority: WO
Inventors: 壮一大和
Original assignee: 株式会社ニコン
Priority date: 2009-10-22
Filing date: 2010-10-14
Publication date: 2011-04-28
Also published as: JP2011090165A

Abstract

Disclosed is a spatial light modulator (25) which modulates illuminating light. The spatial light modulator is provided with: a plurality of fine divided ring resonators (20X, 20Y), each of which is disposed in each of pixels (5) on the optical path of the illuminating light, and is composed of a conductive body having a width equivalent to or smaller than the wavelength of the illuminating light; and a modulating section (19), which modulates the resonance frequency of the divided ring resonators (20X, 20Y) for each of the pixels (5). The spatial light modulator (25) can be used as a ultraviolet transmissive modulator, and has a high response speed.

Description

Spatial light modulator, optical apparatus, and exposure apparatus

The present invention relates to a spatial light modulator that modulates the amount of illumination light for each of a plurality of regions, an optical apparatus having the spatial light modulator, an exposure apparatus having the optical apparatus, and a device manufacturing method using the exposure apparatus.

For example, in an exposure apparatus such as a batch exposure type such as a stepper used in a lithography process for manufacturing a device (electronic device) such as a semiconductor element or a scanning exposure type such as a scanning stepper, a plurality of devices to be manufactured In order to form different circuit patterns for the layers, exposure is performed by exchanging masks for each layer. As described above, when the mask is exchanged for each device and each layer, the throughput of the exposure process is lowered.

Therefore, instead of the mask, two reflective spatial light modulators each having a large number of movable micromirrors arranged in an array are used, and the directions of reflected light of the micromirrors of the two spatial light modulators. There has been proposed an exposure apparatus that generates a light intensity distribution corresponding to a transfer pattern by controlling (see, for example, Patent Document 1).

JP 2006-13518 A

When a reflective spatial light modulator having a conventional movable micromirror is used as a mask, in order to make the projection optical system telecentric on the image plane side, a beam is placed between the illumination optical system and the spatial light modulator. There is a problem in that a splitter needs to be arranged, and the optical system becomes large and the utilization efficiency of illumination light is low. Further, when the beam splitter is not arranged as described above, the projection optical system becomes non-telecentric on the image plane side, so that the optical system becomes complicated as a whole.

When a liquid crystal panel is used as the spatial light modulator, the liquid crystal panel can be used as a transmissive mask. However, the liquid crystal panel has a problem that the transmittance with respect to ultraviolet light generally used as exposure light in the current exposure apparatus is low and the response speed is as low as about 1 ms.
In view of such circumstances, the present invention provides a spatial light modulator that can be used as a transmission type with respect to ultraviolet light and has a high response speed, and an optical technique and an exposure technique using the spatial light modulator. The purpose is to do.

According to the first aspect of the present invention, in the spatial light modulator that modulates the illumination light, each of the spatial light modulators is disposed in a plurality of regions on the optical path of the illumination light, and is equal to or more than the wavelength of the illumination light. A spatial light modulator is provided that includes a plurality of microresonators made of a conductor having a small width, and a modulation mechanism that modulates the resonance frequency of the plurality of microresonators for each of the plurality of regions.
According to the second aspect of the present invention, the spatial light modulator according to the first aspect of the present invention, a drive system for driving the modulation mechanism of the spatial light modulator, and the spatial light modulation with illumination light. An optical device is provided that includes an illumination system that illuminates an illumination region that includes the plurality of regions of the instrument, and a projection system that forms an image of the plurality of regions of the spatial light modulator.

According to the third aspect of the present invention, in the exposure apparatus that exposes the substrate with illumination light, the optical device according to the second aspect of the present invention and the substrate disposed on the image plane of the projection system are held. An exposure apparatus is provided that includes a moving stage and a control device that controls the drive system of the optical device in accordance with a pattern formed on the substrate.
According to the fourth aspect of the present invention, the exposure apparatus according to the third aspect of the present invention is used to transfer the pattern to the substrate, and the substrate to which the pattern is transferred is based on the pattern. And a device manufacturing method is provided.

According to the spatial light modulator of the first aspect of the present invention, the width of the plurality of microresonators is set to about ultraviolet light, and the resonance frequency of the microresonator is set between the frequency of the ultraviolet light and other frequencies. By modulating with, the amount of ultraviolet light transmitted through each region can be controlled for each of a plurality of regions. Further, the resonance frequency of the microresonator can be controlled at a high response speed. Therefore, the spatial light modulator can be used as a transmission type for ultraviolet light and has a high response speed.

It is a figure which shows schematic structure of the exposure apparatus of 1st Embodiment. (A) is an enlarged perspective view showing a part of the spatial light modulator 25 in FIG. 1, and (B) is an enlarged perspective view showing one pixel 5 in FIG. 2 (A). FIG. 3A is an enlarged cross-sectional view taken along line III-III in FIG. 2B, and FIG. 3B is a diagram illustrating an example of a resonance frequency of an SRR (split ring resonator). (A) is a figure which shows an example of the variable pattern of the spatial light modulator 25, (B) is a figure which shows another example of the variable pattern of the spatial light modulator 25. (A) is a diagram showing an example of the mask pattern MP, (B) is a diagram showing a state in which the transfer area 26M has moved from the state of FIG. 5 (A), and (C) is from the state of FIG. 5 (B). FIG. 8 is a diagram showing a state in which the transferred region 26M has moved. (A) is a view showing a shot area of a wafer at the time of scanning exposure, and (B) is a view showing a shot area of the wafer at the time of exposure by the step-and-repeat method. It is a flowchart which shows an example of the exposure operation | movement of 1st Embodiment. (A) is an enlarged sectional view showing a modified SRR 20Y and a modulating unit 19A, and (B) is an enlarged sectional view showing a state in which the gap of the SRR 20Y is changed. (A) is an enlarged sectional view showing the SRR 20YA and the modulator 19B of the second embodiment, and (B) is an enlarged sectional view showing a state in which the gap of the SRR 20YA is changed. (A) is an expanded sectional view showing the principal part of the spatial light modulator of the modification, and (B) is an enlarged perspective view showing the SRR 20C of another modification. It is a figure which shows the principal part of the other modification of a spatial light modulator.

[First Embodiment]
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.
FIG. 1 shows a schematic configuration of an exposure apparatus EX of the present embodiment. In FIG. 1, an exposure apparatus EX includes a light source 14 that emits pulsed light, an illumination optical system ILS that illuminates a surface to be irradiated with ultraviolet light (exposure light) IL for exposure from the light source 14, and the irradiation target. And a spatial light modulator 25 having a large number of pixels 5 arranged in a two-dimensional array on the surface or a surface in the vicinity thereof and each having a variable transmittance. Further, the exposure apparatus EX receives illumination light IL from a transmissive variable pattern generated by a large number of pixels 5 and projects an image of the variable pattern onto the upper surface of the wafer W (photosensitive substrate). A system PL, a wafer stage WST for positioning and moving the wafer W, a main control system 30 comprising a computer for overall control of the operation of the entire apparatus, various control systems, and the like are provided. Hereinafter, the Z axis is set parallel to the optical axis AX of the projection optical system PL, the Y axis is set in a direction parallel to the plane of FIG. 1 in a plane perpendicular to the Z axis (substantially horizontal plane), and perpendicular to the plane of FIG. An explanation will be given by setting the X-axis in various directions. The rotation directions (inclination directions) around the X axis, the Y axis, and the Z axis are referred to as a θx direction, a θy direction, and a θz direction, respectively. In the present embodiment, the wafer W is scanned in the Y direction (scanning direction) during exposure.

As the light source 14 for exposure, a harmonic generator of a YAG laser that emits a pulse of substantially linearly polarized ultraviolet laser light with a wavelength of 355 nm composed of the third harmonic of the fundamental wave at a frequency of, for example, about 1 to 2 MHz is used. As the light source 14, an excimer laser light source such as another solid-state pulse laser light source that generates harmonics of laser light output from a semiconductor laser or the like, or a KrF excimer laser that generates ultraviolet light can also be used.

The light source 14 is connected to a power source unit 12 for controlling light emission timing and pulse energy (light quantity). The main control system 30 supplies the power supply unit 12 with a light emission trigger pulse TP instructing the pulse light emission timing and pulse energy. Illumination light IL consisting of ultraviolet laser light pulsed from the light source 14 enters the illumination optical system ILS.
The illumination optical system ILS includes, for example, a diffractive optical element and the like, as disclosed in, for example, US Patent Application Publication No. 2003/0025890. It includes a light amount distribution setting optical system to be set, an illuminance uniformizing optical system including an optical integrator (fly eye lens, rod integrator, etc.), a reticle blind (variable field stop), a condenser optical system, and the like.

The illumination optical system ILS has an illumination area 26 (see FIG. 4A) on a large number of pixels 5 of the spatial light modulator 25 disposed on or near the irradiated surface (surface on which the designed mask pattern is disposed). ) With a uniform illumination distribution. The illumination optical system ILS and the spatial light modulator 25 are supported by a frame (not shown). The spatial light modulator 25 is a rectangular flat plate elongated in the X direction, and has a large number of pixels 5 arranged between a first glass plate 6 and a second glass plate 8 that transmit the illumination light IL. A thin spacer 6a is provided between the

glass plates

6 and 8 to define the interval.

FIG. 4A is a plan view showing the spatial light modulator 25 of the present embodiment. In FIG. 4A, the light receiving surface of the spatial light modulator 25 has a rectangular shape elongated in the X direction, and is close to the light receiving surface at a constant pitch in the X direction and the Y direction. Are arranged. That is, on the light receiving surface, the pixels 5 are arranged at i-th (i = 1, 2,...) In the X direction and j-th (j = 1, 2,...) Position P (i, j) in the Y direction. Has been. In FIG. 4A and the like, the pixel 5 is drawn larger than the actual size. As an example, the ratio of the length in the X direction and the width in the Y direction (scanning direction of the wafer W) of the light receiving surface of the spatial light modulator 25 is 4: 1, and the width in the X direction and the Y direction of each pixel 5 is The number of pixels 5 arranged in the Y direction on the light receiving surface is several thousand. The illumination area 26 is set to an area slightly inside the contour of the light receiving surface of the spatial light modulator 25. The light receiving surface of the spatial light modulator 25 may be substantially square.

In addition, the pixels 5 of the spatial light modulator 25 are each independently independent of each other with a first transmittance (transmission pattern state) having an average transmittance equal to or higher than a predetermined value and a second transmittance (less than a predetermined value). It is possible to switch at high speed with a response speed of, for example, about 1 μs. As an example, if the predetermined value is 50%, the first transmittance is approximately 60 to 80%, and the second transmittance is approximately 40 to 20%. Note that the difference between the transmission pattern and the light shielding pattern is whether or not the exposure amount of the resist applied to the wafer W exceeds a predetermined threshold, and therefore the difference between the first transmittance and the second transmittance. Does not have to be very large.

As will be described later, every time a predetermined number of pulses are emitted, the main control system 30 in FIG. 1 supplies the modulation control unit 18 with information on the pattern to be exposed on the wafer W. The transmittance of the pixel 5 is set to the first transmittance or the second transmittance. Hereinafter, the pixel 5 set to the first transmittance is referred to as a transmissive pixel 5P, and the pixel 5 set to the second transmittance is referred to as a light-shielded pixel 5N. A transmissive variable pattern (a part of the mask pattern) is formed by the combination of the transmissive pixel 5P and the light-shielding pixel 5N. The configuration of the spatial light modulator 25 will be described later.

Referring back to FIG. 1, the projection optical system PL supported by a column (not shown) is a double-sided telecentric reduction projection optical system. The projection optical system PL uses the illumination light IL transmitted through each pixel 5 of the spatial light modulator 25 to generate an image with a predetermined reduction magnification β of the variable pattern formed by each pixel 5 in the exposure region 27 ( (Illumination area 26 and an optically conjugate area). The wafer W is obtained by applying a resist (photosensitive agent) to the surface of a disk-shaped base material such as silicon. The reduction magnification β of the projection optical system PL is, for example, about 1/10 to several hundredths. For example, if the size of the pixel 5 is about 10 μm square, a variable pattern with a line width of about 100 nm can be projected onto the wafer W by setting the reduction ratio β to about 1/100. As illumination conditions, modified illumination such as dipole illumination is used and, as disclosed in, for example, US Patent Application Publication No. 2005/259234, a local area between the projection optical system PL and the wafer W is used. An immersion method for supplying a liquid that transmits the illumination light IL to a certain region may be applied.

Wafer W is sucked and held on top of wafer stage WST via a wafer holder (not shown), and wafer stage WST moves stepwise in the X and Y directions on the upper surface of a wafer base (not shown) and is constant in Y direction. Move at speed. The position of wafer stage WST in the X and Y directions, the rotation angle in the θz direction, and the like are formed by laser interferometer 33, and this measurement information is supplied to stage control system 32. Stage control system 32 controls the position and speed of wafer stage WST via drive system 34 such as a linear motor based on control information from main control system 30 and measurement information from laser interferometer 33. In order to perform alignment of the wafer W, an alignment system (not shown) for detecting the position of the alignment mark on the wafer W is also provided.

Next, the configuration of the spatial light modulator 25 in FIG. 1 will be described.
FIG. 2A is an enlarged perspective view showing a part of the spatial light modulator 25. In FIG. 2A, the spatial light modulator 25 includes a first glass plate 6 and a large number of rectangular transparent conductive films elongated in the X direction and formed on the upper surface of the glass plate 6 at predetermined intervals in the Y direction. An electrode line 7, a second glass plate 8 disposed on the upper surface of the glass plate 6 at a predetermined interval, and a rectangular transparent conductive film elongated in the Y direction and formed on the bottom surface of the glass plate 8 at a predetermined interval in the X direction. And a large number of electrode lines 9 made of a film. The

electrode lines

7 and 9 are, for example, indium tin oxide films (ITO films). In this case, the pixel 5 is a substantially square area at a position P (i, j) sandwiched between the i-th electrode line 9 in the X direction and the j-th electrode line 7 in the Y direction. The modulation control unit 18 in FIG. 1 controls the voltage between the electrode line 7 and the electrode line 9 that sandwich the pixel 5 at each position P (i, j).

2B, in the pixel 5 at the position P (i, j), a large number of split ring resonators 20X elongated in the X direction and a large number of elongated shapes in the Y direction are included. The split ring resonator 20Y is formed close to each other and in a substantially uniform distribution. The split ring resonator 20X has a shape obtained by rotating the split ring resonator 20Y by 90 ° around an axis parallel to the Z axis. Hereinafter, split ring resonators (Split-Ring-Resonators) 20X, 20Y, etc. are referred to as

SRRs

20X, 20Y, etc. The width in the longitudinal direction of the

SRRs

20X and 20Y is about the wavelength of the illumination light IL (here, 355 nm) or shorter, and the width in the short side direction of the

SRRs

20X and 20Y is about 1/3 of the width in the longitudinal direction. . When the shape of the pixel 5 is, for example, about 10 μm square, the

SRRs

20X and 20Y are formed in the pixel 5 in about 50 rows × 50 columns.

Also, the

SRRs

20X and 20Y are each provided with a modulator 19 that changes the resonance frequency for the incident light. In this case, the illumination light incident substantially perpendicularly on the surface of the pixel 5 has the electric field vector EVX oscillating in the X direction (that is, having the magnetic field vector BVY oscillating in the Y direction) and linearly polarized illumination light ILX in the X direction. , The transmittance of the illumination light ILX is controlled by the SRR 20X having the X direction as the longitudinal direction and the modulation unit 19. On the other hand, the illumination light incident substantially perpendicularly on the surface of the pixel 5 is the illumination light ILY linearly polarized in the Y direction having the electric field vector EVY oscillating in the Y direction (that is, having the magnetic field vector BVX oscillating in the X direction). In some cases, the transmittance of the illumination light ILY is controlled by the SRR 20Y and the modulation unit 19 whose longitudinal direction is the Y direction.

A dielectric film 22A is formed on the upper surface of the electrode line 7 and the dielectric film 22A is opposed to the bottom surface of the electrode line 9, as shown in FIG. Thus, a dielectric film 22B is formed. The

dielectric films

22A and 22B (insulators) are made of a material that transmits the illumination light IL, for example, a thin film of PLZT (transparent ferroelectric ceramics). As the

dielectric films

22A and 22B, for example, a thin film in which lithium niobate (LiNbO ₃ ) or the like is formed so as to transmit the illumination light IL can be used. Further, the

dielectric films

22A and 22B are respectively formed on the entire surface of each pixel 5 in FIG.

The SRR 20Y includes a first member 20YA, a second member 20YB, a third member 20YC, and a fourth member 20YD that are obtained by dividing a ring-shaped member around an axis parallel to the X axis as a whole. Has been. The members 20YA to 20YD are made of metal such as silver (Ag), gold (Au), copper (Cu), or aluminum (Al). The members 20YA and 20YB are formed on the upper surface of the dielectric film 22A at a predetermined interval in the Y direction, and the members 20YD and 20YC are formed on the lower surface of the dielectric film 22B so as to face the members 20YA and 20YB, respectively. It is formed at predetermined intervals in the direction. The width (height) b in the Z direction is set smaller than the width a in the Y direction of the SRR 20Y. In addition,

dielectrics

21A and 21B are installed in gaps in the Z direction between the members 20YA and 20YD and between the members 20YB and 20YC, respectively. The

dielectrics

21A and 21B are made of the same material as the

dielectric films

22A and 22B, for example. The

dielectrics

21A and 21B may be formed of a ferroelectric material such as PZT (lead zirconate titanate) or SBT (bismuth strontium tantalate).

A modulation unit 19 that switches the resonance frequency of the SRR 20Y is configured by the

electrode lines

7 and 9, the

dielectric films

22A and 22B, and the

dielectrics

21A and 21B. A variable voltage is applied between the

electrode lines

7 and 9 by the voltage control unit 18a in the modulation control unit 18 of FIG.
As a method of manufacturing the SRR 20Y and the modulation unit 19, for example, the electrode line 7, the dielectric film 22A, the members 20YA and 20YB, and the

dielectrics

21A and 21B are first formed on the upper surface of the glass plate 6 using a lithography process. Next, the electrode line 9, the dielectric film 22B, and the members 20YC and 20YD are formed on one surface of the glass plate 8 using a lithography process, and then the glass so that the

dielectrics

21A and 21B and the members 20YD and 20YC face each other. A glass plate 8 may be placed on the plate 6. At this time, by forming the spacer 6a (see FIG. 1) between the

glass plates

6 and 8 slightly thinner than the width b (height) of the SRR 20Y, the

dielectrics

21A and 21B and The members 20YD and 20YC can be in close contact with each other. In addition, when forming the members 20YA and 20YB (20YC and 20YD) on the dielectric film 22A (22B), a so-called MEMS (Microelectromechanical Systems) technique may be used.

The SRR 20Y has a shape in which one ring is divided into four parts, but the number of divisions N (N = 2, 3, 4, 5,...) Of the SRR (split ring resonator) is arbitrary, and the SRR 20Y is arbitrary A plurality of L-shaped (or fan-shaped) members can be used. In this case, the document "A. Ishikawa, T. Tanaka and S. Kawata:" Frequency dependence of the magnetic response of split-ring resonators, "J. Opt. Soc. Am. B (USA), Vol. 24, No. 3, pp. 510-515 (2007) ”(hereinafter referred to as Reference A), the imaginary part of the relative permeability of the SRR 20Y for light incident on the SRR 20Y in the Z direction with a magnetic field vector oscillating in the X direction. μIm changes as shown in FIG.

In FIG. 3B, the horizontal axis is the frequency f [THz] of light incident on the SRR 20Y, and the solid line characteristic B1 is obtained when the voltage between the

electrode lines

7 and 9 in FIG. The imaginary part μIm of the relative permeability. In the characteristic B1, the frequencies f1, f2, and f3 are resonance frequencies when the width a (shape) of the SRR 20Y is gradually reduced. Since the value of the imaginary part μIm of the relative permeability with respect to the light with the frequency f1, f2, or f3 is large, the absorption amount of the SRR 20Y with respect to the light incident on the SRR 20Y at the frequencies f1 to f3 or in the vicinity thereof is large, and the transmittance of the light Decreases. Further, as the width a of the SRR 20Y is decreased, the resonance frequency f3 and the like are increased and the corresponding wavelength is shortened.

Here, it is assumed that the resonance frequency is f3, and the frequency fy of the illumination light ILY supplied from the illumination optical system ILS in FIG. 1 is set to a value slightly deviating from the resonance frequency f3. Therefore, when the voltage between the

electrode lines

7 and 9 is 0, the illumination light ILY transmits the SRR 20Y almost as it is. For example, when the resonance frequency f3 is about 840 THz (wavelength is 350 nm), the width a of the SRR 20Y is about 200 nm.

Further, in FIG. 3A, when the voltage between the

electrode lines

7 and 9 is changed, the optical path length between the members 20YA and 20YB and the members 20YD and 20YC is caused by the dielectric polarization of the

dielectrics

21A and 21B in the SRR 20Y. The conversion gap changes, and the resonance frequency of the SRR 20Y changes slightly. In the present embodiment, when it is desired to absorb the illumination light ILY by the SRR 20Y, the resonance frequency of the SRR 20Y is set to the illumination light by controlling the voltage between the

electrode lines

7 and 9, as indicated by the dotted line characteristic B2 in FIG. Move to or near the frequency fy of ILY. The voltage between the

electrode lines

7 and 9 at this time is VN. In this state, the resonance frequency of the SRR 20Y is substantially the same as the frequency fy of the illumination light ILY, and the illumination light ILY is absorbed by the SRR 20Y. Therefore, the transmittance of the illumination light ILY in the pixel 5 to which the SRR 20Y belongs is reduced. When the potential between the

electrode lines

7 and 9 is further increased from VN, the resonance frequency of the SRR 20Y is shifted from the frequency of the illumination light ILY, and the transmittance of the illumination light ILY is increased.

In FIG. 3A, the potentials of all the electrode lines 7 of the spatial light modulator 25 are set to 0, and the potentials of all the electrode lines 9 are also set to 0, whereby the SRRs 20Y in all the pixels 5 are set. Since the resonance frequency is different from the frequency of the illumination light ILY, all the pixels 5 are transmissive pixels with respect to the illumination light ILY. On the other hand, by setting the potential of the j-th electrode line 7 to 2 × VN and setting the potential of the i-th electrode line 9 to 3 × VN, for example, only the pixel 5 at the position P (i, j) is used. Since the voltage between the

electrode lines

7 and 9 is VN and the potential between the

electrode lines

7 and 9 is 0 or 2 × VN or more in the other pixels 5, the pixel 5 only at the position P (i, j) is illuminated. It can be a light-shielded pixel with respect to the light ILY. As described above, the modulation control unit 18 controls the voltage of the

multiple electrode lines

7 and 9 of the spatial light modulator 25 of FIG. 2A, thereby spatially modulating the illumination light ILY with a high response speed. Each pixel 5 in the container 25 can be set to either the transmission pixel 5P having the first transmittance (high transmittance) or the light-shielding pixel 5N having the second transmittance (low transmittance).

Similarly, the SRR 20X in the pixel 5 in FIG. 2B can control the amount of absorption and thus the transmittance of the illumination light ILX polarized in the X direction. Therefore, each pixel 5 in the spatial light modulator 25 can be set to either the transmissive pixel 5P or the light-shielding pixel 5N with respect to the illumination light ILX. Therefore, each pixel 5 in the spatial light modulator 25 can be set to either the transmission pixel 5P or the light-shielding pixel 5N with respect to the linearly polarized illumination light IL (or circularly polarized illumination light).

Next, an example of the exposure operation by the exposure apparatus EX of the present embodiment will be described with reference to the flowchart of FIG. In this case, as an example, a reduced image of the mask pattern MP shown in FIG. Information on the mask pattern MP is stored in the storage unit of the main control system 30. Mask patterns MP are line and space patterns (hereinafter referred to as L & S patterns) 40A to 40C arranged at a predetermined pitch in the X direction, L & S patterns 41A to 41D arranged at a predetermined pitch in the Y direction, and relatively L &

S patterns

42A, 42B, and 43 arranged at a rough pitch are included. Note that the L & S patterns 40A to 40C and the like are enlarged and displayed. In practice, the mask pattern MP may have a different shape from the pattern projected onto the wafer W.

Further, a region on the mask pattern MP in FIG. 5A corresponding to the illumination region 26 on the spatial light modulator 25 in FIG. In the present embodiment, the transfer area 26M is virtually moved in the Y direction on the mask pattern MP at a constant speed in the image memory in the main control system 30, and changes in time series in the transfer area 26M. A light intensity distribution corresponding to the pattern to be generated is generated by a large number of pixels 5 of the spatial light modulator 25 in FIG. 4A, and the scanning direction corresponding to the wafer W in FIG. 1 is synchronized with the movement of the transferred region 26M. Move in the Y direction. A hatched portion (L & S pattern 40A, etc.) of the mask pattern MP in FIG. 5A shows a portion having a high light intensity, and the spatial light modulators in FIG. 4A and FIG. The transmissive pixel 5P in the shaded area of 25 is a portion with high light intensity.

First, after applying a resist to the wafer W in step 121 in FIG. 7, in step 101, the wafer W is loaded onto the wafer stage WST in FIG. As shown in FIG. 6A, the surface of the wafer W is exposed to a reduced image of the mask pattern MP of FIG. 5A (for the sake of convenience, an erect image) at a predetermined pitch in the X and Y directions. Is divided into shot areas SA. In the next step 102, the main control system 30 sets the illumination condition of the illumination optical system ILS to, for example, quadrupole illumination.

In the next step 103, after the alignment of the wafer W, in order to expose the shot areas SA21, SA22,... Arranged in a line in the Y direction on the upper surface of the wafer W in FIG. 5 is positioned at the scanning start position, scanning of the transfer area 26M in the + Y direction is virtually started on the mask pattern MP in FIG. 5A, and the wafer W is synchronized with the wafer W via the wafer stage WST. Starts scanning at a constant speed in the + Y direction. An arrow in the shot area SA21 and the like in FIG. 5A indicates the relative movement direction of the exposure area 27 with respect to the wafer W.

In the next step 104, the main control system 30 selects the pattern 28A composed of the L & S patterns 40A to 40C as the transfer pattern from within the transferred region 26M in FIG. In this embodiment, as an example, in order to optimize the exposure amount for each type of pattern, the same type of pattern is exposed together, but all the patterns in the transfer area 26M are simply selected as transfer patterns. May be.

In the next step 105, the main control system 30 controls the transmittance of all the pixels 5 of the spatial light modulator 25 via the modulation control unit 18, and the selection is made as shown in FIG. The distribution of the transmissive pixels 5P and the light shielding pixels 5N corresponding to the pattern 28A is set. In the next step 106, the main control system 30 supplies the light emission trigger pulse TP to the power supply unit 12 of FIG. 1, causes the light source 14 to emit the illumination light IL by a predetermined number of pulses, and causes the exposure region 27 on the wafer W to be emitted. The image of the pattern 28A shown in FIG. 4A is exposed. The predetermined number of pulses may be one pulse or a plurality of pulses such as 5 pulses or 10 pulses. Further, the predetermined number of pulses may be variable. Since the operations of step 104 and the following step 107 are performed at a very high speed, the illumination light IL is pulsed substantially continuously during the scanning exposure of the wafer W.

In the next step 107, if there remains a pattern that has not been transferred in the mask pattern MP in FIG. 5A, the process returns to step 104 to select a pattern for transfer. The operation of setting the transmittance of the pixel 5 of the modulator 25 and the exposure operation for a predetermined number of pulses (steps 105 and 106) are repeated. Note that steps 104 to 106 may be repeated a plurality of times for the same pattern (for example, the L & S pattern 40A in FIG. 5A). At this time, since the wafer W is scanned, the pattern generated by the spatial light modulator 25 in FIG. 1 is also shifted in the Y direction. Finally, the predetermined number of pulses is set so that the integrated exposure amount with respect to the wafer W for each pattern (for example, the L & S pattern 40A) in the mask pattern MP of FIG. Is adjusted.

As shown in FIG. 5B, when the transfer area 26M moves, the transfer area 26M includes an L & S pattern 41A in the Y direction in addition to the L & S patterns 40A to 40C in the X direction. ing. In this case, as an example, only the L & S patterns 40A to 40C are selected as the transfer pattern 28B. Next, as shown in FIG. 5C, when the transfer area 26M moves, only the L & S patterns 41A to 41C in the Y direction are selected as the transfer pattern 28C. Correspondingly, in the spatial light modulator 25, the distribution of the transmissive pixels 5P and the light shielding pixels 5N is set as shown in FIG. 4B.

Thereafter, when the transfer area 26M moves to the position 29A indicated by the two-dot chain line in FIG. 5A, only the L & S patterns 41B to 41C in the Y direction are selected as the transfer pattern 28D, and then the transfer area 26M is selected. When the transfer area 26M moves to the position 29B in FIG. 5B, only the L & S pattern 42A having a coarse pitch is selected as the transfer pattern 28E. By selecting such a transfer pattern, the exposure amount can be optimized for each type of pattern.

In step 107, when there is no untransferred pattern in the mask pattern MP of FIG. 5A, the scanning exposure to one shot area SA21 of the wafer W is completed as shown in FIG. 6A. Therefore, the operation proceeds to step 108 to determine whether or not an unexposed shot area remains on the wafer W. At this point in time, as shown in FIG. 6A, since the shot area SA22 adjacent to the shot area SA21 of the wafer W is not exposed, the operation returns to step 103. In this case, while the wafer W is scanned in the same direction, the transfer region 26M is virtually moved to the end portion in the −Y direction of the mask pattern MP as shown in FIG. It is sufficient to repeat the operations of .about.107. At the boundary between shot areas SA21 and SA22 adjacent to the upper surface of wafer W in the scanning direction, as shown by positions 29D1 and 29D2 in FIG. 5C, transfer area 26M is set at both ends of mask pattern MP. Then, a pattern obtained by synthesizing the patterns in the positions 29D1 and 29D2 is generated by the spatial light modulator 25 of FIG. 4A, so that the exposure can be continuously performed from the shot areas SA21 to SA22.

In step 108, when the exposure shifts to the column including the shot areas SA31 and SA32 adjacent in the X direction of the wafer W in FIG. 6A, the process returns to step 103 to drive the wafer stage WST to drive the wafer. Step W in the X direction. Then, the scanning direction of the wafer W with respect to the exposure area at the position 27R is set to the −Y direction, and in FIG. 5A, the virtual moving direction of the transfer area 26M on the mask pattern MP is set to the −Y direction. Steps 104 to 107 may be repeated.

In step 108, when there is no unexposed shot area on the wafer W, the process proceeds to step 109, where the wafer W is unloaded and the next wafer is exposed (step 110). In addition, the exposed wafer is subjected to processing for forming a circuit pattern such as resist development, heating (curing) of the developed wafer, and etching in step 122. After repeating such exposure and development (lithography process) and processing on the wafer, the semiconductor is subjected to a device assembly step (including processing processes such as a dicing process, a bonding process, and a package process), thereby providing a semiconductor. Devices etc. are manufactured.

As described above, in the exposure apparatus EX of the present embodiment, by generating a transmissive variable pattern using the spatial light modulator 25, the patterns of a plurality of layers of various electronic devices are respectively processed in a maskless manner. Each shot area of W can be exposed.
The effects and the like of this embodiment are as follows.
(1) The exposure apparatus EX of the present embodiment includes a spatial light modulator 25 that modulates illumination light IL in the ultraviolet region. The spatial light modulator 25 is disposed in each of a plurality of pixels 5 (regions) on the optical path of the illumination light IL, and a plurality of SRRs made of a conductor having a width that is the same as or smaller than the wavelength of the illumination light IL. (Split ring resonators) 20X and 20Y (microresonators) and a modulation unit 19 that modulates the resonance frequencies of the plurality of

SRRs

20X and 20Y for each of the plurality of pixels 5.

According to the spatial light modulator 25 of the present embodiment, the longitudinal width a (size) of the

SRRs

20X and 20Y is approximately equal to or smaller than the wavelength of the illumination light IL that is ultraviolet light, and the resonance frequencies of the

SRRs

20X and 20Y. Is modulated approximately between the frequency of the illumination light IL and the other frequency, the transmittance (light quantity) of the illumination light IL transmitted through the plurality of pixels 5 can be controlled for each pixel 5. Further, the resonance frequency of the

SRRs

20X and 20Y can be controlled at a high response speed. Therefore, the spatial light modulator 25 can be used as a variable pattern having a high response speed that is transmissive to ultraviolet light.

(2) Further, the SRR 20Y (the same applies to the SRR 20X) includes the members 20YA and 20YB and the members 20YD and 20YC which are arranged in a ring shape with a predetermined gap therebetween. Therefore, the resonance frequency of the SRR 20Y can be controlled by controlling the gap or the optical path length of the gap.
(3) Further, the modulation unit 19 applies illumination light IL for applying a voltage to the

dielectrics

21A and 21B disposed between the members 20YA and 20YB and the members 20YD and 20YC, and the

dielectrics

21A and 21B, respectively.

Electrode lines

7 and 9 that pass through. Therefore, the resonance frequency (transmittance) of the SRR 20Y can be easily controlled for each pixel 5 only by controlling the voltage between the

electrode lines

7 and 9.

(4) Further, in the plurality of pixels 5, a plurality of SRRs 20Y and a plurality of SRRs 20X having a shape obtained by rotating the SRR 20Y by 90 ° are arranged. Therefore, the transmittance of linearly polarized illumination light in various directions can be controlled for each pixel 5.
(5) Further, the illumination light IL is pulsed light, and the modulation unit 19 controls the plurality of

SRRs

20X and 20Y each time the illumination light IL is emitted a predetermined number of pulses under the control of the modulation control unit 18. The resonance frequency is modulated. Therefore, by switching the variable pattern generated by the spatial light modulator 25 during the pulse emission of the illumination light IL, exposure of an unnecessary pattern can be suppressed.

(6) Further, the exposure apparatus EX (optical apparatus) of the present embodiment includes a spatial light modulator 25, a modulation control unit 18 that drives the modulation unit 19 of the spatial light modulator 25, and spatial light modulation with illumination light IL. An illumination optical system ILS (illumination system) that illuminates an illumination region 26 including a plurality of pixels 5 of the unit 25; a projection optical system PL (projection system) that forms an image of the plurality of pixels 5 of the spatial light modulator 25; It has. In this case, since the spatial light modulator 25 can be used as a transmissive variable pattern even if the illumination light IL is ultraviolet light, a double-sided telecentric optical system can be used as the projection optical system PL. Therefore, the configuration of the optical system can be simplified and the arrangement of the optical system is easy as compared with the case of using a reflective projection optical system.

(7) The exposure apparatus EX is an exposure apparatus that exposes the wafer W. The exposure apparatus EX further includes a wafer stage WST that holds and moves the wafer W placed on the image plane of the projection optical system PL, and a wafer W The main control system 30 (control apparatus) which controls the modulation control part 18 according to the pattern formed in an upper surface is provided. The illumination area 26 of the illumination optical system ILS is a slit-like area having a narrow width in the Y direction (predetermined direction), and the main control system 30 corresponds to the control of the modulation control unit 18 and the Y direction of the wafer stage WST. The movement in the scanning direction (Y direction) is performed in synchronization.

Therefore, even if the spatial light modulator 25 is small, by scanning the wafer W with respect to the image of the variable pattern generated by the spatial light modulator 25, a desired area can be obtained over a wide area of the wafer W by a maskless method. The pattern image can be scanned and exposed.
(8) Further, in the method of manufacturing the semiconductor device (electronic device) of the present embodiment, the pattern is transferred to the wafer W (substrate) using the exposure apparatus EX (steps 1103 to 108). And processing the wafer W based on the pattern (circuit pattern formation processing in step 122, etc.).

According to this device manufacturing method, it is not necessary to manufacture masks for different semiconductor devices and different layers, and therefore various semiconductor devices can be manufactured at low cost.
In addition, this embodiment can be modified as follows.
(1) In this embodiment, the wafer W is exposed by the step-and-scan method. However, as shown in FIG. 6B, the wafer W is exposed by the step-and-repeat method. Also good. In FIG. 6B, when the shot area SA21 of the wafer W is exposed, the shot area SA21 is divided into a plurality of partial areas SB1 to SB5 with the width of the exposure area 27 as a unit. Then, each partial area SBi (i = 1, 2,...) Is moved stepwise to the exposure area 27 via the wafer stage WST, and a reduced image of the variable pattern set in the exposure area 27 by the spatial light modulator 25. By repeating the batch exposure operation, a desired pattern image can be exposed on the entire surface of the shot area SA21.

(2) In this embodiment, as shown in FIG. 3A,

dielectrics

21A and 21B are installed between the members 20YA and 20YB of the SRR 20Y and the members 20YD and 20YC. However, as shown in the modification of FIG. 8A, the gap between the members 20YA and 20YB and the members 20YD and 20YC of the SRR 20Y may be a variable gap. In this case, the resonance frequency of the SRR 20Y can be changed by changing the gap g between the gap portions. The gap variable mechanism for this purpose is the modulation section 19A including the

electrode lines

7 and 9 and the

dielectric films

22A and 22B.

In this modified example, when the voltage between the

electrode lines

7 and 9 is set to 0 by the voltage control unit 18a, for example, the resonance frequency of the SRR 20Y is different from the frequency of the illumination light ILY. To Penetrate. On the other hand, by applying a predetermined voltage between the

electrode lines

7 and 9 of the modulating unit 19A by the voltage control unit 18a, as shown in FIG. The gap portion of the SRR 20Y is reduced to g1. In this state, by making the resonance frequency of the SRR 20Y substantially coincide with the frequency of the illumination light ILY, the amount of absorption of the illumination light ILY by the SRR 20Y increases, and the pixel 5 to which the SRR 20Y belongs becomes a light-shielding pixel.

In consideration of variations in the gap of the SRR 20Y due to the voltage between the

electrode lines

7 and 9, for example, reference members 23 serving as reference heights in FIG. You may keep it. By the reference member 23, the gap portions of the plurality of SRRs 20Y at different positions are accurately set to g1.

[Second Embodiment]
A second embodiment of the present invention will be described with reference to FIGS. 9 (A) and 9 (B). The appearance of the spatial light modulator of the present embodiment is substantially the same as the shape obtained by removing the second glass plate 8 from the spatial light modulator 25 of FIG. Further, a plurality of SRRs (divided ring resonators) and modulators are arranged in a plurality of pixels in the same array as the plurality of pixels 5 in FIG. In the following, in FIG. 9A, portions corresponding to those in FIG. 3A are denoted by the same reference numerals, and detailed description thereof is omitted.

FIG. 9A is an enlarged cross-sectional view showing an SRR (divided ring resonator) 24Y and a modulator 19B elongated in the Y direction according to the present embodiment. 9A,

electrode lines

7A and 7B made of a transparent conductive film are formed on the upper surface of the glass plate 6, and a U-shaped first member 20E made of the same metal as the member 20YA is formed on the upper surface of the electrode line 7A. Has been. In addition, the electrode line 7B is disposed in the vicinity of the −Y direction of the electrode line 7A, and the first via the support member 21C made of a conductor on the electrode line 7B and the support member 21D made of an insulator on the glass plate 6. A flat plate-like second member 20F made of the same metal as the member 20YA is fixed so as to face the one member 20E. In the present embodiment, the SRR 24Y is formed from the first member 20E and the second member 20F as a whole and having a gap portion having a gap g2 (value in an initial state) at both ends in the Y direction.

In addition, a modulation unit 19B that changes the resonance frequency of the SRR 24Y by changing the gap g2 between the first member 20E and the second member 20F of the SRR 24Y is configured from the

electrode lines

7A and 7B and the conductive support member 21C. Yes. A variable voltage can be applied between the

electrode lines

7A and 7B by the voltage controller 18a for each pixel of the spatial light modulator. The SRR 24Y and the modulation unit 19B can be manufactured using, for example, MEMS technology.

In this case, it is assumed that the resonance frequency of the SRR 24Y is different from the frequency of the illumination light ILY when the voltage between the

electrode lines

7A and 7B and thus the voltage between the

members

20E and 20F is 0 (initial state). On the other hand, when a predetermined voltage is applied between the

electrode lines

7A and 7B of the modulation unit 19B, as shown in FIG. 9B, the distance between the first member 20E and the second member 20F is narrowed due to elastic deformation, and the SRR 24Y Is assumed to be substantially equal to the frequency of the illumination light ILY. In this state, since the SRR 24Y absorbs the illumination light ILY, the transmittance of the pixel to which the SRR 24Y belongs becomes small. Therefore, the SRR 24Y can be used as a resonator that transmits or absorbs the illumination light ILY polarized in the Y direction in the ultraviolet region, similar to the SRR 20Y of the first embodiment.

Further, an SRR (divided ring resonator) having a shape obtained by rotating the SRR 24Y and the modulation unit 19B by 90 ° is also provided (not shown). Similar to the SRR 20X of the first embodiment, this SRR can be used as a resonator that transmits or absorbs illumination light polarized in the X direction.
The first and second embodiments described above can be modified as follows.
(1) Although the spatial light modulator 25 of the above-described embodiment is a transmission type, the spatial light modulator 25 can be used as a reflection type modulator. For example, in order to make the spatial light modulator 25 provided with the SRR 20Y and the modulation unit 19 of FIG. 3 (A) a reflection type, as shown in the first modification of FIG. 10 (A), the first glass plate 6 A flat mirror 24 whose entire surface is a reflective surface may be provided on the bottom surface side. In FIG. 10A, when the resonance frequency of the SRR 20Y is different from the frequency of the illumination light ILY, the illumination light ILY incident on the SRR 20Y is reflected by the plane mirror 24 after passing through the vicinity of the SRR 20Y and the glass plate 6, The light again passes through the vicinity of the SRR 20Y and is returned to the + Z direction.

On the other hand, when the resonance frequency of the SRR 20Y substantially matches the frequency of the illumination light ILY, the illumination light ILY incident on the SRR 20Y is absorbed by the SRR 20Y, and the illumination light ILY is not reflected in the + Z direction. Therefore, the spatial light modulator in which the plane mirror is arranged on the back surface of the spatial light modulator 25 in FIG. 2A can be used as a reflective spatial light modulator.
Similarly, also in the embodiment of FIG. 9A, by arranging a plane mirror on the back surface of the glass plate 6, it can be used as a reflective spatial light modulator.

(2) In the above embodiment, as shown by

SRRs

20X and 20Y in FIG. 2B, for example, resonators for the illumination lights ILX and ILY polarized in the X direction and the Y direction are individually formed. On the other hand, as shown in the second modification of FIG. 10B, a U-shaped first portion 21GX along the X direction and a U-shaped second portion 21GY along the Y direction are included. An SRR composed of a first cruciform member 21G and a second cruciform member 21H including a first portion 21HX and a second portion 21HY arranged to face the first portion 21GX and the second portion 21GY. (Split ring resonator) 20C may be used. The SRR 20C also includes a modulation unit (not shown) similar to the modulation unit 19A of FIG. 8A, for example, a modulation unit that changes the gap between the

cross-shaped members

21G and 21H.

The SRR 20C can change the resonance frequency for both the illumination light polarized in the X direction and the illumination light polarized in the Y direction, and thus can control the transmittance for the illumination light polarized in both directions.
(3) Further, as shown in FIG. 11, as a large number of elements of the spatial light modulator, SRRs (divided ring resonance) each having a U-shaped metal first member 20K1 and second member 20K2 facing each other. It is also possible to use 24KY. In this modification, the first member 20K1 and the second member 20K2 are formed on the surface of the dielectric film 22 of the glass plate 6 via the

electrode lines

7A and 7B, respectively. In this modification, by applying a predetermined voltage between the

electrode lines

7A and 7B, the gap between the upper ends of the members 20K1 and 20K2 changes, and the resonance frequency of the SRR 24KY with respect to incident light changes. Therefore, the transmittance for incident light can be controlled as in the above embodiment.

(4) In the above embodiment, for example, the spatial light modulator 25 is used as a variable mask pattern. However, the spatial light modulator 25 may be used as a variable aperture stop in the illumination optical system ILS. Is possible.
(5) In the above embodiment, pulsed light is used as the illumination light IL. However, as the illumination light IL, for example, light from an ultraviolet LED, or a continuous in a substantially ultraviolet range selected from a wavelength range including, for example, g-line (wavelength 436 nm), h-line (wavelength 405 nm) and i-line (wavelength 365 nm). Light may be used.
Further, the present invention is not limited to the application to the manufacturing process of a semiconductor device. For example, a manufacturing process such as a liquid crystal display element and a plasma display, an imaging element (CMOS type, CCD, etc.), a micromachine, a MEMS ( (Microelectromechanical Systems), thin-film magnetic heads, and DNA chips and other devices (electronic devices, microdevices) can be widely applied to manufacturing processes.

The spatial light modulator 25 of the above embodiment can be used not only as a mask or aperture stop of an exposure apparatus but also as a variable slide of a projector (optical apparatus) that uses visible light as illumination light.
As described above, the present invention is not limited to the above-described embodiment, and various configurations can be taken without departing from the gist of the present invention.
It should be noted that the disclosures in the above-mentioned publications, international publication pamphlets, US patents, or US patent application publication specifications described in the present application are incorporated herein by reference. Also, the entire disclosure of Japanese Patent Application No. 2009-243927 filed on October 22, 2009, including the description, claims, drawings, and abstract, is incorporated herein by reference in its entirety. ing.

EX ... exposure apparatus, ILS ... illumination optical system, PL ... projection optical system, W ... wafer, 5 ... pixel, 6,8 ... glass plate, 7,9 ... electrode line, 14 ... light source, 18 ... modulation control unit, 19 ... Modulator, 20X, 20Y ... SRR (split ring resonator), 21A, 21B ... Dielectric, 22A, 22B ... Dielectric film, 25 ... Spatial light modulator, 30 ... Main control system

Claims

In a spatial light modulator that modulates illumination light,
A plurality of microresonators made of a conductor each disposed in a plurality of regions on the optical path of the illumination light and having a width that is the same as or smaller than the wavelength of the illumination light;
A modulation mechanism for modulating the resonance frequency of the plurality of microresonators for each of the plurality of regions;
A spatial light modulator comprising:
The space according to claim 1, wherein the modulation mechanism switches the resonance frequency of the microresonator between a frequency different from the frequency of the illumination light and a frequency substantially the same as the frequency of the illumination light. Light modulator.
3. The spatial light modulator according to claim 1, wherein the microresonator has a ring shape as a whole and includes a first member and a second member arranged with a predetermined gap therebetween.
The modulation mechanism is
A dielectric element disposed between the first member and the second member;
A first electrode line and a second electrode line that transmit the illumination light, respectively, for applying a voltage to the dielectric element;
The spatial light modulator according to claim 3, wherein
The spatial light modulator according to claim 3, wherein the modulation mechanism is a gap variable mechanism that changes a gap between the first member and the second member.
The gap variable mechanism is
6. The spatial light modulator according to claim 5, further comprising a first electrode line and a second electrode line that are arranged so as to sandwich the first member and the second member and each transmit the illumination light. .
The plurality of microresonators in the plurality of regions include a plurality of first microresonators and a plurality of second microresonators each having a shape obtained by rotating the first microresonator by 90 °. The spatial light modulator according to any one of claims 1 to 6, wherein:
The illumination light is pulsed light,
The space according to any one of claims 1 to 7, wherein the modulation mechanism modulates resonance frequencies of the plurality of microresonators each time the illumination light is emitted by a predetermined number of pulses. Light modulator.
A spatial light modulator according to any one of claims 1 to 8,
A drive system for driving the modulation mechanism of the spatial light modulator;
An illumination system that illuminates an illumination area including the plurality of areas of the spatial light modulator with illumination light;
A projection system for forming an image of the plurality of regions of the spatial light modulator;
An optical device comprising:
In an exposure apparatus that exposes a substrate with illumination light,
An optical device according to claim 9;
A stage that holds and moves the substrate disposed on the image plane of the projection system;
A control device for controlling the drive system of the optical device according to a pattern formed on the substrate;
An exposure apparatus comprising:
The illumination area of the optical device is a slit-like area having a narrow width in a predetermined direction,
The exposure apparatus according to claim 10, wherein the control device performs control of the drive system and movement of the stage in a direction corresponding to the predetermined direction in synchronization.
Using the exposure apparatus according to claim 10 or 11 to transfer a pattern to the substrate;
Processing the substrate on which the pattern is transferred based on the pattern;
A device manufacturing method including: